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• Encoding with ffmpeg : video quality drops

  21 mai 2014, par Adi Ulici

  I’m trying to encode a set of pictures into a video with ffmpeg. I’m new to this stuff, but I managed to get it work. I have only one problem : the first second or two of video look good but as the time goes the video quality keeps dropping and dropping. At the end (it’s a video of about 16 seconds) the quality is really bad and I can’t understand why.

  I’m using AV_CODEC_ID_MPEG1VIDEO as video codec (frankly, it’s the only one I could make work) and here is a sample of my code :

  c = avcodec_alloc_context3(codec);
  
  if (!c) {
  
      fprintf(stderr, "Could not allocate video codec context\n");
  
      exit(1);
  
  }
  
  
  
  c->bit_rate = 400000;
  
  c->width = width;
  
  c->height = height;
  
  struct AVRational time_base = {1, 25};
  
  c->time_base = time_base;
  
  c->gop_size = 10;
  
  c->max_b_frames = 1;
  
  c->pix_fmt = AV_PIX_FMT_YUV420P;
  
  
  
  if (codec_id == AV_CODEC_ID_H264)
  
      av_opt_set(c->priv_data, "preset", "slow", 0);
  
  
  
  // Open the codec
  
  if (avcodec_open2(c, codec, NULL) < 0) {
  
      fprintf(stderr, "Could not open codec\n");
  
      exit(1);
  
  }
  
  
  
  fopen_s(&f, filename, "wb");
  
  if (!f) {
  
      fprintf(stderr, "Could not open %s\n", filename);
  
      exit(1);
  
  }
  
  
  
  frame = av_frame_alloc();
  
  if (!frame) {
  
      fprintf(stderr, "Could not allocate video frame\n");
  
      exit(1);
  
  }
  
  frame->format = c->pix_fmt;
  
  frame->width  = c->width;
  
  frame->height = c->height;
  
  
  
  ret = av_image_alloc(frame->data, frame->linesize, c->width, c->height,
  
                       c->pix_fmt, 32);
  
  if (ret < 0) {
  
      fprintf(stderr, "Could not allocate raw picture buffer\n");
  
      exit(1);
  
  }
  
  
  
  struct SwsContext *frameConvertContext = sws_getContext(width, height,
  
        PIX_FMT_RGB24,
  
        c->width, c->height,
  
        c->pix_fmt,
  
        SWS_LANCZOS | SWS_ACCURATE_RND, NULL, NULL, NULL);
  
  
  
  for (i = 0; i < framesNr; i++) {
  
      // Read an image
  
      std::stringstream filename;
  
      filename << "input/image-" << (i+1) << ".jpg";
  
      Image* img;
  
      img = Image::fromJpeg((char*) filename.str().c_str());
  
      int srcSliceY[1] = { img->getWidth() * 3 };
  
      const uint8_t* imgbuf[1] = { (uint8_t*) img->getData(sizeof(uint8_t)) };
  
  
  
      av_init_packet(&pkt);
  
      pkt.data = NULL;
  
      pkt.size = 0;
  
  
  
      fflush(stdout);
  
      frameConvertContext = sws_getCachedContext(frameConvertContext, width, height,
  
        PIX_FMT_RGB24,
  
        c->width, c->height,
  
        c->pix_fmt,
  
        SWS_LANCZOS | SWS_ACCURATE_RND, NULL, NULL, NULL);
  
  
  
      sws_scale(frameConvertContext, imgbuf, srcSliceY, 0, img->getHeight(), frame->data, frame->linesize);
  
  
  
      frame->pts = i;
  
  
  
      /* encode the image */
  
      ret = avcodec_encode_video2(c, &pkt, frame, &got_output);
  
      if (ret < 0) {
  
          fprintf(stderr, "Error encoding frame\n");
  
          exit(1);
  
      }
  
  
  
      if (got_output) {
  
          printf(".");
  
          fwrite(pkt.data, 1, pkt.size, f);
  
          av_free_packet(&pkt);
  
      }
  
  
  
      // Free the memory
  
      delete img;
  
  }

  Any tips ? Thanks a lot !

• Which version of FFmpeg.AutoGen should I use ?

  5 décembre 2024, par Leo Pripos Marbun

  I'm trying to use FFMediaToolkit library which uses FFmpeg.AutoGen.
And I encountered an error Invalid data found when processing input when calling ffmpeg.avformat_open_input this line. I tried run in windows & ubuntu using the latest version ffmpeg, it works fine.

  


  But when I run in Nvidia Jetson, it throws error. I tried to figure out the issue and MABYE it is because of the mismatch version of installed ffmpeg and FFmpeg.AutoGen. But somehow, I can't update the ffmpeg in jetson.

  


  Here the libraries inside '/usr/lib/aarch64-linux-gnu` :

  


  libavcodec.so.57
libavcodec.so.57.107.100
libavdevice.so.57
libavdevice.so.57.10.100 
libavfilter.so.6 
libavfilter.so.6.107.100
libavformat.so.57
libavformat.so.57.83.100
libavresample.so.3
libavresample.so.3.7.0
libavutil.so.55
libavutil.so.55.78.10


  


  Anyone know which version of FFmpeg.AutoGen should I use ?
Or as alternative, how to get the latest version of ffmpeg for Nvidia Jetson Nano ?

  


  Thanks,

  


• encode .wav file using ffmpeg in objective c or c

  15 février 2017, par deshu

  I have to encode .wav file and write it into same file,or other file using

  ffmpeg library,here is my code for encoding

  -(void)audioencode:(const char *)fileName
  
  {
  
  
  
      AVFrame *frame;
  
      AVPacket pkt;
  
      int i, j, k, ret, got_output;
  
      int buffer_size;
  
      FILE *f;
  
      uint16_t *samples;
  
  
  
      const char *format_name = "wav", 
  
  
  
  
  
  const char *file_url = "/Users/xxxx/Downloads/simple-drum-beat.wav";
  
  
  
      avcodec_register_all();
  
  
  
      av_register_all();
  
  
  
      AVOutputFormat *format = NULL;
  
  
  
      for (AVOutputFormat *formatIter = av_oformat_next(NULL); formatIter != NULL; formatIter = av_oformat_next(formatIter) 
  
  {
  
          int hasEncoder = NULL != avcodec_find_encoder(formatIter->audio_codec);
  
          if (0 == strcmp(format_name, formatIter->name)) {
  
              format = formatIter;
  
              break;
  
          }
  
      }
  
  
  
  
  
      AVCodec *codec = avcodec_find_encoder(format->audio_codec);
  
  
  
      NSLog(@"tet test tststs");
  
  
  
      AVCodecContext *c;
  
  
  
          c = avcodec_alloc_context3(codec);
  
  
  
          if (!c) {
  
              fprintf(stderr, "Could not allocate audio codec context\n");
  
              exit(1);
  
          }
  
  
  
          c->sample_fmt = AV_SAMPLE_FMT_S16;
  
          if (!check_sample_fmt(codec, c->sample_fmt)) {
  
              fprintf(stderr, "Encoder does not support sample format %s",
  
                      av_get_sample_fmt_name(c->sample_fmt));
  
              exit(1);
  
          }
  
      c->bit_rate = 64000;//705600;
  
     c->sample_rate    = select_sample_rate(codec);
  
      c->channel_layout = select_channel_layout(codec);
  
      c->channels       = av_get_channel_layout_nb_channels(c->channel_layout);
  
      c->frame_size = av_get_audio_frame_duration(c, 16);
  
  
  
      int bits_per_sample = av_get_bits_per_sample(c->codec_id);
  
  
  
  
  
      int frameSize   = av_get_audio_frame_duration(c,16);
  
  
  
          /* open it */
  
          if (avcodec_open2(c, codec, NULL) < 0) {
  
              fprintf(stderr, "Could not open codec\n");
  
              exit(1);
  
          }
  
  
  
          f = fopen(fileName, "wb");
  
          if (!f) {
  
              fprintf(stderr, "Could not open %s\n", fileName);
  
              exit(1);
  
          }
  
  
  
          /* frame containing input raw audio */
  
          frame = av_frame_alloc();
  
          if (!frame) {
  
              fprintf(stderr, "Could not allocate audio frame\n");
  
              exit(1);
  
          }
  
  
  
          frame->nb_samples     = frameSize/*c->frame_size*/;
  
          frame->format         = c->sample_fmt;
  
          frame->channel_layout = c->channel_layout;
  
  
  
          buffer_size = av_samples_get_buffer_size(NULL, c->channels,frameSize /*c->frame_size*/,
  
                                                   c->sample_fmt, 0);
  
          samples = av_malloc(buffer_size);
  
          if (!samples) {
  
              fprintf(stderr, "Could not allocate %d bytes for samples buffer\n",
  
                      buffer_size);
  
              exit(1);
  
          }
  
  
  
          /* setup the data pointers in the AVFrame */
  
          ret = avcodec_fill_audio_frame(frame, c->channels, c->sample_fmt,
  
                                         (const uint8_t*)samples, buffer_size, 0);
  
          if (ret < 0) {
  
              fprintf(stderr, "Could not setup audio frame\n");
  
              exit(1);
  
          }
  
  
  
      float t, tincr;
  
          /* encode a single tone sound */
  
          t = 0;
  
          tincr = 2 * M_PI * 440.0 / c->sample_rate;
  
          for(i=0;i<800;i++) {
  
              av_init_packet(&pkt);
  
              pkt.data = NULL; // packet data will be allocated by the encoder
  
              pkt.size = 0;
  
  
  
              for (j = 0; j < frameSize/*c->frame_size*/; j++) {
  
                  samples[2*j] = (int)(sin(t) * 10000);
  
  
  
                  for (k = 1; k < c->channels; k++)
  
                      samples[2*j + k] = samples[2*j];
  
                  t += tincr;
  
              }
  
              /* encode the samples */
  
              ret = avcodec_encode_audio2(c, &pkt, frame, &got_output);
  
              if (ret < 0) {
  
                  fprintf(stderr, "Error encoding audio frame\n");
  
                  exit(1);
  
              }
  
              if (got_output) {
  
                  fwrite(pkt.data, 1, pkt.size, f);
  
                  av_free_packet(&pkt);
  
              }
  
          }
  
  }

  but after encoded file size is zero,
  Please suggest what m doing wrong,any help will be appreciate, thanks in advance