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• FFmpeg : convert mono interleaved 96 KHz stream to a stereo 48 KHz stream [closed]

  8 mars 2024, par Jochen

  I am using avfoundation with ffmpeg to capture audio with an HDMI-to-USB capture card from a MS2109 chip.

  


  The problem is that this card produces audio as 96Khz ; stereo 16bit 48kHz interleaved (1 sample for left channel, then 1 sample for right channel, alternating).

  


  There is a macOS program available : mono-to-stereo-mac.
This does the conversion and outputs it to a Blackhole virtual device, but it does not work perfectly as it produces crackling sounds.

  


  Is there a possibility to do this efficiently with FFmpeg ?
I came across this command :

  


  ffmpeg -f avfoundation -i :1 -filter_complex "[0:a:0]asetnsamples=1:false,aselect=n=2:e=mod(n\,2)+1[even][odd];[even]asetrate=48000,asetnsamples=1024,asetpts=N/SR/TB[even];[odd]asetrate=48000,asetnsamples=1024,asetpts=N/SR/TB[odd];[even][odd]join=2:stereo:0.0-FL|1.0-FR[aout]" -map "[aout]" 48kHz_stereo.wav


  


  but it does not produce the correct result.

  


• Insert frame in video at specific position with ffmpeg

  19 juin 2017, par user2712414

  I’m trying to hold a specific frame of my video for a number of seconds and then resume the video again with ffmpeg.
  For example let’s say that I have a video “movie.mp4” and I want to hold the frame at second 10 for 20 seconds. So I want ffmpeg to create a video that looks like :
  10 first seconds of movie.mp4 -> 20 seconds of the frame -> the rest of movie.mp4

  In resume, I want to insert a frame in the video.
  My video has audio, that’s one of the things that’s giving me a headache.
  Any idea on how to do it ?
  Thank you !

• FFMpeg's avformat_find_stream_info and avformat_open_input don't return

  26 août 2015, par user2012707

  I have a problem when trying to use FFMpeg to sample images from a UDP stream (i’ll mention that the UDP stream also has a KLV stream in it for telemetry info, but it isn’t relevant to the problem).
  I’m trying the basic usage of FFmpeg and having the code copy-pasted from any of the available tutorials I encounter a problem where every once in a while either avformat_find_stream_info or the avformat_open_input functions simply don’t return, if I try giving them timeout through the callbacks I simply get to the timeout, meanwhile the stream seems to be fine.

  Everytime I encounter the problem I try using ffplay to play the stream and it works perfect (in fact using ffplay I never encounter problems).
  I know I must be doing something wrong, I am working on it in an inside network so can’t easily post my code here, however it is copy pasted from any of the tutorials, and I verified it.

  Any help will be appreciated.

  Thanks !