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

[Ronald S. Bultje]

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?

Ronald