[MPlayer-DOCS] [PATCH] new section: muxing

[Jeff Clagg]

On Tue, Apr 12, 2005 at 01:16:18PM +0000, Guillaume POIRIER wrote:
> Hi,
> Here's a work-in-progress patch towards mencoder.xml.
> 
> Please comment, review.
> 
> Guillaume

>    You can also extract the AC3 stream in order to mux it into containers such
>    as NUT, Matroska or OGM.
> -  <screen>mplayer source_file.vob -aid 129 -dumpaudio -dumpfile sound.ac3</screen>

IMO it would be very bad for MPlayer's image if the official docs in any
way reccommend using OGM. I also think that a guide explaining how to do
so would not be a benefit to the users. Users should never be encouraged
to mux to OGM, not even by the most indirect suggestion. A truly helpful
OGM encoding document would be one that helps the user deal with the
(rather genuine) difficulties of re-muxing OGM files into saner formats.

> +  Now that you have you encoded video, you will more than likely want
> +  to mux it with one or more audio tracks into a movie container, such
> +  as AVI, OGM, Matroska, or NUT.

OGM should be removed from this list, since merely mentioning it may
confuse impressionable newbies into actually doing it. NUT should come
with a disclaimer that it isn't ready for production use yet. The spec
is considered unfinished, and afaik even the current spec isn't
implemented anywhere (but an older version is implemented).

> +  samples).
> +  Unfortunately, the most efficient codec, Vorbis, does not meet
> +  either of these requirements.
> +  Therefore, if you plan to store your movie in AVI, you'll have to
> +  use a less efficient codec such
> +  as MP3 or AC3.

Vorbis is impressive, but it's misleading to claim that it's the most
efficient codec. Also, Michael Niedermayer recently committed an
implementation of vorbis-in-avi in ffmpeg (whether it is actually a good
idea to use this is another question).

> +  The matroska project is a free, open standard container format,
> +  aiming to be able to offer a lot of advanced features, which
> +  older formats like AVI can't handle, on an extensible basis.
> +  Matroska supports for example the storage of Variable Bitrate audio
> +  content (VBR) without any hassles, Variable Framerates (VFR),
> +  Chapters, attachment of files, Error Detection (EDC) and modern
> +  A/V Codecs like "Advanced Audio Coding" (AAC), "Ogg Vorbis" or
> +  "MPEG-4 AVC" (H.264), next to nothing handled by AVI.

VBR audio in AVI works fine with mencoder and maybe some other encoders.
There are also a few pieces of software that screw it up royally, but
this doesn't mean it doesn't work, or that it is a hassle for the user.
As for H.264, most of the useful features of it do not necessarily pose
any special problem for AVI. AAUI, Arbitrary slice ordering is probably
untenable in AVI, but I doubt most users would use it anyway. I'm not an
expert, but I think it is mainly intended for providing error resiliance
in streaming environments.

AVI sucks, and it's great to encourage users to learn about
alternatives. But I don't agree with the tactic of scaring and confusing
users away from the format. And in any case, that exact tactic has been
employed for years, and it has had virtually no effect on the mass market.

Also, most container formats suck, badly. It seems like zealotry to
single out only AVI.