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• ffmpeg make : *** No rule to make target 'distclean'. Stop

  11 octobre 2016, par Djave

  I’m installing ffmpeg using this guide https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu on a Digital Ocean droplet.

  I’ve run all the commands down to

  $ make distclean

  and after I do this I get the error

  make: *** No rule to make target 'distclean'.  Stop.

  How can I get past this step ?

• How to reduce CPU usage on ffmpeg when recording screen (Mac)

  23 septembre 2018, par Gabrielle

  I am trying to record my screen using ffmpeg, but the CPU usage grows A LOT, it gets to 85% of CPU and 20 threads... after 1 hour recording it is impossible to use the computer.

  I’ve tried to set threads=2 to reduce the 20 (I can see the threads on the Activity Monitor) but it didn’t work at all..

  This is the command I am using :

  ffmpeg -threads 2 -f avfoundation -i 1 -capture_cursor 1 -capture_mouse_clicks 1 -video_size 2560x1600 -b:v 2M -maxrate 2M -bufsize 1.5M -tune zerolatency -crf 17 -preset ultrafast -pix_fmt yuv420p -qp 0 -r 20 video.mkv -y -an

  I’ve tried to use .mkv and .mov and there is not much of a difference, others shows a very poor quality, I’ve tried to increase crf, decrease b and maxrate.

  Any idea of how to reduce the CPU usage ? I am already with a terrible video quality (transitions are a mess) and on top of that, I have my computer very slow...

  I know that stack already has some answers to it, but (1) none of them solved/helped my issue ; (2) they are a little bit old, so, maybe new versions came with new solutions to it...

• FFmpeg : Cut from live stream RTSP

  10 septembre 2020, par Jax2171

  I cannot solve my problem and I have not found any solution.

  


  I capture an rtsp stream from an ip camera via the command :

  


  ffmpeg -stimeout 2000000 -abort_on empty_output -rtsp_transport tcp -i rtsp://admin:admin@192.168.1.15/av0_0 -c:v copy -c:a aac -f mpegts -y rec.ts


  


  The native video codec is h264 while the audio one is pcm. I capture the video stream without compression and compress the audio in aac to make it compatible with the ts container.

  


  I need to extract portions of video of X duration through during the capture. The command I use is :

  


  ffmpeg -ss X-i rec.ts -c:v copy -c:a copy -t Y -f mp4 -stimeout 60 -y cut.mp4


  


  Everything seems to work fine with no errors. However, the cut file has a slightly longer audio length than the video length. Sometimes the difference can be up to 1 second.

  


  My problem is that I have to chain all the cuts I make, and this difference in duration causes a very annoying lag between one video and another.

  


  It also happens that there is asynchronousness between audio and video in the cuts. The higher the -ss value, the more the audio anticipates the video.

  


  I state that I am not a professional but from what I have read it could be a problem of different PTS between audio and video, but I'm not sure. However, I am sure that the problem arises from the capture of the stream perhaps not in accordance with my needs.

  


  How can I solve ?