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• avcodec/jpeg2000dec : Allocate lengthinc and data_start arrays as needed

  17 décembre 2017, par Michael Niedermayer

  avcodec/jpeg2000dec : Allocate lengthinc and data_start arrays as needed
  Decreases memory requirements
  
  Fixes : OOM
  
  Fixes : 4525/clusterfuzz-testcase-minimized-6400713073623040
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/jpeg2000.c
  • [DH] libavcodec/jpeg2000.h
  • [DH] libavcodec/jpeg2000dec.c

• cx_Freeze missing ffmpeg

  30 décembre 2017, par Dexstrum

  I am trying to deploy a python application with cx_Freeze. I have my setup.py created as below :

  from cx_Freeze import Executable, setup
  
  import ffmpeg
  
  
  
  build_exe_options = {
  
      'packages': ['os'],
  
      'include_files': [ffmpeg.__file__, ],
  
  }
  
  
  
  setup(
  
      name='myapp',
  
      version='0.0.1',
  
      description='MyApp',
  
      options={'build_exe': build_exe_options},
  
      executables=[Executable('bin/myapp.py')],
  
  )

  I also have a requirements file setup as such :

  ffmpeg-python
  
  cx_Freeze

  When I run python setup.py build, I get the following error :

  File "setup.py", line 2, in <module>
  
      import ffmpeg
  
  ImportError: No module named ffmpeg
  
  </module>

  The program runs fine in PyCharm and ffmpeg is recognized. I’m not sure why cx_Freeze does not recognize it.

• FFmpeg live streaming RGB frame buffer

  23 février 2018, par Mher Didaryan

  When we have a local video file This code works for streaming. What we want to achieve is to change input file with RGB frame buffer that we grab from screen. The code below uses input file’s time_base for PTS and DTS calculation.

  if(pkt.stream_index==videoindex) {
  
      AVRational time_base=ifmt_ctx->streams[videoindex]->time_base;
  
      AVRational time_base_q={1,AV_TIME_BASE};
  
      int64_t pts_time = av_rescale_q(pkt.dts, time_base, time_base_q);
  
      int64_t now_time = av_gettime() - start_time;
  
      if (pts_time > now_time)
  
          av_usleep(pts_time - now_time);
  
  }
  
  
  
  in_stream  = ifmt_ctx->streams[pkt.stream_index];
  
  out_stream = ofmt_ctx->streams[pkt.stream_index];
  
  /* copy packet */
  
  //Convert PTS/DTS
  
  pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
  
  pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
  
  pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);

  Following this answer which increments PTS value by one for every frame VideoSt.Frame->pts = VideoSt.NextPts++; saving in local file or streaming to Wowza server works (low quality) but fails on Youtube and Twitch. av_interleaved_write_frame function returns error -22. To improve quality we lowered qmin and qmax values but the bit-rate of video increased too much (30Mb/s and even more for HD video).

  VideoSt.Ctx->codec_id = VideoCodec->id;
  
  VideoSt.Ctx->width = ViewportSize.X;
  
  VideoSt.Ctx->height = ViewportSize.Y;
  
  VideoSt.Stream->time_base = VideoSt.Ctx->time_base = { 1, 30 };
  
  VideoSt.Ctx->time_base = timeBase;
  
  VideoSt.Ctx->gop_size = 60;
  
  VideoSt.Ctx->bit_rate = 400000;
  
  VideoSt.Ctx->pix_fmt = AV_PIX_FMT_YUV420P;
  
  VideoSt.Ctx->qmin = 1;
  
  VideoSt.Ctx->qmax = 2;
  
  VideoSt.Ctx->max_qdiff = 3;
  
  VideoSt.Ctx->qcompress = 1.0f;

  How can we stream lossless quality video with reasonable bit-rate using flv1 codec ? If streaming to Youtube or Twitch fails is it just a problem with requirements of this services or there’s an issue with encoding ?

  Regarding error code -22 there’s a detailed explanation which explains how we should increment PTS and DTS values.

  In which cases calculating PTS and DTS values are necessary ?

  And by the way what are these PTS and DTS ? After reading many posts and Understanding PTS and DTS in video frames accepted answer I still do not understand.