Question: WRDM-CD is available on channel 20 of a digital cable television service serving how many customers?
Sentence (from "List of Music Choice channels"): This is because the "slideshow" to change pictures for each music channel runs at a very low frame rate, allowing for the compression ratio to be very high for the MPEG-2 digital video compression used in the ATSC standard, until 2012.
Relevant evidence: No