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• Is there a way to include a transition video when using ffmpeg's select filter ?

  19 février 2021, par Tim

  I wanted to take some segments of an input video and make a highlight reel automatically using ffmpeg. I was originally experimenting with trimming and concating but it was difficult because the audio was falling out of sync and also I have a variable number of highlights that I want.

  


  I discovered from the top comment here that the 'select' filter is very powerful. I have a python program that inputs all the parts I want selected into the command and run it in the terminal and it works perfect. Only issue is that I want a quick transition video to play in between each of these highlights. Is this not possible with select ? Do I have to return to using trim and concat ? Thank you !

  


  Edit : for reference, here is an example ffmpeg command I am running

  


  ffmpeg -y -i video.mp4 -i audio.mp4 -vf "select='between(t,56,69)+between(t,60,135)+between(t,73,132)+between(t,152,163)+between(t,251,278)+between(t,600,700)+between(t,774,872)', setpts=N/FRAME_RATE/TB " -af "aselect='between(t,56,69)+between(t,60,135)+between(t,73,132)+between(t,152,163)+between(t,251,278)+between(t,600,700)+between(t,774,872)',asetpts=N/SR/TB" output.mp4


  


• pyav / ffmpeg / libav select number of P-frames and B-frames

  27 mai 2021, par user1315621

  I am streaming from an rtsp source. It looks like half of the frames received are key frames. Is there a way to reduce this percentage and have an higher number of P-frames and B-frames ? If possible, I would like to increase the number of P-frames (not the one of B-frames).
I am using pyav which is a Python wrapper for libav (ffmpeg)

  


  Code :

  


  container = av.open(
    url, 'r',
    options={
        'rtsp_transport': 'tcp',
        'stimeout': '5000000',
        'max_delay': '5000000',
    }
)
stream = container.streams.video[0]
codec_context = stream.codec_context
codec_context.export_mvs = True
codec_context.gop_size = 25  

for packet in self.container.demux(video=0):
    for video_frame in packet.decode():
        print(video_frame.is_key_frame)


  


  Output :

  


  True
False
True
False
...


  


  Note 1 : I can't edit the source. I can just edit the code used to stream the video.

  


  Note 2 : same solution should apply to pyav, libavi and ffmpeg.

  


  Edit : it seems that B-frames are disabled : codec_context.has_b_frames is False

  


• libavutil/hwcontext_qsv : add usage child_device_type argument to explicitly select...

  20 août 2021, par Artem Galin

  libavutil/hwcontext_qsv : add usage child_device_type argument to explicitly select d3d11va/DX11 device type
  UPD : Rebase of last patch set over current master and use DX9 as default device type.
  Makes selection of dxva2/DX9 device type by default as before with explicit d3d11va/DX11 usage to cover more HW configurations.
  
  Added warning message to expect changing default device type in the future.
  Fixes TGL / AV1 decode as requires DX11 with explicit DX11 type
  
  selection.
  Add headless/multi adapter support and fixes :
  
      https://trac.ffmpeg.org/ticket/7511
  
      https://trac.ffmpeg.org/ticket/6827
  
      http://ffmpeg.org/pipermail/ffmpeg-trac/2017-November/041901.html
  
      https://trac.ffmpeg.org/ticket/7933
  
      https://github.com/InitialForce/FFmpeg/commit/338fbcd5bba1de0e1b3e3bad8985eee2fdfbeca1
  
      https://github.com/jellyfin/jellyfin/issues/2626#issuecomment-602153952
  Any other fixes are welcome including OpenCL interop patch since I don't have proper setup to validate this use case
  Decoding, encoding, transcoding have been validated.
  child_device_type option is responsible for d3d11va/dxva2 device selection
  Usage examples :
  DirectX 11 :
  
      -init_hw_device qsv:hw,child_device_type=d3d11va
  
      -init_hw_device qsv:hw,child_device_type=d3d11va,child_device=0
  
  OR
  
      -init_hw_device d3d11va=dx -init_hw_device qsv@dx
  DirectX 9 is still supported but requires explicit selection :
  
      -init_hw_device qsv:hw,child_device_type=dxva2
  
  OR
  
      -init_hw_device dxva2=dx -init_hw_device qsv@dx
  Signed-off-by : Artem Galin <artem.galin@intel.com>
  

  • [DH] doc/ffmpeg.texi
  • [DH] libavutil/hwcontext_qsv.c