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• Realtime recording in multiple encodings python

  3 janvier 2015, par erip

  I am working on a project that requires audio recording and am using python. I would like to use a start button to begin recording and a stop button to stop it. Additionally, I’d like to support multiple filetypes like .wav, .mp3, .aiff.

  As far as I know, there doesn’t exist something that can do this "in one go", meaning I could record something as a .wav and then post-process the file to encode it in different formats using ffmpeg or a similar library.

  This presents a small problem because my project is web-based, so I would have to save the .wav and then save the .*.

  Does anyone know of another solution to my problem ?

  Thanks, erip

• How do I correctly pause and resume recording with ffmpeg without messing with the fps ? [closed]

  8 mai 2024, par 10typesofpeople

  I am recording desktop video and audio with ffmpeg. I am controlling the process with c#. Simplified, my ffmpeg arguments are "ffmpeg -f gdigrab -framerate 30 -i desktop -preset ultrafast -pix_fmt yuv420p output.mp4"

  


  I have some functionality to pause and resume the recording, essentially just suspending and resuming the process. This works, however, it leaves the paused section in the video, just one frame for the entire duration. To fix this, I added "-vf setpts=N/FR/TB" yo the arguments. This resolved that issue, but while recording my framerate was 1.3 fps rather than 30 and the video duration was only a few seconds instead of the minute it so it should have been. The video was also obviously quite sped up.

  


  How do I use "setpts" without it affecting the video in this way, or what alternative do I have to prevent an extended frame in the middle of the recording ?

  


  TLDR : "-vf setpts=N/FR/TB" affects framerate and playback speed in ways I don't understand.

  


• Mjpeg recording with FFMPEG preserving time information

  14 septembre 2012, par Muhammad Adeel Zahid

  I am recording the MJPEG video from an IP camera and saving it to a file but the problem is that file's duration is way smaller than the actual recording time. Its around 9 seconds video for 2 minutes recording. I tried following commands in order

  ffmpeg -f mjpeg -r 8 -i http://c-cam.uchicago.edu/mjpg/video.mjpg -vcodec mpeg4 -b 1000000 -r 8 video_file.avi 

  Then I omitted the most of the flags and tried like this

  ffmpeg -f mjpeg -i http://c-cam.uchicago.edu/mjpg/video.mjpg video_file.avi

  But the problem is that the duration of recorded file is 9 seconds where as the actual recording time is around 2 minutes. I finally tried setpts filter that is supposed to insert the timestamps. The command is as follows

  ffmpeg -f mjpeg -i http://c-cam.uchicago.edu/mjpg/video.mjpg -vf "setpts=1*PTS" video_file.avi

  But result was still the same. Recording time was way more than video duration. How can I add presentational time stamps when recording from mjpeg source using ffmpeg ?