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• Encoded images into H264 video are skipped and/or missing ?

  25 juillet 2013, par Jona

  I'm trying to encode images into an H264 MP4 video. The issues I'm having is that some of the images are skipped or at the end of the video simply missing. I need the video to play every single image I encode since it is an animation.

  Any help setting the encoder properly would be greatly appreciated !

  Encoder settings :

  AVCodecContext *c;
  
  ...
  
  c->codec_id = AV_CODEC_ID_H264;
  
  c->bit_rate = mOutputWidth*mOutputHeight*4;//400000;
  
  /* Resolution must be a multiple of two. */
  
  c->width    = mOutputWidth;
  
  c->height   = mOutputHeight;
  
      /* timebase: This is the fundamental unit of time (in seconds) in terms
  
       * of which frame timestamps are represented. For fixed-fps content,
  
       * timebase should be 1/framerate and timestamp increments should be
  
       * identical to 1. */
  
  c->time_base.den = mFps;
  
  c->time_base.num = 1;
  
  c->gop_size      = 12; /* emit one intra frame every twelve frames at most */
  
  c->pix_fmt       = AV_PIX_FMT_YUV420P;
  
  ...
  
  av_dict_set(&pOptions, "preset", "medium", 0);
  
  av_dict_set(&pOptions, "tune", "animation", 0);
  
  
  
  /* open the codec */
  
  ret = avcodec_open2(c, codec, &pOptions);
  
  if (ret < 0) {
  
      LOGE("Could not open video codec: %s", av_err2str(ret));
  
      return -1;
  
  }

  Update 07/24/13 :
  I was able to achieve a better video by setting the gop_size=FPS and writing the last video frame repeatedly FPS+1 times seemed to resolve all issues. To me it seems odd to do that but might be something standard in the video encoding world ? Any tips feedback about this ?

• Encode images to video by using ffmpeg API？

  18 avril 2013, par Super Astro

  I want to encode some image files into one video file, and play each image for 1 second.

  So I wrote a simple function to encode only one image to a video

      void PhotoStory::test(char* imagefile,char* videoFile)
  
  {
  
      av_register_all();
  
      avcodec_register_all();
  
      AVCodecContext          *pOCtx= NULL;
  
      AVCodec                 *pOCodex = NULL;
  
      pOCodex = avcodec_find_encoder(CODEC_ID_MPEG1VIDEO);
  
      pOCtx= avcodec_alloc_context3(pOCodex);
  
  
  
      pOCtx->bit_rate = 400000;
  
      pOCtx->width = 640;
  
      pOCtx->height = 480;
  
      AVRational rational = {1,25};
  
      pOCtx->time_base= rational;
  
      pOCtx->gop_size = 10; /* emit one intra frame every ten frames */
  
      pOCtx->max_b_frames=1;
  
      pOCtx->pix_fmt = PIX_FMT_YUV420P;
  
  
  
  
  
      int ret = avcodec_open2(pOCtx,pOCodex,NULL);
  
      if(ret < 0)
  
      {
  
           return;
  
      }
  
  
  
      AVFormatContext         *pIFormatCtx = NULL;
  
       ret = avformat_open_input(&pIFormatCtx, imagefile, NULL, NULL);
  
      if(ret < 0)
  
      {
  
          //Cant't open jpg file
  
          return;
  
      }
  
      av_dump_format(pIFormatCtx, 0, imagefile, false);
  
  
  
      AVCodecContext          *pICodecCtx;  //output codec context
  
      pICodecCtx = pIFormatCtx->streams[0]->codec;
  
      /*pICodecCtx->width = 640;
  
      pICodecCtx->height = 480;
  
      pICodecCtx->pix_fmt = PIX_FMT_YUV420P;*/
  
  
  
  
  
      AVCodec *pICodec = avcodec_find_decoder(pICodecCtx->codec_id); //output codec
  
       // Open codec
  
      ret = avcodec_open2(pICodecCtx, pICodec,NULL);
  
      if(ret < 0)
  
      {
  
          //Can't find the decoder
  
          return;
  
      }
  
  
  
      AVFrame *pIFrame = avcodec_alloc_frame();
  
      if (!pIFrame)
  
      {
  
          //Can't alloc the input frame
  
          return ;
  
      }
  
  
  
  
  
      int bufSize = avpicture_get_size(PIX_FMT_YUVJ420P, pICodecCtx->width, pICodecCtx->height);
  
      uint8_t *buffer = (uint8_t *) av_malloc(bufSize * sizeof(uint8_t));
  
  
  
      avpicture_fill((AVPicture *) pIFrame, buffer, PIX_FMT_YUVJ420P, pICodecCtx->width, pICodecCtx->height);
  
  
  
      FILE *outputFile;
  
      if(fopen_s(&outputFile,videoFile,"wb") < 0)
  
      {
  
          //TODO open file error
  
      }
  
  
  
      int outbuf_size = 100000;
  
      outbuf = (uint8_t*)malloc(outbuf_size);
  
  
  
  
  
  
  
  
  
      AVPacket packet;
  
      int frameFinished;
  
      int framesNumber = 0;
  
      while (av_read_frame(pIFormatCtx, &packet) >= 0)
  
      {
  
          if(packet.stream_index != 0)
  
              continue;
  
  
  
          ret = avcodec_decode_video2(pICodecCtx, pIFrame, &frameFinished, &packet);
  
          if (ret > 0)
  
          {
  
              pIFrame->quality = 4;
  
  
  
              for(i=0;i<25;i++) {
  
                  fflush(stdout);
  
                  /* encode the image */
  
                  out_size = avcodec_encode_video(pOCtx, outbuf, outbuf_size, pIFrame);
  
                  fwrite(outbuf, 1, out_size, outputFile);
  
              }
  
          }
  
      }
  
  
  
      /* get the delayed frames */
  
      for(; out_size; i++) {
  
          fflush(stdout);
  
          out_size = avcodec_encode_video(pOCtx, outbuf, outbuf_size, NULL);
  
          fwrite(outbuf, 1, out_size, outputFile);
  
      }
  
  
  
      /* add sequence end code to have a real mpeg file */
  
      outbuf[0] = 0x00;
  
      outbuf[1] = 0x00;
  
      outbuf[2] = 0x01;
  
      outbuf[3] = 0xb7;
  
      fwrite(outbuf, 1, 4, outputFile);
  
      fclose(outputFile);
  
      free(outbuf);
  
  
  
      avcodec_close(pOCtx);
  
      av_free(pOCtx);
  
      av_free(pIFrame);
  
  }

  but, the result seems not correct.
  the output file is only 4 bits.

  Anybody can help me to figure out the problem and correct the function ?

  thanks !

• Concat two mp4 files with ffmpeg without losing quality [migrated]

  13 juin 2013, par jenia

  i have now a problem with concatenating of 2 videos using ffmpeg.
  So, i am encoding the source mp4 files to ts with

     ffmpeg -i output1.mp4 -scodec copy -vbsf h264_mp4toannexb i0.ts

  but the file i get looks much worse, then the source file.

  here is the information about both the files

     Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'output1.mp4':
  
     Metadata:
  
     major_brand     : isom
  
     minor_version   : 1
  
     compatible_brands: isom
  
     creation_time   : 2013-06-13 15:40:36
  
     Duration: 00:00:15.72, start: 0.000000, bitrate: 2053 kb/s
  
     Stream #0.0(und): Video: h264 (High), yuv420p, 1280x720, 1931 kb/s, 25 fps, 25 tbr,   12800 tbn, 50 tbc
  
     Stream #0.1(und): Audio: aac, 44100 Hz, stereo, s16, 128 kb/s
  
  
  
    Input #0, mpegts, from 'i0.ts':
  
    Duration: 00:00:15.64, start: 1.400000, bitrate: 1382 kb/s
  
    Program 1 
  
    Metadata:
  
    service_name    : Service01
  
    service_provider: Libav
  
    Stream #0.0[0x100]: Video: mpeg2video (Main), yuv420p, 1280x720 [PAR 1:1 DAR 16:9], 104857 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
  
    Stream #0.1[0x101](und): Audio: mp2, 44100 Hz, stereo, s16, 128 kb/s

  So, how can i solve this problem ?
  Thanks in advance !