How to fix the 'combing' effect when digitising VHS video tapes?

[Grant Millar]

Hello,

I was wondering, please, if anyone has suggestions for how to remove the 'combing' effect when digitising VHS tapes?

I live in the UK, so am using the PAL TV system when digitising VHS tapes.

At the moment, I am using OBS Studio software to digitise the VHS tapes. This program has a large number of Deinterlacing options, so am really not sure which ones are the best to choose.

But am also wondering when is the best time is to apply Deinterlacing/Anti-combing features? Before digitising, during digitising, or after digitising?

I am using a fairly modern VCR (Panasonic DMR-EZ47V) from 2008, which also has a DVD feature. It might be possible to set the VCR to a playing/recording setting called 'Progressive', which I was thinking might help matters?

I'd really be grateful for any advice on this subject, please. But am thinking there are perhaps no quick fixes for this!

Thank you.

Grant

[Ed Gordon]

How to Deinterlace in DaVinci Resolve? ( Best Explained)

Why is Deinterlacing Important?

In our modern digital era, most display devices, such as LCD, LED televisions, digital projectors, and computer monitors, are designed for progressive scan – they show entire images sequentially. Thus, displaying interlaced footage on these devices can result in visual artifacts and a less-than-optimal viewing experience.

Deinterlacing addresses this by converting the interlaced video into a progressive format, where each frame displays all its lines sequentially. This conversion ensures compatibility with modern displays and provides a clearer, artifact-free image.

The quote is from an article on how to deinterlace with Davinci. Link: https://filmmakingelements.com/how-t...ci-resolve-17/

You can probably find a similar article for the software you prefer.

You did not mention what the content is you are trying to save. If you have video tapes of films you had transferred, your best bet is to digitize the original films.

If your tape player has an option to convert to progressive, I would try it first. Then you can compare the quality of the digitized video with and without changing settings on the tape player. A good tool to have to examine the technical details of the conversion(s) is MediaInfo.

Example:

General
Complete name : D:\Videos\Paul McCartney Carpool Karaoke\Paul McCartney Carpool Karaoke.mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 320 MiB
Duration : 23 min 42 s
Overall bit rate : 1 890 kb/s
Frame rate : 29.970 FPS
Writing application : Lavf54.63.104

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4
Format settings : CABAC / 3 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 3 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 23 min 42 s
Bit rate : 1 756 kb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 29.970 (30000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.028
Stream size : 298 MiB (93%)
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Codec configuration box : avcC

Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 23 min 42 s
Bit rate mode : Constant
Bit rate : 126 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 44.1 kHz
Frame rate : 43.066 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 21.3 MiB (7%)
Default : Yes
Alternate group : 1

[Alwyn Adkins]

The old deinterlacing chestnut. The potential rabbit hole is deep! 😉

At the moment, I am using OBS Studio software to digitise the VHS tapes. This program has a large number of Deinterlacing options, so am really not sure which ones are the best to choose.

My sources say that YADIFx2 is the best of the options.

But am also wondering when is the best time is to apply Deinterlacing/Anti-combing features? Before digitising, during digitising, or after digitising?

The general recommendation of the enthusiasts is to capture interlaced (as that is what the digitiser is putting out) in a lossless format such as Lagarith or UT Video (but can your editor handle the format?) and then de-interlace during post-processing. It depends though on what program you are using to post-process/edit. Deinterlacing during capture means the deinterlacing must occur in realtime and this is generally thought not to be as good as doing it after capture. OBS is doing it in realtime, as well as encoding the video to your selected codec. If you have a beefy system, it should work.

Whether the EZ47's deinterlacer is better than OBS, as Ed has said, can only be assessed by a comparison, although the enthusiasts will suggest to output Interlaced.

It all depends on how much you want to get into the post-processing bit. If you're happy with the OBS output, deinterlace during capture with YADIFx2 at around 4-5000kbps. If you are going to be editing such as cropping, colouring, denoising and have an editor that will deinterlace, you're better off capturing lossless as I mentioned. That will give you a pristine source video to work with.

[Nantawat Kittiwarakul]

THe progressive option of your vhd/dvd combp player, is more than likely for dvd playbackonly. The output from vhs part would probably be always 50i - fifty interlaced fields per second.

The best bet is to convert that 50interlace fields to 50 progressive frames, to preserve both spatial and temporal resolution. The tool of my choice is still the good old VirtualDub program, which provides more than enough tools for video restoration.

[Alwyn Adkins]

Nantawat Kittiwarakul, I like VDub as well. Re your deinterlacing setting, lossless VHS captures are nearly always Top Field First; DV Bottom Field First. It is easy to check: if there is back and forth motion after deinterlacing when stepping through the video frame by frame, you've chosen the wrong field order.

Edited to add: I've checked my EZ-48 and it always outputs Interlaced over S-Video, even when "Progressive On" is selected in the menu. Progressive is output over Component if selected On.

Since Nantawat has mentioned it, here's a blurb from my website regarding use of VDub.

[Nantawat Kittiwarakul]

Forgot to mention that I DIDN'T use lossless capture process. Instead I had been using the av->dv function of this good ole piece for ages...


So the captured files will be always in DV avi format. Not lossless, but seems good enough for casual use. When properly processed the result seems acceptable to my eyes.

https://youtu.be/tdWmqPh_GbI?si=DVqc1FsBxaliA5E6

[Alwyn Adkins]

Nantawat Kittiwarakul Certainly one way of doing it. That quality is great. Dang those pelicans!

[Grant Millar]

Dear Ed,

Thank you for all this info - much appreciated!

And apologies for the delay in replying.

The content I'm looking to digtise is footage from VHS and camcorder tapes from 1993.

I will change the setting on the VCR to Progressive and will try that. And I will try the other things you suggest, too.

Best regards,
Grant.

The quote is from an article on how to deinterlace with Davinci. Link: https://filmmakingelements.com/how-t...ci-resolve-17/

You can probably find a similar article for the software you prefer.

You did not mention what the content is you are trying to save. If you have video tapes of films you had transferred, your best bet is to digitize the original films.

If your tape player has an option to convert to progressive, I would try it first. Then you can compare the quality of the digitized video with and without changing settings on the tape player. A good tool to have to examine the technical details of the conversion(s) is MediaInfo.

Example:

General
Complete name : D:\Videos\Paul McCartney Carpool Karaoke\Paul McCartney Carpool Karaoke.mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 320 MiB
Duration : 23 min 42 s
Overall bit rate : 1 890 kb/s
Frame rate : 29.970 FPS
Writing application : Lavf54.63.104

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4
Format settings : CABAC / 3 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 3 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 23 min 42 s
Bit rate : 1 756 kb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 29.970 (30000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.028
Stream size : 298 MiB (93%)
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Codec configuration box : avcC

Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 23 min 42 s
Bit rate mode : Constant
Bit rate : 126 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 44.1 kHz
Frame rate : 43.066 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 21.3 MiB (7%)
Default : Yes
Alternate group : 1

[Grant Millar]

Dear Alyn,

Thanks for this info - and sorry for the delay in replying to you.

I've heard of Field Order, but have not yet explored this area - but I will.

And I'll visit your website to find out more about using Virtual Dub.

Best regards,
Grant.

Nantawat Kittiwarakul, I like VDub as well. Re your deinterlacing setting, lossless VHS captures are nearly always Top Field First; DV Bottom Field First. It is easy to check: if there is back and forth motion after deinterlacing when stepping through the video frame by frame, you've chosen the wrong field order.

Edited to add: I've checked my EZ-48 and it always outputs Interlaced over S-Video, even when "Progressive On" is selected in the menu. Progressive is output over Component if selected On.

Since Nantawat has mentioned it, here's a blurb from my website regarding use of VDub.

[Grant Millar]

Dear Nantawat,

Thank you for taking the time and effort to write such a helpful reply!

And apologies for the delay in replying to your post.

Am going to try all the things that you, Ed and Alwyn have so kindly suggested.

Best regards,
Grant.

THe progressive option of your vhd/dvd combp player, is more than likely for dvd playbackonly. The output from vhs part would probably be always 50i - fifty interlaced fields per second.

The best bet is to convert that 50interlace fields to 50 progressive frames, to preserve both spatial and temporal resolution. The tool of my choice is still the good old VirtualDub program, which provides more than enough tools for video restoration.

[Alwyn Adkins]

Cheers Grant, come back if you get stuck.