what's the deal about the 525 lines ?

[Zetti]

Hi all,

I understand that the TV broadcast resolution is 525 lines, but.....are these horizontal or vertical lines resolution ?


If these are H, what is the V resolution ? Or vice-versa ?

Thanks,

Zetti

[gshelley61]

The NTSC broadcast signal has 525 horizontal scan lines, but they are not all used to carry picture information. I think 480 interlaced (240 per field) is the maximum for the actual image, but I'm not certain of that. Also, I believe the max vertical resolution is 640. The H and V figures can vary depending on the source. VHS has much lower resolution than laserdisc, for example, but both generate an NTSC signal.

[FOO]

That's how many horizontal lines stacked vertcally or
the vertical resolution.
The horizontal doesnt have lines. It's a continuous analog
waveform until it gets divided into spots by the phosphor
dots on the color screen. B&W is continuous even on the screen.

Some people refer to the EQUIVALENT horizontal resolution in lines.
There is a limit to how small a horizontal spot can be made.

[gshelley61]

That's how many horizontal lines stacked vertcally or
the vertical resolution.
The horizontal doesnt have lines. It's a continuous analog
waveform until it gets divided into spots by the phosphor
dots on the color screen. B&W is continuous even on the screen.

Some people refer to the EQUIVALENT horizontal resolution in lines.
There is a limit to how small a horizontal spot can be made.

Right. Got my H's and V's mixed up. As you mentioned, visible resolution will depend on the type of monitor/TV that is being used, too.

[Zetti]

Thanks both for replying;

Well, if I understood it corrrectly, the Horizontal lines will be what I actually set at my capture sw, right ?

When I capture at 720 X 480, am I actually DEFINING that I wanna 720 lines to be gotten from the continuos waveform ?
And am I losing quality on Vertical, as the source is 525 and I am actually getting just 480 (I know it's the DVD standard) ?

Thanks,

Zetti

[Zetti]

Am I losing quality (resolution) if I capture TV broadcast through a VCR TV tuner, output it from the VCR Composite output (RCA terminal) and still run it through a Datavideo TBC-1000 ?

I'd expect both the VCR and the TBC to degrade (by changing lines of resolution) the broadcast original quality, but still Ulead Video Studio says it sees 525 lines, this is apparently a good new but I am confused as I expected Ulead to do not detect the original TV broadcast resolution...

Don't the VCR and the TBC reduce the original TV broadcast lines resolution ?

Thanks,

Zetti

[Wilbert]

I uploaded a new version of the analogue capture guide a few days ago. You might want to read chapter 3.

[vhelp]

Hi zetti,

With respect to your VCR question..

The poster was refering to the VHS tapes, but not the actual Tuner (or other
video source you might bring into the VCR's Line-In ..only subject to the
"other" sources limitations - (ie, if you hooked up a DV cam to the Line-In
ports of your VCR, you would be subject to the DV cam's lines ie, 520)
or, if you hooked up another VCR (like you would right, hehe) say a SVHS
and played an SVHS pre-recorded tape to your VCR's Line-In, you would be
subject to THAT SVHS 's lines, which would be 400, through your VCR's
Line-In. )

Hope that made sense
-vhelp 2557

[junkmalle]

When I capture at 720 X 480, am I actually DEFINING that I wanna 720 lines to be gotten from the continuos waveform ?

Yes, that is correct.

And am I losing quality on Vertical, as the source is 525 and I am actually getting just 480

No, only about 480 of those scanlines contain the picture. Capture devices pretty much have to capture all 480 scanlines, or 240 scanlines by capturing only one of the two fields that make up each frame.

Am I losing quality (resolution) if I capture TV broadcast through a VCR TV tuner, output it from the VCR Composite output (RCA terminal) and still run it through a Datavideo TBC-1000 ?

Given that video tape is such a low resolution medium the VCR's tuner may not be as good as it could be. And you're definitely losing quality using a composite cable. You will get better results with an S-Video cable. Of course, few VCRs use S-Video since video tape is so low in bandwidth. You're better off getting an old cable box with S-Video out.

I don't think there's any need for a TBC with broadcast TV signals unless you have a very weak signal in your area. Broacast TV is very clean in terms of it's timing (what a TBC corrects).

[lordsmurf]

Do not confuse "525 SCANLINES" with "LINES OF RESOLUTION" (analog TVL measurement of clarity) or "RESOLUTION" (digital measurement of clarity).

x486 is the RESOLUTION of NTSC video (vertically-measured axis, horizontal data). It is displayed across 525 SCANLINES on the television, a path of the electron beam from left ot right (or was it right to left?).

Your horizontally-measured (vertical data) axes provide the definition of the video. The more vertical data that get squished together, the higher the clarity.

Example:
lo res: 1 2 3 4 5 6 7 8 9
hi res: 12345678
(yes, left to right determines definition, not up-to-down on analog)

To further confound matters, the theoretical analog->digital equivalancies of the vertical data may not reach that number in practice (ie, theory ditates standard 336 TVL NTSC broadcast can reach into the 400x range, however a 352x480 disc will still have a higher definition .. why? don't know, just the way it goes).

In the digital realm, as it exists now, 486 is rounded into 480 to be a multiple of 16. Depending on your equipment, this will either be discarded or sampled to make the final 480 from the 486 source. Nothing to cry over.

This is all VERY EASY to confuse. Read carefully. Read slowly.

[gshelley61]

The number of scan lines (vertical information) is always 525, with 486 interlaced lines (243 per field) actually carrying the picture information, correct? This applies regardless of source resolution?

So, then the horizontal "resolution" or detail in analog NTSC signals, being continuous, is limited by exactly what... the display device resolution - or the source material? Both? It is confusing.

If you view a DVD through a standard NTSC TV set, you are effectively displaying 720 pieces of information per line (assuming the display has native resolution high enough to reproduce it)... is that right?

[Alan69]

Am I losing quality (resolution) if I capture TV broadcast through a VCR TV tuner, output it from the VCR Composite output (RCA terminal) and still run it through a Datavideo TBC-1000 ?

I'd expect both the VCR and the TBC to degrade (by changing lines of resolution) the broadcast original quality, but still Ulead Video Studio says it sees 525 lines, this is apparently a good new but I am confused as I expected Ulead to do not detect the original TV broadcast resolution...

Don't the VCR and the TBC reduce the original TV broadcast lines resolution ?

No. The continuous stream of data is used to draw each horizontal line of dots. Then there is a horizontal sync pulse that resets the beam back to the left edge to draw the next line. Multiple I/O will tend to blur the horizontal line of dots, but each line is well seperated time wise. You will tend to lose resolution on the X axis, but it takes an awful lot to lose something on the Y axis. Even then you don't 'lose' dots on the X, it just tends to blur together on the X with enough degradation.

And note that you don't always 'lose' by having an extra component in. You should, but differences in tuners can make it not work out that way. I have a TV with a poor tuner. Straight to it, and the cable picture sucks. VCR first, and then to the TV in the same input and the picture is much better. The VCR has a much better tuner and eliminates some of the noise, plus puts it all on channel 3 which the TV tunes better plus less other cable noise. The combination is better than just the TV, even though there is an extra pass through.

If any upstream components have low bandwidth it will drop quality fast, if not you can pass through 3 or 4 items or more without noticing much of a drop.

Alan

[Zetti]

I uploaded a new version of the analogue capture guide a few days ago. You might want to read chapter 3.

Wilbert, thanks, but I couldn't find it, could you please post the exact link ?
Thanks,

Well, thanks for all that replied, I am still a bit confused but I think I can see some light at the end of the tunnel, my issue is :

In my Country, the TV broadcast is PAL-M. I have an ATI AiW card that is supposed to accept this format, but actually it doesn't. I have changed Catalyst many times and updated DirectX9.0b, no luck. As if it were not enough to release defective software, it now seems that ATI isn't satisfied with that and decided to release defective hardware as well.

I have an external box, a converter from PAL-M to NTSC. Both are very similar systems, PAL-M is VERY diferent from European PAL.

So, in order to find a way to capture TV broadcast, my idea is :

TV -> VCR Tuner -> VCR Composite output to PAL-M/NTSC converter -> Converter S-Video output to TBC input -> TBC S-Video output to ATI S-Video in port.

The reason to use the TBC is just to take advantage of its multiple I/O ports, I also have a direct NTSC connection through the TBC's Composite in port cause I also have lots of originally NTSC tapes that can't go through the converter of course (it gets lost as it expects PAL-M at its In port);

As far as I understood, maybe it'd be a good idea to skip the TBC step, I just wanna make sure Ia mgetting a NATIVE TV broadcast signal at the ATI card actual IN port, even if the signal goes through the VCR Tuner and the converter box.
As Ulead says the signal has 525 lines, I suppose it's OK, but I also think it's a good idea to ask here to you wise guys

Any comments ?

Thanks,

Zetti

[Zetti]

I uploaded a new version of the analogue capture guide a few days ago. You might want to read chapter 3.

Got it a Doom9, thanks Wilbert.

Zetti

[lordsmurf]

Zetti, you're on a mutant tv system. Blame Brazil, not ATI.

I actually wonder how and why mutant systems exist. Was it the government? Or something else?

I know that's why the French had SECAM-whatever special for them.

[Zetti]

Zetti, you're on a mutant tv system. Blame Brazil, not ATI.

Hi Lord and all, thanks for replying;

Lord, I have just gone to this web site :

http://www.ati.com

You have probably heard about it, right ?
OK, I have made a direct COPY/PASTE, without any editing, of THIS from this site (please, read carefully) :

_____________________________________________

Specifications

System Requirements

Intel® Pentium® 4/III/II/Celeron™, AMD® K6/Athlon® or compatible with AGP 2X (3.3V), AGP 4X (1.5V), or AGP 4X/2X universal bus
128MB of system memory
Installation software requires CD-ROM drive
DVD playback requires DVD drive
Interactive Program guide requires Internet connection for listing updates
Remote control receiver requires available USB port
500MHZ minimum processor speed for MPEG-2 video capture

TV-tuner requirements

TV signal from amplified antenna or cable. Versions available for:
NTSC (North America, Japan, and Latin America*)
MulTView™ requires additional ATI TV WONDER™ card, compatible motherboard and soundcard.
*Features vary from country to country and depending on the television standard. Note that Latin American countries using the PAL M and PAL N standards including Argentina and Brazil are supported by the NTSC version.

__________________________________________

As you can see, they state some conditions that the user HAS TO fullfill in order for their stuff to work. OK, so, BEFORE buying their stuff, I double checked that I had all these conditions OK - actually, I remember having talked to you personally about that some months ago...

Now, what ?

1) The TV Tuner doesn't work. Who is the guilty ? Brazil Government ? Me ? The Pope ? Bin Laden ? or ATI ?

Are you speaking seriously ? :P
OK, let's have some fun, I'm in a good mood today :P :P

2) The TV scheduler doesn't work.
Who is the guilty ? My Computer ? Michael Moore ? Me ? John Kerry ? or ATI ?
Are you speaking seriously ?

As far as I understand - actually, it seems obvious, (or at least it should seem,specially to a 5000 thousand times writer..... ) that, once an user (me, you, or whoever else) has fullfilled ALL a sw's "SYSTEM'S REQUIREMENTS", it has to work - if it doesn't, it's SHIT !
A sw that works for you and doesn't work for me, or that works for BJ_M and doesn't work for Fulcilives, or that works for SatStorm and doesn't work for DJRumpy is (supposing everybody has fullfilled all SYSTEM'S REQUIREMENTS) not more than crappy, a rip-off, it's as clear and as obvious as it gets.... ..or isn't it ?
Opinions ?

3) The File player crashes upon loading.....who is the guilty ? Brazilian Government ? My Computer hardware ? Bush ? Saddam ? or ATI ?
Whoever it is, I'll write again : I have fullfilled ALL "Sustems requirements", or whatever the hell that are :P

4) ATI software writes folders to my HD that are not system's folders, have nothing to do with its instalation, and, unbelievable, can't be deleted unless for HD formatting

5) ATI oficial support told me that I have a creative mind, have nothing to do in my life and have decided to kill time wasting their time....is it reasonable ? If you're ATI related, please forward them this message;

Well, thanks always for your VERY KIND replies along the time we've been meeting here

Returning to this topic, as it doesn't seem reasonable to travel to Canada and beat up the face of the ATI idiot that makes these shit board/sw, and as I live in another Country and can't prosecute them for a refundment, I have found the solution stated above for TV captures. Is it OK in your point of view and other people's ?

Thanks,

Zetti