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

[Muhammad Faiz]

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.

Thank's