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• How to live stream generative video via ffmpeg

  24 septembre 2021, par Ken

  I would like to live-stream generative audio and generative video on the web. It would be an "autonomous" setup, without anyone in front of a camera to address the audience, etc. But it needs to be "live" because it will be interactive (the audience can change parameters that will impact the stream), so it can't all come from a pre-generated file.

  


  Generative audio would come from Reaper, be sent to a virtual audio device and grabbed by ffmpeg, which would then send it to a live streaming platform (say, Youtube).

  


  I think I understand the audio part and got it mostly working.

  


  But what about the video part ? Most examples only mention either a video file or the output of a webcam.

  


  But how does one send the direct output of a program that generates video, such as Processing for example ? Can it be done with piping ? Or should one use a virtual video device ?

  


  Ideally this should work on an Raspberry-Pi but any pointer would be welcome.

  


  This question is related but it's quite old, what would be the best setup for this ?

  


• avformat/evcdec : Avoid nonsense casts

  6 juillet 2023, par Andreas Rheinhardt

  avformat/evcdec : Avoid nonsense casts
  For uint8_t buf[EVC_NALU_LENGTH_PREFIX_SIZE], &buf still points
  
  to the beginning of buf, but it is of type "pointer to array of
  
  EVC_NALU_LENGTH_PREFIX_SIZE uint8_t" (i.e. pointer arithmetic
  
  would operate on blocks of size EVC_NALU_LENGTH_PREFIX_SIZE).
  
  This is of course a different type than uint8_t*, which is why
  
  there have been casts in evc_read_packet(). But these are unnecessary
  
  if one justs removes the unnecessary address-of operator.
  Reviewed-by : James Almer <jamrial@gmail.com>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavformat/evcdec.c

• FFmpeg - can't pick up the rtsp-stream

  26 avril 2021, par Pivoter

  I am trying to get a single frame through ffmpeg, but I run into an error :

  


  ffmpeg -rtsp_transport tcp -i rtsp://5.101.8.197/11 -vframes 1 -q:v 2 /home/test/video/example.jpg


  


  Output :

  


    [rtsp @ 0x560d28b23900] Could not find codec parameters for stream 0 (Video: h264, none): unspecified size
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  Guessed Channel Layout for Input Stream #0.1 : mono
  Input #0, rtsp, from 'rtsp://5.101.8.197/11':
    Metadata:
      title           : WUHAN Ants RtspServer
    Duration: N/A, start: 0.000000, bitrate: 64 kb/s
      Stream #0:0: Video: h264, none, 90k tbr, 90k tbn, 180k tbc
      Stream #0:1: Audio: pcm_mulaw, 8000 Hz, mono, s16, 64 kb/s
  Output #0, image2, to '/home/test/video/example.jpg':
  Output file #0 does not contain any stream


  


  Changing the parameters analyzability and dimension do not give a result. Noticed that this happens with WUHAN Ants RtspServer, others are fine.
Any ideas ?

  


  UPD : Can try to get the stream at the specified address.