He Junyan authored Oct 27, 2022 and GStreamer Marge Bot committed Oct 27, 2022

In fact, all the h264 bit writer have byte aligned output except
the slice header. So we change the API from bit size in unit to
byte size, which is easy to use. For slice header, we add a extra
"trail_bits_num" to return the unaligned bits number.

Part-of: <!3193>