Recommended settings to capture vhs pal without editing

[prodarek]

Hello,
What settings do you use when capturing(store) vhs pal without editing the files later?
- codec x264, qp, preset?
- interlaced or not?
- crop?
- upscaling or not and save as 720:576?
- maybe other filters?

The software I use is ffmpeg.
Hardware Jvc 9850 + Pioneer dvr 540 + Intensity Pro.

[lollo]

Analog PAL SD should be captured 720x576 YUV 4:2:2 interlaced lossless.

[prodarek]

We talking about store large quantities of cassettes so cannot be "lossless"

But your suggestion might be to capture as lossless first and then compress?

[lollo]

Yes

[prodarek]

Ok this can be done but AFTER, the questions about compression, crop and all the rest are still valid.
Doing crop not is better during capture?

[lollo]

After capture, mask the head switching noise, crop to 704x576, fix defects, deinterlace, denoise, sharpen and eventually upscale to 1440x1080, compress h264 with low crf, i.e. 17.

[prodarek]

Thank you,
I'm concerned about cropping and masking, couldn't I do this during capture?
ffv1 codec will be ok?
if I mask the noise of the head and the edges I will get a black frame, wouldn't it be better to just zoom in and get an effect similar to when watching on TV?

[dellsam34]

Video is not like canvas, It's resolution based, any cropping or zooming will change the resolution and will destroy the video, Just do it after capture.

[themaster1]

VLC can do that (record/ convert on the fly from a capture card) and it use ffmpeg, can also deinterlace crop.. Many filters.

[Alwyn]

Cropping does not "destroy" a video. Just crop in the correct proportions. If you crop 4 pixels total off the sides, crop 3 off the top/bottom. Make sure your final frame size is an even number.

I prefer cropping to having black bars on my video.

Added: Deinterlace first.

[Sharc]

Cropping does not "destroy" a video. Just crop in the correct proportions. If you crop 4 pixels total off the sides, crop 3 off the top/bottom. Make sure your final frame size is an even number.

I prefer cropping to having black bars on my video.

You can easily destroy the interlaced structure of your capture when cropping 3 top/bottom as per your recommendation.

Follow the rules:

[prodarek]

Thanks for the scrambled eggs in the brain hehe

Based on the last answer, this will be ok ?
https://i.imgur.com/fbtwjvo.png

[lollo]

Except to what specified in post #6 there is no need to crop (nor to resize) anything

[Sharc]

Thanks for the scrambled eggs in the brain hehe

Based on the last answer, this will be ok ?
https://i.imgur.com/fbtwjvo.png

Yes.
Sidenote: You assume that the source PAR (PixelAspectRatio) of your PAL capture is 16:15.
However, I am pretty sure that the PAR of your PAL capture is 12:11 rather than 16:15. Anyway, the difference is ~2% only. You can easily live with it.
Or as per post #6: crop to 704x576 and mask the top and bottom crud rather than just cropping vertically.

[prodarek]

I didn't set it, it's the default auto, I will check 12:11 value .

[prodarek]

Looks like 12:11 help a lot.

16:15 only crop -8 -8 left right, up to 1080p


12:11, up to 1080p

..Anyway, the difference is ~2% only...

I would like to get the perfect image ratio without image distortion.

[Sharc]

Now it's perfect.

[prodarek]

Org video
https://drive.usercontent.google.com/download?id=1ap2skDKr7h2wm4LlLc4f7oFa-JLEI2h6&exp...oad&authuser=0

crf 17, superfast, qtgmc medium and crop like above, up to 1080 lanczos.
https://drive.usercontent.google.com/download?id=1-O1h3Qdhfxg27BodFXAabqbV4oPJGoyu&exp...oad&authuser=0

[Sharc]

I wouldn't recommend 'superfast' for encoding. It may be good enough for poor sources or for a quick test. For clean sources you risk producing visible artifacts like banding in "flat" scenes (e.g. sky), for example.
It's all up to you.

[prodarek]

I thought that it would only increase the file size and that it would have no impact on the quality, on the contrary.
So medium?

With medium file size will be ~150MB 8Mb/s bitrate, superfast ~ 250MB 14Mb/s bitrate. How can the quality be worse? medium looks definitely worse.

[Leanoric]

I thought that you had to roughly crop to 4:3 when resizing to square pixel?

Cropping to 692x566 and resizing straight to square pixel is ok?

If so, whats the point in padding to 704x576 before resizing to 1440x1080

Sorry, I know weve been through this before but it still makes my head spin.

[Sharc]

I thought that it would only increase the file size and that it would have no impact on the quality, on the contrary.
So medium?

With medium file size will be ~150MB 8Mb/s bitrate, superfast ~ 250MB 14Mb/s bitrate. How can the quality be worse? medium looks definitely worse.

You compare apples with oranges. Comparing a 250MB file with a 150MB file doesn't make much sense.
The quality comparison should be based on equal file size (means equal compression). You would have to adjust the crf accordingly (a difficult hit and miss) or use 2-pass encoding.
Simplifying:
- lower crf means less compression means higher file size means better quality (less artifacts)
- slower encoder settings means better compression means lower file size (for same quality)
Find your compromise.

(Also, I think your clip deserves some denoising).

[Sharc]

I thought that you had to roughly crop to 4:3 when resizing to square pixel?

Cropping to 692x566 and resizing straight to square pixel is ok?

Yes. That's what he did now before upscaling the square pixels to 1440x1080 (still square pixels).

If so, whats the point in padding to 704x576 before resizing to 1440x1080

A generic rule for PAL captures with a PAR (PixelAspectRatio) of 12/11 to prevent picture distortions (circles remain circles) when played at exactly 4:3 DAR.

Sorry, I know weve been through this before but it still makes my head spin.

It may be helpful for the understanding to imagine a sheet of 'elastic' paper with squares on it and think what happens to the squares and sheet size when you
a) take scissors and cut the sheet (=cropping = changing the size of the sheet, its DAR). The squares on the sheet remain squares.
b) stretch or shrink the elastic sheet horizontally and/or vertically (= resizing = changing the PAR (PixelAspectRatio)). The sqares on the sheet become rectangles.

Otherwise AvsPmod includes a nice resize calculator.

[Alwyn]

You can easily destroy the interlaced structure of your capture when cropping 3 top/bottom as per your recommendation.

My recommendation included making the final frame an EVEN number, so MOD2. Further, Virtual Dub and my NLE will not permit an illegal resize.

[Sharc]

You can easily destroy the interlaced structure of your capture when cropping 3 top/bottom as per your recommendation.

My recommendation included making the final frame an EVEN number, so MOD2. Further, Virtual Dub and my NLE will not permit an illegal resize.

You wrote "cropping does not destroy a video" which is not correct in general. Also "just crop in the correct proportions, ...." doesn't help much.
It matters how one crops the video at a particular stage in the workflow, format dependent. That was my point. Nice when tools prevent flaws.

[Leanoric]

I thought that you had to roughly crop to 4:3 when resizing to square pixel?

Cropping to 692x566 and resizing straight to square pixel is ok?

Yes. That's what he did now before upscaling the square pixels to 1440x1080 (still square pixels).

But when you take 28 off the sides, do you not need to 21 off of the top and bottom? 28/21 =1.33, if youre upscaling to square pixels?

692x566 isnt 4:3

[Sharc]

I thought that you had to roughly crop to 4:3 when resizing to square pixel?

Cropping to 692x566 and resizing straight to square pixel is ok?

Yes. That's what he did now before upscaling the square pixels to 1440x1080 (still square pixels).

But when you take 28 off the sides, do you not need to 21 off of the top and bottom? 28/21 =1.33, if youre upscaling to square pixels?

692x566 isnt 4:3

Of course not. It is 692/566=1.2222. The PAL capture is not square pixels but has a PAR of 12/11=1.0909... Cropping the PAL source to 4:3 does not make these pixels square as cropping does not change the PAR. For watching the picture undistorted the player must force the playback of the 692/566 video to 4:3 by stretching it horizontally by 1.333/1.2222=1.0909... = the PAR of the source = 12/11=1.0909....
The stretching is done on the fly by the player when you force it to play the 692/566 video as 4:3 (a setting of the player), or when the player reads and follows the PAR signalling of 12/11 included as metadata in the stream or in the container.
Alternatively you can do the resizing to square pixels yourself, by applying to the 692x566 source 'someresizer(768,576)' or 'someresizer(1440,1080)' for upscaling. Caution: Avoid vertical resizing like in this example from 566->576 when you footage is still interlaced. Deinterlace before applying any vertical resizing, or keep it at 566 vertical and resize to (754,566) for square pixels.
Use paper, pencil and rulers to understand the principle. It doesn't make sense to drown people in formulas and numbers.
Or take a look at the resize calculator of AvsPmod and trust it.

Or forget the square pixel mania, crop to whatever you want and encode with x264 using --sar 12/11 in an *.mp4 container and trust that any modern player will play the picture undistorted (means circle=circle).
Or if you prefer double-stitching crop to 704x576, replace the remaining crud with black borders (=masking) to keep the overall frame size to 704x576 and encode x264 using --sar12/11 and just play it as 4:3. That was the point of post#6.

[Leanoric]

I thought that Id got my head round this last year when I first asked but I clearly hadn't.

Last questions, I promise.


If cropping and upscaling straight to 1440x1080, the sides divided by top and bottom have to equal close to 1.22 (par12/11). Would say cropping to 688x564 be ok to upscale without padding? 688/564=1.219.


If I crop and the sides divided by t&b dont equal 1.22, then I have to pad up to 704x576 before upscaling. For example, cropping to 700x562 would equal 1.24. So I would have to pad up to 704x576 (12:11) and then upscale?

[Sharc]

Re-read the above (or dozens of other posts on that subject), or try your proposal and see what you get....
You just have to understand what you are doing.

[Leanoric]

Or if you prefer double-stitching crop to 704x576, replace the remaining crud with black borders (=masking) to keep the overall frame size to 704x576 and encode x264 using --sar12/11 and just play it as 4:3. That was the point of post#6.

Ok, I didnt realise that you could cover the actual video with black borders. I thought that they had to be completely cropped off and borders added to bring the size back up to where to wanted it.