ffmpeg, codecs and debian

[Fabian Greffrath]

Hi Guy,

I forward your mail to the pkg-multimedia list, which is the 
appropriate place for questions regarding ffmpeg in Debian.

Guy Heatley schrieb:
> 1) I only downloaded the source for ffmpeg, not libavcodec52. Yet I
> needed to install *both* the newly compiled deb packages in order to
> achieve success. (Is this to do with build-dep or something?)

Ffmpeg and all its libraries are built from the same source code, so 
if you rebuilt the source you necessarily rebuild *all* the packages 
generated from this source. It should only be necessary to install the 
newly built libavcodec52 package, the ffmpeg frontend ist unaffected.

> Which one is disabled in Debian? i.e. Is the MPEG-4 encoder available in
> the standard debian libavcodec52, but ffmpeg has the disallowed codecs
> "unplugged", or, are both packages crippled?

MPEG4 encoders are removed from the Debian ffmpeg package, that is the 
reason the source is called ffmpeg-debian. The upstream ffmpeg source 
has all it's encoders enabled, of course.

> If the latter, how did I achieve success without installing the source
> for libavcodec52?

You installed the original unmodified sources when you ran the 
get-orig-source rule of debian/rules.

> 2) Now APT always tries to upgrade ffmpeg and libavcodec52 to the
> standard Debian packages. What is the best way to get apt to leave these
> packages alone?

If you are running stable, you could simply increase the debian 
revision number in debian/changelog from 0.svn20080206-17+lenny1 to 
e.g. 0.svn20080206-17+lenny1+guy1 before you rebuild the package.

> I think I could "hold" the package with aptitude:
> # aptitude hold ffmpeg

You will also need to hold libavcodec52.

> or
> recompile with my own version number in debian/control
> Probably the 2nd is better. Are there any pitfalls to doing this?

debian/changelog, yes, as I explained before. No, there are no 
drawbacks if you change the version number by adding "+something". the 
next possible security update will have "+lenny2" and override your 
privately created packages, though.

> I will produce a page with advice for people who want to do this
> modification to ffmpeg if you can clarify these points!
> (I am fairly new to building deb packages)

I hope this will be unnecessary in near future, because we plan to 
provide unstripped packages from a central ressource soon.

Cheers,
Fabian



-- 
Dipl.-Phys. Fabian Greffrath

Ruhr-Universität Bochum
Lehrstuhl für Energieanlagen und Energieprozesstechnik (LEAT)
Universitätsstr. 150, IB 3/134
D-44780 Bochum

Telefon: +49 (0)234 / 32-26334
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E-Mail:  greffrath at leat.ruhr-uni-bochum.de