I think compression technology do effect the PQ.
My two reasons are,
1, All dth are compresing hard but those with mpeg4 are having better PQ.
2, As mpeg 4 creates more space, same number of channels on different tps with different compressions i.e, mpeg 2 and mpeg 4, the PQ of mpeg 4 will be better, as more space remain on the same tp.
Its my personal view.
Expert can have their say.
My two reasons are,
1, All dth are compresing hard but those with mpeg4 are having better PQ.
2, As mpeg 4 creates more space, same number of channels on different tps with different compressions i.e, mpeg 2 and mpeg 4, the PQ of mpeg 4 will be better, as more space remain on the same tp.
Its my personal view.
Expert can have their say.