Mass Media & Technology

Help with recording video over HDMI

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LL
Larry the Loafer
I'm hoping somebody can offer me some advice. I'm looking for a new method to capture TV recordings over HDMI. I used to use a no-name USB recorder I found on Amazon that would record 720p50 to a USB stick, and I'd transfer the files to my computer to edit and compress them into a final video file. However, recently the recorder has gotten into a habit of corrupting whatever USB device is connected to it, or not saving whatever it records. I think it's time for a replacement.

So far I've tried three HDMI-to-USB adaptors on Amazon that claim to capture 1080p60 and encourage the use of OBS. I found this a bit jolting at first as it seems more tailed for game capture rather than just recording things off TV. However every one I've tried so far can't capture any higher than 30fps and the audio quality sounds, well... off. I've tinkered with every setting I can find in OBS and I can only assume it's a limitation of the adaptor. Despite it claiming the capability of recording 1080p60, the documentation states it's using USB 2.0. I'm making a blind assumption that USB 2.0 can't handle 1080p60 and that's why the frame rate is limited. Before I make a third return to Amazon, I just wanted to see if anyone knew something else to try, or something else I can troubleshoot to see if it's something other than the adaptor.

I'm trying everything I can to avoid investing in a rather costly capture card along the lines of an Elgato but I'm running out of options. Does anyone here use something along these lines to capture video in 50fps? If so, what would you recommend? And is there a cheaper option than opting for an Elgato?

Thank you for reading and any advice would be greatly appreciated!
EL
eladkse
I've had good experience with this: https://www.amazon.co.uk/gp/product/B08C9Z5BD2/

USB 3.0, and accepts up to 2160p60 with HDR over HDMI 2.0 (downscales to 1080p60 SDR for capture, pass-through unaffected). No HDCP issues as far as I've seen either.

Can't comment too much on if the audio is any good - the source I was using for testing in OBS was 5.1, but the card was only onpassing the first two channels to my laptop. I'm sure it'll be fine if you're after stereo.

Might be overkill for you if you just want HD capture though. I chose this because of it's ability to handle 4K and HDR signals, which is perfect for my homemade ambilight.
LL
Larry the Loafer
It's a hell of a lot less than anything in the Elgato tier so I'll give it a try! Cheers Very Happy
Last edited by Larry the Loafer on 10 February 2021 4:14pm
JA
jamesw83
If you're willing to report back, please do so - I'm going through exactly the same thing at the moment now I've upgraded most of my kit, my capture rig is still stuck on component AV, so I'm looking to upgrade.
Last edited by jamesw83 on 10 February 2021 4:52pm
NG
noggin Founding member
A lot of these USB capture devices usually quote two different capabilities - though some are poor at differentiating them. They appear as UVC style webcams - hence the suggestion to use OBS to capture them - though ffmpeg will also work OK.

1. The video formats they accept as HDMI inputs.
2. The video formats that they output to the connected PC.

A lot of devices cap the output format to a max of 1080p30, whilst they will accept 1080p60 (and in some cases 2160p60). Also a lot of these take 1080i25 and output 1080p25 (with a poor-quality de-interlace - sometimes just line-doubling one field per frame)

USB 2.0 devices will have to use compression to get anything above SD into a PC - most cheap capture dongles will be using MJPEG compression if they are designed to allow HDMI cameras to be used as Webcams (as it has low latency), though some may use MPEG2 or h.264 compression (which will allow for lower data rates but retain reasonable video quality)

There are two types of low-ish cost capture dongles I've found so far :

USB 2.0 ones that max out at 1080p30 for what they output - but will capture 720p50, 1080p25 etc. and pass it through at 50 or 25Hz respectively.

USB 3.0 ones that max out at 1080p60 for what they output - but will only output 30 or 60Hz - even if they capture 25/50Hz sources, they won't output at that frame rate.

The Amazon link above visually looks to be one of the USB 3.0 'virtual webcam' models that outputs only 30/60Hz captures of 25/50Hz sources.

Info about evaluating capture solutions below :

It's quite easy to get a USB Web Cam Capture solution to report its capture capabilities in Linux (say on a Raspberry Pi or similar) either using ffmpeg or v4lutils.
( https://trac.ffmpeg.org/wiki/Capture/Webcam )

You can also capture the EDID from the HDMI port on the capture card (i.e. read what they flag to connected to devices that they support as input formats) if you plug a Raspberry Pi (or similar) HDMI output into their capture port and do the following :

tvservice -d edid.dat
edidparser edid.dat

You may need to install edidparser.

It's a lot easier to do this over SSH as you may not be able to see the Pi output via the Webcam capture !
Last edited by noggin on 11 February 2021 8:32am - 2 times in total
Larry the Loafer and London Lite gave kudos
SP
Steve in Pudsey
This might be worth a look - although given that his source materials will be NTSC I don't know how well it translates to PAL
NG
noggin Founding member
If you REALLY want the highest quality VHS capture - there is work done on RF capture from the VHS video heads - with software defined demodulators, timebase correctors, FM audio and chroma decoders. This has sprung out of the Laser Disc Decode work that also does this - and includes a software implementation of the formerly-BBC-patented Transform decoder. (The BBC let the patents lapse)

This is still very much work in progress - but looks like a promising route for a lot of analogue VT formats (from 2" Quad via 3/4" UMatic to VHS and Betamax)
VM
VMPhil
I have a stack of tapes that I want to capture stuff from but it does seem like a difficult process... really didn't want to have to buy a DVD recorder just to capture them properly but it seems that's the easiest option?

I tried one of those USB things and the quality isn't great. Plus I kept getting an annoying flash in the top left that wasn't there on the TV. Example:

RI
Richard
Interesting upload. That must have been when they used a new, widescreen enabled OB truck for Trooping the Colour, complete with 14:9 in a 4:3 raster (unusual for the time) and a BBC logo at the end which was a third wider than it should have been.
VM
VMPhil
Interesting upload. That must have been when they used a new, widescreen enabled OB truck for Trooping the Colour, complete with 14:9 in a 4:3 raster (unusual for the time) and a BBC logo at the end which was a third wider than it should have been.

Yes! I can't find it now (just my luck) but I did do a bit of searching around a while ago, and found a DS thread with a post saying it was shown internally to BBC staff as a test, on widescreen TVs. So it was a proper widescreen production and not fake 14:9 letterboxing.

That's the only thing on that tape by the way, the full Trooping the Colour (starts mid-titles) and then everything I uploaded above.
Richard, UKnews and London Lite gave kudos
LL
Larry the Loafer
I've just tried the capture card eladkse recommended and it seems to be spot on so far! Thank you so much eladkse!
NG
noggin Founding member
Interesting upload. That must have been when they used a new, widescreen enabled OB truck for Trooping the Colour, complete with 14:9 in a 4:3 raster (unusual for the time) and a BBC logo at the end which was a third wider than it should have been.


Yes - that looks like a native 16:9 production with the graphics device running in 4:3 mode (so everything is stretched by a third horizontally), possibly because it was so early that the Cap Gen didn't have a 16:9 mode and the operator didn't do a horizontal squish/vertical stretch on their artwork and fonts (which would have remedied it).

The BBC converted one of their late 70s/early 80s Type V OB trucks to run in 16:9, using Philips LDK91 (I think) cameras (and also with COM3 - Component Compatible Composite - encoders to improve the picture quality) and so it may have been shot using that truck.

(Another of the BBC Type V OB trucks was sold and used by Planet 24 as production facilities for The Big Breakfast I believe)
Last edited by noggin on 19 February 2021 9:43am

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