We’ve made our ogg video derivatives slightly better via:
- minor bump up to “thusnelda” release
- “upgrade” from 1-pass video encoding to 2-pass video encoding
- direct ffmpeg creation of the video (you’ll need to re/compile ffmpeg minimally with “–enable-libtheora –enable-libvorbis” configure flags)
ffmpeg -y -i ‘camels.avi’ -q:vscale 3 -b:v 512k -vcodec libtheora -pix_fmt yuv420p -vf yadif,scale=400:300 -r 20 -threads 2 -map_metadata -1,g:0,g -pass 1 -an -f null /dev/null;
ffmpeg -y -i ‘camels.avi’ -q:vscale 3 -b:v 512k -vcodec libtheora -pix_fmt yuv420p -vf yadif,scale=400:300 -r 20 -threads 2 -map_metadata -1,g:0,g -pass 2 -map 0:0 -map 0:1 -acodec libvorbis -ac 2 -ab 128k -ar 44100 -metadata TITLE=’Camels at a Zoo’ -metadata LICENSE=’http://creativecommons.org/licenses/by-nc/3.0/’ -metadata DATE=’2004′ -metadata ORGANIZATION=’Dumb Bunny Productions’ -metadata LOCATION=http://archive.org/details/camels camels.ogv
some notes:
- You’d want to adjust the “scale=WIDTH:HEIGHT” accordingly, as well as the “-r FRAMES-PER-SECOND” related args, to your source video.
- I made a small patch to allow *both* bitrate target *and* quality level for theora in ffmpeg, after comparing the other popular tool “ffmpeg2theora” code with the libtheoraenc.c inside ffmpeg. It may not be necessary, but I believe I saw *slightly* better quality coming out of theora/thusnelda ogg video. For what it’s worth, my minor patch is here: http://archive.org/~tracey/downloads/patches/ffmpeg-theora.patch
- The way we compile ffmpeg (ubuntu/linux) is here. (Alt MacOS version here )
- (Edited post above after I removed this step)
It’s *quite* odd, I realize to have ffmpeg transcode both the audio/video together, only to split/demux them back out temporarily. However, for some videos, the “oggz-comment” step would wipe out the first video keyframe and cause unplayability in chrome (and the expected visual artifacts for things that could play it). So, we split, comment the audio track, then re-stitch it back together.
Thanks for this. I still prefer Ogg Theora for encoding 480p MPEG2 captures in a compressed format.
actually, looks like I can simplify this (after one of our vids came up with a surprisingly wrong/long duration in the final step above) to these two simpler lines:
ffmpeg -y -i ‘camels.avi’ -q:vscale 3 -b:v 512k -vcodec libtheora -pix_fmt yuv420p -vf yadif,scale=400:300 -r 20 -threads 2 -map_metadata -1,g:0,g -pass 1 -an -f null /dev/null;
ffmpeg -y -i ‘camels.avi’ -q:vscale 3 -b:v 512k -vcodec libtheora -pix_fmt yuv420p -vf yadif,scale=400:300 -r 20 -threads 2 -map_metadata -1,g:0,g -pass 2 -map 0:0 -map 0:1 -acodec libvorbis -ac 2 -ab 128k -ar 44100 -metadata TITLE=’Camels at a Zoo’ -metadata LICENSE=’http://creativecommons.org/licenses/by-nc/3.0/’ -metadata DATE=’2004′ -metadata ORGANIZATION=’Dumb Bunny Productions’ -metadata LOCATION=http://archive.org/details/camels camels.ogv
I will update the above post in 1-2 days after large-scale battery of testing completes…
A very interesting challenge and adventure which I hope to be using quite often and a very interesting site for using time wisely. Something I hope to be using in the future for learning and for a passtime.