103da56fba
The copy from old buffer is only needed when appending (when decode_bitstream is called more than once in one frame). This avoids map old buffer -> memcpy to new buffer which can get expensive with large buffers. Reviewed-by: David (Ming Qiang) Wu <David.Wu3@amd.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29318>