avformat_find_stream_info
来源：互联网 发布：在线模拟装机软件 编辑：程序博客网 时间：2024/06/06 17:32
视频解码为H264时的跟踪:
1. for(;;)中count执行了206次才退出
2. 第206次退出的地方:
if (st->time_base.den > 0 && av_rescale_q(codec_info_duration[st->index], st->time_base, AV_TIME_BASE_Q) >= ic->max_analyze_duration)
break;
满足了av_rescale_q(codec_info_duration[st->index], st->time_base, AV_TIME_BASE_Q) >= ic->max_analyze_duration导致退出
av_rescale_q(codec_info_duration[st->index], st->time_base, AV_TIME_BASE_Q) >= ic->max_analyze_duration还得研究?
3. 设置数据断点发现st->codec->pix_fmt设置为PIX_FMT_YUV420P的地方:
函数堆栈try_decode_frame()->avcodec_open()->avctx->codec->init()->H264.c中的decode_init()下的
avctx->pix_fmt= avctx->get_format(avctx, avctx->codec->pix_fmts);
4.当前流退出av_find_stream_info的判断不仅是has_codec_parameters:
if (!has_codec_parameters(st->codec))
break;
if( tb_unreliable(st->codec)
&& duration_count[i]<20 && st->codec->codec_type == CODEC_TYPE_VIDEO)
break;
if(st->parser && st->parser->parser->split && !st->codec->extradata)
break;
if(st->first_dts == AV_NOPTS_VALUE)
break;
int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options){//avformat_find_stream_info int i, count, ret = 0, j; int64_t read_size; AVStream *st; AVPacket pkt1, *pkt; int64_t old_offset = avio_tell(ic->pb); // new streams might appear, no options for those int orig_nb_streams = ic->nb_streams; int flush_codecs = ic->probesize > 0; int64_t max_analyze_duration = ic->max_analyze_duration2; if (!max_analyze_duration) max_analyze_duration = ic->max_analyze_duration; av_opt_set(ic, "skip_clear", "1", AV_OPT_SEARCH_CHILDREN); if (!max_analyze_duration) { if (!strcmp(ic->iformat->name, "flv") && !(ic->ctx_flags & AVFMTCTX_NOHEADER)) { max_analyze_duration = 10*AV_TIME_BASE; } else max_analyze_duration = 5*AV_TIME_BASE; } if (ic->pb) av_log(ic, AV_LOG_DEBUG, "Before avformat_find_stream_info() pos: %"PRId64" bytes read:%"PRId64" seeks:%d\n", avio_tell(ic->pb), ic->pb->bytes_read, ic->pb->seek_count); for (i = 0; i < ic->nb_streams; i++) { const AVCodec *codec; AVDictionary *thread_opt = NULL; st = ic->streams[i]; if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO || st->codec->codec_type == AVMEDIA_TYPE_SUBTITLE) {/* if (!st->time_base.num) st->time_base = */ if (!st->codec->time_base.num) st->codec->time_base = st->time_base; } // only for the split stuff if (!st->parser && !(ic->flags & AVFMT_FLAG_NOPARSE)) { st->parser = av_parser_init(st->codec->codec_id); if (st->parser) { if (st->need_parsing == AVSTREAM_PARSE_HEADERS) { st->parser->flags |= PARSER_FLAG_COMPLETE_FRAMES; } else if (st->need_parsing == AVSTREAM_PARSE_FULL_RAW) { st->parser->flags |= PARSER_FLAG_USE_CODEC_TS; } } else if (st->need_parsing) { av_log(ic, AV_LOG_VERBOSE, "parser not found for codec " "%s, packets or times may be invalid.\n", avcodec_get_name(st->codec->codec_id)); } } codec = find_decoder(ic, st, st->codec->codec_id); /* Force thread count to 1 since the H.264 decoder will not extract * SPS and PPS to extradata during multi-threaded decoding. */ av_dict_set(options ? &options[i] : &thread_opt, "threads", "1", 0); /* Ensure that subtitle_header is properly set. */ if (st->codec->codec_type == AVMEDIA_TYPE_SUBTITLE && codec && !st->codec->codec) { if (avcodec_open2(st->codec, codec, options ? &options[i] : &thread_opt) < 0) av_log(ic, AV_LOG_WARNING, "Failed to open codec in av_find_stream_info\n"); } // Try to just open decoders, in case this is enough to get parameters. if (!has_codec_parameters(st, NULL) && st->request_probe <= 0) { if (codec && !st->codec->codec) if (avcodec_open2(st->codec, codec, options ? &options[i] : &thread_opt) < 0) av_log(ic, AV_LOG_WARNING, "Failed to open codec in av_find_stream_info\n"); } if (!options) av_dict_free(&thread_opt); } for (i = 0; i < ic->nb_streams; i++) {#if FF_API_R_FRAME_RATE ic->streams[i]->info->last_dts = AV_NOPTS_VALUE;#endif ic->streams[i]->info->fps_first_dts = AV_NOPTS_VALUE; ic->streams[i]->info->fps_last_dts = AV_NOPTS_VALUE; } count = 0; read_size = 0; for (;;) { if (ff_check_interrupt(&ic->interrupt_callback)) { ret = AVERROR_EXIT; av_log(ic, AV_LOG_DEBUG, "interrupted\n"); break; } /* check if one codec still needs to be handled */ for (i = 0; i < ic->nb_streams; i++) { int fps_analyze_framecount = 20; st = ic->streams[i]; if (!has_codec_parameters(st, NULL)) break; /* If the timebase is coarse (like the usual millisecond precision * of mkv), we need to analyze more frames to reliably arrive at * the correct fps. */ if (av_q2d(st->time_base) > 0.0005) fps_analyze_framecount *= 2; if (!tb_unreliable(st->codec)) fps_analyze_framecount = 0; if (ic->fps_probe_size >= 0) fps_analyze_framecount = ic->fps_probe_size; if (st->disposition & AV_DISPOSITION_ATTACHED_PIC) fps_analyze_framecount = 0; /* variable fps and no guess at the real fps */ if (!(st->r_frame_rate.num && st->avg_frame_rate.num) && st->info->duration_count < fps_analyze_framecount && st->codec->codec_type == AVMEDIA_TYPE_VIDEO) break; if (st->parser && st->parser->parser->split && !st->codec->extradata) break; if (st->first_dts == AV_NOPTS_VALUE && !(ic->iformat->flags & AVFMT_NOTIMESTAMPS) && (st->codec->codec_type == AVMEDIA_TYPE_VIDEO || st->codec->codec_type == AVMEDIA_TYPE_AUDIO)) break; } if (i == ic->nb_streams) { /* NOTE: If the format has no header, then we need to read some * packets to get most of the streams, so we cannot stop here. */ if (!(ic->ctx_flags & AVFMTCTX_NOHEADER)) { /* If we found the info for all the codecs, we can stop. */ ret = count; av_log(ic, AV_LOG_DEBUG, "All info found\n"); flush_codecs = 0; break; } } /* We did not get all the codec info, but we read too much data. */ if (read_size >= ic->probesize) { ret = count; av_log(ic, AV_LOG_DEBUG, "Probe buffer size limit of %d bytes reached\n", ic->probesize); for (i = 0; i < ic->nb_streams; i++) if (!ic->streams[i]->r_frame_rate.num && ic->streams[i]->info->duration_count <= 1 && ic->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO && strcmp(ic->iformat->name, "image2")) av_log(ic, AV_LOG_WARNING, "Stream #%d: not enough frames to estimate rate; " "consider increasing probesize\n", i); break; } /* NOTE: A new stream can be added there if no header in file * (AVFMTCTX_NOHEADER). */ ret = read_frame_internal(ic, &pkt1); if (ret == AVERROR(EAGAIN)) continue; if (ret < 0) { /* EOF or error*/ break; } if (ic->flags & AVFMT_FLAG_NOBUFFER) free_packet_buffer(&ic->packet_buffer, &ic->packet_buffer_end); { pkt = add_to_pktbuf(&ic->packet_buffer, &pkt1, &ic->packet_buffer_end); if (!pkt) { ret = AVERROR(ENOMEM); goto find_stream_info_err; } if ((ret = av_dup_packet(pkt)) < 0) goto find_stream_info_err; } st = ic->streams[pkt->stream_index]; if (!(st->disposition & AV_DISPOSITION_ATTACHED_PIC)) read_size += pkt->size; if (pkt->dts != AV_NOPTS_VALUE && st->codec_info_nb_frames > 1) { /* check for non-increasing dts */ if (st->info->fps_last_dts != AV_NOPTS_VALUE && st->info->fps_last_dts >= pkt->dts) { av_log(ic, AV_LOG_DEBUG, "Non-increasing DTS in stream %d: packet %d with DTS " "%"PRId64", packet %d with DTS %"PRId64"\n", st->index, st->info->fps_last_dts_idx, st->info->fps_last_dts, st->codec_info_nb_frames, pkt->dts); st->info->fps_first_dts = st->info->fps_last_dts = AV_NOPTS_VALUE; } /* Check for a discontinuity in dts. If the difference in dts * is more than 1000 times the average packet duration in the * sequence, we treat it as a discontinuity. */ if (st->info->fps_last_dts != AV_NOPTS_VALUE && st->info->fps_last_dts_idx > st->info->fps_first_dts_idx && (pkt->dts - st->info->fps_last_dts) / 1000 > (st->info->fps_last_dts - st->info->fps_first_dts) / (st->info->fps_last_dts_idx - st->info->fps_first_dts_idx)) { av_log(ic, AV_LOG_WARNING, "DTS discontinuity in stream %d: packet %d with DTS " "%"PRId64", packet %d with DTS %"PRId64"\n", st->index, st->info->fps_last_dts_idx, st->info->fps_last_dts, st->codec_info_nb_frames, pkt->dts); st->info->fps_first_dts = st->info->fps_last_dts = AV_NOPTS_VALUE; } /* update stored dts values */ if (st->info->fps_first_dts == AV_NOPTS_VALUE) { st->info->fps_first_dts = pkt->dts; st->info->fps_first_dts_idx = st->codec_info_nb_frames; } st->info->fps_last_dts = pkt->dts; st->info->fps_last_dts_idx = st->codec_info_nb_frames; } if (st->codec_info_nb_frames>1) { int64_t t = 0; if (st->time_base.den > 0) t = av_rescale_q(st->info->codec_info_duration, st->time_base, AV_TIME_BASE_Q); if (st->avg_frame_rate.num > 0) t = FFMAX(t, av_rescale_q(st->codec_info_nb_frames, av_inv_q(st->avg_frame_rate), AV_TIME_BASE_Q)); if ( t == 0 && st->codec_info_nb_frames>30 && st->info->fps_first_dts != AV_NOPTS_VALUE && st->info->fps_last_dts != AV_NOPTS_VALUE) t = FFMAX(t, av_rescale_q(st->info->fps_last_dts - st->info->fps_first_dts, st->time_base, AV_TIME_BASE_Q)); if (t >= max_analyze_duration) { av_log(ic, AV_LOG_VERBOSE, "max_analyze_duration %"PRId64" reached at %"PRId64" microseconds\n", max_analyze_duration, t); break; } if (pkt->duration) { st->info->codec_info_duration += pkt->duration; st->info->codec_info_duration_fields += st->parser && st->need_parsing && st->codec->ticks_per_frame ==2 ? st->parser->repeat_pict + 1 : 2; } }#if FF_API_R_FRAME_RATE if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) ff_rfps_add_frame(ic, st, pkt->dts);#endif if (st->parser && st->parser->parser->split && !st->codec->extradata) { int i = st->parser->parser->split(st->codec, pkt->data, pkt->size); if (i > 0 && i < FF_MAX_EXTRADATA_SIZE) { if (ff_alloc_extradata(st->codec, i)) return AVERROR(ENOMEM); memcpy(st->codec->extradata, pkt->data, st->codec->extradata_size); } } /* If still no information, we try to open the codec and to * decompress the frame. We try to avoid that in most cases as * it takes longer and uses more memory. For MPEG-4, we need to * decompress for QuickTime. * * If CODEC_CAP_CHANNEL_CONF is set this will force decoding of at * least one frame of codec data, this makes sure the codec initializes * the channel configuration and does not only trust the values from * the container. */ try_decode_frame(ic, st, pkt, (options && i < orig_nb_streams) ? &options[i] : NULL); st->codec_info_nb_frames++; count++; } if (flush_codecs) { AVPacket empty_pkt = { 0 }; int err = 0; av_init_packet(&empty_pkt); for (i = 0; i < ic->nb_streams; i++) { st = ic->streams[i]; /* flush the decoders */ if (st->info->found_decoder == 1) { do { err = try_decode_frame(ic, st, &empty_pkt, (options && i < orig_nb_streams) ? &options[i] : NULL); } while (err > 0 && !has_codec_parameters(st, NULL)); if (err < 0) { av_log(ic, AV_LOG_INFO, "decoding for stream %d failed\n", st->index); } } } } av_opt_set(ic, "skip_clear", "0", AV_OPT_SEARCH_CHILDREN); // close codecs which were opened in try_decode_frame() for (i = 0; i < ic->nb_streams; i++) { st = ic->streams[i]; avcodec_close(st->codec); } ff_rfps_calculate(ic); for (i = 0; i < ic->nb_streams; i++) { st = ic->streams[i]; if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) { if (st->codec->codec_id == AV_CODEC_ID_RAWVIDEO && !st->codec->codec_tag && !st->codec->bits_per_coded_sample) { uint32_t tag= avcodec_pix_fmt_to_codec_tag(st->codec->pix_fmt); if (avpriv_find_pix_fmt(ff_raw_pix_fmt_tags, tag) == st->codec->pix_fmt) st->codec->codec_tag= tag; } /* estimate average framerate if not set by demuxer */ if (st->info->codec_info_duration_fields && !st->avg_frame_rate.num && st->info->codec_info_duration) { int best_fps = 0; double best_error = 0.01; if (st->info->codec_info_duration >= INT64_MAX / st->time_base.num / 2|| st->info->codec_info_duration_fields >= INT64_MAX / st->time_base.den || st->info->codec_info_duration < 0) continue; av_reduce(&st->avg_frame_rate.num, &st->avg_frame_rate.den, st->info->codec_info_duration_fields * (int64_t) st->time_base.den, st->info->codec_info_duration * 2 * (int64_t) st->time_base.num, 60000); /* Round guessed framerate to a "standard" framerate if it's * within 1% of the original estimate. */ for (j = 0; j < MAX_STD_TIMEBASES; j++) { AVRational std_fps = { get_std_framerate(j), 12 * 1001 }; double error = fabs(av_q2d(st->avg_frame_rate) / av_q2d(std_fps) - 1); if (error < best_error) { best_error = error; best_fps = std_fps.num; } } if (best_fps) av_reduce(&st->avg_frame_rate.num, &st->avg_frame_rate.den, best_fps, 12 * 1001, INT_MAX); } if (!st->r_frame_rate.num) { if ( st->codec->time_base.den * (int64_t) st->time_base.num <= st->codec->time_base.num * st->codec->ticks_per_frame * (int64_t) st->time_base.den) { st->r_frame_rate.num = st->codec->time_base.den; st->r_frame_rate.den = st->codec->time_base.num * st->codec->ticks_per_frame; } else { st->r_frame_rate.num = st->time_base.den; st->r_frame_rate.den = st->time_base.num; } } } else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) { if (!st->codec->bits_per_coded_sample) st->codec->bits_per_coded_sample = av_get_bits_per_sample(st->codec->codec_id); // set stream disposition based on audio service type switch (st->codec->audio_service_type) { case AV_AUDIO_SERVICE_TYPE_EFFECTS: st->disposition = AV_DISPOSITION_CLEAN_EFFECTS; break; case AV_AUDIO_SERVICE_TYPE_VISUALLY_IMPAIRED: st->disposition = AV_DISPOSITION_VISUAL_IMPAIRED; break; case AV_AUDIO_SERVICE_TYPE_HEARING_IMPAIRED: st->disposition = AV_DISPOSITION_HEARING_IMPAIRED; break; case AV_AUDIO_SERVICE_TYPE_COMMENTARY: st->disposition = AV_DISPOSITION_COMMENT; break; case AV_AUDIO_SERVICE_TYPE_KARAOKE: st->disposition = AV_DISPOSITION_KARAOKE; break; } } } if (ic->probesize) estimate_timings(ic, old_offset); if (ret >= 0 && ic->nb_streams) /* We could not have all the codec parameters before EOF. */ ret = -1; for (i = 0; i < ic->nb_streams; i++) { const char *errmsg; st = ic->streams[i]; if (!has_codec_parameters(st, &errmsg)) { char buf[256]; avcodec_string(buf, sizeof(buf), st->codec, 0); av_log(ic, AV_LOG_WARNING, "Could not find codec parameters for stream %d (%s): %s\n" "Consider increasing the value for the 'analyzeduration' and 'probesize' options\n", i, buf, errmsg); } else { ret = 0; } } compute_chapters_end(ic);find_stream_info_err: for (i = 0; i < ic->nb_streams; i++) { st = ic->streams[i]; if (ic->streams[i]->codec->codec_type != AVMEDIA_TYPE_AUDIO) ic->streams[i]->codec->thread_count = 0; if (st->info) av_freep(&st->info->duration_error); av_freep(&ic->streams[i]->info); } if (ic->pb) av_log(ic, AV_LOG_DEBUG, "After avformat_find_stream_info() pos: %"PRId64" bytes read:%"PRId64" seeks:%d frames:%d\n", avio_tell(ic->pb), ic->pb->bytes_read, ic->pb->seek_count, count); return ret;} 0 0
- avformat_find_stream_info
- avformat_find_stream_info 崩溃
- avformat_find_stream_info分析
- avformat_find_stream_info函数卡住问题
- avformat_find_stream_info接口延迟降低
- FFMPEG avformat_find_stream_info替换
- FFMEPG函数avformat_find_stream_info作用
- FFmpeg源代码简单分析：avformat_find_stream_info()
- FFmpeg函数简单分析：avformat_find_stream_info()
- 解决 ffmpeg 在avformat_find_stream_info执行时间太长
- ffmpeg源码跟踪笔记之avformat_find_stream_info
- 解决 ffmpeg 在avformat_find_stream_info执行时间太长
- ffmpeg学习七：avformat_find_stream_info函数源码分析
- 针对ffmpeg做rtsp客户端时，avformat_find_stream_info长时间等待问题
- 图解FFMPEG打开媒体的函数avformat_open_input&avformat_find_stream_info
- VLC优化（1） avformat_find_stream_info接口延迟降低
- VLC初始加载优化：avformat_find_stream_info接口延迟降低
- ffmpeg源码分析--8.avformat_find_stream_info及一些参数的确定
- 替换xml中的非法字符及不可见字符
- linux中强大的screen命令
- 用Python生成不依赖dll的exe的操作步骤简介
- 花生壳与MDaemon架设邮件服务器案例图文教程
- 《编程珠玑》阅读小记（11） — 堆
- avformat_find_stream_info
- git服务器的建立和简单使用(ubuntu)
- MVC视图中@Html.DisplayFor 控件 日期的显示格式
- CentOS下yum安装mysql,jdk以及tomcat
- SD--如何在输出控制中增加自定义字段
- 第十二章，菜单小demo（Android）
- OJ积累--对象数组输入与输出
- npm install mongoose 无响应
- 简单数据结构之队列(C++模板库实现)
