[FFmpeg-devel] [PATCH] pgssubdec: only set w/h/linesize when allocating data

[Andreas Cadhalpun]

On 23.11.2016 14:48, wm4 wrote:
> On Wed, 9 Nov 2016 23:27:04 +0100
> Andreas Cadhalpun <andreas.cadhalpun at googlemail.com> wrote:
> 
>> Rects with positive w/h/linesize but no data are invalid.
>>
>> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
>> ---
>>  libavcodec/pgssubdec.c | 9 +++++----
>>  1 file changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/libavcodec/pgssubdec.c b/libavcodec/pgssubdec.c
>> index cef477d..b50b37b 100644
>> --- a/libavcodec/pgssubdec.c
>> +++ b/libavcodec/pgssubdec.c
>> @@ -556,12 +556,13 @@ static int display_end_segment(AVCodecContext *avctx, void *data,
>>  
>>          sub->rects[i]->x    = ctx->presentation.objects[i].x;
>>          sub->rects[i]->y    = ctx->presentation.objects[i].y;
>> -        sub->rects[i]->w    = object->w;
>> -        sub->rects[i]->h    = object->h;
>> -
>> -        sub->rects[i]->linesize[0] = object->w;
>>  
>>          if (object->rle) {
>> +            sub->rects[i]->w    = object->w;
>> +            sub->rects[i]->h    = object->h;
>> +
>> +            sub->rects[i]->linesize[0] = object->w;
>> +
>>              if (object->rle_remaining_len) {
>>                  av_log(avctx, AV_LOG_ERROR, "RLE data length %u is %u bytes shorter than expected\n",
>>                         object->rle_data_len, object->rle_remaining_len);
> 
> Is there any indication that API users are fine with rects that have
> w=h=0 (or that the API allows it), and that they don't access data with
> memcpy? Seems a bit odd. Since error handling set w=h=0 before, it's
> probably ok though.

Since rects can contain either a bitmap, or text/ass or both, API users
have to deal gracefully with rects without bitmap, i.e. w=h=0.

Best regards,
Andreas