I use ProgDVB to receive DVB-Tin my country - Poland .
DVB-T tuner is AF9015Filter.
I have access to two digital TV packages - MUX 2 and MUX 3
On all channels MUX2 package is valid picture and sound
But in television programs in the package MUX3 i have only picture and I have no sound.
What might that be?
All programs in both the digital TV packages are transmitted in MPEG-4
PLease help me .

Is it AC3 sound? try install ac3filter.

I was installed package AC3FILTER , but it's no helped ,
I installed package K LITE MEGA CODEC PACK but it also does not help.
I am using 64-bit Win 7 and 64-bit wersion Progdvb
Please for further advice.
On Linux, for the receive of DVB-T using Kaffeine player and there are no problems, sound is correct.
In WindowsMediaCenter sound is also correct.
Why Progdvb causes problems ?

Do you use x64 version of ac3 filter and ProgDVB? Your other software is x32 afaik.