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• Error in video streaming using libavformat : VBV buffer size not set, muxing may fail

  15 janvier 2014, par Blue Sky

  I stream a video using libavformat as follows :

  static AVStream *add_stream(AVFormatContext *oc, AVCodec **codec,
  
                          enum AVCodecID codec_id)
  
  {
  
  AVCodecContext *c;
  
  AVStream *st;
  
  /* find the encoder */
  
  *codec = avcodec_find_encoder(codec_id);
  
  if (!(*codec)) {
  
      fprintf(stderr, "Could not find encoder for '%s'\n",
  
              avcodec_get_name(codec_id));
  
      exit(1);
  
  }
  
  st = avformat_new_stream(oc, *codec);
  
  if (!st) {
  
      fprintf(stderr, "Could not allocate stream\n");
  
      exit(1);
  
  }
  
  st->id = oc->nb_streams-1;
  
  c = st->codec;
  
  switch ((*codec)->type) {
  
  case AVMEDIA_TYPE_AUDIO:
  
      c->sample_fmt  = (*codec)->sample_fmts ?
  
          (*codec)->sample_fmts[0] : AV_SAMPLE_FMT_FLTP;
  
      c->bit_rate    = 64000;
  
      c->sample_rate = 44100;
  
      c->channels    = 2;
  
      break;
  
  case AVMEDIA_TYPE_VIDEO:
  
      c->codec_id = codec_id;
  
      c->bit_rate = 400000;
  
      /* Resolution must be a multiple of two. */
  
      c->width    = outframe_width;
  
      c->height   = outframe_height;
  
      /* 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 = STREAM_FRAME_RATE;
  
      c->time_base.num = 1;
  
      c->gop_size      = 12; /* emit one intra frame every twelve frames at most */
  
      c->pix_fmt       = STREAM_PIX_FMT;
  
      if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
  
          /* just for testing, we also add B frames */
  
          c->max_b_frames = 2;
  
      }
  
      if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
  
          /* Needed to avoid using macroblocks in which some coeffs overflow.
  
           * This does not happen with normal video, it just happens here as
  
           * the motion of the chroma plane does not match the luma plane. */
  
          c->mb_decision = 2;
  
      }
  
  break;
  
  default:
  
      break;
  
  }
  
  /* Some formats want stream headers to be separate. */
  
  if (oc->oformat->flags & AVFMT_GLOBALHEADER)
  
      c->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  return st;
  
  }

  But when I run this code, I get the following error/warning :

  [mpeg @ 01f3f040] VBV buffer size not set, muxing may fail

  Do you know how I can set the VBV buffer size in the code ? In fact, when I use ffplay to display the streamed video, ffplay doesn't show anything for short videos but for long videos, it start displaying the video immediately. So, it looks like ffplay needs a buffer to be filled up by some amount so that it can start displaying the stream. Am I right ?

• ffmpeg mysteriously adding start delay [migrated]

  13 janvier 2014, par swizzcheez

  When converting a mp4 to TS, I am observing ffmpeg adding a "start" delay that the input file did not seem to possess. For my input, ffprobe reveals :

  ffprobe version N-57943-g7b76976 Copyright (c) 2007-2013 the FFmpeg developers
  
    built on Nov  6 2013 14:00:40 with gcc 4.4.5 (Debian 4.4.5-8)
  
    configuration: --enable-libx264 --enable-gpl
  
    libavutil      52. 52.100 / 52. 52.100
  
    libavcodec     55. 41.100 / 55. 41.100
  
    libavformat    55. 21.100 / 55. 21.100
  
    libavdevice    55.  5.100 / 55.  5.100
  
    libavfilter     3. 90.102 /  3. 90.102
  
    libswscale      2.  5.101 /  2.  5.101
  
    libswresample   0. 17.104 /  0. 17.104
  
    libpostproc    52.  3.100 / 52.  3.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'output.mp4-in-7A8FEADA-5EA6-11E3-AD13-4DD2258FBC88.mp4':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: mp42mp41
  
      creation_time   : 2013-11-08 15:15:12
  
    Duration: 00:00:11.56, start: 0.000000, bitrate: 2994 kb/s
  
      Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv), 1280x720 [SAR 1:1 DAR 16:9], 2807 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
  
      Metadata:
  
        creation_time   : 2013-11-08 15:15:12
  
        handler_name    : ?Mainconcept Video Media Handler
  
      Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 189 kb/s (default)
  
      Metadata:
  
        creation_time   : 2013-11-08 15:15:12
  
        handler_name    : #Mainconcept MP4 Sound Media Handler

  But when processed using ffmpeg :

  ffmpeg -i '/tmp/test-no-qp.C2162DFC-6297-11E3-A68D-05E505A3FB93/output.mp4-in-7A8FEADA-5EA6-11E3-AD13-4DD2258FBC88.mp4' -s 1920x1080 -preset ultrafast -f mpegts -c:v libx264 -qp:v 18 `enter code here`

  I get an extra start delay :

  (Snipping the same headers from the input side)
  
  Input #0, mpegts, from 'output.mp4-out-7A8FEADA-5EA6-11E3-AD13-4DD2258FBC88.mp4':
  
    Duration: 00:00:11.55, start: 1.400000, bitrate: 1985 kb/s
  
    Program 1 
  
      Metadata:
  
        service_name    : Service01
  
        service_provider: FFmpeg
  
      Stream #0:0[0x100]: Video: h264 (Constrained Baseline) ([27][0][0][0] / 0x001B), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
  
      Stream #0:1[0x101](eng): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, s16p, 128 kb/s

  Duration seems to have been adjusted as well, but I didn't ask for the adjustment. How do I get rid of that ? What did I do that triggered that effect ? Is there something else about my ffmpeg line that looks off ?

  (ffmpeg version is the same as the ffprobe above.)

• Convert raw yuv to mp4 crashed on android

  19 décembre 2013, par Sunderr

  Here is my steps :

  1. Decode a jpeg file to rgb565 ;(Success) ;

  2. Convert rgb565 to yuv420 ;(Not sure if it works, function "Bitmap2Yuv420")

  3. Convert yuv420 to mp4. (Crash when call avcodec_open2) ;

  And that is the codes :

  void ADKJpegDecoder::Bitmap2Yuv420(const char * outfilename) {
  
  unsigned char *destination = new unsigned char[m_Width * m_Height
  
          * m_BytesPerPixel / 2];
  
  unsigned char* rgb = m_RawImage;
  
  size_t image_size = m_Width * m_Height;
  
  size_t upos = image_size;
  
  size_t vpos = upos + upos / 4;
  
  size_t i = 0;
  
  
  
  for (size_t line = 0; line < m_Height; ++line) {
  
      if (!(line % 2)) {
  
          for (size_t x = 0; x < m_Width; x += 2) {
  
              char r = rgb[3 * i];
  
              char g = rgb[3 * i + 1];
  
              char b = rgb[3 * i + 2];
  
  
  
              destination[i++] = ((66 * r + 129 * g + 25 * b) >> 8) + 16;
  
  
  
              destination[upos++] = ((-38 * r + -74 * g + 112 * b) >> 8)
  
                      + 128;
  
              destination[vpos++] = ((112 * r + -94 * g + -18 * b) >> 8)
  
                      + 128;
  
  
  
              r = rgb[3 * i];
  
              g = rgb[3 * i + 1];
  
              b = rgb[3 * i + 2];
  
  
  
              destination[i++] = ((66 * r + 129 * g + 25 * b) >> 8) + 16;
  
          }
  
      } else {
  
          for (size_t x = 0; x < m_Width; x += 1) {
  
              char r = rgb[3 * i];
  
              char g = rgb[3 * i + 1];
  
              char b = rgb[3 * i + 2];
  
  
  
              destination[i++] = ((66 * r + 129 * g + 25 * b) >> 8) + 16;
  
          }
  
      }
  
  }
  
  
  
  ADKVideoEncoder::getInstance()->startEncodeVideo(destination);
  
  delete[] destination;

  }

  void ADKVideoEncoder::startEncodeVideo(unsigned char* rawDatas) {
  
  AVFormatContext* oc;
  
  AVOutputFormat* fmt;
  
  AVStream* video_st;
  
  AVCodecContext* c;
  
  
  
  double video_pts;
  
  uint8_t* video_outbuf;
  
  AVFrame* picture;
  
  int size;
  
  int ret;
  
  int video_outbuf_size;
  
  
  
  const char* filename = "/sdcard/test.mpg";
  
  
  
  av_register_all();
  
  
  
  fmt = av_guess_format(NULL, filename, NULL);
  
  oc = avformat_alloc_context();
  
  oc->oformat = fmt;
  
  snprintf(oc->filename, sizeof(oc->filename), "%s", filename);
  
  
  
  video_st = NULL;
  
  if (fmt->video_codec != CODEC_ID_NONE) {
  
      video_st = av_new_stream(oc, 0);
  
      c = video_st->codec;
  
      c->codec_id = fmt->video_codec;
  
      c->codec_type = AVMEDIA_TYPE_VIDEO;
  
      c->bit_rate = 400000;
  
      c->width = 320;
  
      c->height = 480;
  
      c->time_base.num = 1;
  
      c->time_base.den = 1;
  
      c->gop_size = 12;
  
      c->pix_fmt = PIX_FMT_YUV420P;
  
      c->max_b_frames = 0;
  
      if (!strcmp(oc->oformat->name, "mp4")
  
              || !strcmp(oc->oformat->name, "mov")
  
              || !strcmp(oc->oformat->name, "3gp")) {
  
          c->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
      }
  
  }
  
  
  
  av_dump_format(oc, 0, filename, 1);
  
  if (video_st) {
  
      AVCodec* codec = avcodec_find_encoder(c->codec_id);
  
      if (!codec) {
  
          return;
  
      }
  
      AVDictionary *optionsDict = NULL;
  
      if (avcodec_open2(c, codec, &optionsDict) < 0) {
  
          return;
  
      }
  
      if (!(oc->oformat->flags & AVFMT_RAWPICTURE)) {
  
          video_outbuf_size = 20000;
  
          video_outbuf = (uint8_t*) av_malloc(video_outbuf_size);
  
      }
  
      picture = avcodec_alloc_frame();
  
      size = avpicture_get_size(c->pix_fmt, c->width, c->height);
  
      avpicture_fill((AVPicture*) picture, rawDatas, c->pix_fmt, c->width,
  
              c->height);
  
  }
  
  
  
  if (!(fmt->flags & AVFMT_NOFILE)) {
  
      if (avio_open(&oc->pb, filename, AVIO_FLAG_WRITE) < 0) {
  
          return;
  
      }
  
  }
  
  avformat_write_header(oc, 0);
  
  
  
  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*/) {
  
      return;
  
  }
  
  c = video_st->codec;
  
  size = c->width * c->height;
  
  
  
  picture->data[0] = rawDatas;
  
  picture->data[1] = rawDatas + size;
  
  picture->data[2] = rawDatas + size * 5 / 4;
  
  
  
  if (oc->oformat->flags & AVFMT_RAWPICTURE) {
  
      AVPacket pkt;
  
      av_init_packet(&pkt);
  
      pkt.flags |= AV_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 |= AV_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);
  
      av_free(video_outbuf);
  
  }
  
  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)) {
  
      avio_close(oc->pb);
  
  }
  
  av_free(oc);

  }

  So can anyone find out the problem ? Thanks very much ! ;