[gst-devel] Tell me about y4menc and other encoders.

[Benjamin M. Schwartz]

On 12/03/2010 04:53 PM, wally_bkg wrote:
> I first tried: jpegenc, mpeg2enc, and theoraenc.  I could eliminate mpeg2enc
> from a combination of too high CPU load and too low video quality (using
> only the defaults).

All of these elements take an argument that allows you to specify your
desired bitrate/quality.  There's nothing especially great about the
defaults, which may be incomparable from one element to another.

> Both
> pipelines seem to work OK but CPU usage seems high with theoraenc being
> about 40% more CPU but with about half the file size of jpegenc.

This is not a surprise.  Theora compresses video by comparing frames to
each other, while JPEG compresses each frame independently.  Theora will
always achieve better quality in the same output filesize, but will use
more CPU.

   My
> problem here is while the files play back fine in Totem, there is something
> wrong with them if I try to play them on a Windows system (that is set up
> for MJPEG and OGG/Theora).

If you want help debugging this you'll need to be more specific about the
playback system and the problem.  Latest VLC generally plays back Theora
correctly under Windows.

> Then I discovered y4menc:
> while it gives about 30X the file size of theoraenc it uses very little CPU,
> less than half of the jpegenc pipeline. 

y4m is uncompressed lossless raw video.  Maybe you would enjoy
http://xiph.org/video/vid1.shtml

--Ben

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