[theora] Range Coding

[Hrishikesh Kulkarni]

Hello,

But can we get an overall gain by using range coding over the coding
used in libtheora1.1.1.

I tried dumping tokens and coding it with the range coder given by
http://www.compressconsult.com/rangecoder
The ogv file i get from the theora which has the information, extra
bits and coded tokens(by VLC) is smaller than the file i get
from coding only tokens with the range coder.

Have anyone tried this? Or Anyone who can guide me where i am goin wrong?

Regards,
hrishi

On Mon, May 17, 2010 at 9:55 PM, tterribe <tterribe at email.unc.edu> wrote:
>
>> Timothy Terriberry estimates a simple self-training range-coding
>> backend could be reasonably expected to decrease bit usage overhead by
>> 15-20%.
>>
>> Is it really true? I found one implementation....
>> http://svn.xiph.org/trunk/ghost/libentcode/
>>
>> Did anyone verified this gain? How much is the exact gain?
>
> The number quoted there comes from the result of similar experiments
> performed during the development of H.264 (they're in the JVT archives
> somewhere, but it's been years since I actually looked for this particular
> one). I think I originally told Monty "12-20%", but the exact number isn't
> really important as it varies from sequence to sequence, and also depends
> on how one sets up the context modeling, which is still more of an art than
> a science. No one has measured an exact value for Theora, that I know of.
> _______________________________________________
> theora mailing list
> theora at xiph.org
> http://lists.xiph.org/mailman/listinfo/theora
>

On Mon, May 17, 2010 at 3:46 PM, Hrishikesh Kulkarni
<hrishikeshkulkarni at gmail.com> wrote:
> Dear all,
>
> I have been going through below mentioned update.
>
> http://web.mit.edu/xiphmont/Public/theora/demo.html
>
> I found this line-
> Timothy Terriberry estimates a simple self-training range-coding
> backend could be reasonably expected to decrease bit usage overhead by
> 15-20%.
>
> Is it really true? I found one implementation....
> http://svn.xiph.org/trunk/ghost/libentcode/
>
> Did anyone verified this gain? How much is the exact gain?
>
> Regards,
> hrishi
>