LWLibavAudioSource ignores audio offset

[radpopl]

The audio track offset is set to 2s, but LWLibavAudioSource ignores it.

I tried setting av_sync to true, but then I get no audio at all. The bottom two channels are LWLibavAudioSource.

Vegas.Mercalli.6.Stabilization.-.audio.+2s.mp4

a=BSSource("Vegas Mercalli 6 Stabilization - audio +2s.mp4")
b=AudioDub(LWLibavVideoSource("Vegas Mercalli 6 Stabilization - audio +2s.mp4"), LWLibavAudioSource("Vegas Mercalli 6 Stabilization - audio +2s.mp4",av_sync=false))
AudioDub(a, MergeChannels(a,b))

[Asd-g]

You can try the attached version here.