[theora] Theora blurriness in Windows players

Basil Mohamed Gohar abu_hurayrah at hidayahonline.org
Sat Feb 6 20:56:31 PST 2010

I just finished using my mother's PC which is running Windows XP.  I
downloaded & installed, or already had installed, the latest versions of
VLC Media Player (1.0.5), Media Player Classic - Home Theater (last
release was in August 2009), Miro (already installed), Mozilla Firefox
(3.6), Google Chrome (latest from website today), Opera (10.50 Alpha,
latest build from the website), and SMplayer (the recommended GUI for
Mplayer on Windows, apparently, again, latest from website today).

ALL of the players, with the exception of Mozilla Firefox (3.6) & Google
Chrome displayed significant blurriness.  In fact, the sharpest render
came from Mozilla Firefox, something I found quite interesting.  Miro
may or may not have had the same issue, but it crashed while playing the
file, after first saying it didn't support Ogg Theora files (!), AFTER
showing a preview.  It then played it the second time I tried to load
it, but then crashed.  I was unable to play a video standalone in Opera
- I suppose this is because it supports playing the videos within
<video>, but not as a standalone file (i.e., directly from the URL).  I
did not take the time yet to prepare a simple page to replicate this
test in that manner.

The two files I used for testing were the following:


What inspired me to make this test is the fact that gmaxwell (I think)
in #theora mentioned the problem, and linked to a reddit comment he made
in response to someone's criticism of libtheora's quality compared with
some H.264 video.  I thought to just test VLC first, but when I noticed
it again in SMplayer, I just decided to test all the players that I
could find.  After this test, I am much dismayed to find that the vast
majority of users will be experiencing subpar Theora performance, as
outside of Firefox & Google Chrome, the blurriness appears to be
present.  I am fairly sure that all of the above-mentioned media
players, aside from Firefox, use some form of libav*.  However, I
thought Google Chrome likewise used an ffmpeg-based video library, which
I thought was libav*.

I believe this to be a significant hindrance to adoption of Theora as
video standard, because the latest versions of a wide variety of players
all appear to display this bug.

Notably absent is any mention of Xiph-based decoders, such as DirectShow
filters.  I did not take the same to test those yet, but perhaps I will
take some more time and do that on my own PC.

      Basil Mohamed Gohar
abu_hurayrah at hidayahonline.org
basilgohar on irc.freenode.net
GPG Key Fingerprint:  5AF4B362

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