is this true? resolution myths?

[FulciLives]

Hello :)

I have an AverTV Stereo capture card.
Should I capture NTSC at 720 or 704 ?
There was some talk in this thread that with some capture cards it might be better to capture at 704 instead but I don't know if that applies to the card I have or not?

Thank you!

- John "FulciLives" Coleman

[FredThompson]

Typically, capture at 720x480, crop off the ragged edges, process, resize if desired, compress.

When you capture at 720x480 you will typically see only 704 pixels are used for the actual content.

[vhelp]

hmm...

Surely this must be w/ respect to capturing VHS sources :rolleyes:
and using Analog Capture cards as your device for obtaining the video
source.

I'm wondering what a CAM (using pass-through) has anything to add in
this myth as well as other DV devices ie, ADVC-100 etc :rolleyes:
.
.
Never the less.. all is interesting :)

-vhelp

[FredThompson]

Originally posted by SeeMoreDigital
We should also, all be aware, that NTSC and PAL capturing don't follow the same rules and therefore the chipsets respond to the input signal in different ways.Yes, absolutely. Perhaps not specificying the format leads to a lot of confusion.I live in a PAL area. And my prefered method of capturing (for home use anyway) is either DV cam pass thru' or very high bitrate (9000+kbps) Mpeg2 capturing using the ADS USB 2.0 device (my thanks to Fred for this tip).

However, at the end of the day the ADS is the easiest device to setup and use and 'way' cheaper than buying an DV camcorder. Sure editing is more difficult to do with Mpeg2 but you get used to it!Good to hear you like the ADS. It's also nice because it will handle PAL, NTSC, SECAM and variants. Pretty cool for <$200 USD.

[SeeMoreDigital]

Originally posted by FredThompson
Typically, capture at 720x480, crop off the ragged edges, process, resize if desired, compress.

When you capture at 720x480 you will typically see only 704 pixels are used for the actual content. It's also worth noting that even if you decide to keep the frame size at 720 (with a bordered 704 image). On most TV's you won't notice the side borders. It all depends on how well or badly your TV has been set up!

In much the same way you don't notice the side borders on many 1.85:1 DVD's. Well PAL DVD's anyway!

Cheers

[FredThompson]

Originally posted by vhelp
Surely this must be w/ respect to capturing VHS sources :rolleyes:
and using Analog Capture cards as your device for obtaining the video
source.No, all NTSC. I started with a capture card and how do DV passthru or hardware MPEG2.I'm wondering what a CAM (using pass-through) has anything to add in
this myth as well as other DV devices ie, ADVC-100 etc :rolleyes:Not myth, spec, research it and be careful of sources whose author(s) get confused by the difference between square and rectangular pixels.

Passthru doesn't give you anything special. NTSC DV does have 4:1:1 colorspace which is horrible for anything with sharp edges so conversion to 4:2:2 with 411Helper for VirtualDub or Reinterpolate411 for AviSynth is wise.

DV camcorders typically will shoot a full 720x480 image. Given an NTSC analog feed, ~704 with 16 letterbox to yield 720.

[vhelp]

.
.
Interesting about your DV comments..

I've ben wrestling w/ the "saw tooth" along horizontals when shooting
in 16x9 mode. When at 4:3 mode, all edges age clear and perfect, but
as soon as I switch to 16x9, all is saw tooth.

what's with this 4:2:2 and 411 helper (not to vear too far from orig.
topic) ?? ..and, if that might help w/ my 16x9 "saw tooth" situation.

See new topic start on this here:

* Shooting DV footage w/ "saw tooth" output issues (http://forum.doom9.org/showthread.php?s=&threadid=60917)

-vhelp

[FulciLives]

Originally posted by vhelp
.
.
Interesting about your DV comments..

I've ben wrestling w/ the "saw tooth" along horizontals when shooting
in 16x9 mode. When at 4:3 mode, all edges age clear and perfect, but
as soon as I switch to 16x9, all is saw tooth.

what's with this 4:2:2 and 411 helper (not to vear too far from orig.
topic) ?? ..and, if that might help w/ my 16x9 "saw tooth" situation.

See new topic start on this here:

* Shooting DV footage w/ "saw tooth" output issues (http://forum.doom9.org/showthread.php?s=&threadid=60917)

-vhelp
I don't know anything about the 411 helper stuff but I've heard that you can buy a special lenz attachment that will allow you to shoot in full frame 4:3 but at 16x9 due to the stretching of the image by the lenz attachment. Perhaps this might help with the "saw tooth" problem?

- John "FulciLives" Coleman

[FredThompson]

Sigh...over the past couple of weeks I've explained the 4:1:1 issue a number of times. Perhaps I should colude with the powers-that-be to create a sticky in the DV forum which will summarize and link to the original threads.

Real quick...NTSC DV is 4:1:1 which means one chroma (color) value for 4 horizontal pixels. DV MPEG2 is 4:2:0, one chroma value for a "square" of pixels. OK, so that's a mismatch, right? That's not all. 4:1:1 is horrible for sharp edges.

I noticed this with DV passthru of video bugs (station logos) and video of houses (look at window pane dividers.) It all started to make sense when IanD asked for help with the Star Wars laserdisc captured through the Canopus ADVC-100. Xesdeeni's site and mine (http://www.geocities.com/fredthompson6) show the problem.

I suspect, but have not fully tested, these "corrections" would also help with some diagonal lines. NTSC DV hates diagonals of about 15 degrees. A lot of my camcorder source is of machinery. Lots of chromed moving surfaces and shallow angles. Probably the best example of DV's shortcomings I've ever seen.

Give me some time to get a proper writeup done and posted. I'll ask bb to make it sticky and get the same info to Wilbert.

[Joe Fenton]

I just read through this thread and it seems to me that a lot of people never learned traditional TV engineering.

Back when TVs were actually made from 100% analog parts (you know, transistors, tubes - that sort of thing) you didn't have dots or pixels, you had frequencies and bandwidth. The way they measured the resolution of a display was to actually draw a picture and display it on the TV. The picture was just a set of alternating vertical black and white lines. You made the lines thinner and closer together until you could no longer distinguish the lines on the TV. You then counted the number of lines drawn on the picture. It was found that you could discern about 80 lines per 1 MHz of signal.

Now a black line followed by a white line can be represented as a square wave - that is how it would look on an o-scope if you had lots of bandwidth. We are still talking ANALOG signals here. The fourier of a squarewave is a sine at the fundamental frequency plus a lower amplitude sine at the third harmonic plus an even lower amplitude sine at the fifth harmonic, etc. To see EXACTLY a black line followed by a white line would require the TV to handle a signal at a set frequency plus several odd harmonics. Since the TV has a limit or bandwidth, many of the odd harmonics are lost and the signal becomes less like a squarewave and more like a sinewave. At the limit of the TV to produce a discernable line, you have only the fundamental frequency and no harmonics. That is why if a TV has a bandwidth of 3 MHz, you can discern 240 lines which actually appear as a sinewave that goes from shades of black through shades of white.

Since a TV has a set number of scanlines, you would think that the vertical resolution would be exactly the same as the number of visible scanlines. However, the scanlines on a CRT are scanned (hence the name) and combined in the brain through persistence of vision. This reduces the number of horizontal lines that can be discerned to less than the number of scanlines drawn. Even more, TV displays are interlaced which affects the number of discernable lines even more. The general rule found with long persistence phosphores was that the number of horizontal lines discernable to be about 85% the number of visible interlaced scanlines. So a TV with 440 visible interlaced scanlines gives a vertical resolution of about 374 lines.

I would hope that clears that issue up a bit, but I imagine it has some folks even more confused than ever. :)

[SeeMoreDigital]

Hey Joe! (sorry I could'nt resist)

I'm so glad you wrote this. I took pen to paper myself trying to come up with an 'easy to understand' version of how resolution was measured in the old days.... but my version ran to quite a few hundred words and was still not as simple to understand as your post!

I think I really should have paid more attention in my English lessons at school. But it was a long time ago. And was also at a time when 'typing' was considered a 'girly' thing to do.... And look at me now!

My, how times have changed!

Cheers

[ppera2]

Very good explanation, Jeo Fenton.

Is there some research about how human perception sees vertical lines on progressive scan monitors? I think that it should be little better case (more %).

Btw. that about bandwith, and sine form by higher freq. stays for VGA monitors and cards too. Therefore are so high freq. of RAMDAC's and high bandwiths of monitors.

[SeeMoreDigital]

Hi ppera2,
Is there some research about how human perception sees vertical lines on progressive scan monitors? I think that it should be little better case (more %). Joe mentioned at the beginning of his post "Back when TVs were actually made from 100% analog parts (you know, transistors, tubes - that sort of thing) you didn't have dots or pixels, you had frequencies and bandwidth"

Todays TV and PC monitors are totally different pieces of equipment. So much so infact, I would probably be right in thinking that there's not a single TV or PC monitor that does not process the video digitally at some stage!

Personally I hate 100Hz (digital) processing on modern TV's. As to me, the presented image looks like a 'water colour painting'. It just does'nt look real!

My parents have just been conned into buying a 100Hz 32" widescreen Panasonic 100Hz TV. And to me, the picture looks crap!

Cheers

[Kika]

And to me, the picture looks crap!

On most 100Hz-TVs you are able to disable the Digital Image-Processing (like Noise-Reduction and other Stuff).
Turn this Features of, and the picture might be much more look natural.

[SeeMoreDigital]

Thanks Kika,

I did actually try 'all' the different Panasonic settings. And the picture still looked crap!

At the time my father was watching a live golf broadcast. And it's the first time I've seen grass without individual blades.

I even thought of visiting a garden centre to find out if this 'new' type of grass was available to buy. As it would be far easier to maintain!

Seriously though, the only decent 100Hz processing TV's I've seen have been by Philips!

Oh, and another bad thing about the Panasonic. Why does it always want to alter the aspect ratio of a 4:3 image to fit the 16:9 screen. You just can't turn this function 'off' either!

Cheers

[r6d2]

Hi guys,

I though you might me interested in this. Trying different frame sizes on my TV I found that using 480x480 (SVCD) only revealed enough detail pertaining to CVD (352x480). Only if using non standard frame sizes like 528x480 or 544x480 I could see the detail a typical SVCD frame size was encoding.

This has to do with something similiar to what @Joe Fenton explained about vertical resolution on a previous post, but horizontally.

I built a small tool to measure the horizontal resolution which may be of use to you. Please check it out at:

http://forum.doom9.org/showthread.php?s=&postid=378891#post378891

[SeeMoreDigital]

Originally posted by r6d2
... Trying different frame sizes on my TV I found that using 480x480 (SVCD) only revealed enough detail pertaining to CVD (352x480). Only if using non standard frame sizes like 528x480 or 544x480 I could see the detail a typical SVCD frame size was encoding... You can perform the same 'horizontal scaling' tests with DivX. Take any PAL DVD and rip a 'fast action' chapter from it. Then encode the chapter at 900kbps 2pass VBR using 720x576 'anamorphic frame' pixels. And then again at 1024x576 'true frame' pixels.

Then report back which one looks best!

For some reason you can only do this with PAL pixel frame sizes. 854x480 NTSC pixel frame sizes (or it's near 16 pixel equivalent) just don't work!

Cheers

[r6d2]

Originally posted by SeeMoreDigital
Then report back which one looks best!
Sorry, I don't do DivX since I cannot play them on my TV, and I don't have access to PAL sources. I was just interested in measuring the horizontal resolution, for which I built a pattern image.

[SeeMoreDigital]

Originally posted by r6d2
Sorry, I don't do DivX since I cannot play them on my TV, and I don't have access to PAL sources. I was just interested in measuring the horizontal resolution, for which I built a pattern image. Shame. Maybe other forum members can confirm!

I forgot to mention that this 'trick' it also works with low bitrate Mpeg1 encodes too (never tried with Mpeg2)!

Cheers

[ppera2]

Originally posted by SeeMoreDigital

Todays TV and PC monitors are totally different pieces of equipment. So much so infact, I would probably be right in thinking that there's not a single TV or PC monitor that does not process the video digitally at some stage!
Cheers

I wouldn't agree that fact that todays monitors have many digital parts has much influence on still analogue nature of VGA video.

Video can be processed digitally, but it still wont change that final stage amplifier, which goes to pic tube is analogue. So, all about bandwith stays.

Just to say, that I work as servicer of TV's and monitors, and I know how them are built.

[SeeMoreDigital]

Originally posted by ppera2
.... Just to say, that I work as servicer of TV's and monitors, and I know how them are built. I service and repair all our equipment too. So I don't understand why you don't agree that most if not all PC monitors and TV's don't digitize some element of an inputed signal!

Cheers

[Joe Fenton]

I worked one summer as a TV repairman back when TVs were moving from transistors to ICs. Quasars and RCA were our bane, while Sylvania and Philco were a joy to work on.

Unless you have a pulse-width-modulated LCD or plasma display panel, all displays eventually have to convert the signal back to analog before reaching the CRT. The problem with properly displaying a squarewave is exactly why computer monitors have such a high bandwidth. Consider a monitor trying to display 640 pixels horizontally at 60Hz vertical refresh rate. 640 pixels displays 320 lines, but we want them to be crisp pixels, not barely discernable lines, so we need to allow for a seventh harmonic. So 320 / 80 X 2 X 7 = 56 MHz.

As to progressive vs. interlaced, there are more studies being performed now that prgressive scan monitors of decent size are available. I was able to find this:

Interlace has been introduced in the beginning of television broadcast for good reasons. The spectrum that can be displayed with interlace is well adapted to the Human Visual System (HVS), and the use of interlace reduced the required channel capacity. However, interlaced video signals suffer from various artifacts. Already in the beginning of the thirties, Engstrom [6] revealed the effect of line flicker, i.e. flickering that appears at horizontal edges in the image. Another effect associated with interlace is line crawl, which becomes visible when the eye scans the picture vertically at a speed of an odd number of scanning lines per field. The structure of the scanning becomes visible and it seems to ‘crawl’ across the picture. And as a third deficiency, interlace reduces the vertical resolution (only) in case of vertical camera or object motion.

On the other hand, an interlaced signal has twice the vertical resolution in comparison to the progressive video signal, for non-vertical moving image parts. Only in case of so-called critical velocities (odd vertical velocities), the vertical resolution drops to the same resolution as the progressive format as illustrated in Figure 2. As an example, a progressive video signal with 625 scanning lines requires the same sampling frequency as an interlaced video signal with 1250 scanning lines.

So, stationary pictures, e.g. down-loaded from the Internet, Teletext, or receiver–side generated graphics, could profit from the superior vertical resolution of an interlaced display format. It is, however, not obvious, that such an interlaced format is also (perceptually) preferred. The advantage of the increased vertical resolution of the interlaced scanning format is payed with possibly annoying line flicker on the display. A decent comparison between the various options is lacking in the literature so far, probably because a high quality video format conversion at a consumer price level is only available recently.

[SeeMoreDigital]

Hi Joe,

I think you must be as old as I am!

I'll show you mine. If you show me yours!

Cheers

[ppera2]

Originally posted by SeeMoreDigital
I service and repair all our equipment too. So I don't understand why you don't agree that most if not all PC monitors and TV's don't digitize some element of an inputed signal!
Cheers

Perhaps you should read my post more carefully. And then, perhaps you will not claim something what I didn't write.

[SeeMoreDigital]

ppera2

I'm sorry if I have upset or confused you or even become confused myself!

I'm not a big fan of digital technology because of it's 'big brother' abilities.

My biggest fear is that when CRT screens disappear altogether in favour of flat plasma, LCD etc screens, there will be no need to have any analog element at all.

When this happens. And it will! Even the screens themselves could be used as encryption tools. As it's very easy for a chip to be programmed and then instruct which pixel goes/appears where!

Cheers

[Joe Fenton]

Originally posted by SeeMoreDigital
Hi Joe,

I think you must be as old as I am!

I'll show you mine. If you show me yours!

Cheers

38 and feeling every bit of it. :D

Analog displays still have quite a bit of life yet. As far as flat screens go, cold cathode emission displays can still take back the crown from LCD and plasma display, especially considering the short life span on those two technologies. Plasma displays in particular start to lose cells in as little as five years. They will get better, but analog display technologies will only get cheaper as time passes. Why should I buy a 17" LCD display for $330 when I can get a 17" CRT for $110? I just noticed, 15" LCDs now under $200. Boy, they've come a long way from when they were first released.

[SeeMoreDigital]

Originally posted by Joe Fenton
38 and feeling every bit of it. :D

Analog displays still have quite a bit of life yet. As far as flat screens go, cold cathode emission displays can still take back the crown from LCD and plasma display, especially considering the short life span on those two technologies. Plasma displays in particular start to lose cells in as little as five years. They will get better, but analog display technologies will only get cheaper as time passes. Why should I buy a 17" LCD display for $330 when I can get a 17" CRT for $110? I just noticed, 15" LCDs now under $200. Boy, they've come a long way from when they were first released. 41! I think I win there. Or should that be lose!!!

I have first hand experience with regard to plasma cell degradation as we have 2no 42" screens, at the moment. I have to admit we did not feel the need to spend large amounts of money on them because they are used at exhibitions, seminars or presentations. And as such are moved around quite a bit!

It is good to see the prices of LCD and plasmas fall. But as usual the manufactureres have started tempting us with new, high definition 'XGA' models. And boy do these look good!

Well out of my price range though.... at the moment!

Cheers

[ppera2]

Originally posted by SeeMoreDigital
ppera2
I'm sorry if I have upset or confused you or even become confused myself!...

No upsession, I'm too old for such things (48) :)

I don't think that they will implement some heavy protections in displays soon - it must have first some standard to be worldwide etc...

[Kika]

Hey, let's build the "League of Extraordinary (old) Gentlemen". :D

I'm 40...

[SeeMoreDigital]

I wonder if Doom9 will ever reveal his (or maybe her) age?

Maybe Doom9 isn't a person at all. Could be a supercomputer. A digital super spy! :)

How about a "League of Extraordinary (old) Farts":D

Cheers

[Joe Fenton]

Originally posted by SeeMoreDigital
I wonder if Doom9 will ever reveal his (or maybe her) age?

Maybe Doom9 isn't a person at all. Could be a supercomputer. A digital super spy! :)

How about a "League of Extraordinary (old) Farts":D

Cheers

You forgot to put on your aluminum foil hat. :)

The moment they add protection to TVs, I'm making my own. I'm currently kicking around some ideas on how to make a projection TV at home on a reasonable budget. I can't see giving someone $12,000 to $25,000 for something with less than $50 in parts in it. If I bought LCD light modulators from Digi-Key I'd pay less than a $500 for a home-built projector.

[ppera2]

Originally posted by SeeMoreDigital
I wonder if Doom9 will ever reveal his (or maybe her) age?
...

According to his posts, he currently studies. So, age is not secret.

[\AX]

Joe Fenton: how do you plan to do it for 50usd if you said the bulbs themselves cost 500usd??. If you can pull it off i think EVERYBODY would be interested. I know i would be. I tried once to turn my 27" into a 100" using mirrors and a piece of glass. Worked out ok but the light just suk'd. To me normal lighting is..err..like 1 light in 1 corner and another light in another corner. Total of like 150watts for both bulbs combined. My project failed. I wound up paying like 70usd for parts and never really using what i made. Actually at 45-50"'s it looked good under normal lighting, but anything over that looked really faded and with more than like ~150watts in the room it looked faded at 50". With all the lights out, well it looked really good at 50". Even with all the lights out it still looked faded at like the 55-60" inch mark...so i guess it would of worked at 50".

Do you REALLY have concrete ideas about this? Im wondering because in my venture of what i explained above i ran across some manufacturer somewhere on earth (been a few years) that offered lcd replacement bulbs for the type of lcds you find people using for powerpoint presentations for like 180usd. That was 1 bulb without anythign though.

If you can come up with some concrete ideas, i think i got the right person in mind i know here locally that would be willing to dish out the money to try it.

Reply back if you got something concrete or whatever. Maybe your missing a few key elements right now (or maybe not), but hopefully you find a solid median for price on how to build your own. Also mention the resolution your aiming for. 1024x768 really isnt high enough for the price and risk it might take to try such a project. Hopefully your thinking of a resolution higher than 1024x768.

Oh i would like to mention that i got a friend who has a lcd that does 1280x1024 on "borrow" from his current employer. Dude, that thing in his basement rules. It blows up to ~180"'s, he has no windows in his basement and he turns out the lights...o yeh :-). Ive only been to his house 1 or 2 times since he got it, but we played Soul Calibur just 2 nights ago with it, amazing...AWESOME!! Only thing i didnt like is that it was harder to play. I had to stretch my eyes farther across his wall to predict counters/attacks/defense etc...and it made the timing really hard. I always seemed to be slow on the touch because there was just so much area to cover on the wall before i could make up my mind on what to do. I think you know what i mean.

[r6d2]

Originally posted by ppera2
According to his posts, he currently studies. So, age is not secret.
I'm studying too and I'm 39 :D

Back on topic:

@Joe Fenton,

If your stuff works, I'll buy it.

[SeeMoreDigital]

This 'age' questions and answers thing is'nt making me feel as bad as I imagined!

Maybe we should have a 'seniors' section and leave the 'young turks' to it. Me thinks the cut off age should be 30... You know like on Logan's Run!

Eeek, hang on. Everyone over 30 dies in Logan's Run. Best keep things as they are then!

Cheers

[Joe Fenton]

My TV plans are just that at the moment - plans. I'm still looking through the latest and greatest for the best homebrew solution. Candidates include: electrowetting, electroluminescence, and the more traditional LCD modulated projection.

As to getting parts at a low price, if you've ever worked in the electronics business, especially related to TVs, you know how the mark-up business works. If John Q. Public can buy a part from Digi-Key for $100, someone in the TV repair business can get it in lots of less than 10 for $10 to $20, and a manufacturer can get it in lots of a thousand for $1 to $2. It's the nature of the business. We'd stick a $1.35 horizontal osc amplifier transistor into the TV and charge the customer $6.75 for parts and $20 for labor. Five times markup on parts and $20 per hour labor, minimum of 1 hour. Believe me, replacing that transistor took maybe a minute. After working at that TV repairshop a summer, I vowed I'd never take a TV in myself. I get the parts from Mousser or Digi-Key and fix it myself. Once, I took two broken TVs and made one working TV from the pair. Do you REALLY believe that projection TV bulb REALLY costs $180? :D

I generally send a request for samples on business letterhead and get parts for free. Depending on what and how many, you can get a lot of stuff free that way. :cool:


I read a paper on a laser projector once. NASA has one for shuttle launches. They "paint" the image on the side of one of their buildings for the people to watch. They are hand made by a company and run $100,000 US each. I looked into it; I can get the different color lasers at a reasonable price for home brew, but the killer is the mirrors. Think about it - you need a mirror for the horizontal scanning that moves back and forth tens of thousands of times per second with precision. Too expensive for my budget. But this did give me an idea. Combine this with a traditional LCD projection. Get smaller LCD modulator panels. Instead of 640x480, which are pricey, get 64x64 or something similar which are cheap. Then get cheaper mirrors and scan the image from the LCD modulator. Since it is projecting 64 lines at once, the horizontal rate is much lower, so you really don't need the super fast high precision mirrors like with the laser. The larger the LCD panel, the slower the mirrors, so you have a trade-off. Balance LCD price against the mirrors.

As to what I'm shooting for - I want 2048x1024 with a 2:1 aspect ratio for that movie experience. It would also handle 1920x1080i HDTV with a minimum of clipping.

[ppera2]

Joe Fenton:

I must say that this idea with small LCD will not work - simple, because LCD is too slow for something like that. If want to scan 64x64 display for example, to get 640x640 you will need 100x bigger refresh rate on this small display, what is of course impossible with LCD.
I disagree about relations in prices for parts too. There is no so big difference as you say. Also, Idea to build TV from parts will result in bigger prices than complete TV - spare parts are always expensiver than prices for manufacturers. You can use some parts from your own collection, but most expensive parts like tube, hor. deflection trafo etc. will hardly be adequate for some new TV build.

[Joe Fenton]

I am aware of the LCD response time issue. However, LCDs are getting better. You can get faster panels for a higher price. It still remains to be seen if this aspect will cause this avenue of exploration to be abandoned.

Yes, there IS such a big difference. I have experienced every position mentioned: as a non-commercial buyer paying full price, as a repairman paying wholesale, and as a manufacturer paying bulk OEM. It is EXACTLY like I put it. Sorry, but it's the way business works. It offends people the first time they learn about it, but it's been going on for more decades than you can count. Some parts won't have that large a variance, but many others are much worse than the example I gave. A company I worked for sold a special cable for $30 that cost us 10 cents to have made in Taiwan. Markup: 300x.

I agree completely with the last part, but you need to phrase it this way: if you build a current design set with new parts, you will pay more for it since spare parts are so expensive (see paragraph above). I am seeking to build something different, not something current. I can also utilize other avenues for parts: I can scrap broken electronics equipment bought at auctions and yard sales. This cuts the price for parts considerably. Like I said in my last message, I once made one working TV from two broken ones. The two broken TVs cost me a total of $5 at two different yard sales. I sold the working TV I put together for $100. I am not trying to go into the TV business, I am just trying to make my own home-brew TV. I might publish an article on how to make it yourself describing how I did it, but I won't be making sets for other people (other than maybe a family member or close friend).

[mikewillnot]

I appreciate the intricacies of this discussion. At the end of the day, though (or the beginning) I'm trying to figure out how to work the equipment and do one "simple" task--probably a very common one: convert my VHS (NTSC) tapes to DVD.

Do I correctly deduce from the early stages of this thread that capturing at 720x480 and then downsizing to 352x240 will give better results than simply capturing & authoring at 352x240? Or was it 340x240? Or was it 340x480? Help, Mr. Wizard, help! Help!

-------------------
current setup:
ATI AIW 8500, MMC 8.x, Ulead Video Studio 7.0

[SeeMoreDigital]

If you have a mid-range DV camcorder with analog input you could use this to capture from VCR!

Some DV camcorders are even able to convert analog to digital 'on the fly' via firewire direct to your PC. So you don't need to record onto DV tape!

I personally use an ADS USB2.0 device which can create very high bitrate Mpeg2 files. Which is just the correct format for storing encodes on DVD.

That said, I am aware that NTSC capturing is not as straight forward as PAL capturing!

So, if you are going to store you encodes on DVD, keep the bitrate as high as you can. And keep the image pixel frame size at 720x480 - which is, after all the DVD standard anyway.

Cheers

[FredThompson]

If you have a decent encoder (ProCoder is best for interlaced of the "big three" but also the slowest) I suggest filtering and re-enconding high bitrate captures to a final destination format for DVD. If you go for MPEG2 capture, the ADS device is hard to beat. Its encoder chip is the same used in many of the standalone DVD recorders. For VHS source, I capture at full res, filter, crop off the edges to get 704x480 then re-encode as 352x480. The built-in filters for the ADS are cute but not as powerful or effective as AviSynth filtering.

MPEG2 capture is a far better option than NTSC DV if your destinatino format is MPEG2.

Oh, and btw, SeeMoreDigital is fairly knowledgable...for a Brit :)

[SeeMoreDigital]

Iyyyyyyyyyy.... thank you!

[mikewillnot]

Originally posted by SeeMoreDigital
If you have a mid-range DV camcorder with analog input you could use this to capture from VCR!

I do have, and use it, and it works great. It can't handle macrovision, though, so for those kinds of source tapes I resort to the ATI AIW that I have access to. The current setup, hacked, seems to work on all but some of the luma gain fluctuations (bright-dim-bright). I'm thinking I might capture to AVI, try the avisynth scripts I've found out there (lordsmurf.com), and then convert to mpeg2. It's my first experience with avisynth, though, with a new learning curve. Haven't got to that yet. Any other (software) solutions to THAT problem would be very interesting, but perhpaps another thread. (I know there are various "hardware" solutions -- TBC's, "clarifiers," etc; I'm trying to keep the overhead down.

[trevlac]

@mike

lovely thread ... lots of interesting comments. Joe Fenton seems to know what's what.


Here is how I see it:

- VHS has a low resoltion ~ 320x480
- ATI has an ok resizer
- Avisynth and VDub have better resizers.
- 352x480 is a big enough frame for VHS

So, 1) cap at 704x480 (lanczos) resize to 352x480 may be the sharpest. 2) Cap at 352x480 may have less sharpness than the above, but hardly noticable on real source.

Lordsmurf will tell you to do #2. You should just run a test and see what works for you.

[vhelp]

FWIW..

I used to do #2 (not to be mistaken for you know what hehe)

But, I no longer go that route. I now always capture at 720x480, or
704x480 (704 depends on what I'm doing and the source as well, and
also the source device ie, vcr vs. dv cam vs. dvd etc etc)

In my experience, (IME) there are a number of factors that violate
the process to some degree. Be it the:

* Capture device (ie, analog cards or dv devices)
...and even their various versions/brands
* Drivers for cap card
* Device being captured (ie, vcr)
* Quality of the source material
* Software used (ie, filtering and/or frameserving)
* Encoder software (or hardware for that matter)
...some Encoders do a poorer job at resizing. So even if you have
...a prestine setup above, in the end, it could be your Encodere that
...kills your final output (or fools you into thinking that it's you
...cap card or vcr equip or wires or ground loop or whatever.. pfew!
* Cable/wires

But, as trevlac said, best that you test the various options (what
ever they may be) and then make up your mind which is best for your
given project.

But, do bare in mind that most capture cards and mobo almost always
result in Noise in the final captured .avi file. I'v upgraded my
mobo just this past weekend, and I still suffer Line Noise :(

But, as for my video endeavors, I find (based in my own persoanl
capturign experiences) that capturing at highest resolution and then
resizing down to your desired resolution is best. If anything, you
at least have a multitude of options for resizing your source, and
in some case (or most) you'll probably get better results (if done
correctly)

Because I have an advc-100, I by default, cap at max resolution (720)
and resize (if I'm in that project mode) if need be, down to 352.

In my experience thus far w/ VHS sources. Here is my preference.

If my source is fullscreen (as most VHS movies are) I will capture at
highest (in my case, 720) and resize down to 352 x 480. I find this
to be very good quality (per my eyes) for CVD encodes for my VHS projects.
I'm from NTSC, so the quality is not as good as PAL vhs sources (based
on my observation of samples that have past my way recently) But, since
the majority of us are NTSC, we to be in that NTSC mode of excellence,
and assume that it's w/in maximum quality. Well, it made sense to me :)
.
.
Now, if the VHS movie source is Widescreen, then I will NOT resize it
and go w/ the 720 x 480, and encode w/ 16:9 in mind. I'm am still
debuggin this process, as it's ben giving me various reasons for
having doubts in the Aspect Ratio department.. another topic for discussion.
.
.
Just breifly, Aspect Ratio (imo) is very important to a final output
quality. But, as I said, this is not the thread for this discussion,
I don't think :confused:

So, to recap, in my experience..

* If VHS source is Fullscreen, then what I would do is cap at 720 and
...resize (use what's best technique you have at your arson) to 352.
* If VHS source is Widescreen, then what I would do is cap at 720 and
...and leave at 720, but perfect the AR properly and encode to 16:9 as
...your final output, and author to DVD.

Many ways to do all these fun (and sometimes) confusing processes/methods
of obtaining maximum final MPEG authoring projects.

-vhelp

-vhelp

[FredThompson]

You should look into 411Helper and Reinterpolte411. NTSC DV and MPEG2 use different color allocation methods. You'll have better results with these filters.