[theora] Marketing stuff

[Maik Merten]

Aaron Colwell schrieb:
> In my opinion I believe that these claims are anecdotal at best. Has
> anyone actually
> done a true bake off between Theora and the codecs mentioned? Has anyone
> done PNSR
> vs bitrate or similar comparisons across a large and diverse body of
> content? For
> me these types of comparisons are far more compelling than a zoomed in
> area of a single
> frame where the deblocking filter happened to do a good job.

First of all PSNR is of course no usable quality metric. Nothing but
human eyes can judge quality, which is what makes tuning codecs a
non-trivial thing.

I'm doing claims regarding some codecs that happen to not have an
in-loop deblocking filter. From today's point of view they are dated but
still widely used.

At extremely low bitrates the lack of advanced deblocking obviously is a
problem:

http://people.xiph.org/~maikmerten/sign_irene_484_mpeg4-2.png

http://people.xiph.org/~maikmerten/sign_irene_484_theora.png

(no postprocessing applied, QCIF, 25 fps, ~130 kbps)


The obvious problem with this small comparision is the "no
postprocessing applied", which is a pretty uncommon setup for MPEG-4
Part 2 as most players *do* apply some postprocessing (so quality also
does depend on the player software). Then again most players *don't*
apply postprocessing on Theora albeit the library offers powerful
built-in postprocessing (which is not enabled by default). Finding a
common and fair ground for comparisons sadly isn't trivial.


To put it into a nutshell:

I did some tests to make sure I am not making completely misguided
statements - but to be 100% fair I perhaps indeed should not mention any
competing codecs until there's an exhaustive set of experimental results.

Thanks for your input.


Maik