[theora-dev] Thanks again - request for info

Monty xiphmont at xiph.org
Thu Sep 26 19:51:28 PDT 2002

> Is the theora release's version of VP3 subject to any particular 'format'
> restrictions, such as being limited to a particular set of framerates,
> bitrates, frame sizes, or whatever?

The restrictions are roughly the same as the original VP3 (because
that's what theora still is :-) The frame width and height each must
be a maultiple of 16 (this is enforced by the encoder; it will rought
other input sizes down to the nearest multiple).

There are not framerate restrictions, and bitrate functions as in VP3.

>  I assume the example encoder takes its 
> settings (framerate, size) from the incoming yuv4mpeg stream?  


> Presuming I can get things worked out, would it be helpful for me to post
> a sort of micro-howto?

A micro-micro howto is alreade in the README. Feel free to add to it.

One question I haven't found an answer to, though: When outputiing
from mplayer into yuv4mpeg format, mplayer will not fill in frames the
original encoding dropped (eg, decoding a DiVX with dropped frames to
meet the bitrate target).  Because yuv4mpeg2 contains no timing
information, there's no way to tell the theora decoder that video just
lost sync with audio.

Is there an easy way that I'm missing to have mplayer fill in the
dropped frames?  If not, I'll have to hack one...

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