if( (asset->video_length = ff->ff_video_frames(vstream)) < 2 )
asset->video_length = asset->video_length < 0 ? 0 : -1;
asset->frame_rate = ff->ff_frame_rate(vstream);
if( (asset->video_length = ff->ff_video_frames(vstream)) < 2 )
asset->video_length = asset->video_length < 0 ? 0 : -1;
asset->frame_rate = ff->ff_frame_rate(vstream);