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• Increase Duration of a video FFMPEG C++

  9 avril 2015, par Shahroz Tariq

  I am using the code from the samples of FFmpeg which encodes a picture into a video. All I want to do is to give it a series of pictures and it gives me a video with each picture is taking one second`Code below is just taking one picture from my file system & creating video from it

  AVCodec *codec;
  
  AVCodecContext *c = NULL;
  
  int i, ret, x, y, got_output;
  
  FILE *f;
  
  
  
  AVPacket pkt;
  
  uint8_t endcode[] = { 0, 0, 1, 0xb7 };
  
  
  
  printf("Encode video file %s\n", filename);
  
  
  
  /* find the mpeg1 video encoder */
  
  codec = avcodec_find_encoder((AVCodecID)codec_id);
  
  if (!codec)
  
  {
  
      fprintf(stderr, "Codec not found\n");
  
      exit(1);
  
  }
  
  
  
  c = avcodec_alloc_context3(codec);
  
  if (!c)
  
  {
  
      fprintf(stderr, "Could not allocate video codec context\n");
  
      exit(1);
  
  }
  
  
  
  /* put sample parameters */
  
  c->bit_rate = 400000;
  
  /* resolution must be a multiple of two */
  
  c->width = 200;
  
  c->height = 200;
  
  /* frames per second */
  
  AVRational rational;
  
  rational.num = 1;
  
  rational.den = 25;
  
  c->time_base = rational;
  
  /* emit one intra frame every ten frames
  
  * check frame pict_type before passing frame
  
  * to encoder, if frame->pict_type is AV_PICTURE_TYPE_I
  
  * then gop_size is ignored and the output of encoder
  
  * will always be I frame irrespective to gop_size
  
  */
  
  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 it */
  
  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);
  
  }
  
  AVFrame *frame = OpenImage("..\\..\\..\\..\\..\\..\\1.jpg");
  
  //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;
  
  /* the image can be allocated by any means and av_image_alloc() is
  
  * just the most convenient way if av_malloc() is to be used */
  
  
  
  int screenHeight = 200;
  
  int screenWidth = 200;
  
  for (i = 0; i < 25; i++)
  
  {
  
      av_init_packet(&pkt);
  
      pkt.data = NULL;    // packet data will be allocated by the encoder
  
      pkt.size = 0;
  
  
  
      fflush(stdout);
  
  
  
  
  
  
  
      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("Write frame %3d (size=%5d)\n", i, pkt.size);
  
          fwrite(pkt.data, 1, pkt.size, f);
  
          av_free_packet(&pkt);
  
      }
  
  }
  
  
  
  /* get the delayed frames */
  
  for (got_output = 1; got_output; i++)
  
  {
  
      fflush(stdout);
  
  
  
      ret = avcodec_encode_video2(c, &pkt, NULL, &got_output);
  
      if (ret < 0)
  
      {
  
          fprintf(stderr, "Error encoding frame\n");
  
          exit(1);
  
      }
  
  
  
      if (got_output)
  
      {
  
          printf("Write frame %3d (size=%5d)\n", i, pkt.size);
  
          fwrite(pkt.data, 1, pkt.size, f);
  
          av_free_packet(&pkt);
  
      }
  
  }
  
  
  
  /* add sequence end code to have a real mpeg file */
  
  fwrite(endcode, 1, sizeof(endcode), f);
  
  fclose(f);
  
  
  
  avcodec_close(c);
  
  av_free(c);
  
  av_freep(&frame->data[0]);
  
  av_frame_free(&frame);
  
  printf("\n");`

• Create MPEG-DASH Initialization segment

  5 janvier 2016, par Mahout

  I am looking to convert between HLS and MPEG Dash. I do not access to the original fully concatenated video file, only the individual HLS segments.

  In doing this transformation to MPEG Dash I need to supply an initialziation segment for the Dash manifest .mpd file.

  My questions are :

  1. What is the structure of a Dash video initialization segment ?
  2. How can I generate/create one without the need for the original full file ?

  Perhaps a solution would involve getting MP4Box to convert the ’.ts’ HLS segments to Dash ’.m4s’ segments which are self initializing, but I am unsure how to go about this this ?

  Any ideas are much appreciated.

  Many thanks.

  UPDATE :
  Snippet to stream using original hls segments. Video plays all the way through but is just black.

    <representation width="426" height="238" framerate="25" bandwidth="400000">
  
      <segmentlist timescale="25000" duration="112500">
  
             <segmenturl media="video_0_400000/hls/segment_0.ts"></segmenturl>
  
             <segmenturl media="video_0_400000/hls/segment_1.ts"></segmenturl>
  
            <segmenturl media="video_0_400000/hls/segment_2.ts"></segmenturl>
  
      </segmentlist>
  
     </representation>

• FFmpeg using Intel quicksync

  3 mars 2016, par KevinA

  I’m trying to use FFmpeg with Intel QuickSync(qsv)

  Finding the codec works, but when I go to open the codec I get a -40

  I’ve traced it to :
  ret = MFXVideoENCODE_GetVideoParam(q->session, &q->param) ;

  Below in my initialzation code :

  AVCodec* m_codec = ::avcodec_find_encoder_by_name("h264_qsv");
  
  if (!m_codec){
  
      DBGPRINTF("Could not find encoder");
  
      return E_INVALIDARG;
  
  }
  
  
  
  AVCodecContext* m_context = ::avcodec_alloc_context3(m_codec);
  
  if (!m_context){
  
      DBGPRINTF("Could not alloc AV context");
  
      return E_INVALIDARG;
  
  }
  
  
  
  mfxIMPL impl = MFX_IMPL_AUTO;
  
  mfxVersion ver = { { 1, 1 } };
  
  
  
  MFXInit(impl, &ver, &m_qsvContext->session);
  
  
  
  m_qsvContext->iopattern             = MFX_IOPATTERN_IN_OPAQUE_MEMORY;
  
  m_qsvContext->opaque_alloc          = 1;
  
  m_qsvContext->nb_opaque_surfaces    = 16;
  
  
  
  m_context->hwaccel_context          = m_qsvContext;    
  
  m_context->profile                  = FF_PROFILE_H264_BASELINE;
  
  
  
  AVRational fps;
  
  AVRational sar;
  
  fps.num                             = static_cast(m_targetFPS);
  
  fps.den                             = 1;
  
  sar.num                             = m_iHeightOut;
  
  sar.den                             = m_iWidthOut;
  
  //m_context->bit_rate               = 400000;
  
  m_context->width                    = m_iWidthOut;
  
  m_context->height                   = m_iHeightOut;
  
  m_context->has_b_frames             = 0;
  
  m_context->sample_aspect_ratio      = sar;
  
  m_context->time_base                = fps;
  
  
  
  m_context->gop_size                 = s_keyFramesMax;
  
  m_context->pix_fmt                  = AV_PIX_FMT_QSV;
  
  m_context->flags                   |= AV_CODEC_FLAG_QSCALE;
  
  m_context->flags                   |= CODEC_FLAG_PASS1;
  
  m_context->thread_count             = 1;
  
  m_context->codec_type               = AVMEDIA_TYPE_VIDEO;
  
  
  
  ::av_opt_set(m_context->priv_data, "preset", "fast", 0);
  
  ::av_opt_set(m_context->priv_data, "look_ahead", "0", 0);
  
  
  
  int ret = avcodec_open2(context, codec, nullptr);
  
  if (ret < 0) {
  
      DBGPRINTF("Could not open codec h264_qsv with code %d", ret);
  
      return ret;
  
  }

  I’m obviously missing something, but i’m not sure what. Can someone help point me in the correct direction ?