[FFmpeg-devel] [PATCH] aac_fixed: fix overflow in sbr_sum_square_c

Andreas Cadhalpun andreas.cadhalpun at gmail.com
Wed Nov 18 23:51:18 CET 2015

On 16.11.2015 02:59, Michael Niedermayer wrote:
> On Fri, Nov 13, 2015 at 10:32:47PM +0100, Andreas Cadhalpun wrote:
>> Because these samples aren't tested with the aac_fixed decoder:
>>  * aac/ct_faac-adts.aac is only used to test the aac demuxer.
>>  * aac/al07_96.mp4 is for some reason only tested with the aac decoder.
>> There the overflow happens on lines like:
>> che->ch[0].ret[j] = (int32_t)av_clipl_int32((int64_t)che->ch[0].ret[j]<<7)+0x8000;
>> I guess the +0x8000 was meant to be inside av_clipl_int32.
> could be
> also there was a different patch about a overflow in that
> 0729 11:58 Nedeljko Babic  (1.8K) [FFmpeg-devel] [PATCH] avcodec/aacdec_fixed: Fix integer overflow
> that case was a bug elsewhere though
> in that light, my first question, is, is the overflowing value used
> (aka affects the decoder output) ?

Simply removing the '+0x8000' doesn't change the framecrc output for these two samples,
so I guess the answer is no.

Best regards,

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