MythTV/mythtv — comment on commit 2c930a727e4d0f9227684ae4825ea558597f82a5
File: mythtv/libs/libmythtv/mythplayer.cpp line 1003
By phel:

With this the player always opens in 4x3 when entering live-tv from the menu. It also starts playback of wide content in 4x3 sometimes while switching channels. Re-tune/re-open the same channel within live-tv restores correct aspect ratio. I'm using vdpau if that matters.