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• Feed avcodec_encode_video2 more frames than the desired output framerate [closed]

  9 septembre 2024, par muniategui

  I am capturing frames at a variable rate and sending them after getting encoded in a livestream (low latency configuration). The send stream is the raw H264 without encapsulating it in any media container. The input/captured frames goes from 60 fps to 70-75 fps. These frames are feed directly to avcodec_encode_video2, with the context configured to :

  


  c->time_base.num=1;
c->time_base.den=60;
c->framerate.num=60;
c->framerate.den=1;


  


  The expected behavior of the encoder would be to get got_packet_ptr = 0 as output of avcodec_encode_video2 multiple times when the amount of frames exceeds the desired output frame rate. However, what I get is that every single call produces a frame and sending all the frames results in exceeding the desired frame rate.

  


  I have tried to set AVFrame::pts to :

  


  in_frame->pts = pts;
pts++;


  


  So basically increase pts by one on each frame (ignoring got_packet_ptr is always increased).

  


  This did not fix the problem. Reading more, I think that I have to use something like av_rescale_q to set the pts, but as said, the input frame rate is not constant. I am missing another field to set related to time stamps ? I do have to calculate my self the FPS for the input frames ? I am in the wrong path and the problems is not related to this ?

  


  In order to reproduce it, just feed the encoder directly with an amount of frame per second faster than the output and check that packets are always returned with the default configuration of the encoder except profile to lowlatency (NVENC in this case but x264 has the same problem)

  


• I Need Help Making Our FIRST Robotics Competition Driver Station Video Feed Faster [closed]

  30 mars, par Joshua Green

  I am currently using FFmpeg on a Raspberry Pi 4 Model B using an ArduCam UC-844 Rev. B as the camera. We do not need any audio and I don't care about the quality of the video. All we need is for the stream to be as fast as possible. The video from the camera is being streamed to the driver station via FFmpeg and being picked up on the driver station via FFplay. Right now we are getting a delay that we wish could go away or be significantly shortened. These are the commands we are using.

  


  


  • Raspberry Pi : ffmpeg -i /dev/video0 -c:v libx264 -crf 45 -maxrate 1M -bufsize 1.2M -preset ultrafast -tune zerolatency -filter:v fps=30 -f mpegts -omit_video_pes_length 0 udp://10.2.33.5:554

    


  


  • Driver Station : ffplay -fflags nobuffer -flags low_delay -probesize 32 -analyzeduration 0 -f mpegts -vf setpts=0 udp://10.2.33.5:554

    


  


  


• I Need Help Making Our Driver Station Video Feed Faster [closed]

  30 mars, par Joshua Green

  I am currently using FFmpeg on a Raspberry Pi 4 Model B using an ArduCam UC-844 Rev. B as the camera. We do not need any audio and I don't care about the quality of the video. All we need is for the stream to be as fast as possible. The video from the camera is being streamed to the driver station via FFmpeg and being picked up on the driver station via FFplay. Right now we are getting a delay that we wish could go away or be significantly shortened. These are the commands we are using.

  


  


  • Raspberry Pi : ffmpeg -i /dev/video0 -c:v libx264 -crf 45 -maxrate 1M -bufsize 1.2M -preset ultrafast -tune zerolatency -filter:v fps=30 -f mpegts -omit_video_pes_length 0 udp://10.2.33.5:554

    


  


  • Driver Station : ffplay -fflags nobuffer -flags low_delay -probesize 32 -analyzeduration 0 -f mpegts -vf setpts=0 udp://10.2.33.5:554