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• 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.)

• 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 ?

• Android h264 decode non-existing PPS 0 referenced

  22 janvier 2014, par nmxprime

  In Android JNI, using ffmpeg with libx264 use below codes to encode and decode raw rgb data !. I should use swscale to convert rgb565 to yuv420p as required by H.264. But not clear about this conversion.Please help, where i am wrong, with regard the log i get !

  Code for Encoding

  codecinit()- called once(JNI wrapper function)

  int Java_com_my_package_codecinit (JNIEnv *env, jobject thiz) {
  
  avcodec_register_all();
  
  codec = avcodec_find_encoder(AV_CODEC_ID_H264);//AV_CODEC_ID_MPEG1VIDEO);
  
  if(codec->id == AV_CODEC_ID_H264)
  
      __android_log_write(ANDROID_LOG_ERROR, "set","h264_encoder");
  
  
  
  if (!codec) {
  
      fprintf(stderr, "codec not found\n");
  
      __android_log_write(ANDROID_LOG_ERROR, "codec", "not found");
  
  
  
  }
  
      __android_log_write(ANDROID_LOG_ERROR, "codec", "alloc-contest3");
  
  c= avcodec_alloc_context3(codec);
  
  if(c == NULL)
  
      __android_log_write(ANDROID_LOG_ERROR, "avcodec","context-null");
  
  
  
  picture= av_frame_alloc();
  
  
  
  if(picture == NULL)
  
      __android_log_write(ANDROID_LOG_ERROR, "picture","context-null");
  
  
  
  c->bit_rate = 400000;
  
  c->height = 800;
  
  c->time_base= (AVRational){1,25};
  
  c->gop_size = 10; 
  
  c->max_b_frames=1;
  
  c->pix_fmt = AV_PIX_FMT_YUV420P;
  
  outbuf_size = 768000;
  
  c->width = 480;
  
  
  
  size = (c->width * c->height);
  
  
  
  if (avcodec_open2(c, codec,NULL) < 0) {
  
  
  
  __android_log_write(ANDROID_LOG_ERROR, "codec", "could not open");
  
  
  
  
  
  }
  
  
  
  ret = av_image_alloc(picture->data, picture->linesize, c->width, c->height,
  
                       c->pix_fmt, 32);
  
  if (ret < 0) {
  
          __android_log_write(ANDROID_LOG_ERROR, "image","alloc-failed");
  
      fprintf(stderr, "could not alloc raw picture buffer\n");
  
  
  
  }
  
  
  
  picture->format = c->pix_fmt;
  
  picture->width  = c->width;
  
  picture->height = c->height;
  
  return 0;
  
  
  
  }

  encodeframe()-called in a while loop

  int Java_com_my_package_encodeframe (JNIEnv *env, jobject thiz,jbyteArray buffer) {
  
  jbyte *temp= (*env)->GetByteArrayElements(env, buffer, 0);
  
  Output = (char *)temp;
  
  const uint8_t * const inData[1] = { Output }; 
  
  const int inLinesize[1] = { 2*c->width };
  
  
  
  //swscale should implement here
  
  
  
      av_init_packet(&pkt);
  
      pkt.data = NULL;    // packet data will be allocated by the encoder
  
      pkt.size = 0;
  
  
  
      fflush(stdout);
  
  picture->data[0] = Output;
  
  ret = avcodec_encode_video2(c, &pkt, picture,&got_output);
  
  
  
      fprintf(stderr,"ret = %d, got-out = %d \n",ret,got_output);
  
       if (ret < 0) {
  
                  __android_log_write(ANDROID_LOG_ERROR, "error","encoding");
  
          if(got_output > 0)
  
          __android_log_write(ANDROID_LOG_ERROR, "got_output","is non-zero");
  
  
  
      }
  
  
  
      if (got_output) {
  
          fprintf(stderr,"encoding frame %3d (size=%5d): (ret=%d)\n", 1, pkt.size,ret);
  
          fprintf(stderr,"before caling decode");
  
          decode_inline(&pkt); //function that decodes right after the encode
  
          fprintf(stderr,"after caling decode");
  
  
  
  
  
          av_free_packet(&pkt);
  
      }
  
  
  
  
  
  fprintf(stderr,"y val: %d \n",y);
  
  
  
  
  
  (*env)->ReleaseByteArrayElements(env, buffer, Output, 0);
  
  return ((ret));
  
  }

  decode_inline() function

  decode_inline(AVPacket *avpkt){
  
  AVCodec *codec;
  
  AVCodecContext *c = NULL;
  
  int frame, got_picture, len = -1,temp=0;
  
  
  
  AVFrame *rawFrame, *rgbFrame;
  
  uint8_t inbuf[INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE];
  
  char buf[1024];
  
  char rawBuf[768000],rgbBuf[768000];
  
  
  
  struct SwsContext *sws_ctx;
  
  
  
  memset(inbuf + INBUF_SIZE, 0, FF_INPUT_BUFFER_PADDING_SIZE);
  
  avcodec_register_all();
  
  
  
  c= avcodec_alloc_context3(codec);
  
  if(c == NULL)
  
      __android_log_write(ANDROID_LOG_ERROR, "avcodec","context-null");
  
  
  
  codec = avcodec_find_decoder(AV_CODEC_ID_H264);
  
  if (!codec) {
  
      fprintf(stderr, "codec not found\n");
  
      fprintf(stderr, "codec = %p \n", codec);
  
      }
  
  c->pix_fmt = AV_PIX_FMT_YUV420P;
  
  c->width = 480;
  
  c->height = 800;
  
  
  
  rawFrame = av_frame_alloc();
  
  rgbFrame = av_frame_alloc();
  
  
  
  if (avcodec_open2(c, codec, NULL) < 0) {
  
      fprintf(stderr, "could not open codec\n");
  
      exit(1);
  
      }
  
  sws_ctx = sws_getContext(c->width, c->height,/*PIX_FMT_RGB565BE*/
  
              PIX_FMT_YUV420P, c->width, c->height, AV_PIX_FMT_RGB565/*PIX_FMT_YUV420P*/,
  
              SWS_BILINEAR, NULL, NULL, NULL);
  
  
  
  
  
  frame = 0;
  
  
  
  unsigned short *decodedpixels = &rawBuf;
  
  rawFrame->data[0] = &rawBuf;
  
  rgbFrame->data[0] = &rgbBuf;
  
  
  
  fprintf(stderr,"size of avpkt %d \n",avpkt->size);
  
  temp = avpkt->size;
  
  while (temp > 0) {
  
          len = avcodec_decode_video2(c, rawFrame, &got_picture, avpkt);
  
  
  
          if (len < 0) {
  
              fprintf(stderr, "Error while decoding frame %d\n", frame);
  
              exit(1);
  
              }
  
          temp -= len;
  
          avpkt->data += len;
  
  
  
          if (got_picture) {
  
              printf("saving frame %3d\n", frame);
  
              fflush(stdout);
  
          //TODO  
  
          //memcpy(decodedpixels,rawFrame->data[0],rawFrame->linesize[0]); 
  
          //  decodedpixels +=rawFrame->linesize[0];
  
  
  
              frame++;
  
              }
  
  
  
          }
  
  
  
  avcodec_close(c);
  
  av_free(c);
  
  //free(rawBuf);
  
  //free(rgbBuf);
  
  av_frame_free(&rawFrame);
  
  av_frame_free(&rgbFrame);

  }

  The log i get

  For the decode_inline() function :

  ---

  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] non-existing PPS 0 referenced
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] decode_slice_header error
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] non-existing PPS 0 referenced
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] decode_slice_header error
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] non-existing PPS 0 referenced
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] decode_slice_header error
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] non-existing PPS 0 referenced
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] decode_slice_header error
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] non-existing PPS 0 referenced
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] decode_slice_header error
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] non-existing PPS 0 referenced
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] decode_slice_header error
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] non-existing PPS 0 referenced
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] decode_slice_header error
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] non-existing PPS 0 referenced
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] decode_slice_header error
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] non-existing PPS 0 referenced
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] decode_slice_header error
  
  01-02 14:50:50.160: I/stderr(3407): [h264 @ 0x8db540] Invalid mix of idr and non-idr slices
  
  01-02 14:50:50.160: I/stderr(3407): Error while decoding frame 0

  Edit : Changing GOP value :

  If i change c->gop_size = 3; as expected it emits one I frame every three frames. The non-existing PPS 0 referenced message is not there for in every third execution, but all other have this message