mp4/mkv to webm (I see lots of posts going the other way but not TO webm)

[AshleyQuick]

What is recommended? I have avidemux and handbrake and neither seem to convert to webm. I've tried some online services but they max out at 100mb.

[Bernix]

Are you talking about webm container? Mentioned MP4 and MKV? So in avidemux choose copy video copy audio output format Webm muxer. But probably you mean audio and video format. So better ask about h264, h265, aac, ac3 and so on


Bernix

[AshleyQuick]

Are you talking about webm container? Mentioned MP4 and MKV? So in avidemux choose copy video copy audio output format Webm muxer. But probably you mean audio and video format. So better ask about h264, h265, aac, ac3 and so on


Bernix

I want to convert the entire file(s) from mkv to webm (audio and video). No quality/dimension increase or decrease.

[Bernix]

Ok, problem with avidemux is it not supported VP8 VP9 and other video conversion. But I believe KDENlive can export to webm easily. Lots of NLE software export to webm by default.


Edit - The problem is you have video in format that is not supported with webm container. If you have video in vp8 or vp 9 not in h263, h264 or h265 so there is no problem. You need to find software that can export video to VP 8 or 9 and audio to vorbis or opus. Then you can mux it to webm container in avidemux. But good luck with this video codec.
I wouldn't personaly touch anything to have something common with google with 10 foot long pole....




Bernix

[JVRaines]

Use FFmpeg.

ffmpeg.exe -i myinput.mp4 -c:v libvpx -crf 10 -c:a libvorbis myoutput.webm

[AshleyQuick]

Use FFmpeg.

ffmpeg.exe -i myinput.mp4 -c:v libvpx -crf 10 -c:a libvorbis myoutput.webm

Good timing. Just read on the avidemux forums that ffmpeg is suggested for this. Thanks.

[AshleyQuick]

Use FFmpeg.

ffmpeg.exe -i myinput.mp4 -c:v libvpx -crf 10 -c:a libvorbis myoutput.webm

Hey this just finished and the quality was noticeably reduced. Is there a tweak that will maintain the quality?

[JVRaines]

You can try a lower number for crf and add a few other options as well. See this page for details. You could also try the VP9 encoder.

[AshleyQuick]

Trying this now:

ffmpeg -i input.mp4 -c:v libvpx -qmin 0 -crf 5 -b:v 1M -c:a libvorbis output.webm

[gdx]

Better try this, a little slow but great quality (11 fps for a 720p video in a i7-7700HQ running at 2.8 Ghz):

"ffmpeg.exe" -i input.mp4 -c:v libvpx-vp9 -pass 1 -passlogfile logfile -crf 24 -b:v 1000k -minrate 10k -maxrate 4000k -threads 8 -deadline good -cpu-used 4 -tile-columns 0 -frame-parallel 0 -qmax 32 -auto-alt-ref 1 -lag-in-frames 24 -g 240 -aq-mode 0 -an -f null NUL
"ffmpeg.exe" -i input.mp4 -c:v libvpx-vp9 -pass 2 -passlogfile logfile -crf 24 -b:v 1000k -minrate 10k -maxrate 4000k -row-mt 1 -threads 8 -deadline good -cpu-used 1 -tile-columns 2 -tile-rows 0 -frame-parallel 0 -qmax 32 -auto-alt-ref 1 -lag-in-frames 24 -g 240 -aq-mode 0 -c:a libopus -b:a 96k -ac 2 -f webm "output.webm"