ATSC 1.0 MPEG-4 older TVs no video
In 2008 the ATSC ratified the MPEG-4 TV broadcast standard. Numerous ATSC 1.0 TVs were sold before this standard was ratified, and still operate today. TV manufacturers continued to make some non-MPEG-4 TVs for a decade after the standard was ratified. The need to lighthouse ATSC 1.0 broadcasts while implementing ATSC 3.0 broadcasts has led numerous broadcasters to use MPEG-4 encoding for their ATSC 1.0 broadcasts.
Previously MPEG-2 was the only widespread encoding standard for ATSC 1.0 broadcasts. Until recently, a typical ATSC 1.0 broadcast channel layout was to have one 1080i channel and several 480i channels, or 1-2 720p channel(s) with several more 480i channels. The number of channels depends on the broadcaster’s choice of resolution and the number of subchannels they want to broadcast vs. the bandwidth per channel. This database lists the channels available in a given area. Click “Technical Data” to see the resolution and encoding of each channel.
As ATSC 3.0 broadcasts roll out, the number of ATSC 1.0 channels will decrease. A mitigation for broadcasters is to switch to MPEG-4 encoding for the ATSC 1.0 broadcasts, which is more efficient than MPEG-2 and allows packing more channels into the same transmitter bandwidth. This leaves older TVs and receivers with audio-only on MPEG-4 channels. This MPEG-4 list is missing some broadcasters.
A solution for the end user lacking an MPEG-4-capable TV is to buy an ATSC receiver box that supports MPEG-4. These can be obtained for less than $50. The ATSC 3.0 receivers are available for less than $100 if desired to access ATSC 3.0 broadcasts not available even on some new TVs.
Enthusiasts make their “band scan” data available for TV and FM radio typically using a Raspberry Pi to enjoy and share the hobby of broadcast DXing.