[FFmpeg-devel] [PATCH] swresample/resample: do not allow negative dst_size return value

[Michael Niedermayer]

On Tue, Dec 13, 2016 at 11:15:30PM +0700, Muhammad Faiz wrote:
> On 12/13/16, Michael Niedermayer <michael at niedermayer.cc> wrote:
> > On Tue, Dec 13, 2016 at 02:16:03PM +0700, Muhammad Faiz wrote:
> >> This should fix Ticket6012
> >>
> >> Signed-off-by: Muhammad Faiz <mfcc64 at gmail.com>
> >> ---
> >>  libswresample/resample.c | 7 ++++---
> >>  1 file changed, 4 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/libswresample/resample.c b/libswresample/resample.c
> >> index 71dffb9..ce6a82f 100644
> >> --- a/libswresample/resample.c
> >> +++ b/libswresample/resample.c
> >> @@ -478,8 +478,9 @@ static int swri_resample(ResampleContext *c,
> >>          int64_t incr= (1LL<<32) * c->dst_incr / c->src_incr;
> >>          int new_size = (src_size * (int64_t)c->src_incr - frac +
> >> c->dst_incr - 1) / c->dst_incr;
> >>
> >> -        dst_size= FFMIN(dst_size, new_size);
> >> -        c->dsp.resample_one(dst, src, dst_size, index2, incr);
> >> +        dst_size = FFMAX(FFMIN(dst_size, new_size), 0);
> >> +        if (dst_size > 0)
> >> +            c->dsp.resample_one(dst, src, dst_size, index2, incr);
> >>
> >>          index += dst_size * c->dst_incr_div;
> >>          index += (frac + dst_size * (int64_t)c->dst_incr_mod) /
> >> c->src_incr;
> >> @@ -494,7 +495,7 @@ static int swri_resample(ResampleContext *c,
> >>          int64_t delta_frac = (end_index - c->index) * c->src_incr -
> >> c->frac;
> >>          int delta_n = (delta_frac + c->dst_incr - 1) / c->dst_incr;
> >>
> >> -        dst_size = FFMIN(dst_size, delta_n);
> >> +        dst_size = FFMAX(FFMIN(dst_size, delta_n), 0);
> >
> > Shouldnt this and other things be done outside the loop that
> > calls swri_resample() ?
> 
> For performance reason probably yes, even swri_resample should be integrated
> to multiple_resample to avoid redundant calculations.
> 
> But this is bugfix patch, and swri_resample should return proper dst_size.
> I just follow current code flow.
> 
> Patch that improve performance is outside the scope of this patch. Probably
> I will post that if this patch is accepted.

LGTM

thx

[...]
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