I was wondering ?

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gremlin411

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May 16, 2008
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For a reciever to pick up 4:2:2 video. And also for one to be able to blind scan , is it a software thing are a hardware thing. I read that the pc cards can pick up 4:2;2 video with a added codec. So I was just wondering. How it works.
 
Well, so it appears what you know is fairly accurate. There is, I believe, an expensive standalone STB that will decode 4:2:2. My PCI and USB receivers will do that just fine - with the appropriate software decoders, as you are aware.

The trouble I run into is that the PC-connected receivers do not blind scan (nor am I aware of any that do). As a stop-gap, the STBs that blind scan will actually lock and scan in DVB feeds sent as 4:2:2. It's just they won't display them. So it's a manual process, for me at least, to copy over frequency and transponder data to the PC in order to see what's going on. I'm sort-of working on a software solution to this, but my initial estimates predict it will be slower than the current manual method ---

Which brings us of course to your blind scan question. I've always viewed a hardware v. software scan as a non-issue, as long as the scan finds the feeds. Speed is somewhat important, I guess, depending on the users interests. I tend to want accuracy, so speed is less important to me.

I could go on for another hour on this topic, but I don't want to ramble. Such is my experience with the hardware I have available. I'm happy to expand on anything, and I hope the follow-ups will add to my knowledge as well..

Happy hunting!
 
For a reciever to pick up 4:2:2 video. And also for one to be able to blind scan , is it a software thing are a hardware thing. I read that the pc cards can pick up 4:2;2 video with a added codec. So I was just wondering. How it works.


I've wondered the same thing. If an inexpensive pc card can do it, I don't see why more STB have the capability.
 
Boomer, if any pay service had mpeg2 and 4.2.2 only you can bet there would be boxes designed to pick it up. As it is, not enough demand for it here, appparently.
 
Boomer, if any pay service had mpeg2 and 4.2.2 only you can bet there would be boxes designed to pick it up. As it is, not enough demand for it here, appparently.


I suppose you are right. I don't know how many they would have to sell to make it worthwhile but, I bet an inexpensive 4:2:2 HD box would sell pretty good amongst the members here as well as another site I visit.
 
Thanks for the reply.
If it is a software I was thinking of trying to talk a friend of mind into taking a look at it to see if he could help. I am thinking about a cs8100. But I just do not know why only one receiver and some pc cards will decode 4:2:2. I was hoping it was a software thing also.
 
Decoding 4:2:2 IS a software thing. All pc-cards are simply tuners . 4:2:2 is a video format that is mostly unsupported by consumer receivers, but using a computer and a pc-card AND the appropriate software codec, 4:2:2 video can be decoded easily.
:)
 
For a reciever to pick up 4:2:2 video. And also for one to be able to blind scan , is it a software thing are a hardware thing. I read that the pc cards can pick up 4:2;2 video with a added codec. So I was just wondering. How it works.

blind scan can be software or hardware.
PC cards don't usually have hardware blind scan so
their blindscan tends to be slower than the set top
boxes that usually have hardware blind scan.
 
4:2:2 is a software issue but alot of recievers may not even have a fast enough CPU (guess on my part). Writing codecs for a STB to decode 4:2:2 may also be a problem if you aren't a computer engineer (I'm not). I'm not sure of the proccesing power involed, but even a 1GHz computer is many factors ahead of the average STB. STB are designed to run the slowest CPU that they can, while still being able to process what they are designed for.

If the pay providers used 4:2:2 you could bet that either the FTA STB manufactures, or the pirates would have a solution.

You are really stuck with a PCI/usb tuner and a computer, or a Qualiti in order to get 4:2:2 video. The only other option is professional broadcast receivers, and they will cost you $$$$.
 
4:2:2 is a software issue but alot of recievers may not even have a fast enough CPU (guess on my part). Writing codecs for a STB to decode 4:2:2 may also be a problem if you aren't a computer engineer (I'm not).

On a PC it is a software problem because the PC's CPU decodes the mpeg2 stream. It might have the help of a video card for some codecs, but it is pretty much a software decode.

On a STB it is a hardware problem because the STB's system-on-a-chip CPU includes a hardware mpeg2 decoder. The cpu manages the UI and controls the tuning and decoding, but doesn't do that itself. All the cpu does is shovel the data from the tuner to the decoder and even that might use a dma arrangement which offloads the actual transfer of data from the cpu as well.

Google the STi5518 datasheet and you can read about a common STB cpu core. Typical speeds are 200mhz or less.

I don't know much about the actual 4:2:2 format, other than what you can find via wikipedia and google, but I am pretty sure that is no way to shoehorn a 4:2:2 codec onto such a slow system. Maybe a faster system could filter the stream down somehow without fully decoding it, but it seems unlikely.
 
On a PC it is a software problem because the PC's CPU decodes the mpeg2 stream. It might have the help of a video card for some codecs, but it is pretty much a software decode.

On a STB it is a hardware problem because the STB's system-on-a-chip CPU includes a hardware mpeg2 decoder. The cpu manages the UI and controls the tuning and decoding, but doesn't do that itself. All the cpu does is shovel the data from the tuner to the decoder and even that might use a dma arrangement which offloads the actual transfer of data from the cpu as well.

Google the STi5518 datasheet and you can read about a common STB cpu core. Typical speeds are 200mhz or less.

I don't know much about the actual 4:2:2 format, other than what you can find via wikipedia and google, but I am pretty sure that is no way to shoehorn a 4:2:2 codec onto such a slow system. Maybe a faster system could filter the stream down somehow without fully decoding it, but it seems unlikely.


Well then I guess we'll have to see what's in the inner workings of the Quali-TV
 
Yes that would be the trick. To take a good look inside one. But I do not have one and can not buy one.


Well I'm sure we can get the specs and probably even inside pics from some of the members here if it served any purpose. I'm guessing but, I would venture to say Iceberg would give some info. I know he has one now.
 
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