FLOSS Multimedia Support in Fedora

Dominik 'Rathann' Mierzejewski dominik at greysector.net
Mon Feb 9 11:20:20 UTC 2009


On Monday, 09 February 2009 at 04:35, Gregory Maxwell wrote:
> On Sun, Feb 8, 2009 at 10:08 PM, Kevin Kofler <kevin.kofler at chello.at> wrote:
> > Gregory Maxwell wrote:
[...]
> >> Some of the proprietary-codecs focused tools provide their own home
> >> grown implementations of the codecs (i.e. ffmpeg).

FFmpeg is NOT proprietary-codecs focused. It just strives to be able to decode
any audio and video codec and demux any container that has ever been used.

> >> These often do not
> >> implement the full spec, so its important to test their behaviour.
> >
> > Huh? FFmpeg uses libvorbis and libtheora.
> 
> Only optionally, unfortunately. I.e. see ffmpeg libavcodec/vp3.c.

What's unfortunate about that? libtheora and libvorbis are not written
in an optimal way according to FFmpeg developers.

> Or try playing http://people.xiph.org/~xiphmont/test-vectors/vorbis/lsp-test.ogg
> with something that uses ffmpeg (like mplayer): crackles and sputters.
> The ffmpeg Vorbis decoder doesn't implement the full spec, only the
> more commonly used parts.

Indeed, thanks for the sample. The bug is now tracked at:
http://roundup.ffmpeg.org/roundup/ffmpeg/issue829

> FFmpeg even ships its own totally broken Vorbis encoder that delivers
> miserable quality even at high bitrates, which it uses if you ask for
> "vorbis". :(   It's really a mess.
> 
> There is a culture of associated with many of these proprietary codec
> libraries where they use their own version of everything— which
> reduces dependency problems, and isn't a big deal for the non-free
> codecs where their is no official version.  But at as a result of this
> plus an overall indifference towards free codecs, support for the free
> stuff generally stinks in these libraries.  I have no interest in
> fixing FFmpeg's Theora and Vorbis codecs, they should be using the BSD
> licensed reference implementations, other people with the expertise
> feel the same way.  FFMpeg wants to have their own version for their
> own reasons. ::shrugs:: It has been this way for years, it's an
> upstream problem, and I don't think Fedora should count on fixing it,
> especially since Fedora will never ship these pieces of software
> except in highly patched and cut down forms.

While I agree that FFmpeg's Vorbis implementation has its own problems,
I resent your suggestion that there is a "proprietary codec culture"
at FFmpeg. Most of FFmpeg developers are from the Europe, where
software is generally not patentable, so they simply don't care about
stupid US patent law. H.264 codec has an open specification and is
superior to ANY libre video codec, maybe excluding Dirac (but Dirac
is incomplete and Snow is better anyway). Also it is one of the most
popular commercially used codecs, so it's only natural that there is
significant interest in having a superior implementation of it in FFmpeg.

Regards,
R.

-- 
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"Faith manages."
        -- Delenn to Lennier in Babylon 5:"Confessions and Lamentations"




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