ffmpeg从AVFrame取出yuv数据到保存到char*中

ffmpeg从AVFrame取出yuv数据到保存到char*中

 

很多人一直不知道怎么利用ffmpeg从AVFrame取出yuv数据到保存到char*中，下面代码将yuv420p和yuv422p的数据取出并保存到char*buf中。

其他格式可以自己去扩展，前提先看戏yuv的各种格式，yuv的各种格式链接：数据格式分析

 

先确保视频格式sws_getContext()转换后是YUV格式：

     out_buffer=(uint8_t *)av_malloc(avpicture_get_size(PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height));//分配AVFrame所需内存
     avpicture_fill((AVPicture *)pFrameYUV, out_buffer, PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height);//填充AVFrame

     img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,
             pCodecCtx->width, pCodecCtx->height, PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);

那么在后续的视频数据处理时，可以把YUV视频格式数据进行存储：

 //如果是视频
 else if (pstream_info[i].dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO)
 {
     int new_videosize = pkt.size;
     int video_decode_size = avpicture_get_size(pstream_info->dec_ctx->pix_fmt, Zoom_Width,Zoom_Height);
     uint8_t * video_decode_buf =( uint8_t *)calloc(,video_decode_size *  * sizeof(char)); //最大分配的空间，能满足yuv的各种格式

     // Decode video frame
     avcodec_decode_video2(pstream_info->dec_ctx, pDecodeFrame, &frameFinished,&pkt);
     if(frameFinished)
     {
         if (pstream_info->dec_ctx->pix_fmt == AV_PIX_FMT_YUV420P) //如果是yuv420p的
         {
             for(i = ; i < pstream_info->dec_ctx->height; i++)
             {
                 memcpy(video_decode_buf+pstream_info->dec_ctx->width*i,
                         pDecodeFrame->data[]+pDecodeFrame->linesize[]*i,
                         pstream_info->dec_ctx->width);
             }
             for(j = ; j < pstream_info->dec_ctx->height/; j++)
             {
                 memcpy(video_decode_buf+pstream_info->dec_ctx->width*i+pstream_info->dec_ctx->width/*j,
                         pDecodeFrame->data[]+pDecodeFrame->linesize[]*j,
                         pstream_info->dec_ctx->width/);
             }
             for(k =; k < pstream_info->dec_ctx->height/; k++)
             {
                 memcpy(video_decode_buf+pstream_info->dec_ctx->width*i+pstream_info->dec_ctx->width/*j+pstream_info->dec_ctx->width/*k,
                         pDecodeFrame->data[]+pDecodeFrame->linesize[]*k,
                         pstream_info->dec_ctx->width/);
             }
         }
         else if (pstream_info->dec_ctx->pix_fmt == AV_PIX_FMT_YUV422P)//如果是yuv422p的
         {
             for(i = ; i < pstream_info->dec_ctx->height; i++)
             {
                 memcpy(video_decode_buf+pstream_info->dec_ctx->width*i,
                     pDecodeFrame->data[]+pDecodeFrame->linesize[]*i,
                     pstream_info->dec_ctx->width);
             }
             for(j = ; j < pstream_info->dec_ctx->height; j++)
             {
                 memcpy(video_decode_buf+pstream_info->dec_ctx->width*i+pstream_info->dec_ctx->width/*j,
                     pDecodeFrame->data[]+pDecodeFrame->linesize[]*j,
                     pstream_info->dec_ctx->width/);
             }
             for(k =; k < pstream_info->dec_ctx->height; k++)
             {
                 memcpy(video_decode_buf+pstream_info->dec_ctx->width*i+pstream_info->dec_ctx->width/*j+pstream_info->dec_ctx->width/*k,
                     pDecodeFrame->data[]+pDecodeFrame->linesize[]*k,
                     pstream_info->dec_ctx->width/);
             }
         }
         else
         {
             //可扩展
         }
         video_decode_size = avpicture_get_size(pstream_info->dec_ctx->pix_fmt, pstream_info->dec_ctx->width,pstream_info->dec_ctx->height);
         new_videosize = video_decode_size;

         //缩放或格式转换
         if (pstream_info->dec_ctx->width != Zoom_Width ||
             pstream_info->dec_ctx->height != Zoom_Height ||
             pstream_info->dec_ctx->pix_fmt != Zoom_pix_fmt)
         {
             new_videosize = VideoScaleYuvZoom(Is_flip,pstream_info->dec_ctx->width ,pstream_info->dec_ctx->height,(int)pstream_info->dec_ctx->pix_fmt,
             Zoom_Width,Zoom_Height,Zoom_pix_fmt,video_decode_buf);
         }
         //这里可以取出数据
         frame_info->stream_idx = pstream_info->stream_idx;
         //frame_info->pts = pDecodeFrame->pkt_pts * 1000 * av_q2d(pstream_info->stream->time_base); //转化成毫秒
         frame_info->pts = pDecodeFrame->pkt_pts;
         frame_info->timebase_den = pstream_info->stream->time_base.den;
         frame_info->timebase_num = pstream_info->stream->time_base.num;
         frame_info->bufsize = new_videosize;
         memcpy(frame_info->buf,video_decode_buf,new_videosize);
     }
     else
     {
         //缓存
         frame_info->stream_idx = pstream_info->stream_idx;
         frame_info->pts = ;
         frame_info->timebase_den = ;
         frame_info->timebase_num = ;
         frame_info->bufsize = ;
         memset(frame_info->buf,,MAX_FRAME_SIZE);
     }
     if (video_decode_buf)
     {
         free(video_decode_buf);
         video_decode_buf = NULL;
     }
     video_decode_size = ;
 }

也可以把YUV数据进行存储为PPM格式(Linux系统下的图片格式)：

 //如果是视频
 else if (pstream_info[i].dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO)
 {
     // Decode video frame
     avcodec_decode_video2(pstream_info->dec_ctx, pDecodeFrame, &frameFinished,&pkt);
     if(frameFinished)
     {
         sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, , pCodecCtx->height, pFrameYUV->data, pFrameYUV->linesize);
         if((++k<=) && (k%==)) {
             SaveFrame(pFrameYUV, pCodecCtx->width, pCodecCtx->height, k);
         }
     }
 }

 void SaveFrame(AVFrame *pFrame, int width, int height, int iFrame)
 {
     FILE *pFile;
     char szFilename[];
     int  y;

     SDL_Log("%d * %d", width, height);
     // Open file
     sprintf(szFilename, "frame/frame%d.ppm", iFrame);
     pFile=fopen(szFilename, "wb");
     if(pFile==NULL)
     return;

     // Write header
     fprintf(pFile, "P6\n%d %d\n255\n", width, height);

     // Write pixel data
     for(y=; y<height; y++) {
         fwrite(pFrame->data[]+y*pFrame->linesize[], , width*, pFile);
     }

     // Close file
     fclose(pFile);
 }