Or add -strict experimental (or the alias -strict -2) if you are stuck with outdated ffmpeg.

Use a newer ffmpeg as Opus in MP4 is no longer experimental in newer ffmpeg versions.

If you get this error: opus in MP4 support is experimental, add '-strict -2' if you want to use it.Ĭould not write header for output file #0 (incorrect codec parameters ?): Experimental feature Point being, the -c part is the same meaning in both cases.) If you get error: 'opus in MP4 support is experimental' Step 2: Now create a folder with the name FFMPEG in the C drive of your windows and then paste the copied files. (Note that if you were copying only the video and not the audio, you would use -c:v copy instead of -c copy. With these simple steps, you can now FFmpeg convert WebM to MP4: Step 1: First, you will need to go to and download FFmpeg for the conversion. No re-encoding occurs, so no quality is lost and the process is very fast. This will copy the VP9/VP8 video and Opus/Vorbis audio from WebM to MP4. If you want to stream copy (re-mux) and avoid re-encoding: ffmpeg -i input.webm -c copy output.mp4 So your output mp4 file info ( ffmpeg -i. You configure ffmpeg to generate new pts (a.k.a Presentation TimeStamp) for each frame and you set the target frame-rate to 24. So by calling : ffmpeg -fflags +genpts -i 1.webm -r 24 1.mp4 The encoder generate a different result, 16k tbn, 1k tbc (default) But I have one stream with an additional audio track.I was able to convert by ffmpeg -i video.webm -strict experimental video.mp4.Īs your input file report a strange frame rate value 1k fps coming from the tbs and tbr value (look here for their definition) The examples just show how to convert to mp4 when you have 2 single streams (audio and video).

Now I want a mp4 file and checked the ffmpeg.js from muaz-khan. If your input file is having both Audio & Video, then you need to specify output codec for both tracks here as following. As per the provided code sample, your recorder stream is having only one audio & one video tracks.

Ffmpeg copy codec webm to mp4