[HELP] after encoding ass into mp4, but there is no subtitle at all

[ssdde]

please send me a good dev version for test. in this page, there is only rev version, no dev
https://www.selur.de/downloads

only this lag mp4 file remux to mkv with another sup subtitle, can't see subtitle effect. if remux a good mp4 to mkv, it will be good.