[theora-dev] Theora file size

Unga unga888 at yahoo.com
Sat Oct 7 07:49:53 PDT 2006

--- David Kuehling <dvdkhlng at gmx.de> wrote:

> two things come to my mind:
> * AFAIK macro-blocks are smaller in Theora than they
> are in MPEG4.
>   Theora is thus not as well-suited for HDTV content
> as MPEG4.
> * What is Y4M, and how did you feed your Y4M-File
> into encoder_example?
>   Are you sure that the Theora file and the
> MPEG4-File you created have
>   the same chroma sampling?  Else it wouldn't be a
> fair comparison.
>   Actually I doubt that Theora and MPEG4 currently
> work with anything
>   else than YUV12, but who knows...

Y4M is YUV4MPEG2, which is YUV12.

./encoder_example -o movie.ogg -v 10 movie.y4m

> BTW there is a hidden option in encoder_example that
> allows trading file
> size for sharpness.  Might be a good idea to
> sacrifice some sharpness
> for HDTV content.  Also you can increase the
> keyframe distance.  I
> attach the patch of my local copy of
> encoder_example.c, that was "tuned"
> that way.

I have applied your patch. I even made ti.quick_p=0.
But result is still the same:

movie.ogg         61742755 bytes

movie-192-256.ogg 61742755 bytes

Is there a way to know either from the movie or from
the encoder_example what are its keyframe_frequency
and keyframe_frequency_force values?


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