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• Is it possible to stream video over RTP without transcoding or compressing input file before transmitting using FFMpeg commandline ?

  11 avril 2017, par Souvik Das

  FFmpeg supports 2 type of RTP payload type : MPEGTS/MP2T (PT 33) & Dynamic (PT 96). Dynamic PT requires explicit SDP presence at receiver while MPEGTS/MP2T doesn’t.
  I used FFmpeg as both transmitter and receiver (with Loopback/localhost) and compared PSNR of the respective streams :

  Case 1 : FFmpeg Dynamic RTP

  Sender:
  
  
  
      ffmpeg -re -i 'sample.avi' -c:a copy -c:v copy -f rtp -y 'rtp://@225.0.0.1:5555' > sample.sdp
  
  
  
  Receiver:
  
  
  
      ffmpeg -protocol_whitelist file,udp,rtcp,rtp -i sample.sdp -y rec.ts
  
  
  
  Result:
  
  
  
      PSNR avg. = 38
  
  
  
  This means that in idle condition, we are still not getting a perfect stream. I suspect, it's because Transcoding still takes place which downgrades the quality of video before transmitting at sender.

  Case 2 : FFmpeg MPEGTS RTP

  Sender:
  
  
  
      ffmpeg -re -i 'sample.avi' -c:a copy -c:v copy -f rtp_mpegts -y 'rtp://@225.0.0.1:5555'
  
  
  
  Receiver:
  
  
  
  
  
      ffmpeg -protocol_whitelist file,udp,rtcp,rtp -i sample.sdp -f mpegts -y rec.ts
  
  
  
  Result:
  
  
  
      Large # Frame Losses!
  
  
  
  So, at Receiver, I used VLC for recording the streams. Although there was no/negligible frame loss, but PSNR avg. = 18 !!

  Earlier in a dedicated VLC Streamer & Recorder test, when the same video was streamed, PSNR avg. = Infinity (No Quality Loss). I want to shift to FFMpeg alternative for streaming because, I want to introduce some programmability factors for a sophisticated research work.

  Hence, It would be really great, if somebody could provide me some input as to how I can achieve uncompressed & lossless video streaming using FFMpeg over RTP.

  Notes :

  1. I must use RTP only. I can't use RTSP or other streaming methods incl. direct UDP (udp://)
  
  2. VLC Media Player / Libvlc used in this case, also used RTP for all cases.
  
  3. It can assumed that Streamer and Recorder are present on same disk or has same access to storage.
  
  4. Must support multicast!

• Webcam Serverless Live stream

  23 juillet 2021, par curiouscoder

  I'm trying to live stream my webcam in a serverless way in the following flow :

  


  webcam browser >> s3 bucket >> lambda/ffmpeg encoding >> s3 output bucket >> dash player

  


  This is working really good so far but I'm facing the following problem :

  


  ffmpeg will only encode those seconds received (I stream the webcam to s3 each X seconds with some 300kb .webm file). So the .mpd file generated by ffmpeg encoder will have the type 'static' when ffmpeg finishes encoding and not the 'dynamic' type desired. Therefore, the dash player won't request the other files from s3 and the streaming will stop. For example, if I let the webcam streaming running for 15 seconds, the viewer is able to watch the 15 minutes. But if I keep sending the streams each 2 seconds the viewer will be able to watch only the first 2 seconds because browser won't request any other .m4s files.

  


  So, I have the following question :

  


  Is there a way to force the dash player to reload the .mpd file that is stored in s3 even when the type is static instead of dynamic ?

  


  Thanks in advance !

  


• Preserve attached picture by cutting audio file with FFMPEG [closed]

  29 avril 2023, par Riccardo Volpe

  I know that there are similar topics already opened and answered here, but none of them can explain what is happening to me :

  


  I need to cut an audio file which has a picture attached to it.

  


  If I do :

  


  ffmpeg -i input.mp3 -ss 00:00:04.50 -t 00:03:07.16 -map_metadata 0 -c:v copy -disposition:v:0 attached_pic -ar 44100 -b:a 320k -f mp3 output.mp3


  


  it doesn't work, that is the output.mp3 file doesn't maintain the original attached cover.

  


  I need to do a three steps job to achieve it :

  


  ffmpeg -i input.mp3 -an -c:v copy -update 1 cover.png

ffmpeg -i input.mp3 -ss 00:00:04.50 -t 00:03:07.16 -c copy output_cut.mp3


  


  in the previous last step I receive a warning about the missed picture which I'm going to add in the following third and last step :

  


  ffmpeg -i output_cut.mp3 -i cover.png -c copy -map 0 -map 1 output.mp3


  


  It works, but here I would ask you if there is a way to do it with just one FFMPEG command, thank you.