Mass Media & Technology

Help with recording video over HDMI

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JA
james-2001
That sort of thing did happen a fair bit, I seem to remember the end credits on Question Time appeared stretched well into the 00s. Can think of a few examples of the reverse too- programmes which were in 4:3 but some of the captions looked like they were made for 16:9 so are stretched vertically. Look at the Coronation Street ITV generic smoky hearts credits on late 2000/2001 episodes for example (and on Emmerdale from the same era, though in that case the logo's properly proportioned but the credit text is still stretched). Some of the captions on SM:TV Gold at the back end of 2003 as well.
Last edited by james-2001 on 19 February 2021 12:04am - 2 times in total
NG
noggin Founding member
That sort of thing did happen a fair bit, I seem to remember the end credits on Question Time appeared stretched well into the 00s.


I think Question Time often used PowerPoint on a PC driven by a member of their production team for their captions and credits as a cost-saving solution...
RO
roo
QT was still using PowerPoint as of a couple of years ago 😱
bilky asko, IanJRedman and AndrewPSSP gave kudos

14 days later

MM
MMcG198
For a number of years, I transferred VHS material to DVD, using a Sony DVD recorder - with pretty decent results.

However, due to a failure with the recorder and the need to digitise more VHS material, I'm now looking at transferring VHS, which ultimately gets channeled through HDMI to the capture device.

I've managed to address a dot crawl issue - particularly on reds and greens - by making a small adjustment to Luma Horizontal Bandwidth.

But one persistent issue is the distortion of yellows/oranges. Anything of that colour seems to experience an odd "shimmering" effect. An example is the page headings on these Ceefax pages. If you expand the video to full screen, you'll see the shimmering around the 'WEATHER' heading on the first page and the 'AIR' lettering on the second page.

https://wp.me/PcyR9S-73A

Any ideas what might be causing this?

I'm using an Elgato video capture device.

I have to say, trying to get decent results from VHS has been an agonising process of experimentation. I feel I'm very close to a decent result - bar this one outstanding problem.
NG
noggin Founding member
For a number of years, I transferred VHS material to DVD, using a Sony DVD recorder - with pretty decent results.

However, due to a failure with the recorder and the need to digitise more VHS material, I'm now looking at transferring VHS, which ultimately gets channeled through HDMI to the capture device.

I've managed to address a dot crawl issue - particularly on reds and greens - by making a small adjustment to Luma Horizontal Bandwidth.

But one persistent issue is the distortion of yellows/oranges. Anything of that colour seems to experience an odd "shimmering" effect. An example is the page headings on these Ceefax pages. If you expand the video to full screen, you'll see the shimmering around the 'WEATHER' heading on the first page and the 'AIR' lettering on the second page.

https://wp.me/PcyR9S-73A

Any ideas what might be causing this?

I'm using an Elgato video capture device.

I have to say, trying to get decent results from VHS has been an agonising process of experimentation. I feel I'm very close to a decent result - bar this one outstanding problem.


That's an artefact of PAL composite encoding/decoding - possibly not helped by VHS. Different composite capture solutions will have different PAL decoders in them (that convert the single composite, or dual S-video input to RGB or Component before they are captured) and perform differently.

Your DVD recorder may have had a better decoder - certainly our early Sony DVD recorder had an excellent PAL decoder and appeared to do a pretty good TBC (Time Base Correction) too.

It's an obvious artefact because it's very saturated (so a high level of subcarrier) transitioning to an area that is less saturated, and with a very sharp transition. You often see these wobbly edges on recordings of colour bars too.
Last edited by noggin on 6 March 2021 4:53pm - 2 times in total
MM
MMcG198
For a number of years, I transferred VHS material to DVD, using a Sony DVD recorder - with pretty decent results.

However, due to a failure with the recorder and the need to digitise more VHS material, I'm now looking at transferring VHS, which ultimately gets channeled through HDMI to the capture device.

I've managed to address a dot crawl issue - particularly on reds and greens - by making a small adjustment to Luma Horizontal Bandwidth.

But one persistent issue is the distortion of yellows/oranges. Anything of that colour seems to experience an odd "shimmering" effect. An example is the page headings on these Ceefax pages. If you expand the video to full screen, you'll see the shimmering around the 'WEATHER' heading on the first page and the 'AIR' lettering on the second page.

https://wp.me/PcyR9S-73A

Any ideas what might be causing this?

I'm using an Elgato video capture device.

I have to say, trying to get decent results from VHS has been an agonising process of experimentation. I feel I'm very close to a decent result - bar this one outstanding problem.


That's an artefact of PAL composite encoding/decoding - possibly not helped by VHS. Different composite capture solutions will have different PAL decoders in them (that convert the single composite, or dual S-video input to RGB or Component before they are captured) and perform differently.

Your DVD recorder may have had a better decoder - certainly our early Sony DVD recorder had an excellent PAL decoder and appeared to do a pretty good TBC (Time Base Correction) too.

It's an obvious artefact because it's very saturated (so a high level of subcarrier) transitioning to an area that is less saturated, and with a very sharp transition. You often see these wobbly edges on recordings of colour bars too.


Thanks very much for taking the time to respond noggin.

The old Sony DVD recorder produced very good results and I was very happy with it. But, times change, and irrespective of the fault with the machine, I want to move on from having to put VHSs to DVD first.

The Elgato capture device is excellent for recording HD off-airs. I can't fault it there.

However, addressing analogue TV anomalies has been very painful. Every time I think I'm winning, something new turns up. I have 2 VHSs which contain a range of different recordings which cumulatively provide a very good test of the VHS digitisation.

I naively wasn't aware of such variations in PAL decoders. I've seen lots of examples of colour bleed over the years - but I've not seen that odd shimmering effect before. Colour bleed is unfortunately a feature of VHS. But that particular example on the Ceefax clip is one I don't really want to have on my VHS transfers, if I can avoid it.

I decided to use an existing Panasonic DVD recorder as an elaborate SCART -> HDMI converter. The VHS SCART output is channeled through the Panasonic machine. The HDMI from the Panasonic is then fed to the capture device. The Panasonic has quite a lot of picture adjustment features which allow me to remedy some analogue issues.

I did put the Panasonic HDMI output through a splitter as well - one feed going to the capture device and one to a standalone monitor. And yes, it very much proves your point about the issue being the Elgato PAL decoder. The yellow Ceefax heading text looks as expected on the monitor (with the usual bit of VHS bleed) - but the shimmering is present on the output from the Elgato device.

Are any of the current batch of capture devices particularly good for VHS transfers? A lot of them are now geared towards HD, 4k etc. TBH, apart from that glitch with Elgato, it's not producing bad results for VHS. I heard some complaints from people re Hauppauge a few years back - but I don't know if it has improved since.

Someone mentioned the Kdely Game Capture Card on the last page. Do we know how good it is for VHS?

I've learned over the years that most expensive doesn't necessarily mean the best result.
NG
noggin Founding member
Sorry - not much I can advise I'm afraid. I haven't had to capture much VHS recently. When I did I used to use a cheap USB 2.0 Composite / S-video decoder and hardware MPEG2 encoder solution that I got in a Maplin sale years ago. It outputs 8Mbs MPEG2 captures - so is far from great - but was 'good enough'. None of my capture content had stuff that would have stressed a PAL decoder in the way CEEFAX in-vision would so I didn't really look at it.

I know there is a lot of interest in RF capture from VHS decks (where you take the 'off tape' RF from the heads, and do all the colour-under processing, video demodulation, FM audio demodulation, time base correction, PAL decoding etc. in software after capturing via a PC. This is enthusiast territory stuff - and involves quite a lot of hardware hacking - but it's likely to be the highest quality route available eventually. (The same technique is already delivering results better than hardware LaserDisc players)
MMcG198 and IanJRedman gave kudos
IJ
IanJRedman
Sorry - not much I can advise I'm afraid. I haven't had to capture much VHS recently. When I did I used to use a cheap USB 2.0 Composite / S-video decoder and hardware MPEG2 encoder solution that I got in a Maplin sale years ago. It outputs 8Mbs MPEG2 captures - so is far from great - but was 'good enough'. None of my capture content had stuff that would have stressed a PAL decoder in the way CEEFAX in-vision would so I didn't really look at it.

I know there is a lot of interest in RF capture from VHS decks (where you take the 'off tape' RF from the heads, and do all the colour-under processing, video demodulation, FM audio demodulation, time base correction, PAL decoding etc. in software after capturing via a PC. This is enthusiast territory stuff - and involves quite a lot of hardware hacking - but it's likely to be the highest quality route available eventually. (The same technique is already delivering results better than hardware LaserDisc players)

Are there any available examples of RF capture versus a more traditional method?
NG
noggin Founding member
Sorry - not much I can advise I'm afraid. I haven't had to capture much VHS recently. When I did I used to use a cheap USB 2.0 Composite / S-video decoder and hardware MPEG2 encoder solution that I got in a Maplin sale years ago. It outputs 8Mbs MPEG2 captures - so is far from great - but was 'good enough'. None of my capture content had stuff that would have stressed a PAL decoder in the way CEEFAX in-vision would so I didn't really look at it.

I know there is a lot of interest in RF capture from VHS decks (where you take the 'off tape' RF from the heads, and do all the colour-under processing, video demodulation, FM audio demodulation, time base correction, PAL decoding etc. in software after capturing via a PC. This is enthusiast territory stuff - and involves quite a lot of hardware hacking - but it's likely to be the highest quality route available eventually. (The same technique is already delivering results better than hardware LaserDisc players)

Are there any available examples of RF capture versus a more traditional method?


Have a look for 'vhs-decode' on YouTube. It's still quite early days - but the software TBC is pretty good.

Also a lengthy thread here : https://forum.videohelp.com/threads/394168-Current-status-of-ld-decode-vhs-decode-%28true-backup-of-RF-signals%29

There are two main ways of capturing - using a specific video card that can be 'persuaded' to capture 8 (and I think 10) bits at far higher sample rates than are required for PAL/NTSC baseband video, or by using the Domesday Duplicator hardware designed for Laser Discs (that is capable of higher quality sampling at greater bit depth)
Last edited by noggin on 8 March 2021 11:47am - 2 times in total
JA
james-2001
I wonder if there'll ever be a way we can get data off magnetic media without needing the original players like we've done with records and the likes? Would help massively with saving contents from obsolete media.
NJ
Neil Jones Founding member
I wonder if there'll ever be a way we can get data off magnetic media without needing the original players like we've done with records and the likes? Would help massively with saving contents from obsolete media.


Didn't they already do that? Wasn't there an episode or two of Morecambe & Wise from the 1960s that had fallen through the wiping machine years ago and the only existing copy was some tatty old print that was beyond economic repair and you couldn't even look at in case it fell to pieces? Or was that a film/telerecording?
IN
intracube
I wonder if there'll ever be a way we can get data off magnetic media without needing the original players like we've done with records and the likes? Would help massively with saving contents from obsolete media.


I've been wondering about this for some years and had hoped that a radically different solution might arrive which doesn't rely on using ageing VCRs to read the tapes.

Something like a linear audio head, but subdivided along one dimension (across the tape) to capture the helical scans as-is and then decode later. But it would need an array of microscopic heads at a similar density to CMOS/CCD sensors and maybe it's not possible to scale down that far.

On video capture; has anyone experimented with recent PCIe solutions for HD/SD? These days I record HD directly from DVB-S/S2 so this is more about analogue capture. BlackMagic Decklink cards seem popular but there were some question marks over their onboard TBC on the VideoHelp forums (also fan noise). I also use Linux which complicates things (driver support).

Didn't they already do that? Wasn't there an episode or two of Morecambe & Wise from the 1960s that had fallen through the wiping machine years ago and the only existing copy was some tatty old print that was beyond economic repair and you couldn't even look at in case it fell to pieces? Or was that a film/telerecording?

That was a telerecording and the restoration method involved destructively cutting it up into small blocks with a laser!
https://www.bbc.co.uk/rd/blog/2017-12-morecambe-wise-video-film-archive-restoration

Edit:
Also hello! Long-time forum reader/lurker here - thought I'd take the opportunity to ask about video capture while the forums are still open for business.
Last edited by intracube on 8 March 2021 5:43pm

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