How should I mux a mkv file so that sound could be played on Android?

[Hello, World]

Hi,
I have a H.264 video source and a PCM audio source.

I want to mux them into a mkv file by myself so that it can be played properly on Android.
But, the mkv file generated can be played well on Windows (either with WMP or with VLC) and Ubuntu (either with the default player or with VLC) only.
There is no sound when playing with the default player on Android but it is fine when playing with MX Player.

Also, if I mux the mkv file with some existing software like MKVToolNix with the same source, the generated mkv file could be played well on android (even with the default player).

So, I believe that it is the mkv format's problem. I somehow mux them so that the android's default player can't analyze the audio frames.

How can I fix the problem? Thanks!
(Edit: Some more information provided on #3.)


PS. Am I posting on the right forum?