ffmpeg - very slow conversion

Question

I create web app in JavaEE which displays many video formats. I use ffmpeg solution to convert videos to formats which is supported natively by main browsers.

According to : http://www.jwplayer.com/html5/formats/ I convert to WEBM container (VP8/VORBIS or VP9/OPUS). But conversion is very slow, bit rate equals to ~ 200kbits/s. To convert I execute following command

ffmpeg -i file.mov -c:v libvpx -preset ultrafast result.webm How to speed up conversion to natively supported formats by main browsers?

Solution

Use the -speed number (e.g. 8), not the -preset setting (e.g. ultrafast). The latter is for x264/x265 encoding.

A Higher number means faster encoding, so ultrafast would map to 8 or so. Very slow/placebo maps to 0, and values in between map accordingly. 1-2 still gives reasonably good results and settings like 4-5 tend to be relatively fast but not entirely crap quality.

Comments

[karoluch]

I set speed argument to 16 but it is still to slow for me, ffmpeg 13MB mov file converts to 7b webm file within 30 seconds. Are there any other arguments to speed up conversion? Probably ffmpeg server can help me with stream file 'Live'?

[Ronald S. Bultje]

Try -deadline realtime -cpu-used -16 (-cpu-used is the same as -speed), that's a realtime setting, the quality will definitely suffer but it'll be significantly faster. Also make sure you're running a recent libvpx+ffmpeg version.

[karoluch]

Ok, I used it before. Thank you ;)

[Eric]

I didn't see -speed or -cpu-used in man manual of ffmpeg ... , and wondering what's the default cpu count to use, if not specified.

[Eric]

In my test, -preset ultrafast makes it faster, and -speed 8 doesn't make any change.