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• How to dump the H264/RTP stream to a file without losing time info ?

  3 février 2014, par Fernando Silveira

  I coded an application to receive RTP packets via TCP (no packets are lost) from a hardware camera and dump its H264 packets to a file so I could play the video using MPlayer or VLC. This is already working and I pretty much did the steps described here. The commands to play the video are mplayer -fps 24 -demuxer h264es foobar.h264 and vlc foobar.h264.

  The issue is now when I play the video. The camera changes the FPS frequently and because I drop the RTP info when writing the H264 file, the timestamp of each frame is lost. My question is : what do I have to do to fix the frame frequency ? Should I create empty/blank P-frames (if that is possible) ? If so, how would I do it ?

  Any solution using Linux compatible tools or libraries (like ffmpeg, libx264, libavcodec) using shell, C/C++ or Python is very much welcome.

  PS : I have almost no experience with video encoding and RTP.

• FFMpeg : CUDA_ERROR_NOT_SUPPORTED on ubuntu20.04

  22 décembre 2020, par Superminaren

  I've been trying to get CUDA working on Ubuntu 20.04 for a while now.

  


  ffmpeg -vsync 0 -hwaccel cuvid -c:v h264_cuvid -i input.mp4 -c:a copy -c:v h264_nvenc -b:v 5M output.mp4


  


  Running the sample command linked above, I get the following error :

  


  


  [AVHWDeviceContext @ 0x5618466f7f80] cu->cuCtxCreate(&hwctx->cuda_ctx, desired_flags, hwctx->internal->cuda_device) failed -> CUDA_ERROR_NOT_SUPPORTED : operation not supported
Device creation failed : -1313558101.
[h264_cuvid @ 0x561846731940] No device available for decoder : device type cuda needed for codec h264_cuvid.

  


  


  I am not sure what causes this.

  


  All relevant environment parameters look like this.

  


  CUDADIR=/usr/local/cuda-11.2/   LD_LIBRARY_PATH=/usr/local/cuda-11.2/lib64   CUDA_HOME=/usr/local/cuda-11.2/   PATH=/usr/local/cuda-11.2/bin:/opt/ffmpeg/bin/

  


  Running 'nvidia-smi' gives this response :

  


  This looks rather normal afaik too.

  


  If someone with more experience could help me that'd be greatly appreciated.

  


• Play playlist of audio on website using node to create a jukebox / radio app

  1er juillet 2022, par neff

  So I have some time on my hands and thought I would make myself a little jukebox / radio type app.

  



  It would be fairly simple, just a collection of MP3's on the server, one is chosen at random, it plays, on completion, the next one is chosen and plays. The front of this would just be a super simple page that has a player and displays the metadata.

  



  I don't really have any experience with server programming but I'm going to look in to Node, seems like it would be good for this. I've already written a little script in Python that chooses a song from a selection and plays it (using VLC at the moment) so it should be simple to port it to Node / js.

  



  Just wondering if someone could point me in the right direction for how to link the "player" with the "playlist".

  



  Looking in to it, I can only find solutions involving a client and server using shoutCast or ICEcast or similar - so the playlist streams audio to a shoutcast server, and the website is just a player looking at the shoutCast URL - that seems unnecessary for me, as the streaming and the site would be the same thing.

  



  New to a lot of this :) but I have time at the moment so happy to get stuck in !

  



  Thanks in advance