[theora-dev] Theora file size

[Unga]

--- Maik Merten <maikmerten at gmx.net> wrote:

> You can try increasing decreasing the keyframe
> interval. The default is 
> suitable for streaming (which is what Theora seems
> to be most successful 
> in and where it's important to have a usable picture
> after a few 
> seconds), so the it's placing a keyframe every 64
> pictures. XviD places 
> far fewer keyframes, thus making streaming less
> viable but saving on 
> file size.
> 
> in encoder_example.c you can toy around with
> following values
> 
> 
>    ti.quick_p=1;
> 
> Setting this to 0 makes encoding much slower, but is
> supposed to predict 
> motion better.
> 
>    ti.keyframe_frequency=64;
> 
> You can increase this to 500 or so ;
> (keyframe usally after 20 seconds on with a 25fps
> video)
> 
>    ti.keyframe_frequency_force=64;
> 
> You can increase this to 1000
> (force keyframe after 40 seconds (when input is
> 25fps) so you can still 
> seek)
> 
>    ti.noise_sensitivity=1;
> 
> You can toy around with this, too (I think valid
> values or 0, 1 or 2)
> 
> I think you can shave off a fare bit from Theora
> filessize. XviD, 
> however, is simply a very very good MPEG4 encoder
> which has received 
> plenty of tuning. It has a very good performance and
> would be perfect if 
> it wasn't using patented methods.
> 
> Theora reference encoder in it's current form
> performs more like a MPEG4 
> encoder from around 2000. The Theora spec defines
> some advanced features 
> that could inrease coding efficiency a lot - but
> there's no encoder yet 
> using those features.
> 
> To put it into a nutshell:
> 
> Theora is stable and usable
> Theora is perfect if you don't want to pay licensing
> fees
> Theora is not as efficient as XviD or other highly
> tuned encoders 
> (especially when using 2 pass encoding - which
> Theora doesn't have), 
> although there is room for improvement
> 

Thanks for the reply. I have changed ti values but it
did not change the file size. Please see my previous
post.

Regards
Unga

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