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.
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.