Why is Picture sometimes different?

[dbalone]

I am new to directv and notice that the picture quality can change from day to day. Somedays it is very good, others just fair. Seems to happen mostly on local channels. Why is this? I have the tivo dvr unit.

 

[boba]

Compression ratios vary from program to program depending on bandwidth needed. A live sporting event needs more bandwidth than a cartoon to deliver the same quality of picture. Local channels will also vary due to the reception at the uplink, some stations provide a fiber connection to the uplink others are received by a TV antenna so raw signal varies before Directv even sees the signal.