- info->pixel_aspect_width = st->sample_aspect_ratio.num ?
- st->sample_aspect_ratio.num : 1;
- info->pixel_aspect_height = st->sample_aspect_ratio.den ?
+ info->pixel_aspect_width = st && st->sample_aspect_ratio.num ?
+ st->sample_aspect_ratio.num : 1;
+ info->pixel_aspect_height = st && st->sample_aspect_ratio.den ?