[Theora-dev] HD WMV9 videos for download...

[Christoph Lampert]

On Sun, 19 Sep 2004, illiminable wrote:
> Came across this page... intended to showcase the high-end capabilities of 
> WMV9...
> 
> http://www.microsoft.com/windows/windowsmedia/content_provider/film/ContentShowcase.aspx
> 
> Just thought some people might be interested in it to make some 
> comparisons... and it's also probably some of the highest quality sample 
> material i've found on the net... 

The highest quality HD-material I know of (just test sequences, not 
movie-like) are the 1080p/1080i//720p HDTV-test clips available at 
TU Muechen: 

ftp://ftp.ldv.e-technik.tu-muenchen.de/pub/test_sequences/
http://www.ldv.ei.tum.de/liquid.php?PRINTVIEW=1&page=70

It's uncompressed YUV 4:2:0, which is a major difference to all other 
HD-sources I know of, because high frequencies aren't quantized away. 
It's amazing how bad codecs start to behave if you feed them with 
uncompressed input instead of the typical DVD-"quality" VOBs. 


> so it's also useful for me to use as 
> source material for testing high res transcoding in theora... and 6 channel 
> audio in the highest res.

I did some transcoding testing with those for XviD a while ago. It's
rather easy to recompress at much lower bitrate at no real visible
differences. I guess that's because WMV is somewhat close to MPEG-4, and
in particular, these WMV files are intended for HD-DVDs and not tweaked to
get the most out of the bitrate. So, if Theora performs well, that's a
good sign, but don't get too excited.

Christoph