迭代的是人，递归的是神Email：[e-mail] 目录视图摘要视图订阅 FFmpeg浅尝辄止（二）——YUV视频序列编码为视频

上一篇已经写了如何配置好开发环境，这次就先小试牛刀，来个视频的编码。搞视频处理的朋友肯定比较熟悉YUV视频序列，很多测试库提供的视频数据都是YUV视频序列，我们这里就用用YUV视频序列来做视频。关于YUV视频序列，我就不多讲了，可以看书学习，通常的视频序列都是YUV420格式的。

步骤也就那几步，添加视频流，打开编码器，开辟相应的内存空间，然后就可以打开YUV序列逐帧写入数据了，so easy！记得最后要做好文件的关闭和内存的释放，因为FFmpeg是c风格的（不知道新版本是否是c++风格的），这些工作都需要自己做好啊。过多的说明是没用的，直接上代码：

这里我补充一下，大多数的视频格式好像只支持YUV格式的视频帧AVFrame，我试图直接把RGB的视频序列直接编码到视频这条路好像走不通，都需要把RGB的视频帧再转成YUV视频帧才行，不知道高手有没有其他高见。

#include <stdio.h>#include <string.h>extern "C"{#include <libavcodec\avcodec.h>#include <libavformat\avformat.h>#include <libswscale\swscale.h>};void main(int argc, char ** argv){AVFormatContext* oc;AVOutputFormat* fmt;AVStream* video_st;double video_pts;uint8_t* video_outbuf;uint8_t* picture_buf;AVFrame* picture;// AVFrame* pictureRGB;int size;int ret;int video_outbuf_size;FILE *fin = fopen("akiyo_qcif.yuv", "rb"); //视频源文件 const char* filename = "test.mpg";// const char* filename;// filename = argv[1];av_register_all();// avcodec_init(); // 初始化codec库// avcodec_register_all(); // 注册编码器fmt = guess_format(NULL, filename, NULL);oc = av_alloc_format_context();oc->oformat = fmt;snprintf(oc->filename, sizeof(oc->filename), "%s", filename);video_st = NULL;if (fmt->video_codec != CODEC_ID_NONE){AVCodecContext* c;video_st = av_new_stream(oc, 0);c = video_st->codec;c->codec_id = fmt->video_codec;c->codec_type = CODEC_TYPE_VIDEO;c->bit_rate = 400000;c->width = 176;c->height = 144;c->time_base.num = 1;c->time_base.den = 25; c->gop_size = 12;c->pix_fmt = PIX_FMT_YUV420P;if (c->codec_id == CODEC_ID_MPEG2VIDEO){c->max_b_frames = 2;}if (c->codec_id == CODEC_ID_MPEG1VIDEO){c->mb_decision = 2;}if (!strcmp(oc->oformat->name, "mp4") || !strcmp(oc->oformat->name, "mov") || !strcmp(oc->oformat->name, "3gp")){c->flags |= CODEC_FLAG_GLOBAL_HEADER;}}if (av_set_parameters(oc, NULL)<0){return;}dump_format(oc, 0, filename, 1);if (video_st){AVCodecContext* c;AVCodec* codec;c = video_st->codec;codec = avcodec_find_encoder(c->codec_id);if (!codec){return;}if (avcodec_open(c, codec) < 0){return;}if (!(oc->oformat->flags & AVFMT_RAWPICTURE)){video_outbuf_size = 200000;video_outbuf = (uint8_t*)av_malloc(video_outbuf_size);}picture = avcodec_alloc_frame();size = avpicture_get_size(c->pix_fmt, c->width, c->height);picture_buf = (uint8_t*)av_malloc(size);if (!picture_buf){av_free(picture);}avpicture_fill((AVPicture*)picture, picture_buf, c->pix_fmt, c->width, c->height);}if (!(fmt->flags & AVFMT_NOFILE)){if (url_fopen(&oc->pb, filename, URL_WRONLY) < 0){return;}}av_write_header(oc);for (int i=0; i<300; i++){if (video_st){video_pts = (double)(video_st->pts.val * video_st->time_base.num / video_st->time_base.den);}else{video_pts = 0.0;}if (!video_st/* || video_pts >= 5.0*/){break;}AVCodecContext* c;c = video_st->codec;size = c->width * c->height;if (fread(picture_buf, 1, size*3/2, fin) < 0){break;}picture->data[0] = picture_buf;  // 亮度picture->data[1] = picture_buf+ size;  // 色度 picture->data[2] = picture_buf+ size*5/4; // 色度 // 如果是rgb序列，可能需要如下代码// SwsContext* img_convert_ctx;// img_convert_ctx = sws_getContext(c->width, c->height, PIX_FMT_RGB24, c->width, c->height, c->pix_fmt, SWS_BICUBIC, NULL, NULL, NULL);// sws_scale(img_convert_ctx, pictureRGB->data, pictureRGB->linesize, 0, c->height, picture->data, picture->linesize);if (oc->oformat->flags & AVFMT_RAWPICTURE){AVPacket pkt;av_init_packet(&pkt);pkt.flags |= PKT_FLAG_KEY;pkt.stream_index = video_st->index;pkt.data = (uint8_t*)picture;pkt.size = sizeof(AVPicture);ret = av_write_frame(oc, &pkt);}else{int out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture);if (out_size > 0){AVPacket pkt;av_init_packet(&pkt);pkt.pts = av_rescale_q(c->coded_frame->pts, c->time_base, video_st->time_base);if (c->coded_frame->key_frame){pkt.flags |= PKT_FLAG_KEY;}pkt.stream_index = video_st->index;pkt.data = video_outbuf;pkt.size = out_size;ret = av_write_frame(oc, &pkt);}}}if (video_st){avcodec_close(video_st->codec);// av_free(picture->data[0]);av_free(picture);av_free(video_outbuf);// av_free(picture_buf);}av_write_trailer(oc);for (int i=0; i<oc->nb_streams; i++){av_freep(&oc->streams[i]->codec);av_freep(&oc->streams[i]);}if (!(fmt->flags & AVFMT_NOFILE)){url_fclose(oc->pb);}av_free(oc);}

对应的工程下载链接：http://download.csdn.net/detail/yang_xian521/4398576，希望你能喜欢。