[FFmpeg-devel] [RFC] AAC Encoder, now more optimal

[Michael Niedermayer]

On Sat, Sep 06, 2008 at 02:12:22PM +0200, Guillaume POIRIER wrote:
> Hello,
> 
> On Sat, Sep 6, 2008 at 1:43 PM, Guillaume POIRIER <poirierg at gmail.com> wrote:
> > Hello,
> >
> > On Sat, Sep 6, 2008 at 1:21 PM, Robert Swain <robert.swain at gmail.com> wrote:
> >> 2008/9/6 Guillaume POIRIER <poirierg at gmail.com>:
> >>> Hello,
> >>>
> >>> On Fri, Sep 5, 2008 at 3:13 PM, Kostya <kostya.shishkov at gmail.com> wrote:
> >>>> After some time (I'd like to have more free time to spend on it though),
> >>>> I want to expose my new AAC encoder.
> >>>
> >>> Is it possible to test your encoder with the files you sent?
> >>> I tried ~/Prgm/ffmpeg/ffmpeg -i flog.flac -acodec aac ~/Music/flog.m4a
> >>> but I'm getting:
> >>> FFmpeg version SVN-r15217, Copyright (c) 2000-2008 Fabrice Bellard, et al.
> >>>  configuration: --enable-gpl
> >>>  libavutil     49.10. 0 / 49.10. 0
> >>>  libavcodec    51.71. 0 / 51.71. 0
> >>>  libavformat   52.22. 0 / 52.22. 0
> >>>  libavdevice   52. 1. 0 / 52. 1. 0
> >>>  built on Sep  6 2008 13:04:25, gcc: 4.0.1 (Apple Inc. build 5465)
> >>> Input #0, flac, from 'met080814d1_01_Creeping_Death.flac':
> >>>  Duration: N/A, bitrate: N/A
> >>>    Stream #0.0: Audio: flac, 44100 Hz, stereo, s16
> >>> Unknown encoder 'aac'
> >>>
> >>> I copied all 4 files to ffmpeg/libavcodec/
> >>
> >> You would need to patch the build system too. As I recall I added a
> >> checkout script to the aacenc SoC dir a while ago. I'm not sure if it
> >> will still work though.
> >
> > Yep, found it. Thanks.
> > BTW, in order to compile, the AAC encoder also needs aac.h file from SOC.
> 
> Ok, I tested your encoder with some Rock music. I was a bit
> disapointed by the quality of the encoded audio file: it isn't good. I
> guess it's OK though since the deal is really more to have an LGPL
> encoder.

Id just like to say that to be accepted in svn the encoder MUST be better in
quality per bitrate compared to some other common encoder at least, just
implementing some half buggy rate distortion encoder is not good enough.

The absolutely most important thing is that the encoder is regularely
tested to ensure that there are no quality regressions due to bugs or
misunderstandings of some paper/algo/... .
In that light, can you confirm that the current code is at least better than
the last iteration of the encoder?

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Everything should be made as simple as possible, but not simpler.
-- Albert Einstein
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