On Tue, Oct 12, 2021 at 01:24:43AM +0200, Terje J. Hanssen via Cin wrote:
Den 11.10.2021 22:41, skrev Marco Ciampa via Cin:
Hello people, first time I'm writing here and not native English speaker. So forgive me if I'm not that good at expressing myself.
That said I want to share the content of an article I read somewhere that (unfortunately) I do not remember anymore but I remember the guts of if and think it could be much useful for someone.
The writer tested a lot of (not so) inexpensive PAL/NTSC USB and PCI converters and a few of expensive ones too. Suddenly he remembered that its Digital TV with PAL/NTSC input was _much_ better at displaying video that the video grabbers. To make a long story short he discovered that that was because of an internal analog to digital _and_ the FHD to HD digital downconverter that did the trick. The principle here is "always sample much more that what you want to obtain".
The result is this: forget the explensive and inexpensive grabbers and buy:
- one cheap HDMI to USB3 grabber (you can find models compatible with linux for ~10-20 euros / dollars)
- one cheap PAL/NTSC (SCART) to HDMI converter (you can find models for ~10 euros/dollars)
and that's all. It will also come handy for aquisition of video from reflex/mirrorless cameras and so on...
Hope someone find this handy...
--
Saluton, Marco Ciampa
This looks like a captivating, simple solution, if and when everything work. What I think I've read previous, is that playback of interlaced video looks better on Televisions than on PC displays.
1. My TV has built-in ports for analog video playback (S-Video and RCA/Phono), beside additional SCART and HDMI ports
Yes but unfortunately these are _inputs_ and cannot be used for conversion from analog video to digital video. The converter is _inside_ the TV and unfortunately, you cannot use it. But the thing is that chip is very inexpensive and you can find it in SCART to HDMI converters.
2. If I understand your description right, the HDMI to USB3 grabber should be used to record from a TV HDMI port to a Linux PC?
No. The HDMI to USB3 must be feeded by a cheap (but effective) analog to digital converter. The thing is: the analog to digital converters _and_ the digital grabbers inside cheap pal/ntsc to usb2 are a crap. If you want a really good quality conversion you have to open wide your wallet and buy a really expensive grabber just to be sure that it has inside a good (but not so expensive in itself) analog to digital converter. ... or use a cheap external one like this (just an example): https://www.amazon.com/ZHIYUEN-Adapter-Universal-Converter-Consumption/dp/B0... and to capture use one of these: https://www.amazon.com/IPXOZO-Video-Capture-Card-USB/dp/B08YRWB7VD these are just examples, (I do not work for Amazon! ;-) I picked them randomly and they _SHOULD_ work, but I cannot be 100% sure, never tried those in particular... it is just to explain the principle of this method... that you should give it a go... it's not such a great expense. Please note that if you want a pass through usb video grabber (useful for example to grab games) you have to spend a bit (5xtimes!) more for a device with input _and_ real time output.
While my HDV camera supports HDMI video out, I wonder if TV HDMI ports do that as I have really never tested it.
The camera does output, the TV only INPUT. No luck.
(At least my HD PVRK could not record HDTV via the HDMI cable, only a limited format from the antenna cable. Analog VCR could record SD video via SCART or S-video adapter)
Yes of course.
3. If HDMI video out works, what type of digital signal is expected (format uncompressed and chroma level?)?
HDMI output works only through adapters, see above..
And if works, it has to be recorded as compressed (lossless) on the Linux PC? Among other 4:3 aspect ratio from analog SD video has to be taken care of.
One usually grabs with maximum quality one can afford and only _after_ grabbing thinks about compression. That is the way to preserve much of the original quality. -- Saluton, Marco Ciampa