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• Using ffmpeg, I'm trying to mute all 5.1 channels of audio for a period of time within a video

  1er novembre 2019, par cozmonaut

  I’m wanting to mute audio for a portion of a video clip while keeping the video exactly as it is.

  I came across this online.

  ffmpeg -i ~/Downloads/in.mov -vcodec copy -af "volume=enable='between(t,0,3)':volume=0" ~/Downloads/out2.mov

  Although it works, it converts the 5.1 audio to stereo. Isn’t it possible to mute the first 3 seconds of all 5.1 channels of audio, while keeping the 5.1 channels intact within the finished output video file ?

  Here are the specs on my video/audio clip :

  Stream #0:0[0x100]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], Closed Captions, 59.94 fps, 59.94 tbr, 90k tbn, 119.88 tbc
  
  Stream #0:1[0x101]: Audio: ac3 ([129][0][0][0] / 0x0081), 48000 Hz, stereo, fltp, 192 kb/s
  
  Stream #0:2[0x102]: Audio: ac3 ([129][0][0][0] / 0x0081), 48000 Hz, 5.1(side), fltp, 384 kb/s

  Thank you.

• Is there a way to send ffmpeg data directly to a TCP Client ?

  3 février 2021, par KosmosisDire

  I am using ffmpeg to send screen capture directly to a C# TCP server. However, due to some bug or technical limitation, the Quest 2 (my build device) cannot bind ports. (There is very little info regarding this bug online, but as far as I can tell I can't get around it). So I cannot have a C# server on the Quest, I must have a client on the quest to receive data. However, ffmpeg sends data as a TCP client. So I need ffmpeg to act as a server.

  


  I tried sending the data through a server on my computer that then sends the data to the C# client. But I get less than 1 fps with huge lag. Normally, I get a good 30 fps with low latency when sending directly to a server.

  


  So my question :

  


  Is there a way to get ffmpeg data directly to a client, or indirectly without increasing the latency ?

  


  Here is the ffmpeg command I am using :

  


  ffmpeg -f gdigrab -i desktop -pixel_format rgb8 -video_size 896x504 -vf scale=896:504 -framerate 5 -r 30 -f rawvideo tcp://127.0.0.1:846


  


  I can include code for my C# client and server attempts as well as the middleman server, if I need.

  


  Thanks for any help !

  


• Debayer video with ffmpeg

  26 septembre 2016, par Andrew Spence

  Looking to debayer video with ffmpeg. I can’t find a way to do it without piping raw video between two instances of ffmpeg, because I can’t change the pixel format of my input video "in place" from gray to bayer_gbrg8. So, this command works :

  ffmpeg -i fr_losslessmovie_png_codec.avi -f image2pipe -pix_fmt gray \
  
  -vcodec rawvideo - | ffmpeg -r 25 -f rawvideo -s 2048x700 \
  
  -pix_fmt bayer_gbrg8 -i pipe:0 -y -pix_fmt yuv420p -b:v 25000k \
  
  fr_debayer_compressed.mp4

  I would have given the source movie this pixel format, but didn’t realize ffmpeg suported bayered pixel formatting.

  Didn’t see this exact question online, and have not found a way to change the pixel format with video filters etc. without ffmpeg thinking i’m trying to convert the data. I just want to change the pixel format that the already existing gray data has been assigned.

  Thanks in advance !
  Andrew