HD, Transport Streams, huh, what?

[zehd]

Ok, I admit I can get like an old dog sometimes, and turn a blind eye to new stuff. But it's time I know something about this new fangled HD stuff...

Well, I get most of it, except where it comes to capture cards...

In the last year, I learned that some cards need to have a software capture interface (BDA Multiplexer) to record video. I assumed that it was because that type of interface wasn't on the card like the Hauppauge PVR 150 cards...

At least I thought that a 150 could record a MPG natively... And I think that MPG stream is a Program Stream...

Anyway, the part I'm foggy on is: are all HD cards unable to capture video like the 150 does?

And what the heck is a Transport Stream?

Why can't they just make HD cards like the way the make SD cards?

:confused:

[zehd]

I read some more about the HVR 1600 from Hauppauge. Seems that the HD side gets its signal over the air. Calgary doesn't have that yet. But we can get Cable HD and Sat HD. How would I hook that up to the card and my computer...?

[sub]

You'll have a pretty good grasp on how analog capture devices work (PVR150 etc) - using an chipset for encoding analog TV broadcasts to a MPEG file. The resulting file is in an MPEG format called a 'program stream'. A program stream usually contains one video stream and one (or two) audio streams.

All this additional discussion about transport streams and multiplexer filters relates to digital devices.

Digital can be carried over a few different mediums, so you'll see different names like DVB-T (terrestrial digital), DVB-C (cable digital), DVB-S (digital satellite) and ATSC (USA/Canada terrestrial). Ignoring the differences in the front end tuner for each of them, these digital devices all generally pass data formated as transport streams. A transport stream is a MPEG format designed to carry multiple video and audio streams (each combination making up a channel), and designed to be used in an error prone environment (TS data is lots of little packet so that a small packet loss wont lead to the loss of a big chunk of data).

When GB-PVR does a recording, it tells the device to tune to a specific frequency, then splits the multiple audio/video streams out to separate streams (using a demultiplexer), then a multiplexer filter is used by GB-PVR to recombine an individual audio and video stream into a regular MPEG2 program stream file.

[zehd]

You'll have a pretty good grasp on how analog capture devices work (PVR150 etc) - using an chipset for encoding analog TV broadcasts to a MPEG file. The resulting file is in an MPEG format called a 'program stream'. A program stream usually contains one video stream and one (or two) audio streams.

All this additional discussion about transport streams and multiplexer filters relates to digital devices.

Digital can be carried over a few different mediums, so you'll see different names like DVB-T (terrestrial digital), DVB-C (cable digital), DVB-S (digital satellite) and ATSC (USA/Canada terrestrial). Ignoring the differences in the front end tuner for each of them, these digital devices all generally pass data formated as transport streams. A transport stream is a MPEG format designed to carry multiple video and audio streams (each combination making up a channel), and designed to be used in an error prone environment (TS data is lots of little packet so that a small packet loss wont lead to the loss of a big chunk of data).

When GB-PVR does a recording, it tells the device to tune to a specific frequency, then splits the multiple audio/video streams out to separate streams (using a demultiplexer), then a multiplexer filter is used by GB-PVR to recombine an individual audio and video stream into a regular MPEG2 program stream file.

Wow, you should write a book or something.... Thanks!

So if I have HD Cable w/STB HD out (DVI I think) All I would need is a DVI Capture card to get the video/audio streams onto the PVR... Because all the HD decoding is handled by the STB...?

[sub]

I read some more about the HVR 1600 from Hauppauge. Seems that the HD side gets its signal over the air. Calgary doesn't have that yet. But we can get Cable HD and Sat HD. How would I hook that up to the card and my computer...?

Unfortunately the HVR1600 can only get its digital over the air, so cant help you with cable or sat HD.

There is some comments though that this device's hardware supports cable HD, but its not enabled in the current drivers. I wouldnt count on it, but maybe.

While this specific device isnt able to do Sat HD, there are some north american users using DVB-S cards along with a multidec plugins to do DishNetwork and Bell Vu Express. The details of setting this up are bit more on the illegal side though, so here is not really a good place to discuss the details.

[sub]

The good thing about recording with these digital devices is that you dont have to rely on set top boxes, and there is no re-encoding required, so you effectively record shows exactly bit for bit as they were transmitted by the broadcaster (zero quality loss).

[sub]

So if I have HD Cable w/STB HD out (DVI I think) All I would need is a DVI Capture card to get the video/audio streams onto the PVR... Because all the HD decoding is handled by the STB...?

It doesnt really work like that. There isnt really any (consumer) digital devices that record from the output of a set top box (the devices have no DVI or HDMI inputs, usually just a coax or antenna socket). The capture card tunes the original signal and the software does the remuxing etc.

[zehd]

Bummer. The cable company does provide a PVR STB that does HD, but I'm trying to avoid that. Coming up to a year with you all, and don't want to look back...

[sub]

If I was in that part of the world, I'd probably be doing the Dish/BEV multidec thing I mentioned above. I'd only do it if I was a legit subscriber though, so I'd feel like I was morally within my rights even if I wasnt legally within them...

[zehd]

If I was in that part of the world, I'd probably be doing the Dish/BEV multidec thing I mentioned above. I'd only do it if I was a legit subscriber though, so I'd feel like I was morally within my rights even if I wasnt legally within them...

Good point.... THanks