jpg2avframe

https://stackoverflow.com/questions/3527584/ffmpeg-jpeg-file-to-avframe

  

   

    

     

    
    

     

      AVFrame* OpenImage(const char* imageFileName)
     
    
   

    

     

    
    

     

      {
     
    
   

    

     

    
    

     

       AVFormatContext *pFormatCtx;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 if(av_open_input_file(&pFormatCtx, imageFileName, NULL, 0, NULL)!=0)
     
    
   

    

     

    
    

     

       {
     
    
   

    

     

    
    

     
 printf("Can't open image file '%s'\n", imageFileName);
     
    
   

    

     

    
    

     
 return NULL;
     
    
   

    

     

    
    

     

       } 
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

       dump_format(pFormatCtx, 0, imageFileName, false);
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

       AVCodecContext *pCodecCtx;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

       pCodecCtx = pFormatCtx->streams[0]->codec;
     
    
   

    

     

    
    

     

       pCodecCtx->width = W_VIDEO;
     
    
   

    

     

    
    

     

       pCodecCtx->height = H_VIDEO;
     
    
   

    

     

    
    

     

       pCodecCtx->pix_fmt = PIX_FMT_YUV420P;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 // Find the decoder for the video stream
     
    
   

    

     

    
    

     

       AVCodec *pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
     
    
   

    

     

    
    

     
 if (!pCodec)
     
    
   

    

     

    
    

     

       {
     
    
   

    

     

    
    

     
 printf("Codec not found\n");
     
    
   

    

     

    
    

     
 return NULL;
     
    
   

    

     

    
    

     

       }
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 // Open codec
     
    
   

    

     

    
    

     
 if(avcodec_open(pCodecCtx, pCodec)<0)
     
    
   

    

     

    
    

     

       {
     
    
   

    

     

    
    

     
 printf("Could not open codec\n");
     
    
   

    

     

    
    

     
 return NULL;
     
    
   

    

     

    
    

     

       }
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 // 
     
    
   

    

     

    
    

     

       AVFrame *pFrame;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

       pFrame = avcodec_alloc_frame();
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 if (!pFrame)
     
    
   

    

     

    
    

     

       {
     
    
   

    

     

    
    

     
 printf("Can't allocate memory for AVFrame\n");
     
    
   

    

     

    
    

     
 return NULL;
     
    
   

    

     

    
    

     

       }
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 int frameFinished;
     
    
   

    

     

    
    

     
 int numBytes;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 // Determine required buffer size and allocate buffer
     
    
   

    

     

    
    

     

       numBytes = avpicture_get_size(PIX_FMT_YUVJ420P, pCodecCtx->width, pCodecCtx->height);
     
    
   

    

     

    
    

     
 uint8_t *buffer = (uint8_t *) av_malloc(numBytes * sizeof(uint8_t));
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

       avpicture_fill((AVPicture *) pFrame, buffer, PIX_FMT_YUVJ420P, pCodecCtx->width, pCodecCtx->height);
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 // Read frame
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

       AVPacket packet;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 int framesNumber = 0;
     
    
   

    

     

    
    

     
 while (av_read_frame(pFormatCtx, &packet) >= 0)
     
    
   

    

     

    
    

     

       {
     
    
   

    

     

    
    

     
 if(packet.stream_index != 0)
     
    
   

    

     

    
    

     
 continue;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 int ret = avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);
     
    
   

    

     

    
    

     
 if (ret > 0)
     
    
   

    

     

    
    

     

       {
     
    
   

    

     

    
    

     
 printf("Frame is decoded, size %d\n", ret);
     
    
   

    

     

    
    

     

       pFrame->quality = 4;
     
    
   

    

     

    
    

     
 return pFrame;
     
    
   

    

     

    
    

     

       }
     
    
   

    

     

    
    

     
 else
     
    
   

    

     

    
    

     
 printf("Error [%d] while decoding frame: %s\n", ret, strerror(AVERROR(ret)));
     
    
   

    

     

    
    

     

       }
     
    
   

    

     

    
    

     

      }
     
    
  
 

文章来源: blog.csdn.net，作者：网奇，版权归原作者所有，如需转载，请联系作者。

原文链接：blog.csdn.net/jacke121/article/details/87276790