cloud engineer
If your audio is out of sync, you can fix using ffmpeg.
ffmpeg -i source.mp4 \ -i livestream.mp4 \ -map 0:0 -map 1:1 \ -acodec copy \ -vcodec copy \ -itsoffset 0.100 \ output.mp4 |
ffmpeg -i source.mp4 \ -i livestream.mp4 \ -map 0:0 -map 1:1 \ -acodec copy \ -vcodec copy \ -itsoffset 0.100 \ output.mp4
The ffmpeg fix is fast. A 1GB file took less than 30 seconds to run. Adjust -tsoffset until you find the sweet spot.
If you have a video with audio sync issues, you can easily fix it using ffmpeg. It takes 2 inputs: the filename and delay: 0.100 is 100 ms or 0.1 seconds. Output file has -fixed appended to it. It’s fast. Only takes 2-3 seconds to process a 1.5 hour recording.
Here’s the script.
ffmpeg -i livestream.mp4 \ -itsoffset 0.100 \ -i livestream.mp4 \ -map 0:0 -map 1:1 \ -acodec copy \ -vcodec copy \ livestream-fixed.mp4 |
ffmpeg -i livestream.mp4 \ -itsoffset 0.100 \ -i livestream.mp4 \ -map 0:0 -map 1:1 \ -acodec copy \ -vcodec copy \ livestream-fixed.mp4
How to convert MP3 to OGG audio format.
ffmpeg -i in.mp3 -ar 48000 -vn -c:a libvorbis out.ogg |
ffmpeg -i in.mp3 -ar 48000 -vn -c:a libvorbis out.ogg
If you have sample rate errors, use -vn.