4:2:2 - This refers to chroma subsampling, right?

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Rawmotion

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Dec 18, 2007
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I noticed on AMC-1 there are some NBC channels listed in Lyngsat as 4:2:2. I tried to pick them up, but they're just garbled mess. I can still get the audio, but no luck on the video. I assume this is because my Pansat 3500SD is designed to decode 4:2:0 MPEG2 only.

4:2:2 is a common term in the post industry for luma/chroma sampling, but I don't know if it means the same thing for DVB. Is 4:2:2 actually part of the DVB spec, or is this a new addition that will be supported by more and more receivers as it gets more popular?
 
It means the same thing for DVB. I know the Quality FTA receiver decodes 4:2:2, there might be other FTA receivers that decoded it but I am not sure which ones. If you have a PC DVB card you con decode 4:2:2 with the correct software codecs.
 
Some broadcast-grade receivers will decode a 4:2:2 DVB signal, but these tend to be rather expensive. One such example is the Digitrans 7150, which can do 4:2:2 and 4:2:0 DVB, as well as zero/fixed key Digicipher II.

Only consumer-grade receiver that can do 4:2:2 at this time, as Qwert said, is the QualiTV. It costs nearly $700 in the states, though...
 
Some broadcast-grade receivers will decode a 4:2:2 DVB signal, but these tend to be rather expensive. One such example is the Digitrans 7150, which can do 4:2:2 and 4:2:0 DVB, as well as zero/fixed key Digicipher II.

Only consumer-grade receiver that can do 4:2:2 at this time, as Qwert said, is the QualiTV. It costs nearly $700 in the states, though...

I actually purchased mine on ebay last year for a lot less than that and have had no problems with the receiver. Just checked ebay...here's a link to someone selling one from Germany (by the way, I bought mine from a person in Germany, too): Quali TV* QS 1080 IR *-HDTV -> 4:2:2-Feeds!!! * TOP * - (eBay item 260195953514 end time Dec-30-07 14:03:33 PST).

Very cheap (relatively speaking)!
 
Only consumer-grade receiver that can do 4:2:2 at this time, as Qwert said, is the QualiTV. It costs nearly $700 in the states, though...

A PCIe card sounds like the best bet in this situation. Twinhan seems to be a popular choice. I assume the card takes the MPEG2 stream and sends it to a Directshow filter to be decoded with your codec of choice. From that point it's sent to the video card's overlay and out the DVI connector. Since DVI = (HDMI - audio), I should be able to connect the PC to the flat panel with a DVI -> HDMI cable. Correct?

A big plus would be to have the ability to dump the raw MPEG-2 / audio stream from the card to disk (without recompression). Is this a reasonable expectation?
 
A PCIe card sounds like the best bet in this situation. Twinhan seems to be a popular choice. I assume the card takes the MPEG2 stream and sends it to a Directshow filter to be decoded with your codec of choice. From that point it's sent to the video card's overlay and out the DVI connector. Since DVI = (HDMI - audio), I should be able to connect the PC to the flat panel with a DVI -> HDMI cable. Correct?

A big plus would be to have the ability to dump the raw MPEG-2 / audio stream from the card to disk (without recompression). Is this a reasonable expectation?

That's the biggest advantage, in my opinion, of the PCI tuner cards. You get the raw stream, directly from the satellite, and can record it as a .TS file. Of course, the side benefits are 4:2:2 and HD. Until I acquired my Visionsat IV-200 PVR over a month ago, my PCI DVB cards were the only means I had to record the pristine stream from a satellite. This Visionsat receiver has built-in PVR capability via a USB port, so one can attach an external hard drive to the receiver to record the stream without a PC. The Visionsat, however, can only be used for 4:2:0 SD DVB.
 
That's the biggest advantage, in my opinion, of the PCI tuner cards. You get the raw stream, directly from the satellite, and can record it as a .TS file. <snip>

So the TS file would hold the 188-byte packetized MPEG-2 transport stream coming off the transponder, complete with all the various tables and all the media streams on that transponder?

If so, cool! It would be like a cheap protocol analyzer. I think it would be fun to build up the PAT and PMTs and "learn by doing" with an actual stream of data (even if not real-time) :)

What sort of hardware is known to work to do this, (USB or PCI), if so. That's neat :)
 
P.S.: I'm interested in driving a "blind scan". I guess the trick would be to figure out how to tune the transponder frequency in steps, capture the data in a .TS file (if it works as I'm thinking it does), and then build up the tables if a valid stream comes in, then step to the next frequency and repeat, until the whole range is scanned. Well, that and moving the dish :)

It would be dreadfully slow, but if a machine were dedicated to this task, it wouldn't matter if it took a few hours.

Just thinking it might be kind of fun, in a masochistic sort of way :)
 
Since the Captiveworks CW-3000HD is basically a peecee with Linux and fancy wrappers around VDR and Xine it should have the capability to do 4:2:2, since Xine uses libmpeg2 which is supposed to support 4:2:2. I've never pointed mine at a 4:2:2 feed and right now all the sat equipment is in boxes as I get moved in to my "new" home.
 
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So the TS file would hold the 188-byte packetized MPEG-2 transport stream coming off the transponder, complete with all the various tables and all the media streams on that transponder?

If so, cool! It would be like a cheap protocol analyzer. I think it would be fun to build up the PAT and PMTs and "learn by doing" with an actual stream of data (even if not real-time) :)

What sort of hardware is known to work to do this, (USB or PCI), if so. That's neat :)
take a look at a program called tsreader by coolsf. its really a neet app for seeing what the stream is doing.
 
After a private discussion on the Captiveworks factory forum I found out they are using an older version of Xine that doesn't support 4:2:2. Hopefully they will update to a newer version to provide 4:2:2 support.
 
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