If there is a single group of SPS/PPS before an IDR frame, but no SPS/PPS after that, we will miss the chance to reset idr_sps_seen/idr_pps_seen. No SPS/PPS are inserted afterwards. This patch saves in-band SPS/PPS and insert them before IDR frames when necessary. Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>