Need some help from digital cable stream capture experts

[Trippy]

Okay so I'm finally moving out of the Dark Ages and have Comcast cable in my new location. However I'm confused and having difficulty understanding what I need to be able to capture (QAM) digital cable onto my PC.

On my old setup I had a pair of ATSC (OTA) digital tuners (plus a whole bunch of analog tuners) that were connected to an ancient roof antenna which was good enough to get most of the OTA digital stations in the SF Bay Area including the HD ones (ABC/KGO being one of the exceptions). Most of the major PVR programs support ATSC digital so it was easy enough to set something up to record those shows (I settled on SageTV).

With Comcast digital cable my understanding is that most of the digital channels are encrypted except for the OTA (HD) channels which the FCC supposedly mandates stay unencrypted and a smattering of other channels (like local city channels) which are all supposed to be encoded in QAM. I bought a cheapo HDTV USB box which said it supported QAM (both 64 and 256) but I was only able to grab a minority of the OTA HD channels (CBS and a couple of the smaller networks) so I couldn't get FOX, NBC or ABC, etc.

SageTV doesn't seem to support the box I got (it didn't find any unencrypted digital channels and the box not listed as one of the support QAM tuners) so I had to use the ArcSoft program which came with the box (which actually doesn't look too bad) to scan for the channels.

However, poking around it seems like I should be able to get access to more digital channels on my PC. E.g. this page for MythTV shows a whole bunch that people were apparently able to get at least a year ago in my neighborhood (Cupertino, CA):

http://www.mythtv.org/wiki/index.php/Working_QAM_cable_layout

My local Fry'ses have some of the other QAM tuners that SageTV supports so I'm going to try one of those to see if that helps.

I've also read something about getting a box from Comcast with Firewire output and using that but that seems to just be sending down the unencrypted QAM channels as well. Would that be better than just hooking the cable line straight into a QAM tuner like I'm doing now with my little USB box? I've also read about a product called HDHomeRun but I'm not sure how that would be better than just getting a good QAM tuner for capturing the QAM streams.

Since I've been using my PC as my PVR for the longest time (started with an ATI 9600 AIW) and never used a Tivo or any other DVR would one of those things be an option? E.g. could I have it record a digital channel for me and then somehow transfer that data over to my PC assuming it's just a raw MPEG-2 stream (or close to it) and not in some proprietary format? It's okay if I have to take the hard drive out of the DVR to transfer the data -- I'm willing to do that if that means I get access to the MPEG-2 stream.

[Venkman]

I can't answer anything except the last question, but yes, you should be able to plug your DVR into your PC to do an analog hole output of what you've recorded. My DVR even has a built in menu option for it, but they think it's going to a VCR.

[Trippy]

I can't answer anything except the last question, but yes, you should be able to plug your DVR into your PC to do an analog hole output of what you've recorded. My DVR even has a built in menu option for it, but they think it's going to a VCR.

Don't want to use analog hole method. I want the raw MPEG-2 stream.

Edit: Sorry I should've been more clear. With an ATSC digital tuner and video capture software you capture the raw MPEG-2 stream that's being sent over the air (OTA). The same is true with a QAM digital tuner over cable. No transcoding/reencoding is involved. I don't want/need an MPEG-2 encoding of an analog feed -- I can already do that with all the analog tuners I have hooked up to my PC.

[schild]

Oh man, this is an uphill battle Trippy. My suggestion since you have a decent net connection, just make a donation to TV Torrents.

"Backing Things Up" should take minimal effort on the end user side. 

[Trippy]

Torrent quality of TV shows is crap crap crap. They are designed to fit a 2 hour show on a single CD which is way too few bits for my tastes.

[schild]

I have no clue what you're watching about.

* schild hugs all the bits of his hi-def Generation Kill mkvs.

[angry.bob]

Torrent quality of TV shows is crap crap crap. They are designed to fit a 2 hour show on a single CD which is way too few bits for my tastes.

Trippy, You can get 1080p and 720p HD MKV files of pretty much any show out there. I use USENET to get them, but I imagine thy have torrents of them too. File size for a 720p 40 minute show is about 1.5 gig. What you said was true a couple of years ago when people used VCD to put a 2 hour movie on one CD and SVCD was the best format in use, but things have really changed.

[Soln]

If you have Mac I can help you out.

[Trippy]

If you have Mac I can help you out.

Sure Mac is an option assuming it doesn't require expansion slots (only have a Mac Mini).

[Trippy]

Trippy, You can get 1080p and 720p HD MKV files of pretty much any show out there. I use USENET to get them, but I imagine thy have torrents of them too. File size for a 720p 40 minute show is about 1.5 gig. What you said was true a couple of years ago when people used VCD to put a 2 hour movie on one CD and SVCD was the best format in use, but things have really changed.

Nope quality still not good enough and not enough shows that are in HD are available in that form in any event (I've looked for the shows I'm interested in).

Essentially I want to grab the HD MPEG-2 in its broadcast form. Yes it takes ~7 GB per hour but I'm okay with that. I can then convert it to other, more compact formats as needed. I do NOT want to start with something that's already encoded at some pathetically low bit rate that's usually in the wrong size. E.g. a 720p show typically ends up like 960 x 540 in MKV H.264 format instead of the full 1280 x 720. Basically the people doing the reencoding and uploading on BitTorrent and Usenet are concerned about space, even the HD versions. I don't want those versions.

[Trippy]

I have no clue what you're watching about.

* schild hugs all the bits of his hi-def Generation Kill mkvs.

That's cause you don't realize how much better the original HD MPEG-2 streams are.

[schild]

No, I just weigh the hard drive space of an HD stream like that versus a 720p or 1080p mkv. I don't delete things, I just buy more hard drive space. So I have to be SLIGHTLY rational about what I keep on them. You're talking to a guy who has 2 PS3s and 2 HD-DVD players. I'm FAIRLY sure I recognize the value of uncompressed HD content. ^_^

[Trippy]

Picked up some new hardware and futzed around things some more and I managed to get FOX-HD to work by translating the MythTV channel encoding format to the GB-PVR tuning format

So now I can (hopefully) record and watch Bones in HD on Wednesday

[schild]

Ok, that's a lot of fucking hassle to watch Bones.

I mean, Bones. Trippy, Bones. Comeon. Bones?!

[Trippy]

Not just Bones -- Bones in HD!

[Trippy]

Grrr...signal not strong enough, recording stops after a few minutes. Need to bring my cable/antenna amplifier over.

[Trippy]

Fuck, audio is not in sync.