file->get_audio_for_video(vstream, astream, channel_mask);
if( astrm >= 0 ) file->select_audio_stream(asset, astrm);
if( astrm < 0 || !channel_mask ) channel_mask = (1<<asset->channels)-1;
file->get_audio_for_video(vstream, astream, channel_mask);
if( astrm >= 0 ) file->select_audio_stream(asset, astrm);
if( astrm < 0 || !channel_mask ) channel_mask = (1<<asset->channels)-1;