[FFmpeg-devel] [PATCH] avcodec/aacdec: don't force HE-AACv2 profile if no PS info is present

[Andreas Rheinhardt]

James Almer:
> On 7/18/2022 10:57 AM, Andreas Rheinhardt wrote:
>> James Almer:
>>> On 7/14/2022 9:10 AM, Andreas Rheinhardt wrote:
>>>> James Almer:
>>>>> Should fix ticket #3361
>>>>>
>>>>> Signed-off-by: James Almer <jamrial at gmail.com>
>>>>> ---
>>>>> This also needs an update to some fate ref samples i'll upload before
>>>>> pushing
>>>>> (fate-aac-al_sbr_ps_04_ur and fate-aac-al_sbr_ps_06_ur which are now
>>>>> decoded
>>>>> properly as he_aac mono, so the .s16 files need to be replaced).
>>>>>
>>>>
>>>> We have both a fixed-point AAC as well as a floating point AAC decoder.
>>>> Is there actually a test that tests that the output they produce is
>>>> reasonably close? If not, could we make the test so that the same file
>>>> is decoded once with the fixed-point and once with the floating-point
>>>> decoder and then compared?
>>>
>>> That wouldn't help much, i think. Almost all changes to *_template.c
>>> files are going to affect both decoders, so a breakage would not be
>>> detected if you compare their output with each other as they would both
>>> exhibit it.
>>>
>>
>> I actually thought that the aac_fixed tests used checksums instead of
>> ref files; then changes and breakages would be visible by changes to
>> these files. Apparently I was wrong about that and the ref files are
>> used for both aac and aac_fixed. But a test like the one outlined above
>> would nevertheless obviate the need for a new ref file.
> 
> Judging by
> https://git.videolan.org/?p=ffmpeg.git;a=blob;f=tests/fate/aac.mak;h=1743428f544fad8946dba11dd4ecec0630eb70a6;hb=HEAD#l117
> it seems at least for these samples the fixed decoder does not generate
> a decoded stream comparable to the float one, so I'll just upload a new
> raw pcm file.

When I decode both of these streams with git master, the left channel is
pretty much identical, yet the right channel of the fixed-point decoder
is silent and the right channel of the floating point decoder is not.
With this patch applied, the result are two mono streams that are pretty
much identical: The test sample created by the floating-point decoder
works with the fixed-point decoder test (if one uncomments and modifies
the latter). So the issue with aac-al_sbr_ps_06_ur is not a reason to
upload new samples.

- Andreas

PS: libfdk-aac produces a file that looks pretty much like the floating
point decoder from git master. Are you sure your patch is correct?