Resolution chart comparisons

[fmctm1sw]

I'll start by saying "yes, I know this isn't scientific." "Yes, I know I don't have studio quality equipment." etc, etc, etc.... I'm just having a good time with these test patterns I picked up. I took some BMPs and converted them to DVD compliant MPEG-2 files and authored them. Then I played them back from my Proscan DVD player and recorded on my Sony SLV-575UC in SP mode through the composite input (obviously). the VHS tape I used was recorded on at least once (nothing scientific about me). The cable I used to connect my DVD player to my VCR is rather long but decent quality (JVC I think). The resulting SP VHS tape played back on my:

Sony SLV-575UC


Toshiba SB-88 SVHS (Japanese market)


Victor VX-200 (Japanese market, looks like a JVC 9600)


Then just for kicks, I decided to try recording on SVHS ET mode on my Victor SVHS VCR. Makes quite a bit of difference. This was played back on the same machine:



I'm observing that VHS material played back on a SVHS machine looks better. While it appears to help the resolution, it doesn't do much for that nastly color noise. Also of interest was the convergence test pattern. It was very good at showing the effect of time base correction circuitry. No TBC=shaky lines. TBC=rock solid lines. Not easy to show with a still image though so I'll leave them out....

[leaglebob]

Any way to test your sp-vhs image quality against different mpeg resolutions?

Mpeg-1 should look worse than sp-vhs and mpeg-2 at low bitrates should look worse.

I'm wondering at what bitrate of mpeg1 or 2 the image will come up to and then exceed the sp-vhs image.

I'm also wondering at what level of increasing bitrate can you no longer see any improvement. That would be the max level to record at in order to conserve space.

Scientific method==its a blast!!! I'd try this myself but I don't "quite" follow what you are doing.

***How do you know what you know and how do you change your mind?***

[fmctm1sw]

Scientific method==its a blast!!! I'd try this myself but I don't "quite" follow what you are doing.

Me neither. I've been drinking all night...

[fmctm1sw]

Any way to test your sp-vhs image quality against different mpeg resolutions?

I guess I could, but my target is almost invariably 704x480 MPEG-2 for DVD. I used to dabble in 352x480. Maybe I'll take a look at that....

[leaglebob]

I'll start drinking if that will help???

Unusual--you still dabble with vcr's while doing dvd"s???

What bitrate do you use for your dvd's and did you go thru any comparisons before selecting that rate--or was it just chance.

I constantly take heat for saying quite a few lower resolutions actually look "good enough". Its nice to see real evidence like yours. ((Not saying you agree==just that you are being evidence based!!))

Good Job.

What are you drinking??

[edDV]

This is a camera resolution chart but can help you compare vcrs.

Did you place the arrows out to the edge of the frame? That is necessary for the numbers to be meaningful. On the top 3 charts you can see horizontal resolution fall off just over 200 lines (see vertical wedge and 200 line blocks on left and right). The Sony is having difficulty even at 200 lines. The Victor VX-200 did best. VHS is limited to about 240 lines by the mandatory luminance low pass filter at ~3MHz.

You can also see that all 3 easily exceeded 400 lines in vertical resolution (horizontal wedges) indicating both scan fields are present.

The SVHS machine was getting about 375 lines of horizontal resolution.

The color distortion is due to luminance being detected as color. The S-Video cable would keep the luminance separate from the color decoder preventing this from happening.

[fmctm1sw]

I'll start drinking if that will help???

Unusual--you still dabble with vcr's while doing dvd"s???

What bitrate do you use for your dvd's and did you go thru any comparisons before selecting that rate--or was it just chance.

I constantly take heat for saying quite a few lower resolutions actually look "good enough". Its nice to see real evidence like yours. ((Not saying you agree==just that you are being evidence based!!))

Good Job.

What are you drinking??

Yeah, I saw you get roughed up on the low bitrate thing. I think what I am doing is a little different though. I encoded those BMPs at 9000CBR (I was going to mention that, must have been the brandy) for the sole purpose of taping it onto a VHS tape (and SVHS tape when I find one) and playing it back. I'm into VCRs mainly since I convert VHS tapes to DVD. I post a lot of these picture comparisons and hear a lot of "that ain't right" or "that won't show accurate results" too. Don't feel bad I guess I mainly tested what I've heard about SVHS VCRs playing back VHS material better then VHS VCRs. Mine did better with the resolution but it didn't do much for those colors.

@edDV: I didn't really notice any arrows. I just encoded the bitmaps. I actually did use a S Video cable from my SVHS VCRs. I guess since the signal is already recorded on the tape....

*edit*: Yeah, see the arrows now...

[leaglebob]

I guessed that SVHS was going out of favor when they started going on sale about 1-2 years ago. Today, no store stocks them and very few stores have more than one or two models of VHS models unless there is a DVD along with them.

I do record in SP mode for something I want to copy later--not so much for picture quality as picture stablity??

I think I see a difference, and knowing my own bias about seeing a difference, that is good enough for me. (smile)

Yes, the battle continues on the newbie forum under pal vs ntsc resolutions by Jester.

"They" don't respond with evidence--just continued affirmations and disdain. But maybe bilateral information is transfered???

Really just waiting for terrabyte projected holograms before I upgrade.

[leaglebob]

Sorry to respond so self centeredly.===When playing a vhs tape back on a SVHS player==does the color issue interfere that much?==In other words, on balance, when playing back vcr tapes which would you use--straight vcr or svhs??

I actually have played with buying a SVHS machine to act as a tuner for a Plextor encoder.. Probably more to be a contrarian as the cost of the Plextor with a tuner and hardware encoder is not "that much" higher===but I do have 1356 tapes that will need to be transfered once I figure this DVD thing out.

Will they ever show Rumpole of the Bailey, Fawlty Towers, and I, Claudius on tv again????