Recherche avancée

Sur d’autres sites (5083)

• ffmpeg simple 5fps webcam capturing but results in poor performance

  16 septembre 2022, par irous

  I'm using Windows 10, intel core i5, 8GB ram. and download ffmpeg from official site : https://www.gyan.dev/ffmpeg/builds/

  


  I'm trying to capture 5fps video from webcam but the output fps is only 3.4 and speed is 0.668x. (I also tried with libx264 but the speed is same 0.5).
  
This is my command :

  


  ffmpeg ^
  -f dshow -r 5 -s 640x480 -i video="Sony Visual Communication Camera" ^
  -f rawvideo output.raw


  


  screenshot of console output :


  


  The cpu usage for above ffmpeg command is about 0.1% and also ram/disk usage is relatively low.
  
If I change the fps to 30 (-r 30), the output is : fps 7.9, speed 0.261x and CPU usage is still very low 0.1%.

  


  But I can easily record 30fps video with the same format yuyv422 in Directshow GraphEdit :


  


  So my question is why does ffmpeg show such poor performance even with 5fps video capturing ? If it can only produce 3.4 fps in the first case why it can output up to 7.9 fps in the latter case (when I set desired fps to 30) ? Did I mis-config ffmpeg ?
  
Any help is appreciated.

  


• Convert JPG to MP4 and then concatenate other MP4 with them results in Non-monotonous DTS in output stream error

  25 août 2022, par Babagota

  I know this question has been answered but this isn't similar to my case.
I have many mp4 files that are all the same size, audio, ...

  


  01.mp4
...
25.mp4


  


  And I also have many jpg (all same size as my MP4) that I want to convert to 5s MP4 videos.
I used to convert them by using :

  


  ffmpeg -loop 1 -i myimage.jpg -t 5 myvideo.mp4


  


  Which produces an MP4 video of 5s, but when I want to concatenate all my previous MP4 with MP4 created from JPG with the following command :

  


  ffmpeg -f concat -safe 0 -i allmyvideos.txt -c copy all.mp4


  


  Then I have multiples errors/warnings :

  


  [mp4 @ 0000029eed493f80] Non-monotonous DTS in output stream 0:1; previous: 278633, current: 251856; changing to 278634. This may result in incorrect timestamps in the output file.


  


  And output is weird (freezing frames, ...).

  


  If I concat all my MP4 without the MP4 from JPG, I don't get any error and the output is fine.
So I guess that the problem is when I'm converting JPG.
I tried to add an empty audio to it, with the same sample rate as my MP4 :

  


  ffmpeg -y -f lavfi -i anullsrc=channel_layout=stereo:sample_rate=22050 -loop 1 -i myimage.jpg -c:v copy -c:a aac -shortest -t 5 myvideo.mp4


  


  But I have the same error.
Any help appreciated, thank you.

  


• ffmpeg Node Screen recording does not have audio

  8 avril 2024, par user2500558

  I am building a screen recording application using fluent-ffmpeg.

  


  let command = ffmpeg({ source: '1:0' })
command.inputFormat('avfoundation')
command.fps(60)
command.videoCodec('libx264')
command.audioBitrate('320k')
command.audioCodec('libmp3lame')
command.addOption('-pix_fmt', 'yuv420p')
command.save('output.mp4')


  


  I am able to record the screen, but the audio of the screen is not being recorded. For example : When I play a YouTube clip and record my screen, the video will be there but the audio from the YouTube clip not.

  


  Am I missing an option in ffmpeg ? I cant get the screen audio (I am not talking about a microphone).

  


  Edit : I want to use ffmpeg instead of Electrons desktopCapture as ffmpeg has more options and is more powerful.