FFmpeg源码分析之MpegTS.c
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最近因项目需求需要更改ffmpeg内部源码来完成对ts文件信息的处理，但是在windows下调试的很长世间的ffmpeg都没有搞清楚，主要是因为windows下编译的ffmpeg在单步跟踪的时候不显示调试信息，无奈之下索性把这个文件全部看一遍好了，如果有错误之处，欢迎指正，有不懂得地方欢迎加群445236076讨论
如果有不会windows下编译可以调试的ffmpeg可以参考这篇文章
http://blog.csdn.net/u010380485/article/details/54092264
#include "libavutil/buffer.h"#include "libavutil/crc.h"#include "libavutil/internal.h"#include "libavutil/intreadwrite.h"#include "libavutil/log.h"#include "libavutil/dict.h"#include "libavutil/mathematics.h"#include "libavutil/opt.h"#include "libavutil/avassert.h"#include "libavcodec/bytestream.h"#include "libavcodec/get_bits.h"#include "libavcodec/opus.h"#include "avformat.h"#include "mpegts.h"#include "internal.h"#include "avio_internal.h"#include "mpeg.h"#include "isom.h" //如果同步数据丢失我们将寻找同步数据的最大值#define MAX_RESYNC_SIZE 65536//最大的pes负载#define MAX_PES_PAYLOAD 200 * 1024#define MAX_MP4_DESCR_COUNT 16#define MOD_UNLIKELY(modulus, dividend, divisor, prev_dividend) \ do { \ if ((prev_dividend) == 0 || (dividend) - (prev_dividend) != (divisor)) \ (modulus) = (dividend) % (divisor); \ (prev_dividend) = (dividend); \ } while (0)//mpegts文件过滤器的类型enum MpegTSFilterType { MPEGTS_PES, MPEGTS_SECTION, MPEGTS_PCR,};//mpegts filter 整体结构//struct MpegTSFilter {// int pid;// int es_id;// int last_cc; /* last cc code (-1 if first packet) */// int64_t last_pcr;// enum MpegTSFilterType type;// union {// MpegTSPESFilter pes_filter;// MpegTSSectionFilter section_filter;// } u;//};typedef struct MpegTSFilter MpegTSFilter;//回调函数，获取PEStypedef int PESCallback (MpegTSFilter *f, const uint8_t *buf, int len, int is_start, int64_t pos);typedef struct MpegTSPESFilter { PESCallback *pes_cb;//回调函数 void *opaque;//类指针} MpegTSPESFilter;//回调函数，获取Sectiontypedef void SectionCallback (MpegTSFilter *f, const uint8_t *buf, int len);//回调函数，设置Servicetypedef void SetServiceCallback (void *opaque, int ret);typedef struct MpegTSSectionFilter { int section_index; int section_h_size; int last_ver; unsigned crc; unsigned last_crc; uint8_t *section_buf; unsigned int check_crc : 1; unsigned int end_of_section_reached : 1; SectionCallback *section_cb; void *opaque;} MpegTSSectionFilter;struct MpegTSFilter { int pid; int es_id; int last_cc; /* last cc code (-1 if first packet) */ int64_t last_pcr; enum MpegTSFilterType type; union { MpegTSPESFilter pes_filter; MpegTSSectionFilter section_filter; } u;};#define MAX_PIDS_PER_PROGRAM 64struct Program { unsigned int id; // program id/service id unsigned int nb_pids; unsigned int pids[MAX_PIDS_PER_PROGRAM]; int pmt_found;//标识pmt是否已经找到};struct MpegTSContext { const AVClass *class; /* user data */ AVFormatContext *stream; /** raw packet size, including FEC if present */ int raw_packet_size; int size_stat[3]; int size_stat_count;#define SIZE_STAT_THRESHOLD 10 int64_t pos47_full; /** 如果为真, 所有的pid将会用来去寻找流 */ int auto_guess; /** 对于每个ts包都进行精确的计算 */ int mpeg2ts_compute_pcr; /** 修复 dvb teletext pts */ int fix_teletext_pts; int64_t cur_pcr; /**< used to estimate the exact PCR */ int pcr_incr; /**< used to estimate the exact PCR */ /* data needed to handle file based ts */ /** stop parsing loop */ int stop_parse; /** packet containing Audio/Video data */ AVPacket *pkt; /** to detect seek */ int64_t last_pos; int skip_changes; int skip_clear; int scan_all_pmts; int resync_size; /******************************************/ /* private mpegts data */ /* scan context */ /** structure to keep track of Program->pids mapping */ unsigned int nb_prg; struct Program *prg; int8_t crc_validity[NB_PID_MAX]; /** filters for various streams specified by PMT + for the PAT and PMT */ MpegTSFilter *pids[NB_PID_MAX]; int current_pid;};#define MPEGTS_OPTIONS \ { "resync_size", "set size limit for looking up a new synchronization", offsetof(MpegTSContext, resync_size), AV_OPT_TYPE_INT, { .i64 = MAX_RESYNC_SIZE}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM }//Mpegts的AVOption，标识了与之有关的驱动表，有关AVOption不理解的请自行百度static const AVOption options[] = { MPEGTS_OPTIONS, {"fix_teletext_pts", "try to fix pts values of dvb teletext streams", offsetof(MpegTSContext, fix_teletext_pts), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, AV_OPT_FLAG_DECODING_PARAM }, {"ts_packetsize", "output option carrying the raw packet size", offsetof(MpegTSContext, raw_packet_size), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0, AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_EXPORT | AV_OPT_FLAG_READONLY }, {"scan_all_pmts", "scan and combine all PMTs", offsetof(MpegTSContext, scan_all_pmts), AV_OPT_TYPE_BOOL, { .i64 = -1}, -1, 1, AV_OPT_FLAG_DECODING_PARAM }, {"skip_changes", "skip changing / adding streams / programs", offsetof(MpegTSContext, skip_changes), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, 0 }, {"skip_clear", "skip clearing programs", offsetof(MpegTSContext, skip_clear), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, 0 }, { NULL },};static const AVClass mpegts_class = { .class_name = "mpegts demuxer", .item_name = av_default_item_name, .option = options, .version = LIBAVUTIL_VERSION_INT,};static const AVOption raw_options[] = { MPEGTS_OPTIONS, { "compute_pcr", "compute exact PCR for each transport stream packet", offsetof(MpegTSContext, mpeg2ts_compute_pcr), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, AV_OPT_FLAG_DECODING_PARAM }, { "ts_packetsize", "output option carrying the raw packet size", offsetof(MpegTSContext, raw_packet_size), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 0, AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_EXPORT | AV_OPT_FLAG_READONLY }, { NULL },};static const AVClass mpegtsraw_class = { .class_name = "mpegtsraw demuxer", .item_name = av_default_item_name, .option = raw_options, .version = LIBAVUTIL_VERSION_INT,};//处理ts流的状态enum MpegTSState { MPEGTS_HEADER = 0, MPEGTS_PESHEADER, MPEGTS_PESHEADER_FILL, MPEGTS_PAYLOAD, MPEGTS_SKIP,};/* enough for PES header + length */#define PES_START_SIZE 6//PES开始部位的大小#define PES_HEADER_SIZE 9//PES头的大小#define MAX_PES_HEADER_SIZE (9 + 255)//PES头的最大值typedef struct PESContext { int pid; int pcr_pid; //如果此值为-1，那么所有的包都将被认为包含PCR int stream_type; MpegTSContext *ts; AVFormatContext *stream; AVStream *st; AVStream *sub_st; /**< stream for the embedded AC3 stream in HDMV TrueHD */ enum MpegTSState state; /* used to get the format */ int data_index; int flags; /**< copied to the AVPacket flags */ int total_size; int pes_header_size; int extended_stream_id; uint8_t stream_id; int64_t pts, dts; int64_t ts_packet_pos; /**< position of first TS packet of this PES packet */ uint8_t header[MAX_PES_HEADER_SIZE]; AVBufferRef *buffer; SLConfigDescr sl;} PESContext;extern AVInputFormat ff_mpegts_demuxer;//从一个指定的MpegTSContext获取一个指定的节目//在MpegTSContext中，节目都是以链表的形式存在的，nb_prg为节目的个数，如果找到这个节目则返回，如果没有则返回NULLstatic struct Program * get_program(MpegTSContext *ts, unsigned int programid){ int i; for (i = 0; i < ts->nb_prg; i++) { if (ts->prg[i].id == programid) { return &ts->prg[i]; } } return NULL;}/*//下面这是对AVProgram的解释typedef struct AVProgram {int id;int flags;enum AVDiscard discard; ///< selects which program to discard and which to feed to the callerunsigned int *stream_index;unsigned int nb_stream_indexes;AVDictionary *metadata;int program_num;int pmt_pid;int pcr_pid;int64_t start_time;int64_t end_time;int64_t pts_wrap_reference; ///< reference dts for wrap detectionint pts_wrap_behavior; ///< behavior on wrap detection} AVProgram;*///清空一个指定的AVProgramstatic void clear_avprogram(MpegTSContext *ts, unsigned int programid){ AVProgram *prg = NULL; int i; for (i = 0; i < ts->stream->nb_programs; i++) if (ts->stream->programs[i]->id == programid) { prg = ts->stream->programs[i]; break; } if (!prg) return; prg->nb_stream_indexes = 0;}//清空一个指定的节目信息static void clear_program(MpegTSContext *ts, unsigned int programid){ int i; clear_avprogram(ts, programid); for (i = 0; i < ts->nb_prg; i++) if (ts->prg[i].id == programid) { ts->prg[i].nb_pids = 0; ts->prg[i].pmt_found = 0; }}//清空所有节目信息static void clear_programs(MpegTSContext *ts){ av_freep(&ts->prg); ts->nb_prg = 0;}//将一个制定的节目添加pat表入口，我个人的理解就是在指定的MpegTSContext中新增一个Programstatic void add_pat_entry(MpegTSContext *ts, unsigned int programid){ struct Program *p; if (av_reallocp_array(&ts->prg, ts->nb_prg + 1, sizeof(*ts->prg)) < 0) { ts->nb_prg = 0; return; } p = &ts->prg[ts->nb_prg]; p->id = programid; p->nb_pids = 0; p->pmt_found = 0; ts->nb_prg++;}//将指定的program添加pid，并添加了一些错误判断static void add_pid_to_pmt(MpegTSContext *ts, unsigned int programid, unsigned int pid){ struct Program *p = get_program(ts, programid); int i; if (!p) return; if (p->nb_pids >= MAX_PIDS_PER_PROGRAM)//如果pid的个数超过了最大值则直接返回 return; for (i = 0; i < p->nb_pids; i++)//如果pid已经存在则直接返回 if (p->pids[i] == pid) return; p->pids[p->nb_pids++] = pid;}//设置指定的节目已经被找到，pmt_found为标识节目是否为找到static void set_pmt_found(MpegTSContext *ts, unsigned int programid){ struct Program *p = get_program(ts, programid); if (!p) return; p->pmt_found = 1;}//设置指定节目的pcr的pidstatic void set_pcr_pid(AVFormatContext *s, unsigned int programid, unsigned int pid){ int i; for (i = 0; i < s->nb_programs; i++) { if (s->programs[i]->id == programid) { s->programs[i]->pcr_pid = pid; break; } }} //根据调用者的programs的选择来决定pid是否应该被丢弃 //如果pid只包含在program中并且其discard的值为AVDISCARD_ALL，则返回0static int discard_pid(MpegTSContext *ts, unsigned int pid){ int i, j, k; int used = 0, discarded = 0; struct Program *p; //如果一个节目都没有并且其discard的值为AVDISCARD_ALL，那么我们则必须丢弃这个包 for (k = 0; k < ts->stream->nb_programs; k++) if (ts->stream->programs[k]->discard == AVDISCARD_ALL) break; if (k == ts->stream->nb_programs) return 0; for (i = 0; i < ts->nb_prg; i++) { p = &ts->prg[i]; for (j = 0; j < p->nb_pids; j++) { if (p->pids[j] != pid) continue; // is program with id p->id set to be discarded? for (k = 0; k < ts->stream->nb_programs; k++) { if (ts->stream->programs[k]->id == p->id) { if (ts->stream->programs[k]->discard == AVDISCARD_ALL) discarded++; else used++; } } } } return !used && discarded;}/** * Assemble PES packets out of TS packets, and then call the "section_cb" * function when they are complete. */ //处理section数据并在完成的时候调用回调函数section_cbstatic void write_section_data(MpegTSContext *ts, MpegTSFilter *tss1, const uint8_t *buf, int buf_size, int is_start){ MpegTSSectionFilter *tss = &tss1->u.section_filter; int len;//如果处理已经开始，则直接拷贝数据 if (is_start) { memcpy(tss->section_buf, buf, buf_size); tss->section_index = buf_size; tss->section_h_size = -1; tss->end_of_section_reached = 0; } else { if (tss->end_of_section_reached)//当处理没有开始但是最后一个section已经到达，则错误返回 return; len = 4096 - tss->section_index; if (buf_size < len) len = buf_size; memcpy(tss->section_buf + tss->section_index, buf, len); tss->section_index += len; } //计算section的长度 if (tss->section_h_size == -1 && tss->section_index >= 3) { len = (AV_RB16(tss->section_buf + 1) & 0xfff) + 3; if (len > 4096) return; tss->section_h_size = len; } if (tss->section_h_size != -1 && tss->section_index >= tss->section_h_size) { int crc_valid = 1; tss->end_of_section_reached = 1; if (tss->check_crc) { crc_valid = !av_crc(av_crc_get_table(AV_CRC_32_IEEE), -1, tss->section_buf, tss->section_h_size); if (tss->section_h_size >= 4) tss->crc = AV_RB32(tss->section_buf + tss->section_h_size - 4); if (crc_valid) { ts->crc_validity[ tss1->pid ] = 100; }else if (ts->crc_validity[ tss1->pid ] > -10) { ts->crc_validity[ tss1->pid ]--; }else crc_valid = 2; } if (crc_valid) { tss->section_cb(tss1, tss->section_buf, tss->section_h_size); if (crc_valid != 1) tss->last_ver = -1; } }}//打开一个filter，可以简单的认为是初始化并新增一个pid到MpegTSContextstatic MpegTSFilter *mpegts_open_filter(MpegTSContext *ts, unsigned int pid, enum MpegTSFilterType type){ MpegTSFilter *filter; av_log(ts->stream, AV_LOG_TRACE, "Filter: pid=0x%x type=%d\n", pid, type); if (pid >= NB_PID_MAX || ts->pids[pid]) return NULL; filter = av_mallocz(sizeof(MpegTSFilter)); if (!filter) return NULL; ts->pids[pid] = filter; filter->type = type; filter->pid = pid; filter->es_id = -1; filter->last_cc = -1; filter->last_pcr= -1; return filter;}//可以简单的理解为为一个section分配了一个filer，一下类似的将不再多说static MpegTSFilter *mpegts_open_section_filter(MpegTSContext *ts, unsigned int pid, SectionCallback *section_cb, void *opaque, int check_crc){ MpegTSFilter *filter; MpegTSSectionFilter *sec; if (!(filter = mpegts_open_filter(ts, pid, MPEGTS_SECTION))) return NULL; sec = &filter->u.section_filter; sec->section_cb = section_cb; sec->opaque = opaque; sec->section_buf = av_malloc(MAX_SECTION_SIZE); sec->check_crc = check_crc; sec->last_ver = -1; if (!sec->section_buf) { av_free(filter); return NULL; } return filter;}static MpegTSFilter *mpegts_open_pes_filter(MpegTSContext *ts, unsigned int pid, PESCallback *pes_cb, void *opaque){ MpegTSFilter *filter; MpegTSPESFilter *pes; if (!(filter = mpegts_open_filter(ts, pid, MPEGTS_PES))) return NULL; pes = &filter->u.pes_filter; pes->pes_cb = pes_cb; pes->opaque = opaque; return filter;}static MpegTSFilter *mpegts_open_pcr_filter(MpegTSContext *ts, unsigned int pid){ return mpegts_open_filter(ts, pid, MPEGTS_PCR);}static void mpegts_close_filter(MpegTSContext *ts, MpegTSFilter *filter){ int pid; pid = filter->pid; if (filter->type == MPEGTS_SECTION) av_freep(&filter->u.section_filter.section_buf); else if (filter->type == MPEGTS_PES) { PESContext *pes = filter->u.pes_filter.opaque; av_buffer_unref(&pes->buffer); /* referenced private data will be freed later in * avformat_close_input */ if (!((PESContext *)filter->u.pes_filter.opaque)->st) { av_freep(&filter->u.pes_filter.opaque); } } av_free(filter); ts->pids[pid] = NULL;}//对ts包进行解析，最终返回的类似于数据的质量static int analyze(const uint8_t *buf, int size, int packet_size, int probe){ int stat[TS_MAX_PACKET_SIZE]; int stat_all = 0; int i; int best_score = 0; memset(stat, 0, packet_size * sizeof(*stat)); for (i = 0; i < size - 3; i++) { if (buf[i] == 0x47) { int pid = AV_RB16(buf+1) & 0x1FFF; int asc = buf[i + 3] & 0x30; if (!probe || pid == 0x1FFF || asc) { int x = i % packet_size; stat[x]++; stat_all++; if (stat[x] > best_score) { best_score = stat[x]; } } } } return best_score - FFMAX(stat_all - 10*best_score, 0)/10;}/* autodetect fec presence. Must have at least 1024 bytes *///获取包的大小，根据不同包的得分，返回包的大小static int get_packet_size(const uint8_t *buf, int size){ int score, fec_score, dvhs_score; if (size < (TS_FEC_PACKET_SIZE * 5 + 1)) return AVERROR_INVALIDDATA; score = analyze(buf, size, TS_PACKET_SIZE, 0); dvhs_score = analyze(buf, size, TS_DVHS_PACKET_SIZE, 0); fec_score = analyze(buf, size, TS_FEC_PACKET_SIZE, 0); av_log(NULL, AV_LOG_TRACE, "score: %d, dvhs_score: %d, fec_score: %d \n", score, dvhs_score, fec_score); if (score > fec_score && score > dvhs_score) return TS_PACKET_SIZE; else if (dvhs_score > score && dvhs_score > fec_score) return TS_DVHS_PACKET_SIZE; else if (score < fec_score && dvhs_score < fec_score) return TS_FEC_PACKET_SIZE; else return AVERROR_INVALIDDATA;}typedef struct SectionHeader { uint8_t tid; uint16_t id; uint8_t version; uint8_t sec_num; uint8_t last_sec_num;} SectionHeader;//过滤相同的sectionstatic int skip_identical(const SectionHeader *h, MpegTSSectionFilter *tssf){ if (h->version == tssf->last_ver && tssf->last_crc == tssf->crc) return 1; tssf->last_ver = h->version; tssf->last_crc = tssf->crc; return 0;}//指针地址加一static inline int get8(const uint8_t **pp, const uint8_t *p_end){ const uint8_t *p; int c; p = *pp; if (p >= p_end) return AVERROR_INVALIDDATA; c = *p++; *pp = p; return c;}//指针地址加2static inline int get16(const uint8_t **pp, const uint8_t *p_end){ const uint8_t *p; int c; p = *pp; if (1 >= p_end - p) return AVERROR_INVALIDDATA; c = AV_RB16(p); p += 2; *pp = p; return c;}//根据DVB提供的数据长度分配空间static char *getstr8(const uint8_t **pp, const uint8_t *p_end){ int len; const uint8_t *p; char *str; p = *pp; len = get8(&p, p_end); if (len < 0) return NULL; if (len > p_end - p) return NULL; str = av_malloc(len + 1); if (!str) return NULL; memcpy(str, p, len); str[len] = '\0'; p += len; *pp = p; return str;}//解析section头，*pp是数据头开始的地址，p_end是数据结束的地址，通过对头地址的每次加1或加2来进行数据解析static int parse_section_header(SectionHeader *h, const uint8_t **pp, const uint8_t *p_end){ int val; val = get8(pp, p_end); if (val < 0) return val; h->tid = val;//获取tid *pp += 2; val = get16(pp, p_end); if (val < 0) return val; h->id = val; val = get8(pp, p_end); if (val < 0) return val; h->version = (val >> 1) & 0x1f;//获取版本信息 val = get8(pp, p_end); if (val < 0) return val; h->sec_num = val; val = get8(pp, p_end); if (val < 0) return val; h->last_sec_num = val; return 0;}typedef struct StreamType { uint32_t stream_type; enum AVMediaType codec_type; enum AVCodecID codec_id;} StreamType;//流类型的驱动表，关联指定的解码器与媒体类型static const StreamType ISO_types[] = { { 0x01, AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_MPEG2VIDEO }, { 0x02, AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_MPEG2VIDEO }, { 0x03, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_MP3 }, { 0x04, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_MP3 }, { 0x0f, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_AAC }, { 0x10, AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_MPEG4 }, /* Makito encoder sets stream type 0x11 for AAC, * so auto-detect LOAS/LATM instead of hardcoding it. */#if !CONFIG_LOAS_DEMUXER { 0x11, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_AAC_LATM }, /* LATM syntax */#endif { 0x1b, AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_H264 }, { 0x1c, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_AAC }, { 0x20, AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_H264 }, { 0x21, AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_JPEG2000 }, { 0x24, AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_HEVC }, { 0x42, AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_CAVS }, { 0xd1, AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_DIRAC }, { 0xea, AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_VC1 }, { 0 },};static const StreamType HDMV_types[] = { { 0x80, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_PCM_BLURAY }, { 0x81, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_AC3 }, { 0x82, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_DTS }, { 0x83, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_TRUEHD }, { 0x84, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_EAC3 }, { 0x85, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_DTS }, /* DTS HD */ { 0x86, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_DTS }, /* DTS HD MASTER*/ { 0xa1, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_EAC3 }, /* E-AC3 Secondary Audio */ { 0xa2, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_DTS }, /* DTS Express Secondary Audio */ { 0x90, AVMEDIA_TYPE_SUBTITLE, AV_CODEC_ID_HDMV_PGS_SUBTITLE }, { 0x92, AVMEDIA_TYPE_SUBTITLE, AV_CODEC_ID_HDMV_TEXT_SUBTITLE }, { 0 },};/* SCTE types */static const StreamType SCTE_types[] = { { 0x86, AVMEDIA_TYPE_DATA, AV_CODEC_ID_SCTE_35 }, { 0 },};/* ATSC ? */static const StreamType MISC_types[] = { { 0x81, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_AC3 }, { 0x8a, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_DTS }, { 0 },};static const StreamType REGD_types[] = { { MKTAG('d', 'r', 'a', 'c'), AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_DIRAC }, { MKTAG('A', 'C', '-', '3'), AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_AC3 }, { MKTAG('B', 'S', 'S', 'D'), AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_S302M }, { MKTAG('D', 'T', 'S', '1'), AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_DTS }, { MKTAG('D', 'T', 'S', '2'), AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_DTS }, { MKTAG('D', 'T', 'S', '3'), AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_DTS }, { MKTAG('E', 'A', 'C', '3'), AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_EAC3 }, { MKTAG('H', 'E', 'V', 'C'), AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_HEVC }, { MKTAG('K', 'L', 'V', 'A'), AVMEDIA_TYPE_DATA, AV_CODEC_ID_SMPTE_KLV }, { MKTAG('I', 'D', '3', ' '), AVMEDIA_TYPE_DATA, AV_CODEC_ID_TIMED_ID3 }, { MKTAG('V', 'C', '-', '1'), AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_VC1 }, { MKTAG('O', 'p', 'u', 's'), AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_OPUS }, { 0 },};static const StreamType METADATA_types[] = { { MKTAG('K','L','V','A'), AVMEDIA_TYPE_DATA, AV_CODEC_ID_SMPTE_KLV }, { MKTAG('I','D','3',' '), AVMEDIA_TYPE_DATA, AV_CODEC_ID_TIMED_ID3 }, { 0 },};/* descriptor present */static const StreamType DESC_types[] = { { 0x6a, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_AC3 }, /* AC-3 descriptor */ { 0x7a, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_EAC3 }, /* E-AC-3 descriptor */ { 0x7b, AVMEDIA_TYPE_AUDIO, AV_CODEC_ID_DTS }, { 0x56, AVMEDIA_TYPE_SUBTITLE, AV_CODEC_ID_DVB_TELETEXT }, { 0x59, AVMEDIA_TYPE_SUBTITLE, AV_CODEC_ID_DVB_SUBTITLE }, /* subtitling descriptor */ { 0 },};//获取指定stream的媒体类型static void mpegts_find_stream_type(AVStream *st, uint32_t stream_type, const StreamType *types){ for (; types->stream_type; types++) if (stream_type == types->stream_type) { if (st->codecpar->codec_type != types->codec_type || st->codecpar->codec_id != types->codec_id) { st->codecpar->codec_type = types->codec_type; st->codecpar->codec_id = types->codec_id; st->internal->need_context_update = 1; } st->request_probe = 0; return; }}//设置流信息，主要是对媒体类型，解码器信息进行了设置static int mpegts_set_stream_info(AVStream *st, PESContext *pes, uint32_t stream_type, uint32_t prog_reg_desc){ int old_codec_type = st->codecpar->codec_type; int old_codec_id = st->codecpar->codec_id; int old_codec_tag = st->codecpar->codec_tag; if (avcodec_is_open(st->internal->avctx)) { av_log(pes->stream, AV_LOG_DEBUG, "cannot set stream info, internal codec is open\n"); return 0; } avpriv_set_pts_info(st, 33, 1, 90000); st->priv_data = pes; st->codecpar->codec_type = AVMEDIA_TYPE_DATA; st->codecpar->codec_id = AV_CODEC_ID_NONE; st->need_parsing = AVSTREAM_PARSE_FULL; pes->st = st; pes->stream_type = stream_type; av_log(pes->stream, AV_LOG_DEBUG, "stream=%d stream_type=%x pid=%x prog_reg_desc=%.4s\n", st->index, pes->stream_type, pes->pid, (char *)&prog_reg_desc); st->codecpar->codec_tag = pes->stream_type; mpegts_find_stream_type(st, pes->stream_type, ISO_types); if (pes->stream_type == 4) st->request_probe = 50; if ((prog_reg_desc == AV_RL32("HDMV") || prog_reg_desc == AV_RL32("HDPR")) && st->codecpar->codec_id == AV_CODEC_ID_NONE) { mpegts_find_stream_type(st, pes->stream_type, HDMV_types); if (pes->stream_type == 0x83) { // HDMV TrueHD streams also contain an AC3 coded version of the // audio track - add a second stream for this AVStream *sub_st; // priv_data cannot be shared between streams PESContext *sub_pes = av_malloc(sizeof(*sub_pes)); if (!sub_pes) return AVERROR(ENOMEM); memcpy(sub_pes, pes, sizeof(*sub_pes)); sub_st = avformat_new_stream(pes->stream, NULL); if (!sub_st) { av_free(sub_pes); return AVERROR(ENOMEM); } sub_st->id = pes->pid; avpriv_set_pts_info(sub_st, 33, 1, 90000); sub_st->priv_data = sub_pes; sub_st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO; sub_st->codecpar->codec_id = AV_CODEC_ID_AC3; sub_st->need_parsing = AVSTREAM_PARSE_FULL; sub_pes->sub_st = pes->sub_st = sub_st; } } if (st->codecpar->codec_id == AV_CODEC_ID_NONE) mpegts_find_stream_type(st, pes->stream_type, MISC_types); if (st->codecpar->codec_id == AV_CODEC_ID_NONE) { st->codecpar->codec_id = old_codec_id; st->codecpar->codec_type = old_codec_type; } if ((st->codecpar->codec_id == AV_CODEC_ID_NONE || (st->request_probe > 0 && st->request_probe < AVPROBE_SCORE_STREAM_RETRY / 5)) && st->probe_packets > 0 && stream_type == STREAM_TYPE_PRIVATE_DATA) { st->codecpar->codec_type = AVMEDIA_TYPE_DATA; st->codecpar->codec_id = AV_CODEC_ID_BIN_DATA; st->request_probe = AVPROBE_SCORE_STREAM_RETRY / 5; } /* queue a context update if properties changed */ if (old_codec_type != st->codecpar->codec_type || old_codec_id != st->codecpar->codec_id || old_codec_tag != st->codecpar->codec_tag) st->internal->need_context_update = 1; return 0;}//重置pes包的状态，这个没什么好说的，就是把值重置static void reset_pes_packet_state(PESContext *pes){ pes->pts = AV_NOPTS_VALUE; pes->dts = AV_NOPTS_VALUE; pes->data_index = 0; pes->flags = 0; av_buffer_unref(&pes->buffer);}static void new_data_packet(const uint8_t *buffer, int len, AVPacket *pkt){ av_init_packet(pkt); pkt->data = buffer; pkt->size = len;}//可以简单的理解为把AVPacket的数据给了PESContextstatic int new_pes_packet(PESContext *pes, AVPacket *pkt){ char *sd; av_init_packet(pkt); pkt->buf = pes->buffer; pkt->data = pes->buffer->data; pkt->size = pes->data_index; if (pes->total_size != MAX_PES_PAYLOAD && pes->pes_header_size + pes->data_index != pes->total_size + PES_START_SIZE) { av_log(pes->stream, AV_LOG_WARNING, "PES packet size mismatch\n"); pes->flags |= AV_PKT_FLAG_CORRUPT; } memset(pkt->data + pkt->size, 0, AV_INPUT_BUFFER_PADDING_SIZE); // Separate out the AC3 substream from an HDMV combined TrueHD/AC3 PID if (pes->sub_st && pes->stream_type == 0x83 && pes->extended_stream_id == 0x76) pkt->stream_index = pes->sub_st->index; else pkt->stream_index = pes->st->index; pkt->pts = pes->pts; pkt->dts = pes->dts; /* store position of first TS packet of this PES packet */ pkt->pos = pes->ts_packet_pos; pkt->flags = pes->flags; pes->buffer = NULL; reset_pes_packet_state(pes); sd = av_packet_new_side_data(pkt, AV_PKT_DATA_MPEGTS_STREAM_ID, 1); if (!sd) return AVERROR(ENOMEM); *sd = pes->stream_id; return 0;}static uint64_t get_ts64(GetBitContext *gb, int bits){ if (get_bits_left(gb) < bits) return AV_NOPTS_VALUE; return get_bits64(gb, bits);}//与前边的parse_section_header方法类似，这里不再多说static int read_sl_header(PESContext *pes, SLConfigDescr *sl, const uint8_t *buf, int buf_size){ GetBitContext gb; int au_start_flag = 0, au_end_flag = 0, ocr_flag = 0, idle_flag = 0; int padding_flag = 0, padding_bits = 0, inst_bitrate_flag = 0; int dts_flag = -1, cts_flag = -1; int64_t dts = AV_NOPTS_VALUE, cts = AV_NOPTS_VALUE; uint8_t buf_padded[128 + AV_INPUT_BUFFER_PADDING_SIZE]; int buf_padded_size = FFMIN(buf_size, sizeof(buf_padded) - AV_INPUT_BUFFER_PADDING_SIZE); memcpy(buf_padded, buf, buf_padded_size); init_get_bits(&gb, buf_padded, buf_padded_size * 8); if (sl->use_au_start) au_start_flag = get_bits1(&gb); if (sl->use_au_end) au_end_flag = get_bits1(&gb); if (!sl->use_au_start && !sl->use_au_end) au_start_flag = au_end_flag = 1; if (sl->ocr_len > 0) ocr_flag = get_bits1(&gb); if (sl->use_idle) idle_flag = get_bits1(&gb); if (sl->use_padding) padding_flag = get_bits1(&gb); if (padding_flag) padding_bits = get_bits(&gb, 3); if (!idle_flag && (!padding_flag || padding_bits != 0)) { if (sl->packet_seq_num_len) skip_bits_long(&gb, sl->packet_seq_num_len); if (sl->degr_prior_len) if (get_bits1(&gb)) skip_bits(&gb, sl->degr_prior_len); if (ocr_flag) skip_bits_long(&gb, sl->ocr_len); if (au_start_flag) { if (sl->use_rand_acc_pt) get_bits1(&gb); if (sl->au_seq_num_len > 0) skip_bits_long(&gb, sl->au_seq_num_len); if (sl->use_timestamps) { dts_flag = get_bits1(&gb); cts_flag = get_bits1(&gb); } } if (sl->inst_bitrate_len) inst_bitrate_flag = get_bits1(&gb); if (dts_flag == 1) dts = get_ts64(&gb, sl->timestamp_len); if (cts_flag == 1) cts = get_ts64(&gb, sl->timestamp_len); if (sl->au_len > 0) skip_bits_long(&gb, sl->au_len); if (inst_bitrate_flag) skip_bits_long(&gb, sl->inst_bitrate_len); } if (dts != AV_NOPTS_VALUE) pes->dts = dts; if (cts != AV_NOPTS_VALUE) pes->pts = cts; if (sl->timestamp_len && sl->timestamp_res) avpriv_set_pts_info(pes->st, sl->timestamp_len, 1, sl->timestamp_res); return (get_bits_count(&gb) + 7) >> 3;}/* return non zero if a packet could be constructed */static int mpegts_push_data(MpegTSFilter *filter, const uint8_t *buf, int buf_size, int is_start, int64_t pos){ PESContext *pes = filter->u.pes_filter.opaque; MpegTSContext *ts = pes->ts; const uint8_t *p; int ret, len, code; if (!ts->pkt) return 0; if (is_start) { if (pes->state == MPEGTS_PAYLOAD && pes->data_index > 0) { ret = new_pes_packet(pes, ts->pkt); if (ret < 0) return ret; ts->stop_parse = 1; } else { reset_pes_packet_state(pes);//重置pes包状态 } pes->state = MPEGTS_HEADER; pes->ts_packet_pos = pos; } p = buf; while (buf_size > 0) {//根据不同的头做出不同的解析判断 switch (pes->state) { case MPEGTS_HEADER: len = PES_START_SIZE - pes->data_index; if (len > buf_size) len = buf_size; memcpy(pes->header + pes->data_index, p, len); pes->data_index += len; p += len; buf_size -= len; if (pes->data_index == PES_START_SIZE) { /* 已经获取了完整的pes 或者是 section 头，现在可以开始处理了 */ if (pes->header[0] == 0x00 && pes->header[1] == 0x00 && pes->header[2] == 0x01) { /* it must be an MPEG-2 PES stream */ code = pes->header[3] | 0x100; av_log(pes->stream, AV_LOG_TRACE, "pid=%x pes_code=%#x\n", pes->pid, code); pes->stream_id = pes->header[3]; if ((pes->st && pes->st->discard == AVDISCARD_ALL && (!pes->sub_st || pes->sub_st->discard == AVDISCARD_ALL)) || code == 0x1be) /* padding_stream */ goto skip; /* stream not present in PMT */ if (!pes->st) { if (ts->skip_changes) goto skip; pes->st = avformat_new_stream(ts->stream, NULL); if (!pes->st) return AVERROR(ENOMEM); pes->st->id = pes->pid; mpegts_set_stream_info(pes->st, pes, 0, 0); } pes->total_size = AV_RB16(pes->header + 4); /* NOTE: a zero total size means the PES size is * unbounded */ if (!pes->total_size) pes->total_size = MAX_PES_PAYLOAD; /* allocate pes buffer */ pes->buffer = av_buffer_alloc(pes->total_size + AV_INPUT_BUFFER_PADDING_SIZE); if (!pes->buffer) return AVERROR(ENOMEM); if (code != 0x1bc && code != 0x1bf && /* program_stream_map, private_stream_2 */ code != 0x1f0 && code != 0x1f1 && /* ECM, EMM */ code != 0x1ff && code != 0x1f2 && /* program_stream_directory, DSMCC_stream */ code != 0x1f8) { /* ITU-T Rec. H.222.1 type E stream */ pes->state = MPEGTS_PESHEADER; if (pes->st->codecpar->codec_id == AV_CODEC_ID_NONE && !pes->st->request_probe) { av_log(pes->stream, AV_LOG_TRACE, "pid=%x stream_type=%x probing\n", pes->pid, pes->stream_type); pes->st->request_probe = 1; } } else { pes->pes_header_size = 6; pes->state = MPEGTS_PAYLOAD; pes->data_index = 0; } } else { /* otherwise, it should be a table */ /* skip packet */skip: pes->state = MPEGTS_SKIP; continue; } } break; /**********************************************/ /* PES packing parsing */ case MPEGTS_PESHEADER: len = PES_HEADER_SIZE - pes->data_index; if (len < 0) return AVERROR_INVALIDDATA; if (len > buf_size) len = buf_size; memcpy(pes->header + pes->data_index, p, len); pes->data_index += len; p += len; buf_size -= len; if (pes->data_index == PES_HEADER_SIZE) { pes->pes_header_size = pes->header[8] + 9; pes->state = MPEGTS_PESHEADER_FILL; } break; case MPEGTS_PESHEADER_FILL: len = pes->pes_header_size - pes->data_index; if (len < 0) return AVERROR_INVALIDDATA; if (len > buf_size) len = buf_size; memcpy(pes->header + pes->data_index, p, len); pes->data_index += len; p += len; buf_size -= len; if (pes->data_index == pes->pes_header_size) { const uint8_t *r; unsigned int flags, pes_ext, skip; flags = pes->header[7]; r = pes->header + 9; pes->pts = AV_NOPTS_VALUE; pes->dts = AV_NOPTS_VALUE; if ((flags & 0xc0) == 0x80) { pes->dts = pes->pts = ff_parse_pes_pts(r); r += 5; } else if ((flags & 0xc0) == 0xc0) { pes->pts = ff_parse_pes_pts(r); r += 5; pes->dts = ff_parse_pes_pts(r); r += 5; } pes->extended_stream_id = -1; if (flags & 0x01) { /* PES extension */ pes_ext = *r++; /* Skip PES private data, program packet sequence counter and P-STD buffer */ skip = (pes_ext >> 4) & 0xb; skip += skip & 0x9; r += skip; if ((pes_ext & 0x41) == 0x01 && (r + 2) <= (pes->header + pes->pes_header_size)) { /* PES extension 2 */ if ((r[0] & 0x7f) > 0 && (r[1] & 0x80) == 0) pes->extended_stream_id = r[1]; } } /* we got the full header. We parse it and get the payload */ pes->state = MPEGTS_PAYLOAD; pes->data_index = 0; if (pes->stream_type == 0x12 && buf_size > 0) { int sl_header_bytes = read_sl_header(pes, &pes->sl, p, buf_size); pes->pes_header_size += sl_header_bytes; p += sl_header_bytes; buf_size -= sl_header_bytes; } if (pes->stream_type == 0x15 && buf_size >= 5) { /* skip metadata access unit header */ pes->pes_header_size += 5; p += 5; buf_size -= 5; } if ( pes->ts->fix_teletext_pts && ( pes->st->codecpar->codec_id == AV_CODEC_ID_DVB_TELETEXT || pes->st->codecpar->codec_id == AV_CODEC_ID_DVB_SUBTITLE) ) { AVProgram *p = NULL; while ((p = av_find_program_from_stream(pes->stream, p, pes->st->index))) { if (p->pcr_pid != -1 && p->discard != AVDISCARD_ALL) { MpegTSFilter *f = pes->ts->pids[p->pcr_pid]; if (f) { AVStream *st = NULL; if (f->type == MPEGTS_PES) { PESContext *pcrpes = f->u.pes_filter.opaque; if (pcrpes) st = pcrpes->st; } else if (f->type == MPEGTS_PCR) { int i; for (i = 0; i < p->nb_stream_indexes; i++) { AVStream *pst = pes->stream->streams[p->stream_index[i]]; if (pst->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) st = pst; } } if (f->last_pcr != -1 && st && st->discard != AVDISCARD_ALL) { // teletext packets do not always have correct timestamps, // the standard says they should be handled after 40.6 ms at most, // and the pcr error to this packet should be no more than 100 ms. // TODO: we should interpolate the PCR, not just use the last one int64_t pcr = f->last_pcr / 300; pes->st->pts_wrap_reference = st->pts_wrap_reference; pes->st->pts_wrap_behavior = st->pts_wrap_behavior; if (pes->dts == AV_NOPTS_VALUE || pes->dts < pcr) { pes->pts = pes->dts = pcr; } else if (pes->st->codecpar->codec_id == AV_CODEC_ID_DVB_TELETEXT && pes->dts > pcr + 3654 + 9000) { pes->pts = pes->dts = pcr + 3654 + 9000; } else if (pes->st->codecpar->codec_id == AV_CODEC_ID_DVB_SUBTITLE && pes->dts > pcr + 10*90000) { //10sec pes->pts = pes->dts = pcr + 3654 + 9000; } break; } } } } } } break; case MPEGTS_PAYLOAD: if (pes->buffer) { if (pes->data_index > 0 && pes->data_index + buf_size > pes->total_size) { ret = new_pes_packet(pes, ts->pkt); if (ret < 0) return ret; pes->total_size = MAX_PES_PAYLOAD; pes->buffer = av_buffer_alloc(pes->total_size + AV_INPUT_BUFFER_PADDING_SIZE); if (!pes->buffer) return AVERROR(ENOMEM); ts->stop_parse = 1; } else if (pes->data_index == 0 && buf_size > pes->total_size) { // pes packet size is < ts size packet and pes data is padded with 0xff // not sure if this is legal in ts but see issue #2392 buf_size = pes->total_size; } memcpy(pes->buffer->data + pes->data_index, p, buf_size); pes->data_index += buf_size; /* emit complete packets with known packet size * decreases demuxer delay for infrequent packets like subtitles from * a couple of seconds to milliseconds for properly muxed files. * total_size is the number of bytes following pes_packet_length * in the pes header, i.e. not counting the first PES_START_SIZE bytes */ if (!ts->stop_parse && pes->total_size < MAX_PES_PAYLOAD && pes->pes_header_size + pes->data_index == pes->total_size + PES_START_SIZE) { ts->stop_parse = 1; ret = new_pes_packet(pes, ts->pkt); if (ret < 0) return ret; } } buf_size = 0; break; case MPEGTS_SKIP: buf_size = 0; break; } } return 0;}//新增一个pes，数据来源于MpegTSContextstatic PESContext *add_pes_stream(MpegTSContext *ts, int pid, int pcr_pid){ MpegTSFilter *tss; PESContext *pes; /* if no pid found, then add a pid context */ pes = av_mallocz(sizeof(PESContext)); if (!pes) return 0; pes->ts = ts; pes->stream = ts->stream; pes->pid = pid; pes->pcr_pid = pcr_pid; pes->state = MPEGTS_SKIP; pes->pts = AV_NOPTS_VALUE; pes->dts = AV_NOPTS_VALUE; tss = mpegts_open_pes_filter(ts, pid, mpegts_push_data, pes); if (!tss) { av_free(pes); return 0; } return pes;}//以下不要错误的理解为mp4，它是对每个流的描述的解析，Descr为description的缩写#define MAX_LEVEL 4typedef struct MP4DescrParseContext { AVFormatContext *s; AVIOContext pb; Mp4Descr *descr; Mp4Descr *active_descr; int descr_count; int max_descr_count; int level; int predefined_SLConfigDescriptor_seen;} MP4DescrParseContext;//初始化描述解析器static int init_MP4DescrParseContext(MP4DescrParseContext *d, AVFormatContext *s, const uint8_t *buf, unsigned size, Mp4Descr *descr, int max_descr_count){ int ret; if (size > (1 << 30)) return AVERROR_INVALIDDATA; if ((ret = ffio_init_context(&d->pb, (unsigned char *)buf, size, 0, NULL, NULL, NULL, NULL)) < 0) return ret; d->s = s; d->level = 0; d->descr_count = 0; d->descr = descr; d->active_descr = NULL; d->max_descr_count = max_descr_count; return 0;}//avio_tell内部封装的为avio_seek,如有想了解的请查看avio_seekstatic void update_offsets(AVIOContext *pb, int64_t *off, int *len){ int64_t new_off = avio_tell(pb); (*len) -= new_off - *off; *off = new_off;}static int parse_mp4_descr(MP4DescrParseContext *d, int64_t off, int len, int target_tag);//解析所有描述，我在解析ts文件的时候并没有用到这个函数static int parse_mp4_descr_arr(MP4DescrParseContext *d, int64_t off, int len){ while (len > 0) { int ret = parse_mp4_descr(d, off, len, 0); if (ret < 0) return ret; update_offsets(&d->pb, &off, &len); } return 0;}//解析描述的descr_tag？static int parse_MP4IODescrTag(MP4DescrParseContext *d, int64_t off, int len){ avio_rb16(&d->pb); // ID avio_r8(&d->pb); avio_r8(&d->pb); avio_r8(&d->pb); avio_r8(&d->pb); avio_r8(&d->pb); update_offsets(&d->pb, &off, &len); return parse_mp4_descr_arr(d, off, len);}static int parse_MP4ODescrTag(MP4DescrParseContext *d, int64_t off, int len){ int id_flags; if (len < 2) return 0; id_flags = avio_rb16(&d->pb); if (!(id_flags & 0x0020)) { // URL_Flag update_offsets(&d->pb, &off, &len); return parse_mp4_descr_arr(d, off, len); // ES_Descriptor[] } else { return 0; }}static int parse_MP4ESDescrTag(MP4DescrParseContext *d, int64_t off, int len){ int es_id = 0; int ret = 0; if (d->descr_count >= d->max_descr_count) return AVERROR_INVALIDDATA; ff_mp4_parse_es_descr(&d->pb, &es_id); d->active_descr = d->descr + (d->descr_count++); d->active_descr->es_id = es_id; update_offsets(&d->pb, &off, &len); if ((ret = parse_mp4_descr(d, off, len, MP4DecConfigDescrTag)) < 0) return ret; update_offsets(&d->pb, &off, &len); if (len > 0) ret = parse_mp4_descr(d, off, len, MP4SLDescrTag); d->active_descr = NULL; return ret;}static int parse_MP4DecConfigDescrTag(MP4DescrParseContext *d, int64_t off, int len){ Mp4Descr *descr = d->active_descr; if (!descr) return AVERROR_INVALIDDATA; d->active_descr->dec_config_descr = av_malloc(len); if (!descr->dec_config_descr) return AVERROR(ENOMEM); descr->dec_config_descr_len = len; avio_read(&d->pb, descr->dec_config_descr, len); return 0;}static int parse_MP4SLDescrTag(MP4DescrParseContext *d, int64_t off, int len){ Mp4Descr *descr = d->active_descr; int predefined; if (!descr) return AVERROR_INVALIDDATA;#define R8_CHECK_CLIP_MAX(dst, maxv) do { \ descr->sl.dst = avio_r8(&d->pb); \ if (descr->sl.dst > maxv) { \ descr->sl.dst = maxv; \ return AVERROR_INVALIDDATA; \ } \} while (0) predefined = avio_r8(&d->pb); if (!predefined) { int lengths; int flags = avio_r8(&d->pb); descr->sl.use_au_start = !!(flags & 0x80); descr->sl.use_au_end = !!(flags & 0x40); descr->sl.use_rand_acc_pt = !!(flags & 0x20); descr->sl.use_padding = !!(flags & 0x08); descr->sl.use_timestamps = !!(flags & 0x04); descr->sl.use_idle = !!(flags & 0x02); descr->sl.timestamp_res = avio_rb32(&d->pb); avio_rb32(&d->pb); R8_CHECK_CLIP_MAX(timestamp_len, 63); R8_CHECK_CLIP_MAX(ocr_len, 63); R8_CHECK_CLIP_MAX(au_len, 31); descr->sl.inst_bitrate_len = avio_r8(&d->pb); lengths = avio_rb16(&d->pb); descr->sl.degr_prior_len = lengths >> 12; descr->sl.au_seq_num_len = (lengths >> 7) & 0x1f; descr->sl.packet_seq_num_len = (lengths >> 2) & 0x1f; } else if (!d->predefined_SLConfigDescriptor_seen){ avpriv_report_missing_feature(d->s, "Predefined SLConfigDescriptor"); d->predefined_SLConfigDescriptor_seen = 1; } return 0;}//解析流的描述字符，注意：此处是根据tag进行判断，不同类型进行不同的解析，详细情况请参照ts文档iso13818-1，里边有专门对tag的说明static int parse_mp4_descr(MP4DescrParseContext *d, int64_t off, int len, int target_tag){ int tag; int len1 = ff_mp4_read_descr(d->s, &d->pb, &tag); int ret = 0; update_offsets(&d->pb, &off, &len); if (len < 0 || len1 > len || len1 <= 0) { av_log(d->s, AV_LOG_ERROR, "Tag %x length violation new length %d bytes remaining %d\n", tag, len1, len); return AVERROR_INVALIDDATA; } if (d->level++ >= MAX_LEVEL) { av_log(d->s, AV_LOG_ERROR, "Maximum MP4 descriptor level exceeded\n"); ret = AVERROR_INVALIDDATA; goto done; } if (target_tag && tag != target_tag) { av_log(d->s, AV_LOG_ERROR, "Found tag %x expected %x\n", tag, target_tag); ret = AVERROR_INVALIDDATA; goto done; } switch (tag) { case MP4IODescrTag: ret = parse_MP4IODescrTag(d, off, len1); break; case MP4ODescrTag: ret = parse_MP4ODescrTag(d, off, len1); break; case MP4ESDescrTag: ret = parse_MP4ESDescrTag(d, off, len1); break; case MP4DecConfigDescrTag: ret = parse_MP4DecConfigDescrTag(d, off, len1); break; case MP4SLDescrTag: ret = parse_MP4SLDescrTag(d, off, len1); break; }done: d->level--; avio_seek(&d->pb, off + len1, SEEK_SET); return ret;}static int mp4_read_iods(AVFormatContext *s, const uint8_t *buf, unsigned size, Mp4Descr *descr, int *descr_count, int max_descr_count){ MP4DescrParseContext d; int ret; ret = init_MP4DescrParseContext(&d, s, buf, size, descr, max_descr_count); if (ret < 0) return ret; ret = parse_mp4_descr(&d, avio_tell(&d.pb), size, MP4IODescrTag); *descr_count = d.descr_count; return ret;}static int mp4_read_od(AVFormatContext *s, const uint8_t *buf, unsigned size, Mp4Descr *descr, int *descr_count, int max_descr_count){ MP4DescrParseContext d; int ret; ret = init_MP4DescrParseContext(&d, s, buf, size, descr, max_descr_count); if (ret < 0) return ret; ret = parse_mp4_descr_arr(&d, avio_tell(&d.pb), size); *descr_count = d.descr_count; return ret;}static void m4sl_cb(MpegTSFilter *filter, const uint8_t *section, int section_len){ MpegTSContext *ts = filter->u.section_filter.opaque; MpegTSSectionFilter *tssf = &filter->u.section_filter; SectionHeader h; const uint8_t *p, *p_end; AVIOContext pb; int mp4_descr_count = 0; Mp4Descr mp4_descr[MAX_MP4_DESCR_COUNT] = { { 0 } }; int i, pid; AVFormatContext *s = ts->stream; p_end = section + section_len - 4; p = section; if (parse_section_header(&h, &p, p_end) < 0) return; if (h.tid != M4OD_TID) return; if (skip_identical(&h, tssf)) return; mp4_read_od(s, p, (unsigned) (p_end - p), mp4_descr, &mp4_descr_count, MAX_MP4_DESCR_COUNT); for (pid = 0; pid < NB_PID_MAX; pid++) { if (!ts->pids[pid]) continue; for (i = 0; i < mp4_descr_count; i++) { PESContext *pes; AVStream *st; if (ts->pids[pid]->es_id != mp4_descr[i].es_id) continue; if (ts->pids[pid]->type != MPEGTS_PES) { av_log(s, AV_LOG_ERROR, "pid %x is not PES\n", pid); continue; } pes = ts->pids[pid]->u.pes_filter.opaque; st = pes->st; if (!st) continue; pes->sl = mp4_descr[i].sl; ffio_init_context(&pb, mp4_descr[i].dec_config_descr, mp4_descr[i].dec_config_descr_len, 0, NULL, NULL, NULL, NULL); ff_mp4_read_dec_config_descr(s, st, &pb); if (st->codecpar->codec_id == AV_CODEC_ID_AAC && st->codecpar->extradata_size > 0) st->need_parsing = 0; if (st->codecpar->codec_id == AV_CODEC_ID_H264 && st->codecpar->extradata_size > 0) st->need_parsing = 0; st->codecpar->codec_type = avcodec_get_type(st->codecpar->codec_id); st->internal->need_context_update = 1; } } for (i = 0; i < mp4_descr_count; i++) av_free(mp4_descr[i].dec_config_descr);}static void scte_data_cb(MpegTSFilter *filter, const uint8_t *section, int section_len){ AVProgram *prg = NULL; MpegTSContext *ts = filter->u.section_filter.opaque; int idx = ff_find_stream_index(ts->stream, filter->pid); if (idx < 0) return; new_data_packet(section, section_len, ts->pkt); ts->pkt->stream_index = idx; prg = av_find_program_from_stream(ts->stream, NULL, idx); if (prg && prg->pcr_pid != -1 && prg->discard != AVDISCARD_ALL) { MpegTSFilter *f = ts->pids[prg->pcr_pid]; if (f && f->last_pcr != -1) ts->pkt->pts = ts->pkt->dts = f->last_pcr/300; } ts->stop_parse = 1;}static const uint8_t opus_coupled_stream_cnt[9] = { 1, 0, 1, 1, 2, 2, 2, 3, 3};static const uint8_t opus_stream_cnt[9] = { 1, 1, 1, 2, 2, 3, 4, 4, 5,};static const uint8_t opus_channel_map[8][8] = { { 0 }, { 0,1 }, { 0,2,1 }, { 0,1,2,3 }, { 0,4,1,2,3 }, { 0,4,1,2,3,5 }, { 0,4,1,2,3,5,6 }, { 0,6,1,2,3,4,5,7 },};//解析流的描述字符，注意：此处是根据tag进行判断，不同类型进行不同的解析，详细情况请参照ts文档iso13818-1，里边有专门对tag的说明//这里一定要分明描述符与频道名的区别//ts文件中有service_name，即频道名，跟这个是两个完全不一样的东西int ff_parse_mpeg2_descriptor(AVFormatContext *fc, AVStream *st, int stream_type, const uint8_t **pp, const uint8_t *desc_list_end, Mp4Descr *mp4_descr, int mp4_descr_count, int pid, MpegTSContext *ts){ const uint8_t *desc_end; int desc_len, desc_tag, desc_es_id, ext_desc_tag, channels, channel_config_code; char language[252]; int i;//解析tag，相当于获取类型 desc_tag = get8(pp, desc_list_end); if (desc_tag < 0) return AVERROR_INVALIDDATA;//获取描述符的长度 desc_len = get8(pp, desc_list_end); if (desc_len < 0) return AVERROR_INVALIDDATA; desc_end = *pp + desc_len; if (desc_end > desc_list_end) return AVERROR_INVALIDDATA; av_log(fc, AV_LOG_TRACE, "tag: 0x%02x len=%d\n", desc_tag, desc_len); if ((st->codecpar->codec_id == AV_CODEC_ID_NONE || st->request_probe > 0) && stream_type == STREAM_TYPE_PRIVATE_DATA) mpegts_find_stream_type(st, desc_tag, DESC_types); switch (desc_tag) { case 0x1E: /* SL descriptor */ desc_es_id = get16(pp, desc_end); if (desc_es_id < 0) break; if (ts && ts->pids[pid]) ts->pids[pid]->es_id = desc_es_id; for (i = 0; i < mp4_descr_count; i++) if (mp4_descr[i].dec_config_descr_len && mp4_descr[i].es_id == desc_es_id) { AVIOContext pb; ffio_init_context(&pb, mp4_descr[i].dec_config_descr, mp4_descr[i].dec_config_descr_len, 0, NULL, NULL, NULL, NULL); ff_mp4_read_dec_config_descr(fc, st, &pb); if (st->codecpar->codec_id == AV_CODEC_ID_AAC && st->codecpar->extradata_size > 0) { st->need_parsing = 0; st->internal->need_context_update = 1; } if (st->codecpar->codec_id == AV_CODEC_ID_MPEG4SYSTEMS) mpegts_open_section_filter(ts, pid, m4sl_cb, ts, 1); } break; case 0x1F: /* FMC descriptor */ if (get16(pp, desc_end) < 0) break; if (mp4_descr_count > 0 && (st->codecpar->codec_id == AV_CODEC_ID_AAC_LATM || (st->request_probe == 0 && st->codecpar->codec_id == AV_CODEC_ID_NONE) || st->request_probe > 0) && mp4_descr->dec_config_descr_len && mp4_descr->es_id == pid) { AVIOContext pb; ffio_init_context(&pb, mp4_descr->dec_config_descr, mp4_descr->dec_config_descr_len, 0, NULL, NULL, NULL, NULL); ff_mp4_read_dec_config_descr(fc, st, &pb); if (st->codecpar->codec_id == AV_CODEC_ID_AAC && st->codecpar->extradata_size > 0) { st->request_probe = st->need_parsing = 0; st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO; st->internal->need_context_update = 1; } } break; case 0x56: /* DVB teletext descriptor */ { uint8_t *extradata = NULL; int language_count = desc_len / 5; if (desc_len > 0 && desc_len % 5 != 0) return AVERROR_INVALIDDATA; if (language_count > 0) { /* 4 bytes per language code (3 bytes) with comma or NUL byte should fit language buffer */ av_assert0(language_count <= sizeof(language) / 4); if (st->codecpar->extradata == NULL) { if (ff_alloc_extradata(st->codecpar, language_count * 2)) { return AVERROR(ENOMEM); } } if (st->codecpar->extradata_size < language_count * 2) return AVERROR_INVALIDDATA; extradata = st->codecpar->extradata; for (i = 0; i < language_count; i++) { language[i * 4 + 0] = get8(pp, desc_end); language[i * 4 + 1] = get8(pp, desc_end); language[i * 4 + 2] = get8(pp, desc_end); language[i * 4 + 3] = ','; memcpy(extradata, *pp, 2); extradata += 2; *pp += 2; } language[i * 4 - 1] = 0; av_dict_set(&st->metadata, "language", language, 0); st->internal->need_context_update = 1; } } break; case 0x59: /* subtitling descriptor */ { /* 8 bytes per DVB subtitle substream data: * ISO_639_language_code (3 bytes), * subtitling_type (1 byte), * composition_page_id (2 bytes), * ancillary_page_id (2 bytes) */ int language_count = desc_len / 8; if (desc_len > 0 && desc_len % 8 != 0) return AVERROR_INVALIDDATA; if (language_count > 1) { avpriv_request_sample(fc, "DVB subtitles with multiple languages"); } if (language_count > 0) { uint8_t *extradata; /* 4 bytes per language code (3 bytes) with comma or NUL byte should fit language buffer */ av_assert0(language_count <= sizeof(language) / 4); if (st->codecpar->extradata == NULL) { if (ff_alloc_extradata(st->codecpar, language_count * 5)) { return AVERROR(ENOMEM); } } if (st->codecpar->extradata_size < language_count * 5) return AVERROR_INVALIDDATA; extradata = st->codecpar->extradata; for (i = 0; i < language_count; i++) { language[i * 4 + 0] = get8(pp, desc_end); language[i * 4 + 1] = get8(pp, desc_end); language[i * 4 + 2] = get8(pp, desc_end); language[i * 4 + 3] = ','; /* hearing impaired subtitles detection using subtitling_type */ switch (*pp[0]) { case 0x20: /* DVB subtitles (for the hard of hearing) with no monitor aspect ratio criticality */ case 0x21: /* DVB subtitles (for the hard of hearing) for display on 4:3 aspect ratio monitor */ case 0x22: /* DVB subtitles (for the hard of hearing) for display on 16:9 aspect ratio monitor */ case 0x23: /* DVB subtitles (for the hard of hearing) for display on 2.21:1 aspect ratio monitor */ case 0x24: /* DVB subtitles (for the hard of hearing) for display on a high definition monitor */ case 0x25: /* DVB subtitles (for the hard of hearing) with plano-stereoscopic disparity for display on a high definition monitor */ st->disposition |= AV_DISPOSITION_HEARING_IMPAIRED; break; } extradata[4] = get8(pp, desc_end); /* subtitling_type */ memcpy(extradata, *pp, 4); /* composition_page_id and ancillary_page_id */ extradata += 5; *pp += 4; } language[i * 4 - 1] = 0; av_dict_set(&st->metadata, "language", language, 0); st->internal->need_context_update = 1; } } break; case 0x0a: /* ISO 639 language descriptor */ for (i = 0; i + 4 <= desc_len; i += 4) { language[i + 0] = get8(pp, desc_end); language[i + 1] = get8(pp, desc_end); language[i + 2] = get8(pp, desc_end); language[i + 3] = ','; switch (get8(pp, desc_end)) { case 0x01: st->disposition |= AV_DISPOSITION_CLEAN_EFFECTS; break; case 0x02: st->disposition |= AV_DISPOSITION_HEARING_IMPAIRED; break; case 0x03: st->disposition |= AV_DISPOSITION_VISUAL_IMPAIRED; break; } } if (i && language[0]) { language[i - 1] = 0; av_dict_set(&st->metadata, "language", language, 0); } break; case 0x05: /* registration descriptor */ st->codecpar->codec_tag = bytestream_get_le32(pp); av_log(fc, AV_LOG_TRACE, "reg_desc=%.4s\n", (char *)&st->codecpar->codec_tag); if (st->codecpar->codec_id == AV_CODEC_ID_NONE || st->request_probe > 0) { mpegts_find_stream_type(st, st->codecpar->codec_tag, REGD_types); if (st->codecpar->codec_tag == MKTAG('B', 'S', 'S', 'D')) st->request_probe = 50; } break; case 0x52: /* stream identifier descriptor */ st->stream_identifier = 1 + get8(pp, desc_end); break; case 0x26: /* metadata descriptor */ if (get16(pp, desc_end) == 0xFFFF) *pp += 4; if (get8(pp, desc_end) == 0xFF) { st->codecpar->codec_tag = bytestream_get_le32(pp); if (st->codecpar->codec_id == AV_CODEC_ID_NONE) mpegts_find_stream_type(st, st->codecpar->codec_tag, METADATA_types); } break; case 0x7f: /* DVB extension descriptor */ ext_desc_tag = get8(pp, desc_end); if (ext_desc_tag < 0) return AVERROR_INVALIDDATA; if (st->codecpar->codec_id == AV_CODEC_ID_OPUS && ext_desc_tag == 0x80) { /* User defined (provisional Opus) */ if (!st->codecpar->extradata) { st->codecpar->extradata = av_mallocz(sizeof(opus_default_extradata) + AV_INPUT_BUFFER_PADDING_SIZE); if (!st->codecpar->extradata) return AVERROR(ENOMEM); st->codecpar->extradata_size = sizeof(opus_default_extradata); memcpy(st->codecpar->extradata, opus_default_extradata, sizeof(opus_default_extradata)); channel_config_code = get8(pp, desc_end); if (channel_config_code < 0) return AVERROR_INVALIDDATA; if (channel_config_code <= 0x8) { st->codecpar->extradata[9] = channels = channel_config_code ? channel_config_code : 2; st->codecpar->extradata[18] = channel_config_code ? (channels > 2) : /* Dual Mono */ 255; st->codecpar->extradata[19] = opus_stream_cnt[channel_config_code]; st->codecpar->extradata[20] = opus_coupled_stream_cnt[channel_config_code]; memcpy(&st->codecpar->extradata[21], opus_channel_map[channels - 1], channels); } else { avpriv_request_sample(fc, "Opus in MPEG-TS - channel_config_code > 0x8"); } st->need_parsing = AVSTREAM_PARSE_FULL; st->internal->need_context_update = 1; } } break; default: break; } *pp = desc_end; return 0;}//判断是否为pes流static int is_pes_stream(int stream_type, uint32_t prog_reg_desc){ return !(stream_type == 0x13 || (stream_type == 0x86 && prog_reg_desc == AV_RL32("CUEI")) );}//回调函数，接收pmt表static void pmt_cb(MpegTSFilter *filter, const uint8_t *section, int section_len){ MpegTSContext *ts = filter->u.section_filter.opaque; MpegTSSectionFilter *tssf = &filter->u.section_filter; SectionHeader h1, *h = &h1; PESContext *pes; AVStream *st; const uint8_t *p, *p_end, *desc_list_end; int program_info_length, pcr_pid, pid, stream_type; int desc_list_len; uint32_t prog_reg_desc = 0; /* registration descriptor */ int mp4_descr_count = 0; Mp4Descr mp4_descr[MAX_MP4_DESCR_COUNT] = { { 0 } }; int i; av_log(ts->stream, AV_LOG_TRACE, "PMT: len %i\n", section_len); hex_dump_debug(ts->stream, section, section_len); p_end = section + section_len - 4; p = section; if (parse_section_header(h, &p, p_end) < 0) return; if (skip_identical(h, tssf)) return; av_log(ts->stream, AV_LOG_TRACE, "sid=0x%x sec_num=%d/%d version=%d tid=%d\n", h->id, h->sec_num, h->last_sec_num, h->version, h->tid); if (h->tid != PMT_TID) return; if (!ts->scan_all_pmts && ts->skip_changes) return; if (!ts->skip_clear) clear_program(ts, h->id); pcr_pid = get16(&p, p_end); if (pcr_pid < 0) return; pcr_pid &= 0x1fff; add_pid_to_pmt(ts, h->id, pcr_pid); set_pcr_pid(ts->stream, h->id, pcr_pid); av_log(ts->stream, AV_LOG_TRACE, "pcr_pid=0x%x\n", pcr_pid); program_info_length = get16(&p, p_end); if (program_info_length < 0) return; program_info_length &= 0xfff; while (program_info_length >= 2) { uint8_t tag, len; tag = get8(&p, p_end); len = get8(&p, p_end); av_log(ts->stream, AV_LOG_TRACE, "program tag: 0x%02x len=%d\n", tag, len); if (len > program_info_length - 2) // something else is broken, exit the program_descriptors_loop break; program_info_length -= len + 2; if (tag == 0x1d) { // IOD descriptor get8(&p, p_end); // scope get8(&p, p_end); // label len -= 2; mp4_read_iods(ts->stream, p, len, mp4_descr + mp4_descr_count, &mp4_descr_count, MAX_MP4_DESCR_COUNT); } else if (tag == 0x05 && len >= 4) { // registration descriptor prog_reg_desc = bytestream_get_le32(&p); len -= 4; } p += len; } p += program_info_length; if (p >= p_end) goto out; // stop parsing after pmt, we found header if (!ts->stream->nb_streams) ts->stop_parse = 2; set_pmt_found(ts, h->id); for (;;) { st = 0; pes = NULL; stream_type = get8(&p, p_end); if (stream_type < 0) break; pid = get16(&p, p_end); if (pid < 0) goto out; pid &= 0x1fff; if (pid == ts->current_pid) goto out; /* now create stream */ if (ts->pids[pid] && ts->pids[pid]->type == MPEGTS_PES) { pes = ts->pids[pid]->u.pes_filter.opaque; if (!pes->st) { pes->st = avformat_new_stream(pes->stream, NULL); if (!pes->st) goto out; pes->st->id = pes->pid; } st = pes->st; } else if (is_pes_stream(stream_type, prog_reg_desc)) { if (ts->pids[pid]) mpegts_close_filter(ts, ts->pids[pid]); // wrongly added sdt filter probably pes = add_pes_stream(ts, pid, pcr_pid); if (pes) { st = avformat_new_stream(pes->stream, NULL); if (!st) goto out; st->id = pes->pid; } } else { int idx = ff_find_stream_index(ts->stream, pid); if (idx >= 0) { st = ts->stream->streams[idx]; } else { st = avformat_new_stream(ts->stream, NULL); if (!st) goto out; st->id = pid; st->codecpar->codec_type = AVMEDIA_TYPE_DATA; if (stream_type == 0x86 && prog_reg_desc == AV_RL32("CUEI")) { mpegts_find_stream_type(st, stream_type, SCTE_types); mpegts_open_section_filter(ts, pid, scte_data_cb, ts, 1); } } } if (!st) goto out; if (pes && !pes->stream_type) mpegts_set_stream_info(st, pes, stream_type, prog_reg_desc); add_pid_to_pmt(ts, h->id, pid); av_program_add_stream_index(ts->stream, h->id, st->index); desc_list_len = get16(&p, p_end); if (desc_list_len < 0) goto out; desc_list_len &= 0xfff; desc_list_end = p + desc_list_len; if (desc_list_end > p_end) goto out; for (;;) { if (ff_parse_mpeg2_descriptor(ts->stream, st, stream_type, &p, desc_list_end, mp4_descr, mp4_descr_count, pid, ts) < 0) break; if (pes && prog_reg_desc == AV_RL32("HDMV") && stream_type == 0x83 && pes->sub_st) { av_program_add_stream_index(ts->stream, h->id, pes->sub_st->index); pes->sub_st->codecpar->codec_tag = st->codecpar->codec_tag; } } p = desc_list_end; } if (!ts->pids[pcr_pid]) mpegts_open_pcr_filter(ts, pcr_pid);out: for (i = 0; i < mp4_descr_count; i++) av_free(mp4_descr[i].dec_config_descr);}//回调函数，接收pat表static void pat_cb(MpegTSFilter *filter, const uint8_t *section, int section_len){ MpegTSContext *ts = filter->u.section_filter.opaque; MpegTSSectionFilter *tssf = &filter->u.section_filter; SectionHeader h1, *h = &h1; const uint8_t *p, *p_end; int sid, pmt_pid; AVProgram *program; av_log(ts->stream, AV_LOG_TRACE, "PAT:\n"); hex_dump_debug(ts->stream, section, section_len); p_end = section + section_len - 4; p = section; if (parse_section_header(h, &p, p_end) < 0) return; if (h->tid != PAT_TID) return; if (ts->skip_changes) return; if (skip_identical(h, tssf)) return; ts->stream->ts_id = h->id; clear_programs(ts); for (;;) { sid = get16(&p, p_end); if (sid < 0) break; pmt_pid = get16(&p, p_end); if (pmt_pid < 0) break; pmt_pid &= 0x1fff; if (pmt_pid == ts->current_pid) break; av_log(ts->stream, AV_LOG_TRACE, "sid=0x%x pid=0x%x\n", sid, pmt_pid); if (sid == 0x0000) { /* NIT info */ } else { MpegTSFilter *fil = ts->pids[pmt_pid]; program = av_new_program(ts->stream, sid); if (program) { program->program_num = sid; program->pmt_pid = pmt_pid; } if (fil) if ( fil->type != MPEGTS_SECTION || fil->pid != pmt_pid || fil->u.section_filter.section_cb != pmt_cb) mpegts_close_filter(ts, ts->pids[pmt_pid]); if (!ts->pids[pmt_pid]) mpegts_open_section_filter(ts, pmt_pid, pmt_cb, ts, 1); add_pat_entry(ts, sid); add_pid_to_pmt(ts, sid, 0); // add pat pid to program add_pid_to_pmt(ts, sid, pmt_pid); } } if (sid < 0) { int i,j; for (j=0; j<ts->stream->nb_programs; j++) { for (i = 0; i < ts->nb_prg; i++) if (ts->prg[i].id == ts->stream->programs[j]->id) break; if (i==ts->nb_prg && !ts->skip_clear) clear_avprogram(ts, ts->stream->programs[j]->id); } }}//回调函数，接收sdt表static void sdt_cb(MpegTSFilter *filter, const uint8_t *section, int section_len){ MpegTSContext *ts = filter->u.section_filter.opaque; MpegTSSectionFilter *tssf = &filter->u.section_filter; SectionHeader h1, *h = &h1; const uint8_t *p, *p_end, *desc_list_end, *desc_end; int onid, val, sid, desc_list_len, desc_tag, desc_len, service_type; char *name, *provider_name; av_log(ts->stream, AV_LOG_TRACE, "SDT:\n"); hex_dump_debug(ts->stream, section, section_len); p_end = section + section_len - 4; p = section; if (parse_section_header(h, &p, p_end) < 0) return; if (h->tid != SDT_TID) return; if (ts->skip_changes) return; if (skip_identical(h, tssf)) return; onid = get16(&p, p_end); if (onid < 0) return; val = get8(&p, p_end); if (val < 0) return; for (;;) { sid = get16(&p, p_end); if (sid < 0) break; val = get8(&p, p_end); if (val < 0) break; desc_list_len = get16(&p, p_end); if (desc_list_len < 0) break; desc_list_len &= 0xfff; desc_list_end = p + desc_list_len; if (desc_list_end > p_end) break; for (;;) { desc_tag = get8(&p, desc_list_end); if (desc_tag < 0) break; desc_len = get8(&p, desc_list_end); desc_end = p + desc_len; if (desc_len < 0 || desc_end > desc_list_end) break; av_log(ts->stream, AV_LOG_TRACE, "tag: 0x%02x len=%d\n", desc_tag, desc_len); switch (desc_tag) { case 0x48: service_type = get8(&p, p_end); if (service_type < 0) break; provider_name = getstr8(&p, p_end); if (!provider_name) break; name = getstr8(&p, p_end); if (name) { AVProgram *program = av_new_program(ts->stream, sid); if (program) { av_dict_set(&program->metadata, "service_name", name, 0); av_dict_set(&program->metadata, "service_provider", provider_name, 0); } } av_free(name); av_free(provider_name); break; default: break; } p = desc_end; } p = desc_list_end; }}static int parse_pcr(int64_t *ppcr_high, int *ppcr_low, const uint8_t *packet);//处理接收到的一个包，这是重点static int handle_packet(MpegTSContext *ts, const uint8_t *packet){ MpegTSFilter *tss; int len, pid, cc, expected_cc, cc_ok, afc, is_start, is_discontinuity, has_adaptation, has_payload; const uint8_t *p, *p_end; int64_t pos; pid = AV_RB16(packet + 1) & 0x1fff; if (pid && discard_pid(ts, pid)) return 0; is_start = packet[1] & 0x40; tss = ts->pids[pid]; if (ts->auto_guess && !tss && is_start) { add_pes_stream(ts, pid, -1); tss = ts->pids[pid]; } if (!tss) return 0; ts->current_pid = pid; afc = (packet[3] >> 4) & 3; if (afc == 0) /* reserved value */ return 0; has_adaptation = afc & 2; has_payload = afc & 1; is_discontinuity = has_adaptation && packet[4] != 0 && /* with length > 0 */ (packet[5] & 0x80); /* and discontinuity indicated */ /* continuity check (currently not used) */ cc = (packet[3] & 0xf); expected_cc = has_payload ? (tss->last_cc + 1) & 0x0f : tss->last_cc; cc_ok = pid == 0x1FFF || // null packet PID is_discontinuity || tss->last_cc < 0 || expected_cc == cc; tss->last_cc = cc; if (!cc_ok) { av_log(ts->stream, AV_LOG_DEBUG, "Continuity check failed for pid %d expected %d got %d\n", pid, expected_cc, cc); if (tss->type == MPEGTS_PES) { PESContext *pc = tss->u.pes_filter.opaque; pc->flags |= AV_PKT_FLAG_CORRUPT; } } p = packet + 4; if (has_adaptation) { int64_t pcr_h; int pcr_l; if (parse_pcr(&pcr_h, &pcr_l, packet) == 0) tss->last_pcr = pcr_h * 300 + pcr_l; /* skip adaptation field */ p += p[0] + 1; } /* if past the end of packet, ignore */ p_end = packet + TS_PACKET_SIZE; if (p >= p_end || !has_payload) return 0; pos = avio_tell(ts->stream->pb); if (pos >= 0) { av_assert0(pos >= TS_PACKET_SIZE); ts->pos47_full = pos - TS_PACKET_SIZE; } if (tss->type == MPEGTS_SECTION) { if (is_start) { /* pointer field present */ len = *p++; if (len > p_end - p) return 0; if (len && cc_ok) { /* write remaining section bytes */ write_section_data(ts, tss, p, len, 0); /* check whether filter has been closed */ if (!ts->pids[pid]) return 0; } p += len; if (p < p_end) { write_section_data(ts, tss, p, p_end - p, 1); } } else { if (cc_ok) { write_section_data(ts, tss, p, p_end - p, 0); } } // stop find_stream_info from waiting for more streams // when all programs have received a PMT if (ts->stream->ctx_flags & AVFMTCTX_NOHEADER && ts->scan_all_pmts <= 0) { int i; for (i = 0; i < ts->nb_prg; i++) { if (!ts->prg[i].pmt_found) break; } if (i == ts->nb_prg && ts->nb_prg > 0) { int types = 0; for (i = 0; i < ts->stream->nb_streams; i++) { AVStream *st = ts->stream->streams[i]; if (st->codecpar->codec_type >= 0) types |= 1<<st->codecpar->codec_type; } if ((types & (1<<AVMEDIA_TYPE_AUDIO) && types & (1<<AVMEDIA_TYPE_VIDEO)) || pos > 100000) { av_log(ts->stream, AV_LOG_DEBUG, "All programs have pmt, headers found\n"); ts->stream->ctx_flags &= ~AVFMTCTX_NOHEADER; } } } } else { int ret; // Note: The position here points actually behind the current packet. if (tss->type == MPEGTS_PES) { if ((ret = tss->u.pes_filter.pes_cb(tss, p, p_end - p, is_start, pos - ts->raw_packet_size)) < 0) return ret; } } return 0;}static void reanalyze(MpegTSContext *ts) { AVIOContext *pb = ts->stream->pb; int64_t pos = avio_tell(pb); if (pos < 0) return; pos -= ts->pos47_full; if (pos == TS_PACKET_SIZE) { ts->size_stat[0] ++; } else if (pos == TS_DVHS_PACKET_SIZE) { ts->size_stat[1] ++; } else if (pos == TS_FEC_PACKET_SIZE) { ts->size_stat[2] ++; } ts->size_stat_count ++; if (ts->size_stat_count > SIZE_STAT_THRESHOLD) { int newsize = 0; if (ts->size_stat[0] > SIZE_STAT_THRESHOLD) { newsize = TS_PACKET_SIZE; } else if (ts->size_stat[1] > SIZE_STAT_THRESHOLD) { newsize = TS_DVHS_PACKET_SIZE; } else if (ts->size_stat[2] > SIZE_STAT_THRESHOLD) { newsize = TS_FEC_PACKET_SIZE; } if (newsize && newsize != ts->raw_packet_size) { av_log(ts->stream, AV_LOG_WARNING, "changing packet size to %d\n", newsize); ts->raw_packet_size = newsize; } ts->size_stat_count = 0; memset(ts->size_stat, 0, sizeof(ts->size_stat)); }}/* XXX: try to find a better synchro over several packets (use * get_packet_size() ?) */static int mpegts_resync(AVFormatContext *s, int seekback, const uint8_t *current_packet){ MpegTSContext *ts = s->priv_data; AVIOContext *pb = s->pb; int c, i; uint64_t pos = avio_tell(pb); avio_seek(pb, -FFMIN(seekback, pos), SEEK_CUR); //Special case for files like 01c56b0dc1.ts if (current_packet[0] == 0x80 && current_packet[12] == 0x47) { avio_seek(pb, 12, SEEK_CUR); return 0; } for (i = 0; i < ts->resync_size; i++) { c = avio_r8(pb); if (avio_feof(pb)) return AVERROR_EOF; if (c == 0x47) { avio_seek(pb, -1, SEEK_CUR); reanalyze(s->priv_data); return 0; } } av_log(s, AV_LOG_ERROR, "max resync size reached, could not find sync byte\n"); /* no sync found */ return AVERROR_INVALIDDATA;}/* return AVERROR_something if error or EOF. Return 0 if OK. */static int read_packet(AVFormatContext *s, uint8_t *buf, int raw_packet_size, const uint8_t **data){ AVIOContext *pb = s->pb; int len; for (;;) { len = ffio_read_indirect(pb, buf, TS_PACKET_SIZE, data); if (len != TS_PACKET_SIZE) return len < 0 ? len : AVERROR_EOF; /* check packet sync byte */ if ((*data)[0] != 0x47) { /* find a new packet start */ if (mpegts_resync(s, raw_packet_size, *data) < 0) return AVERROR(EAGAIN); else continue; } else { break; } } return 0;}static void finished_reading_packet(AVFormatContext *s, int raw_packet_size){ AVIOContext *pb = s->pb; int skip = raw_packet_size - TS_PACKET_SIZE; if (skip > 0) avio_skip(pb, skip);}//处理接收到的包，内部关键调用的是handle_packetstatic int handle_packets(MpegTSContext *ts, int64_t nb_packets){ AVFormatContext *s = ts->stream; uint8_t packet[TS_PACKET_SIZE + AV_INPUT_BUFFER_PADDING_SIZE]; const uint8_t *data; int64_t packet_num; int ret = 0; if (avio_tell(s->pb) != ts->last_pos) { int i; av_log(ts->stream, AV_LOG_TRACE, "Skipping after seek\n"); /* seek detected, flush pes buffer */ for (i = 0; i < NB_PID_MAX; i++) { if (ts->pids[i]) { if (ts->pids[i]->type == MPEGTS_PES) { PESContext *pes = ts->pids[i]->u.pes_filter.opaque; av_buffer_unref(&pes->buffer); pes->data_index = 0; pes->state = MPEGTS_SKIP; /* skip until pes header */ } else if (ts->pids[i]->type == MPEGTS_SECTION) { ts->pids[i]->u.section_filter.last_ver = -1; } ts->pids[i]->last_cc = -1; ts->pids[i]->last_pcr = -1; } } } ts->stop_parse = 0; packet_num = 0; memset(packet + TS_PACKET_SIZE, 0, AV_INPUT_BUFFER_PADDING_SIZE); for (;;) { packet_num++; if (nb_packets != 0 && packet_num >= nb_packets || ts->stop_parse > 1) { ret = AVERROR(EAGAIN); break; } if (ts->stop_parse > 0) break; ret = read_packet(s, packet, ts->raw_packet_size, &data); if (ret != 0) break; ret = handle_packet(ts, data); finished_reading_packet(s, ts->raw_packet_size); if (ret != 0) break; } ts->last_pos = avio_tell(s->pb); return ret;}static int mpegts_probe(AVProbeData *p){ const int size = p->buf_size; int maxscore = 0; int sumscore = 0; int i; int check_count = size / TS_FEC_PACKET_SIZE;#define CHECK_COUNT 10#define CHECK_BLOCK 100 if (!check_count) return 0; for (i = 0; i<check_count; i+=CHECK_BLOCK) { int left = FFMIN(check_count - i, CHECK_BLOCK); int score = analyze(p->buf + TS_PACKET_SIZE *i, TS_PACKET_SIZE *left, TS_PACKET_SIZE , 1); int dvhs_score = analyze(p->buf + TS_DVHS_PACKET_SIZE*i, TS_DVHS_PACKET_SIZE*left, TS_DVHS_PACKET_SIZE, 1); int fec_score = analyze(p->buf + TS_FEC_PACKET_SIZE *i, TS_FEC_PACKET_SIZE *left, TS_FEC_PACKET_SIZE , 1); score = FFMAX3(score, dvhs_score, fec_score); sumscore += score; maxscore = FFMAX(maxscore, score); } sumscore = sumscore * CHECK_COUNT / check_count; maxscore = maxscore * CHECK_COUNT / CHECK_BLOCK; ff_dlog(0, "TS score: %d %d\n", sumscore, maxscore); if (check_count > CHECK_COUNT && sumscore > 6) { return AVPROBE_SCORE_MAX + sumscore - CHECK_COUNT; } else if (check_count >= CHECK_COUNT && sumscore > 6) { return AVPROBE_SCORE_MAX/2 + sumscore - CHECK_COUNT; } else if (check_count >= CHECK_COUNT && maxscore > 6) { return AVPROBE_SCORE_MAX/2 + sumscore - CHECK_COUNT; } else if (sumscore > 6) { return 2; } else { return 0; }}/* return the 90kHz PCR and the extension for the 27MHz PCR. return * (-1) if not available */static int parse_pcr(int64_t *ppcr_high, int *ppcr_low, const uint8_t *packet){ int afc, len, flags; const uint8_t *p; unsigned int v; afc = (packet[3] >> 4) & 3; if (afc <= 1) return AVERROR_INVALIDDATA; p = packet + 4; len = p[0]; p++; if (len == 0) return AVERROR_INVALIDDATA; flags = *p++; len--; if (!(flags & 0x10)) return AVERROR_INVALIDDATA; if (len < 6) return AVERROR_INVALIDDATA; v = AV_RB32(p); *ppcr_high = ((int64_t) v << 1) | (p[4] >> 7); *ppcr_low = ((p[4] & 1) << 8) | p[5]; return 0;}static void seek_back(AVFormatContext *s, AVIOContext *pb, int64_t pos) { /* NOTE: We attempt to seek on non-seekable files as well, as the * probe buffer usually is big enough. Only warn if the seek failed * on files where the seek should work. */ if (avio_seek(pb, pos, SEEK_SET) < 0) av_log(s, pb->seekable ? AV_LOG_ERROR : AV_LOG_INFO, "Unable to seek back to the start\n");}//读取ts文件的头static int mpegts_read_header(AVFormatContext *s){ MpegTSContext *ts = s->priv_data; AVIOContext *pb = s->pb; uint8_t buf[8 * 1024] = {0}; int len; int64_t pos, probesize = s->probesize; if (ffio_ensure_seekback(pb, probesize) < 0) av_log(s, AV_LOG_WARNING, "Failed to allocate buffers for seekback\n"); /* read the first 8192 bytes to get packet size */ pos = avio_tell(pb); len = avio_read(pb, buf, sizeof(buf)); ts->raw_packet_size = get_packet_size(buf, len); if (ts->raw_packet_size <= 0) { av_log(s, AV_LOG_WARNING, "Could not detect TS packet size, defaulting to non-FEC/DVHS\n"); ts->raw_packet_size = TS_PACKET_SIZE; } ts->stream = s; ts->auto_guess = 0; if (s->iformat == &ff_mpegts_demuxer) { /* normal demux */ /* first do a scan to get all the services */ seek_back(s, pb, pos);//打开SDT表的过滤器并设置回调函数 mpegts_open_section_filter(ts, SDT_PID, sdt_cb, ts, 1); mpegts_open_section_filter(ts, PAT_PID, pat_cb, ts, 1);//批量处理数据，内部调用的是handle_packet handle_packets(ts, probesize / ts->raw_packet_size); /* if could not find service, enable auto_guess */ ts->auto_guess = 1; av_log(ts->stream, AV_LOG_TRACE, "tuning done\n"); s->ctx_flags |= AVFMTCTX_NOHEADER; } else { AVStream *st; int pcr_pid, pid, nb_packets, nb_pcrs, ret, pcr_l; int64_t pcrs[2], pcr_h; int packet_count[2]; uint8_t packet[TS_PACKET_SIZE]; const uint8_t *data; /* only read packets */ st = avformat_new_stream(s, NULL); if (!st) return AVERROR(ENOMEM); avpriv_set_pts_info(st, 60, 1, 27000000); st->codecpar->codec_type = AVMEDIA_TYPE_DATA; st->codecpar->codec_id = AV_CODEC_ID_MPEG2TS; /* we iterate until we find two PCRs to estimate the bitrate */ pcr_pid = -1; nb_pcrs = 0; nb_packets = 0; for (;;) { ret = read_packet(s, packet, ts->raw_packet_size, &data); if (ret < 0) return ret; pid = AV_RB16(data + 1) & 0x1fff; if ((pcr_pid == -1 || pcr_pid == pid) && parse_pcr(&pcr_h, &pcr_l, data) == 0) { finished_reading_packet(s, ts->raw_packet_size); pcr_pid = pid; packet_count[nb_pcrs] = nb_packets; pcrs[nb_pcrs] = pcr_h * 300 + pcr_l; nb_pcrs++; if (nb_pcrs >= 2) { if (pcrs[1] - pcrs[0] > 0) { /* the difference needs to be positive to make sense for bitrate computation */ break; } else { av_log(ts->stream, AV_LOG_WARNING, "invalid pcr pair %"PRId64" >= %"PRId64"\n", pcrs[0], pcrs[1]); pcrs[0] = pcrs[1]; packet_count[0] = packet_count[1]; nb_pcrs--; } } } else { finished_reading_packet(s, ts->raw_packet_size); } nb_packets++; } /* NOTE1: the bitrate is computed without the FEC */ /* NOTE2: it is only the bitrate of the start of the stream */ ts->pcr_incr = (pcrs[1] - pcrs[0]) / (packet_count[1] - packet_count[0]); ts->cur_pcr = pcrs[0] - ts->pcr_incr * packet_count[0]; s->bit_rate = TS_PACKET_SIZE * 8 * 27000000LL / ts->pcr_incr; st->codecpar->bit_rate = s->bit_rate; st->start_time = ts->cur_pcr; av_log(ts->stream, AV_LOG_TRACE, "start=%0.3f pcr=%0.3f incr=%d\n", st->start_time / 1000000.0, pcrs[0] / 27e6, ts->pcr_incr); } seek_back(s, pb, pos); return 0;}#define MAX_PACKET_READAHEAD ((128 * 1024) / 188)static int mpegts_raw_read_packet(AVFormatContext *s, AVPacket *pkt){ MpegTSContext *ts = s->priv_data; int ret, i; int64_t pcr_h, next_pcr_h, pos; int pcr_l, next_pcr_l; uint8_t pcr_buf[12]; const uint8_t *data; if (av_new_packet(pkt, TS_PACKET_SIZE) < 0) return AVERROR(ENOMEM); ret = read_packet(s, pkt->data, ts->raw_packet_size, &data); pkt->pos = avio_tell(s->pb); if (ret < 0) { av_packet_unref(pkt); return ret; } if (data != pkt->data) memcpy(pkt->data, data, ts->raw_packet_size); finished_reading_packet(s, ts->raw_packet_size); if (ts->mpeg2ts_compute_pcr) { /* compute exact PCR for each packet */ if (parse_pcr(&pcr_h, &pcr_l, pkt->data) == 0) { /* we read the next PCR (XXX: optimize it by using a bigger buffer */ pos = avio_tell(s->pb); for (i = 0; i < MAX_PACKET_READAHEAD; i++) { avio_seek(s->pb, pos + i * ts->raw_packet_size, SEEK_SET); avio_read(s->pb, pcr_buf, 12); if (parse_pcr(&next_pcr_h, &next_pcr_l, pcr_buf) == 0) { /* XXX: not precise enough */ ts->pcr_incr = ((next_pcr_h - pcr_h) * 300 + (next_pcr_l - pcr_l)) / (i + 1); break; } } avio_seek(s->pb, pos, SEEK_SET); /* no next PCR found: we use previous increment */ ts->cur_pcr = pcr_h * 300 + pcr_l; } pkt->pts = ts->cur_pcr; pkt->duration = ts->pcr_incr; ts->cur_pcr += ts->pcr_incr; } pkt->stream_index = 0; return 0;}static int mpegts_read_packet(AVFormatContext *s, AVPacket *pkt){ MpegTSContext *ts = s->priv_data; int ret, i; pkt->size = -1; ts->pkt = pkt; ret = handle_packets(ts, 0); if (ret < 0) { av_packet_unref(ts->pkt); /* flush pes data left */ for (i = 0; i < NB_PID_MAX; i++) if (ts->pids[i] && ts->pids[i]->type == MPEGTS_PES) { PESContext *pes = ts->pids[i]->u.pes_filter.opaque; if (pes->state == MPEGTS_PAYLOAD && pes->data_index > 0) { ret = new_pes_packet(pes, pkt); if (ret < 0) return ret; pes->state = MPEGTS_SKIP; ret = 0; break; } } } if (!ret && pkt->size < 0) ret = AVERROR_INVALIDDATA; return ret;}static void mpegts_free(MpegTSContext *ts){ int i; clear_programs(ts); for (i = 0; i < NB_PID_MAX; i++) if (ts->pids[i]) mpegts_close_filter(ts, ts->pids[i]);}static int mpegts_read_close(AVFormatContext *s){ MpegTSContext *ts = s->priv_data; mpegts_free(ts); return 0;}static av_unused int64_t mpegts_get_pcr(AVFormatContext *s, int stream_index, int64_t *ppos, int64_t pos_limit){ MpegTSContext *ts = s->priv_data; int64_t pos, timestamp; uint8_t buf[TS_PACKET_SIZE]; int pcr_l, pcr_pid = ((PESContext *)s->streams[stream_index]->priv_data)->pcr_pid; int pos47 = ts->pos47_full % ts->raw_packet_size; pos = ((*ppos + ts->raw_packet_size - 1 - pos47) / ts->raw_packet_size) * ts->raw_packet_size + pos47; while(pos < pos_limit) { if (avio_seek(s->pb, pos, SEEK_SET) < 0) return AV_NOPTS_VALUE; if (avio_read(s->pb, buf, TS_PACKET_SIZE) != TS_PACKET_SIZE) return AV_NOPTS_VALUE; if (buf[0] != 0x47) { if (mpegts_resync(s, TS_PACKET_SIZE, buf) < 0) return AV_NOPTS_VALUE; pos = avio_tell(s->pb); continue; } if ((pcr_pid < 0 || (AV_RB16(buf + 1) & 0x1fff) == pcr_pid) && parse_pcr(×tamp, &pcr_l, buf) == 0) { *ppos = pos; return timestamp; } pos += ts->raw_packet_size; } return AV_NOPTS_VALUE;}static int64_t mpegts_get_dts(AVFormatContext *s, int stream_index, int64_t *ppos, int64_t pos_limit){ MpegTSContext *ts = s->priv_data; int64_t pos; int pos47 = ts->pos47_full % ts->raw_packet_size; pos = ((*ppos + ts->raw_packet_size - 1 - pos47) / ts->raw_packet_size) * ts->raw_packet_size + pos47; ff_read_frame_flush(s); if (avio_seek(s->pb, pos, SEEK_SET) < 0) return AV_NOPTS_VALUE; while(pos < pos_limit) { int ret; AVPacket pkt; av_init_packet(&pkt); ret = av_read_frame(s, &pkt); if (ret < 0) return AV_NOPTS_VALUE; if (pkt.dts != AV_NOPTS_VALUE && pkt.pos >= 0) { ff_reduce_index(s, pkt.stream_index); av_add_index_entry(s->streams[pkt.stream_index], pkt.pos, pkt.dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */); if (pkt.stream_index == stream_index && pkt.pos >= *ppos) { int64_t dts = pkt.dts; *ppos = pkt.pos; av_packet_unref(&pkt); return dts; } } pos = pkt.pos; av_packet_unref(&pkt); } return AV_NOPTS_VALUE;}/**************************************************************//* parsing functions - called from other demuxers such as RTP */MpegTSContext *avpriv_mpegts_parse_open(AVFormatContext *s){ MpegTSContext *ts; ts = av_mallocz(sizeof(MpegTSContext)); if (!ts) return NULL; /* no stream case, currently used by RTP */ ts->raw_packet_size = TS_PACKET_SIZE; ts->stream = s; ts->auto_guess = 1; mpegts_open_section_filter(ts, SDT_PID, sdt_cb, ts, 1); mpegts_open_section_filter(ts, PAT_PID, pat_cb, ts, 1); return ts;}/* return the consumed length if a packet was output, or -1 if no * packet is output */int avpriv_mpegts_parse_packet(MpegTSContext *ts, AVPacket *pkt, const uint8_t *buf, int len){ int len1; len1 = len; ts->pkt = pkt; for (;;) { ts->stop_parse = 0; if (len < TS_PACKET_SIZE) return AVERROR_INVALIDDATA; if (buf[0] != 0x47) { buf++; len--; } else { handle_packet(ts, buf); buf += TS_PACKET_SIZE; len -= TS_PACKET_SIZE; if (ts->stop_parse == 1) break; } } return len1 - len;}void avpriv_mpegts_parse_close(MpegTSContext *ts){ mpegts_free(ts); av_free(ts);}//mpegts解复用器AVInputFormat ff_mpegts_demuxer = { .name = "mpegts", .long_name = NULL_IF_CONFIG_SMALL("MPEG-TS (MPEG-2 Transport Stream)"), .priv_data_size = sizeof(MpegTSContext), .read_probe = mpegts_probe,//检测是否为mpegts格式，mpegts_probe为指针函数 .read_header = mpegts_read_header,//读取mpegts头 .read_packet = mpegts_read_packet,//读取mpegts数据 .read_close = mpegts_read_close, .read_timestamp = mpegts_get_dts,//获取pts .flags = AVFMT_SHOW_IDS | AVFMT_TS_DISCONT, .priv_class = &mpegts_class,};AVInputFormat ff_mpegtsraw_demuxer = { .name = "mpegtsraw", .long_name = NULL_IF_CONFIG_SMALL("raw MPEG-TS (MPEG-2 Transport Stream)"), .priv_data_size = sizeof(MpegTSContext), .read_header = mpegts_read_header, .read_packet = mpegts_raw_read_packet, .read_close = mpegts_read_close, .read_timestamp = mpegts_get_dts, .flags = AVFMT_SHOW_IDS | AVFMT_TS_DISCONT, .priv_class = &mpegtsraw_class,};代码全部都贴过来了，有点多，也有点繁琐，很多觉得不需要说明的就没有说明，如果有错误欢迎指正，如果有不明白的地方，欢迎加群445236076讨论，共同进步
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