[Audacity-cvs] FFmpeg 0.5 WAS: lib-src/ffmpeg/libavutil avutil.h...

[Reinhard Tartler]

LRN <lrn1986 at gmail.com> writes:

> Reinhard Tartler wrote:
>> Please keep the CC in tact, and feel free to forward my mails to the
>> audacity mailing lists.
>>
>> LRN <lrn1986 at gmail.com> writes:
>>> Of course, it is possible to add special code to preserve it, but tell
>>> the user that it is not available, but that's still disappointing for
>>> the user. With libamr at least there *was* a possibility for the user
>>> to build amr-enabled libav*, or get it illegally from somewhere. With
>>> Opencore it's simply not there.
>>>     
>>
>> I don't see why it would be more difficult to build ffmpeg against
>> opencore amr compared to build against libamr. Can you please elaborate
>> here?
>>   
> Amr-wb encoding is not implemented in Opencore amr -> ffmpeg does not
> support amr-wb encoding (unless libamr is used, but noone likes libamr)

It might be me clueless, but from my reading of ffmpeg-devel, amr-wb
encoding is not available and not considered as a big problem, because
amr-nb is supported and supposed to be way more common.

However as soon as opencore gets extended to encode amr wb as well, that
support can be enabled in ffmpeg as well.

> -> Audacity does not support amr-wb encoding with or without ffmpeg ->
> advertising amr-wb export support to users is not fair, because it will
> not be available no matter what you do (well, except for using ffmpeg
> with libamr, but that's a rare exception, and also requires Audacity to
> support two different libav* versions, because Opencore amr and libamr
> are mutually exclusive in libav*, that is - they had libamr removed from
> libavcodec roughly the same time they added Opencore amr).

Besides, libamr support is being removed from ffmpeg trunk. Users who
want to link against libamr are encouraged to get an earlier snapshot
the 0.5 release.

> Opencore amr support is a most desired feature, and it's not available
> in 0.5. That is why i rushed to post-0.5 trunk.
> If 0.5.1 comes out with Opencore amr support, i'll just settle with 0.5.1.

Debian and ubuntu already ship a version that is opencore amr
capable. It is not enabled because the openamr package is not available
yet, though.

so it's more or less just a matter of switching the branch to track.

>> Now gst-ffmpeg is still built against an internal copy, but it at least
>> matches the version pretty close to the version it is used with.
>>   
> Last time i checked, gst-ffmpeg links libav* statically.

Not in linux distros, there we link libav* dynamically for the reason
I've outlined above. Yes, gst-ffmpeg upstream recommends that, but this
is not acceptable for linux distros.

(I'm talking about distros, not random 3rd party archives)

> That is, you're getting one big libgstffmpeg-x.x.dll (or .so)
> GStreamer plugin as a result. Don't see how that could affect distro's
> shared versions of libav*.

Unfortunately, this is not the case.

-- 
Gruesse/greetings,
Reinhard Tartler, KeyID 945348A4