mpeg-2 “is” the format most used by ATSC-1. However, it does require licensing to support. It was never adopted as the “universal” format. For that, mpeg-4 was (and still is king there). Adopted because of better streaming handling over bandwidth limited connections. Adoption often times is “due” to “certain players” digging in… regardless, mpeg-2 was not the choice.
With that said, there are other pieces, like audio codec, that also can create problems. Oddly, yet another potential problem with regards to ATSC-3 adoption.
The OG Tablo units transcoded to the universal format, mpeg-4/avc, to ensure almost universal client compatibility (including use of a web browser, for example).
So, mpeg-2, popular? No. Support in Roku (certain models) was very alpha not too many years ago.
Tablo’s 4th gen made a mistake (?).
Realize that broadcaster’s position on “recording” is still “to prevent” or, at a minimum, “fully control”. Broadcaster’s redefined a word, “broadcast”, to include concepts like “transcoding” (this cause SCOTUS to rule against lower courts, but only after the definition changed mid deliberation, talking Aereo’s death sentence). Thus, something that makes a broadcaster’s content available over a network via the use of transcoding requires a “broadcast license” (which they can block, they being themselves… sadly. The “club” you are not allowed to join.). So, the OG Tablos were a “thorn” if continued as they (by broadcaster definition) would require a broadcaster license (I wouldn’t be surprised if this wasn’t leverage used in the acquisition of the brand by the broadcaster in this case?).
Just to clarify, because people don’t really understand Aereo, Aereo was very restricted (oddly) point to point for “a user” (household). It was not a “broad” (as the old definition of the word broadcast) medium. It was a way to get OTA to people that could not reliably receive OTA signal. The “restriction” was number of client devices allowed. The fees they collected were for cloud storage (for the transcoded signal data and recordings, again, not shared, but just for “the person”) and you were renting your own “close to the tower” (not shared at point of watch/record) antenna. It was a clever idea. Note that illegal broadcaster’s operate very differently, and btw, still exist in mass today (emphasis, that is, killing Aereo did nothing to prevent this). Which makes you wonder why they went “ultra hard” against Aereo (?). Aereo created over the network private OTA (allowing disenfranchised users to get OTA).
Btw, OG Tablo, for those that have reception of signal, was far less restricted than Aereo, but again, Aereo provided those “blocked” from getting OTA, to get OTA. So, for some displaced by the broadcaster’s successful assassination of Aereo, we were able to move to OG Tablo. The disenfranchised? Likely using the myriad of illegal broadcast sources I suppose.
Envy? Anyhow, Aereo won every case… until SCOTUS, which they were also winning, until… the redefinition of a word (broadcast includes transcoding). All dissenting remark members are dead. But an interesting read.