[MPlayer-dev-eng] [RFC] internal library copies

[Yuriy Kaminskiy]

On 17.03.2010 22:21, compn wrote:
> On Wed, 17 Mar 2010 13:28:36 +0100, Diego Biurrun wrote:
>> On Wed, Mar 17, 2010 at 08:26:21AM -0400, compn wrote:
>>> On Wed, 17 Mar 2010 13:03:21 +0100, Diego Biurrun wrote:
>>>> We carry around a bunch of externally available libraries and I think
>>>> it's time to review the situation around them.  Some of them we should
>>>> keep, others could be dropped.
>>>>
>>>> * liba52
>>>>
>>>> The internal copy was disabled some time ago, FFmpeg is both faster and
>>>> more featureful.  We support building against the external version.  Our
>>>> copy is patched, but upstream is dead and the patches have been rejected
>>>> IIRC.
>>>> verdict: drop
>>> isnt there some problem wrt downmixing ?
>> I don't think so.  Currently liba52 is not being compiled by default
>> anyway, so it's basically dead code.

Hmm? "not compiled by default" is far from being "dead code".
"dead code" is "#if 0"-ed, or "requires hacking code to enable", or "has serious
bugs". Neither applies to internal liba52.

> i havent tested with 5.1 hardware, maybe i'm remembering outdated
> bugreports.

ffac3 support "internal downmixing" (-channels 2).
ffaac does not.

>>>> * libfaad2
>>>>
>>>> Nobody touch this one, I reserve the privilege to remove it! ;-)
>>>> FFmpeg is way faster.  There are a few AAC variants that FFmpeg does not
>>>> support (yet), but now that SBR has been implemented, all the important
>>>> things are covered.  Compiling against the external version works fine.
>>>> verdict: remove
>>> only if you fix all of the spammed messages in the ffaac decoder.
>>> like this one which occurs 10 per second in many files...
>>> [aac @ 021cc160]SBR not implemented. Update your FFmpeg version to the
>>> newest one from SVN. If the problem still occurs, it means that your
>>> file has a feature which has not been implemented.
>> Didn't Alex fix that message spam?  Can you point out a sample?
> 
> actually... this might be fixed, i dont have latest svn:
> https://roundup.ffmpeg.org/issue1526

SBR (HE aac v1) already implemented [so this stream does not spam about "SBR
unimplemented" anymore], but PS (HE aac v2) still does not...

> sample stream: http://amber.streamguys.com:4210/

... and this stream uses PS too, so with -ac ffaac it is now spamming with

[aac @ 0x8efd830]Parametric Stereo is not implemented. Update your FFmpeg
version to the newest one from SVN. If the problem still occurs, it means that
your file has a feature which has not been implemented.

instead. PS support is in the work, AFAIR; but, "in the work" != "completed";
/when/ it will be completed, /then/ it will make sense to talk about faad2
removing again, IMO.

PS that said, I'm mostly use ffaac, and very happly with it.