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-   -   Cannot capture PAL VHS progressive? (https://www.digitalfaq.com/forum/video-capture/13649-cannot-capture-pal.html)

Atillart 07-29-2023 05:00 PM

Cannot capture PAL VHS progressive?
 
Hello everyone, I have this equipment :
-VCR Samsgung DVD V6600
-Sony RDR HXD870
-Avermedia LGX
-And a good computer : i5 13500 / RTX 2060 Super / 32gb ddr5 / SSD M.2 2to

I know that my equipment capture may cause cardiac arrest to some, but anyway, I don't want to spend thousands of euros on new equipment... And that's just to preserve some trailers :wink2:

I capture commercial VHS movies, which is supposed to be PAL progressive.
I set virtualdub to 720x576 25p, but I have visible interlacing.
Another thing: I have a lot of frame drops when I set the HDMI output of my Sony RDR to 576p.
I have no drops when I take it out in 576i

The Sony RDR is supposed to have a TBC line.
My avermedia only takes HDMI and YUV, and I thought it would be better to use HDMI to only have one A/D conversion (in YUV I would have had A/A/D).

When I capture on Avermedia Recentral, I have no problems with the 576p of my Sony RDR, dropped frames it's only on virtualdub.

So I have several questions:
The "progressive" PAL VHS are still interlaced (without being visible on a TV), and each frame is divided into even / odd fields, which means that if I capture in 25p, it is not good?

Why does the 576p HDMI output give me drops and not the 576i output?

Thanks in advance :)

hodgey 07-29-2023 05:21 PM

If it's set to 576p it's outputting 50 frames per second, not 25, so virtualdub has to compensate by dropping every other frame. So if you really want to let the dvd-recorder do the deinterlacing you will have to set virtualdub to 50fps rather than 25. When set to 576i it's outputting 50 fields - ie 25 frames per second. It's working normally, you would expect to see interlacing in the virtualdub preview, the avermedia probably either outputs 50 fps or just drops every other frame down to 25 (or deinterlaces to 25 fps when you are using 576i).

I would suggest setting the dvd-recorder to 576i and capturing at 25fps, then deinterlacing with a decent deinterlacer afterwards but it's up to you. It shouldn't look too bad with that setup that way honestly. These dvd-recorders do provide some stabilization yes - not as robust to bad tapes as panasonics but should be fine for commercial releases as long as they aren't copy protected. Can also do some tweaking with image settings on the dvd-recorder and also manually adjust image sharpness on the vcr if the auto-adjustment function on it makes it too ringy or too soft.

Eric-Jan 07-29-2023 06:15 PM

component video output will give 625p50 or 625i50 ?

Atillart 07-30-2023 05:48 AM

Quote:

Originally Posted by hodgey (Post 91668)
If it's set to 576p it's outputting 50 frames per second, not 25, so virtualdub has to compensate by dropping every other frame.

I would like to understand how commercial VHS films work:
The source is progressive, and in my opinion, the VCR sends 288 lines even fields, then 288 lines odd fields. Which theoretically generates a full 576 line image.
If I capture at 25fps, I should get 25 "full animations" of 288 lines, (I would have to capture at 50 to get a full 576 lines image).
But when I watch the video, it's jerky. While in my opinion, it should not be the case, even by dropping half of the images.
In the worst case, I should have 25 images 288 lines, without jerking.

Or maybe there's something else I'm missing...

I would like to capture in 50i but I can't find the settings for that, virtualdub automatically captures in 25p

Quote:

Originally Posted by Eric-Jan (Post 91669)
component video output will give 625p50 or 625i50 ?

I don't know, I think he can do both.
But in any case, my concern remains the jerks on Virtualdub during capture when I set the Sony to 576p.
I don't have this problem when I capture with Recentral.
On the other hand, no jerk on Virtualdub when I go out in 576i.

Eric-Jan 07-30-2023 12:50 PM

for starters, "a commercial VHS tape" (analog) played in a VCR is not progressive like you say,
default is interlaced playback, the digital monitor recieves an interlaced signal.(capturing is a different story)
Any real VHS resolution left, is 200/240 lines. commercial tapes can have Macrovision.

Your capture device has only a HDMI input ? Keep in mind this one is designed for game capture, not analog video, game consoles give a much more stable video signal, and use RGB color which is in the full range, not in the limited range like HDMI, this can give incorrect color and brightness levels.
so to me it looks like you're bake in errors, and try to correct it with VirtualDub.
Better use another converter or capture device, be sure to monitor what the real output resolution is from your source you're capturing from, use prosumer devices, not China or Gamers boxes.
Your capture device defeats HDCP ? otherwise use RCA component video output, if your capture device supports the input for this.
A cheap HDMI passthrough device (converter/splitter) would also work against HDCP.

btw, 576 is in the digital realm already, so no lines but pixels,720by576 for PAL or 625i50 lines for analog PAL
(or better ask WiKipedia)

Atillart 07-30-2023 02:11 PM

Quote:

Originally Posted by Eric-Jan (Post 91676)
for starters, "a commercial VHS tape" (analog) played in a VCR is not progressive like you say,
default is interlaced playback, the digital monitor recieves an interlaced signal.(capturing is a different story)

So if I understand correctly, even if the source is progressive (movie cinema 24 to 25fps), the signal sent will always be interlaced.
Like a 1080i50 HDTV movie for example.

How virtualdub can capture in 50i ?

By default, without action on my part, it capture the signal at 25p

lordsmurf 07-30-2023 03:12 PM

Quote:

Originally Posted by Atillart (Post 91679)
So if I understand correctly, even if the source is progressive (movie cinema 24 to 25fps), the signal sent will always be interlaced.

- the original source might be progressive, and high-res film
- your source is VHS, which is not progressive, not film of any kind

That's the difference.

You can only work with what you have, not capture based on the far-removed original source.

hodgey 07-30-2023 03:30 PM

Virtualdub (and most other capture apps) capture 50i as 25 full frames per second with 2 and 2 fields weaved together. I don't know anything that captures as separate fields (some apps will automatically deinterlace 50i to 25p instead though which does drop half the fields. The avermedia app that came with the avermedia card I have does that at least). So if you want to capture 50i setting virtualdub to 25fps is how you want do it. Then you use something to deinterlace to full 50 fps and/or do processing on that output.

latreche34 07-30-2023 08:05 PM

If you're sure your source is film, First you would capture both fields as any VHS tape, then de-interlace with the option blend fields without doubling the frame rate, this will give you back 25p, then you can proceed to reversing the pulldown because if it's film it is most likely 24 frames not 25 frames.

Eric-Jan 08-03-2023 05:50 AM

For starters, first checkout to which settings all your VCR,recorder/combo are set, wnen you have component and HDMI on one device, most of the time, they can not used at the same time so you have to make a selection in a menu, also, in which mode, progressive or interlaced, so you do need a remote to change that, sometimes it can be done with a cheatmode on the device itself, check the manual for that.


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