[FFmpeg-devel] [PATCH] HE-AAC v1 decoder try 4

Måns Rullgård mans
Wed Feb 17 14:20:59 CET 2010

Vladimir Pantelic <pan at nt.tu-darmstadt.de> writes:

> Alexander Strange wrote:
>> On Feb 16, 2010, at 6:19 PM, Alex Converse wrote:
>>>  On Tue, Feb 16, 2010 at 6:01 PM, Alex Converse<alex.converse at gmail.com>wrote:
>>>>  Notes:
>>>>  *All the computation time is spent in ff_sbr_apply() and it's
>>>>  children. If it isn't called from ff_sbr_apply() making it 100% faster
>>>>  isn't going to buy us anything.
>>>>  *Right now the synthesis filterbank is written on top on an MDCT. With
>>>>  appropriate SIMD functions it may make sense to move it to an FFT.
>>>>  Right now the MDCT version is much faster.
>>>>  *SIMD placeholder patch not included
>>>  Wrong patch.
>>>  try 4.1 :)
>>>  <sbr.diff>
>> I tried it with ffplay and it plays 2x too slow. If ffplay needs to be fixed, I wonder if other players will too? Well, it's unavoidable anyway.
>> ffmpeg to wav sounds fine.
> guess its the issue that the container signals the smaller (non-sbr)
> sample rate, e.g. 24khz and the decoder applies SBR and returns
> 48kHz. I had to fix my player to switch to the decoder returned sample
> rate too...

I learned a long time ago not to trust the container values for
anything.  If the decoder says anything at all, that's usually
correct.  Except for dodgy mpeg4 in avi, where it's equally common for
both to be wrong.

M?ns Rullg?rd
mans at mansr.com

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