[FFmpeg-devel] [PATCH 1/2] avcodec/sbrdsp_fixed.c: remove input value limit for sbr_sum_square_c()

Carl Eugen Hoyos ceffmpeg at gmail.com
Wed Feb 6 21:23:15 EET 2019


2019-02-06 20:17 GMT+01:00, Michael Niedermayer <michael at niedermayer.cc>:
> On Wed, Feb 06, 2019 at 01:57:37PM +0100, Carl Eugen Hoyos wrote:
>> 2019-02-03 18:21 GMT+01:00, Michael Niedermayer <michael at niedermayer.cc>:
>> > Fixes: 1377/clusterfuzz-testcase-minimized-5487049807233024
>> > Fixes: assertion failure in sbr_sum_square_c()
>>
>> This changes the output, no?
>
> in normal cases, no it should not
> It may be that one can construct a case thats not yet in the range
> where the old code was undefined, the new code is defined by
> 1 in a Quintillion differently and then the decoder output which is
> not 64bit integers still has a off by 1 difference.
> That could be, or it might be not, i dont know
>
> You can certainly have a differenceof the old code crashing with
> assertion failure though if thst is considered "different"
>
>> Why are the asm implementations not affected?
>
> Please correct me if iam wrong but
> i think only the float but not the integer version
> of this have been optimized.

Thank you for the explanation!

Carl Eugen


More information about the ffmpeg-devel mailing list