Notes on Capturing...

[macm]

Hi fellows,

About SatStorm guide,

I'd read that latest guide and I must make some notes about it!
I agreed with a couple of things, specially under the subtitle "Common Mistakes and unknown facts, not technical related ", but some other I really desagree.
I've been to this analog capture stuff since 1998, so it's six years! Since I got this first ATI AIW Rage (with 8MB!!!) and I found since them, with lots of testing and experiments with all sorts of hardware and software, that it really matters if you can get a good hardware!! Even the expensive ones. It really matters if you get a top Mobo, a video capture device that is able to capture MPEG2 realtime, and so. Why? Why not? Why cap AVI them spend hours (I mean HOURS!!!) making encoding (actually REENCODING) into MPEG2? It is only worth if you plan on making lots of editing...but if your source is acceptable or nice quality, remmember, from VHS to DVD you won't get any better, only the same quality.
I agree also about the Matrox cards, and the Canopus falls into the same rule: they are also very good ones. But the ATI despite all the ugly support, are one of the best. Even their proprietary cap software (MMC) has everything you should need to make best quality captures. In AVI or MPEG1 or MPEG2. I own a ATI AIW 9700 PRO, and it rocks as it should. Also my mobo is a ABIT IC7-G with P4 2.8C HT, and 1GIG OCZ memory PC 3500 DDR 433. Nice? I think this is enough the worth the price, for steady and best quality caps. Drop frames? yes sometimes in a 2 hours cap I drop ~15 or ~20 frames, but it is a source problem, not a hardware/software problem. I really can't notice any difference between capturing to AVI them reencoding to MPEG2 and capturing directly into MPEG2, sometimes the later is better!! I've never, I say NEVER, EVER have any sync issues or any other loss of quality going to MPEG2 at first. If you get the feeling, get everything configured as well, you are done. I agree again, VirtualDub is a really good piece of software, with many settings, but it is worth only for those which has a cheap video card that cannot do the MPEG2 cap realtime. Or has a hardware set that can afford that type of realtime cap (I agree, to make a realtime MPEG2 cap, the first thing to consider is a real fast, robust PC). So, please, don't mention that those willing to get a more expensive hardware set up (mobo, video card, memory, HD, CPU) will overestimate it or spend unnecessry bucks!!!
Also, ATI has choice for PAL and NTSC!!! All my VHS-C was NTSC, and my caps went smooth...best quality ever!!!

MACM

[macm]

Just to complement the above,

I am in a PAL country, and I also cap from cable TV, which is PAL, and ATI does a really nice job!! So Why in the mentioned guide, says ATI does not like PAL???!!!

[Gazorgan]

CBR MPEG2 doesn't take hours to convert. Realtime capture cards are CBR.

If you want to apply any post-processing filters, do any re-sizing, or do more than pure cuts, then you have to re-encode.

MPEG2 was never meant to be edited. The way the video is encapsulated makes this more difficult than using AVI. Not impossible, just more difficult.

Do you listen to MP3's on a microphone? Then why do you capture with a video card.....think about it. Your capture device and your video display share an IRQ, so it's going to be slower than the dedicated card, especially if you are watching the capture occure.

VDUB is crap for capturing, it doesn't support WDM, and the WDM wrapper is ..... problemmatic.


I can capture in realtime mpeg2, never drop a frame, at any bitrate you could burn on a DVD, any resolution all with a $30 card. I have used dedicated realtime MPEG2 encoder cards and can't tell the difference on anything SVHS or below. That's on a 21" CRT doing side-by-side comparisons. PAL or NTSC (I have numerous PAL media), doesn't really matter. I have been doing video editing off and on (and professionally for a year) since 1998 (back when you HAD to use a MAC :P ) and today it's easily possible to do in software what was once only a hardware-only function.

My system is CHEAP!!! Less than $300 for everything but the monitor and drives. $$$ do not guarantee a good capturing system. Propper Planning Prevents Piss Poor Performance Issues.

[FOO]

Is PPPPPP a new acronym ?

Do you listen to MP3's on a microphone? Then why do you capture with a video card.....think about it. Your capture device and your video display share an IRQ, so it's going to be slower than the dedicated card, especially if you are watching the capture occure.

Microphones are input devices.

Think about it , if the video comes in to the capture/video card,
it doesn't even have to necessarily involve the computer at all.

You should explain why sharing an interrupt is slower than 2 interrupts
when the total interrupt rate is the same. I don't think so.

[Gees]

PPPPPPI

it's a confused GOP

[FOO]

It would work if you played it backwards

[Gazorgan]

A video card is an output device.

So, since interrupt level is constant, the entire computer needs only 1 interrupt by your logic.

[macm]

Gazorgan,

I agree, but what I meant was you won't be disapointed about getting a top hardware set up, it's one choice!!
I know there is many really good cheap dedicated video card out there that caps wonderfull (even the old ones).

The ATI AIW uses it's own on board processor (one for caps and a different one for video out, besides it's own DDR memory) so there are no CPU, Memory or IRQ overload. And the IRQ actually is not used for both (cap and monitor out).

Anyway, what is your dedicated video cap card?

[macm]

FOO,

I agree with you!!

The interrupt being used does not matter at all.

The CPU or BIOS microcode is only one!!! The system does not know if it's a video out or video in. It is just a video signal!!

[FOO]

I was talking about the ATI AIW specifically. It's a very non standard
device in several ways. The AGP slot is on the Front side bus - faster
It shares functions between video out and capture - i think

The main reason separate interrupts are better ( i didn't say faster )
is when a device has no buffering and just cannot tolerate not being serviced
immediately without losing data.

Chained interrupts can actually be faster because several drivers (devices)
can be processed with only one hardware interrupt and context switch overhead.