Last couple of recordings are in 720 (two different channels), I thought this might've been an issue with Channels. But I opened the direct HDHR Prime streams in VLC, and sure enough, they all seem to be 720 (h.264). And I know CBS is 1080i.
I've searched online and do see some posts from a few years ago suggesting that Comcast might lower quality to save on their bandwidth, but nothing recently. Anyone else have a CableCard with Xfinity?
All my XFINITY Cable Card HD Channels are 720P h264 been this way for over a year.
Nope, I've been able to get 1080i for ever. I have seen some basic cable stations convert to h.264 over the last year or so, but I'm pretty sure they were 720p prior to the conversion, so not really a change. I don't have a problem with them using a more efficient codec like 264 (over MPEG), but at least keep the resolution to what they're getting from the network.
I'm chatting with Xfinity Support on Reddit, and they're looking into it. But if you're saying you saw this change a year ago, my guess is that it's just hitting us here in Boston. 
Curious, what part of the country are you in @Edwin_Perez?
North West
It's been like this for years in the SF Bay Area. That's just how Comcast does things now.
I don't see this changing anytime soon either -- along with the bandwidth savings from MPEG-4 transcoding, I think Comcast has decided that it doesn't want any interlacing, and they just spent a lot of money sending out MPEG-4 HD DTA's that support 1080i and 720p but not 1080p. So, 720p it is.
For CBS in particular, in most major markets you can get it in 1080p (upscaled from 1080i) via TVE, albiet without surround sound.
Its also been this way in the Northern Virginia area. Its one of the reasons I canceled Comcast. Local channels were in the resolution being broadcast. Everything else is down covered to 720p. And then they compress it to a 2-3 Mpbs stream. Very poor quality.
Disappointing. Their Tech I was talking to on Reddit offered to dispatch a tech free of charge, I literally LOL'd. What are the chances that the tech is even going to know what a CC is?! I bet that since the FCC isn't requiring cable companies to support CC anymore (even though Comcast told me they have no plans on getting rid of them anytime soon), they're lowering the quality in hopes people just stream or rent their boxes. I also read a post that the reason they might be doing this is to for a lower bandwidth connection to phones and tablets, not caring or knowing that some customers use the same signal on a 65" TV where you can see the difference.
I'm guessing this won't change until if/when they support 4K. Looks like I might be switching to antenna HDHR. Although still no 4K ATSC 3.0 here in Boston. It was supposed to roll out this year, but still nothing.
They lowered their stream to 720P and H264 to make it more compatible with devices ... Mpeg2 is an old standard and not suitable for all streaming devices ... I replaced my boxes with FireTV 4K and use XFINITY stream and only rent 1 box. I can setup passes and record to the Cloud and watch my recordings on any device.
Yeah, we use the Stream app up at camp on our Fire edition TV, onky issue is some networks' licenses only allow when at home. I think CBS works fine, but NBC says I have to be at home (or visa versa). On our Roku TV at home as a backup (when Channels DVR fails for some reason like lost power/service). Funny their Stream app has been in Beta for years and still won't install on Android TV.
That is probably a Google thing blocking Install ... I think Apple TV will be next to receive XFINITY Stream.
Streams were all 720p for me back when i had cable card and Xfinity, that has been 3yrs now? i think since i dumped cable, and i had cable card and used Emby before Channels, even then, it was 720P...so, at least 7years or so I can say that Xfinity cable card streams have been 720.
So you're saying I should count myself luck to have had 1080 since then and STFU? 
Still doesn't make it much better though. And don't have an issue with them converting to more effecient h.264, but at least keep the 1080 at 1080.
I'll probably either switch or offset CC with OTA HDHR, as I'm only 45 miles from the stations.
And thank you for all the replies, saves me the trouble of further troubleshooting with them. Funny, I told a buddy that works as a Comcast Business Tech, and he laughed when I told him they wanted to send a tech. He knew the tech would be useless, as almost all of them know nothing about CC. Although even my buddy had no idea about the drop to 720, they probably don't want to advertise it, even internally. Although he said everything is going streaming, he wouldn't be surprised if in the next few years, they don't even offer traditional TV service. They just got huge deal on Comcast's new TV, which has their new UI built into it. It's not bad.
Blast from the past... I looked back and Colorado went through Comcast's switch to 720p back in November 2016. Big deal, STB's had to be upgraded etc. to support MPEG4. They called it something like enhanced HD or some marketing ploy.
Except yeah, it was even worse-compressed video at 720. They wanted to go progressive scan, but wouldn't afford the bandwidth for 1080p. And 720p is good for mobile devices, since everyone is supposedly watching TV on their phones now 
I ragged on them a lot then, including how it screwed up my Windows Media Center installation.
-Alan
For the Chicago zone, it's been several years that Comcast downgrades the 1080I feeds to 720P.