[FFmpeg-devel] [PATCHv2] avcodec/apedec: fix bug introduced in commit d3e5fbb1406995e07fccbff3ca8c1e24f57a1f7b

[Ganesh Ajjanagadde]

On Sat, Oct 3, 2015 at 7:58 AM, Ronald S. Bultje <rsbultje at gmail.com> wrote:
> Hi,
>
> On Sat, Oct 3, 2015 at 8:31 AM, Ganesh Ajjanagadde <gajjanagadde at gmail.com>
> wrote:
>>
>> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
>> ---
>>  libavcodec/apedec.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c
>> index 7b34d26..05cb17e 100644
>> --- a/libavcodec/apedec.c
>> +++ b/libavcodec/apedec.c
>> @@ -1281,7 +1281,7 @@ static void do_apply_filter(APEContext *ctx, int
>> version, APEFilter *f,
>>              /* Update the adaption coefficients */
>>              absres = FFABS(res);
>>              if (absres)
>> -                *f->adaptcoeffs = ((res & (-(1<<31))) ^ (-(1<<30))) >>
>> +                *f->adaptcoeffs = ((res & 0x80000000) ^ (-(1<<30))) >>
>>                                    (25 + (absres <= f->avg*3) + (absres <=
>> f->avg*4/3));
>>              else
>>                  *f->adaptcoeffs = 0;
>> --
>> 2.6.0
>
>
> I wonder if some compilers will complain that this overflows (strictly
> speaking it does) and that it should be -0x80000000 instead?

please ignore current patch, breaks fate. Ronald's idea also breaks fate.

>
> Ronald