rtp: fix adapter flushing in sbc payloader
GstAdapter must be flushed in some cases (flush, new segment, state change) Without it, it may, for example, push some leftover buffer from old segment in new segment. This, in general, breaks timestamps.
GstAdapter must be flushed in some cases (flush, new segment, state change) Without it, it may, for example, push some leftover buffer from old segment in new segment. This, in general, breaks timestamps.