TS program stream selection

I have a multi-program TS file (4 video ES). When I make Qt's QMediaPlayer class point to the ts file it picks one out of the 4 programs. With VLC I can go to "Playback"--> "Program" option and switch between all available streams. QMediaPlayer uses Directshow backend and I have k-lite codes installed. How does directshow decide which ES out of the 4 to present for playback ? is this related to the lav splitter/merit settings in the tweak tool ? I want to programmatically render all available streams in a ts file in concurrent QMediaPlayer windows.. is there anything I could do to have this setup ? thanks

Track selection in DirectShow can be done through IAMStreamSelect interface.

LAV Splitter however may not expose selection for multi-program TS, only for regular tracks.

As an alternative you could use Haali Media Splitter. That does support multi-program TS. But a big fat giant warning, Haali does not support modern video formats such as HEVC, so some (newer) files may not play video when using it.