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。
[cpp] view plain copy #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); }
原文地址：http://blog.csdn.net/yang_xian521/article/details/7698742
转载于:https://www.cnblogs.com/leixiaohua1020/p/3902193.html
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