avpriv_mpeg4audio_sample_rates vector size not correct

[Filippo Della Betta]

in mpeg4audio.c

const int avpriv_mpeg4audio_sample_rates[16] = {

96000, 88200, 64000, 48000, 44100, 32000,
24000, 22050, 16000, 12000, 11025, 8000, 7350

};

but there are only 13 values!

in aacenc.c, the code

for (i = 0; i < 16; i++)

if (avctx->sample_rate == avpriv_mpeg4audio_sample_rates[i])

break;

seems faulty.

IMHO avpriv_mpeg4audio_sample_rates should become

const int avpriv_mpeg4audio_sample_rates[13] = {

96000, 88200, 64000, 48000, 44100, 32000,
24000, 22050, 16000, 12000, 11025, 8000, 7350

};

and in aacenc.c you should safely write something like

for (i = 0; i < FF_ARRAY_ELEMS(avpriv_mpeg4audio_sample_rates); i++)

...

[Carl Eugen Hoyos]

Please send patches to ffmpeg-devel, they receive more attention there.

But note that your change would (for example) complicate the code in libavcodec/aacadtsdec.c, so I am not sure the change is desirable.

[Filippo Della Betta]

Replying to cehoyos:

Please send patches to ffmpeg-devel, they receive more attention there.

But note that your change would (for example) complicate the code in libavcodec/aacadtsdec.c, so I am not sure the change is desirable.

I see, proabably the following change to mpeg4audio.c should be safer and easier

const int avpriv_mpeg4audio_sample_rates[16] = {
96000, 88200, 64000, 48000, 44100, 32000,
24000, 22050, 16000, 12000, 11025, 8000, 7350, 0, 0, 0
};

[Carl Eugen Hoyos]

Wouldn't that be 100% equivalent to the current code?

[Filippo Della Betta]

Replying to cehoyos:

Wouldn't that be 100% equivalent to the current code?

No, it isn't IMHO. It depends on the compiler. Nobody guarantees that memory is initialized to 0.

[Clément Bœsch]

It's guaranteed to be set to 0 by the C standard in this case. And we use that feature all around the code base.

Also, FF_ARRAY_ELEMS will not work as expected given that this array is exported (which is related to another real issue though).

[Filippo Della Betta]

Replying to ubitux:

It's guaranteed to be set to 0 by the C standard in this case. And we use that feature all around the code base.

Also, FF_ARRAY_ELEMS will not work as expected given that this array is exported (which is related to another real issue though).

Thank you for the explanation!