AVS Forum banner
Status
Not open for further replies.
1 - 11 of 11 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
I am looking for high quality HDTV tuner (So I can record it into a .avi)...


I searched around, and mostly found that some card pick up wireless HDTV (which is not an option for me.) While others seem to be "real" HDTV cards like MyHD.


But I still do not understand how it would work.... Although ive never seen HDTV before I am guessing for best quality you would use component cable (and s-video or RCA for inferior quality.) But MyHD does not have an any component connectors (looks like it has two coaxial connection, and two unknowns)... I have also found that with a MyHD sister card you can connect component, but it would connect thru the big vga looking port (wouldn't you lose quality there?).
 

·
Registered
Joined
·
13,423 Posts
Where are you located?

"Wait , what? If I want to record a HD channel it will be in a rubbish format."


Most people consider AVI as the "rubbish" format. An HD Transport Stream is recorded exactly as transmitted from the broadcasted in a compressed (encoded) MPEG2 format. Upon playback a TS recording will have exactly the same image quality as transmitted instead of being down converted to a lower quality AVI.
 

·
Premium Member
Joined
·
13,879 Posts
Yeah, good lord why would you want to use .avi? Blech.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #4 ·
Quote:
Originally Posted by Cliff Watson
Where are you located?.
Ontario, Canada. Unfortunetly shaw is being forced down our throats :( But there not that bad when it comes to tv...

Quote:
Originally Posted by Cliff Watson
"Wait , what? If I want to record a HD channel it will be in a rubbish format."


Most people consider AVI as the "rubbish" format. An HD Transport Stream is recorded exactly as transmitted from the broadcasted in a compressed (encoded) MPEG2 format. Upon playback a TS recording will have exactly the same image quality as transmitted instead of being down converted to a lower quality AVI.
O, ok then thats good news then, can VirtualDub edit it? I just said .avi as an example (something I can play in Media Player Classic 6.4.8.2 and also edit.)


So if it is full quality, is it the same full quality you would get on tv?


Questions left unanswered:
  • What Tv tuner should I get, and why?
  • How will my tv tuner (my MyHD) give me full quality even though its not component?
  • I will still need to purchase the PVR (or what ever it called) from shaw, right?
  • Will I be able to edit the recorded format (in MyHD case it would be .tp)?
 

·
Registered
Joined
·
573 Posts
Quote:
Originally Posted by SignedupGuest
Ontario, Canada. Unfortunetly shaw is being forced down our throats :( But there not that bad when it comes to tv...


O, ok then thats good news then, can VirtualDub edit it? I just said .avi as an example (something I can play in Media Player Classic 6.4.8.2 and also edit.)


So if it is full quality, is it the same full quality you would get on tv?


Questions left unanswered:
  • What Tv tuner should I get, and why?
  • How will my tv tuner (my MyHD) give me full quality even though its not component?
  • I will still need to purchase the PVR (or what ever it called) from shaw, right?
  • Will I be able to edit the recorded format (in MyHD case it would be .tp)?
You've got a lot of research in front of you. :)


Some things to consider - you keep referring to "Shaw". I don't know what that is - but if it's a cable company, you may be out of luck. Here's why: There's OTA HDTV (Off-the-air) - meaning "you receive it from a UHF antenna". This stuff is sent "in the clear" - it's not encoded with copy protection or anything. This is what all these HDTV cards can receive and record. Then there's "Cable" HDTV - this stuff can be encoded or not depending on what your cable company is doing. If it's encoded, you're out of luck - no card out there can decode encoded HDTV. If it's NOT encoded, you still may be out of luck - there are two "clear" formats for HDTV: QAM64 and QAM256. After perusing the AVSForum for quite awhile, it appears NO HDTV card can be guarenteed to tune QAM stuff consistantly - the format seems to vary from cable company to cable company AND even from channel to channel within the same cable company's offerings. It's a crap shoot. I'll probably get jumped on here by the people that have successfully got it working, but as proof I offer this: start an HDTV card thread talking about new software, and see how long it takes before desperate posts about "does it do QAM?" start appearing...


Based on you mentioning "wireless" HDTV not being an option for you, you may simply be out of luck assuming you're referring to OTA HDTV - the only way to record HDTV would be to get an HDTV PVR from your cable company, and I doubt you'll be able to edit the recorded files. You MIGHT get lucky and the HDTV PVR might have firewire out, in which case you MIGHT be able to capture the video to your PC via firewire transfer, but that's a whole different ballgame entirely.


Oh, one last note - if your cable company offers a "PVR", make SURE it can record HDTV in HDTV resolution and spit it out via Component output (not downscaled and output via S-Video or something like that). I'd bet dollars to donuts when they offer a "PVR", they're talking about a non-HDTV PVR - HDTV PVRs cost a lot more than non-HDTV PVRs because the tuners are more expensive, and you need about 9 times as much hard drive space as a non-HDTV PVR.


--KS
 

·
Registered
Joined
·
859 Posts
I'll jump on your post KS :p ... but only for some technicalities/specificity reasons
Quote:
Originally Posted by KlingonScum
Some things to consider - you keep referring to "Shaw". I don't know what that is - but if it's a cable company, you may be out of luck.
Yes, its a cable co., and I believe they do employ encryption (but I'm not possitive).
Quote:
Then there's "Cable" HDTV - this stuff can be encoded or not depending on what your cable company is doing. If it's encoded, you're out of luck - no card out there can decode encoded HDTV.
What KS is talking about is the signal being encrypted, and is not to be confused with decoding of the MPEG encoded TS...a confusion that I could easily see happening by the unaware.
Quote:
there are two "clear" formats for HDTV: QAM64 and QAM256.
This statement is a bit misleading. QAM has nothing to do with whether or not the channel is encrypted or in the clear. QAM is simply a modulation scheme used to convey information on a RF carrier. It happens to be the scheme employed by cable co's (although they can, in some rare cases do/have, use/used other methods).


Cliff addressed the nature of delivery and reception of DTV -- i.e a compressed Mpeg2 transport stream. After which, though you are certainly free to transcode the mpeg to other formats or containers


Regarding the AVI format -- it is only a container. Although old, and certainly not the best, it shouldn't be jumped upon as being inferior for picture quality. Assumptions of which implies the use of a lousy codec, which certainly need not be the case.


As for putting contents of the recorded TS into AVI, you could employ any number of codecs within the container - from lossless formats to even wrapping the original Mpeg within the avi -- and both would certainly perseve the picture quality (although neither is recommended). Or you could even transcode the mpeg to a lousy format with little noticable quality loss ... if you so choose to.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #7 ·
So other then curling up in a corner my only option is to call or email my shaw and ask them if not only the PVR is recorded in HDTV but also has a firewire out.... Doesn't sound like the thing a substandard company like shaw would do, they cant even handle the bandwidth I use (on there ultra slow connection) without harassing me and threatening me :\\


But there is still one thing I do not get.... Isnt there a box that decodes the transmition before its sent to the tv? Isn't there a HDTV tuner that can replicate what ever a tv does when it receives HDTV?
 

·
Premium Member
Joined
·
13,879 Posts
Don't we all wish :). Remember that once it leaves the box it is now uncompressed HD, and requires SIGNIFICANT hardware to capture and record.
 

·
Registered
Joined
·
573 Posts
Quote:
Originally Posted by CityK
What KS is talking about is the signal being encrypted, and is not to be confused with decoding of the MPEG encoded TS...a confusion that I could easily see happening by the unaware.
Hyuck, I knew it wuz won uh them thar "E" words. Ugh. I can't believe I wrote "encoded" instead of "encrypted"...

Quote:
Originally Posted by CityK
This statement is a bit misleading. QAM has nothing to do with whether or not the channel is encrypted or in the clear. QAM is simply a modulation scheme used to convey information on a RF carrier. It happens to be the scheme employed by cable co's (although they can, in some rare cases do/have, use/used other methods).
Poorly worded on my part originally. I should have said "assuming your cable company is sending the signal in the clear, there are two 'formats' the signal can come down the coax to you as: QAM64, and QAM256."


Are you sure you can't get Off-the-air HDTV broadcasts where you are? A lot of people get a surprising amount of success even in multi-path rich (read: lots of reflective surfaces nearby munging up your signal) areas with little set top antennas.


The "Holy Grail" of HTPC Cable-borne HDTV would be a PCI card that accepted a Coaxial HDTV signal from your cable provider and had a "CableCard" slot in it. Dunno if that will ever happen, and if it did, I can pretty much guarentee it'd have some sort of DRM built into it (ask yourself why DirecTV never released a PCI card that does what its settop boxes and DirecTiVos do).


Another "Holy Grail" would be a PCI card that took 480p/720p/1080i Component input directly and "did something with it" on your hard drive. There actually are products out there that will take Component input into your PC - but they're all limited to 480p, which needless to say ain't HDTV resolution. To be fair, I think there may be true 720p/1080i cards that CAN do it, but they're probably upwards of $10k+ US... And there's a very good reason for why they're so expensive - bandwidth...



Warning: I may get some numbers wrong here, but my general gist ought to be correct...


Normal Uncompressed NTSC video = 640x480x30fps. I'm going to ignore color and audio for a moment - that takes bytes too - and just do fairly basic math. You're talking 9,216,000 pixels (bits - remember, I'm ignoring color) pushed per second - that's about 1.1MB/second.


Progressive Scan Uncompressed DVD video = 720x480x60fps. That's 20,736,000 pixels pushed per second, or about 2.5MB/second.


Now for the fun ones. 720p HDTV: 1280x720x60fps. That's 55,296,000 pixels pushed per second, or 6.6MB/second. 1080i HDTV is even worse: 1920x1080x30fps = 62,208,000 pixels pushed per second, or 7.4MB/second.


It's actually a worse than that too - if you allocate 3 bytes per pixel for color instead of 1 bit for "pixel on/pixel off", you multiply those numbers by 3 accordingly. Also, audio: HDTV has AC3 5.1 audio which takes up a LOT more bandwidth than NTSC stereo.


So, how are they getting all that hi def goodness to your TV over the air (or for that matter, 480p on that DVD when doing the math means a 2 hour DVD movie should take up 50GB of space)? Compression. That's what's coming down your antenna/cable coax/satellite coax. The tuner box decompresses that puppy and shoots it out as an analog screen in all its uncompressed glory through the component outputs. But...imagine if you had to take that firehose of data IN through component inputs to your PC. I sort of even wonder if the PCI bus even has the bandwidth to handle it...the card would have to do some really heavy duty re-compression on the fly to then send the information down the PCI bus out to your Hard Drive. If you didn't compress it...well, right now, HDTV tuner cards (OTA) gobble up about 9GB per hour of HDTV recording. If you didn't compress it...I'd be willing to bet it'd take 100GB per hour to record that nasty stream of data uncompressed, and then some...


:)


--KS
 

·
Premium Member
Joined
·
13,879 Posts
You can convert component to SDI, and capture it at about 50gb/hour and then convert that to .ts ;). Costs about $5k to do.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #11 ·
Quote:
You can convert component to SDI, and capture it at about 50gb/hour and then convert that to .ts . Costs about $5k to do.
I dont have that much money :p (400-600$ was the most I wanted to spend for this)... I am going to college and I was thinking of getting a tuner so if ever I did get cable I would not need to get a TV.


In my old p2 1.5ghz intel I have a:
MSI [email protected] (MS-8876) (Silicon Tuner & Conexant Cx881)

But I have been thinking of getting one of the best (apparently) regular tv tuner (if I could not find a decent HDTV card):
MSI THEATER 550PRO PCI TV TUNER MPEG-2 ENCODER (30fps @ 720x480-NTSC and 25fps @ 720x576-PAL)

My old tv tuner quality aint so good (can anyone confirm that the new one will be better, I can not find the resolution for msi [email protected]). MPEG-2...?

Quote:
Are you sure you can't get Off-the-air HDTV broadcasts where you are?
I am moving to a city (~80 000 pop?) so it might be available there, but I do not know were to check its availability (FYI – I am from Ontario, Canada (will be going to Sault Ste. Marie))

Quote:
There actually are products out there that will take Component input into your PC - but they're all limited to 480p, which needless to say ain't HDTV resolution.
I agree, I wouldn't want only 480p.

Quote:
I sort of even wonder if the PCI bus even has the bandwidth to handle it...
Regular pci has 133MB/s while PCI-E has 2.5Gb/s which ends up being about 200/250MB/s (per channel) so I think it can handle it :p


-----------------------------------------------------------------------------------

I spent over 300$ on a DVD recorder and was very disappointed in the quality and convenience, so I decided id ask question this time ;)
 
1 - 11 of 11 Posts
Status
Not open for further replies.
Top