int64_t rel_iframe = granulepos >> video_file->theora_keyframe_granule_shift;
int64_t rel_pframe = granulepos - (rel_iframe << video_file->theora_keyframe_granule_shift);
int64_t rel_current_frame = rel_iframe + rel_pframe;
current_frame = frame_offset + rel_current_frame;
int64_t abs_iframe = current_frame - rel_pframe;
int64_t rel_iframe = granulepos >> video_file->theora_keyframe_granule_shift;
int64_t rel_pframe = granulepos - (rel_iframe << video_file->theora_keyframe_granule_shift);
int64_t rel_current_frame = rel_iframe + rel_pframe;
current_frame = frame_offset + rel_current_frame;
int64_t abs_iframe = current_frame - rel_pframe;