Originally Posted by mrvideo
You gotta be joking. ATSC using MPEG-2 can barely handle a single rapid action 1080i HD stream, let alone two. Rapid action 1080i video has macroblocking issues. It takes 2-pass encoding to allow for the rapid action video to look decent. I do not know of any 2-pass OTA encoders.
The current generation of OTA encoders are designed to do 2HD/4SD on a 6mhz 8VSB channel. Our local NBC and Telemundo station is running 2HD/2SD at 1080i/480i, and while it definitely doesn't look as good as it was when it was 1HD/?SD with just NBC, it doesn't actually look bad. It's a bit flatter, and doesn't have that "wow" effect on the opening sequence of SNL, but the detail is still pretty good, and there isn't obvious macroblocking. The PyeongChang Olympics weren't quite as good as in previous years, but they weren't horrible like Comcast's bit-starved MPEG-4 that look like utter garbage and is totally lacking detail. I'd much rather have 19mbps MPEG-2, which is the gold standard for HD broadcasting, but the current generation of encoders is really, really impressive in how much processing horsepower they can throw at encoding.
I take a lot of 1080i 29.97 ~35 Mbps MPEG-2 4:2:0 video and IVTC/recode it to H.264 23.976 @ 6 Mbps (2-pass encoding). I can even get it down to 4 Mbps and you will not find any issues. I can't say the same to what local affiliates do with the high quality video that they get from the networks (Fox excluded).
The problem is that Comcast's real-time encoders just can't get to 3.8mbps CBR without a massive loss of quality. The local affilitates who are doing MPEG-2 are using a stat mux, so they have some more room to work with. Comcast went from 13-15mbps MPEG-2 for their HD to 3 HDs in a stat mux on a 38mbps QAM to 4 MPEG-2 HDs CBR at 9mbps each for a total of 38mbps in a QAM, and over time the quality didn't get any worse, although they were always a bit beyond the limit of the technology, and had crummy looking video all along. That's an indication of where the encoding technology went. However, when they moved to MPEG-4 and used a 3.8mbps MPEG-4 CBR encode for most channels, with 4.2mbps for a few channels, they went way too far, and the result was a total mess. The technology has improved somewhat, and their channels look slightly less atrocious now, but they're still pretty bad, as scenes with a lot of motion or detail are just too bit starved without a stat mux to expand into. AFAIK
, they are doing all their encoding in software on regular x86 servers on an IP encoding network in Denver that puts the C-band signals onto IP, where they get encoded to MPEG-4 by their software encoding servers, and then moved via IP to local headends across the country where they are "slotted" onto QAMs for the ride to the XG1 or XG2, at which point they are either stored to disk, decoded for viewing, or put back onto an IP network for transport the last few hundred feet via MoCA to satellite box for final decoding.
Originally Posted by Tschmidt
Took a quick look at the study you linked to, thanks for posting. We are in a slightly unusual position.
We use DSL for wired access even though there is DSL and Cable in our town. We have a long driveway; the cost to extend cable 600 feet is high. The good news is several years ago we switched to a CLEC so even using the same POTS loop we have much higher speed and the connection is more reliable.
You are in a very usual position. Most people with rear/flag lots and long driveways are too far away from the CO/wirecenter or DSLAM to get anything decent, and adding .6kft of your own driveway to the distance doesn't help things. There have been numerous posts on DSLReports about how people have built little equipment sheds for their cable modem by the road, and run fiber or used their own VDSL to get the bandwidth to their house, which is a less than ideal solution IMO, but I can see why some do it versus sky-high costs to extend cable plant.
We have always used OTA. The TV digital conversion has worked out well for us, even though we are in a fringe area. Subchannels have increased the number of available channels. Hopefully migration to ATSC 3.0 will improve the situation even with the FCC repack channel reduction.
Hopefully OTA will never go away. Evolution shows that over specialization is dangerous. Having multiple ways of communicating is important. For example in our town we are finalizing renewal of the cable franchise agreement. The cable company is only guaranteeing 24 hours of backup during a power outage. Here in NH week long power outages occur every couple of years due to massive ice storms. Folks that depend on cable will lose: TV, Internet and phone.
You're in a VERY challenging market for OTA, but due to the terrain, and the oddly large size of the Boston DMA, and how far the transmitters in Needham are from the northern parts of the Boston DMA in NH. That's definitely an issue with cable, if you want reliable TV, you have to have OTA or DBS and your own generator and fuel supply to keep things running. If you have no cell service, you can use a cell booster as long as long as there is service within a short distance of your location, and if that is wired to your transfer switch, then you're very likely to have cell phone and internet service via LTE even when all utilities are down.