Capturing interlaced / 50Hz video

for all subjects/topics not covered by the other forum categories
dominicbeesley
Posts: 918
Joined: Tue Apr 30, 2013 11:16 am
Contact:

Capturing interlaced / 50Hz video

Post by dominicbeesley » Tue Sep 03, 2019 8:30 am

I'd like to be able record my demos to proper interlaced 576i PAL type video for posting up on the net. I've tried a few cheapo capture cards but most are just garbage and either don't work or come with such crap software as to be virtually unusable.

Has anyone tried the Roxio Game Capture or Game Capture HD or the Banggood box? They look as if they should all be able to do 25i but I'm wary! I'd like to run on Win 10 if possible.

The closest I've got to capturing off screen is using Cinema FV-5 on my Android phone but that only does 25fps and so all the smoothness of my 50Hz demo judders along...

Other ideas for smoother video capture?

D

User avatar
tricky
Posts: 3859
Joined: Tue Jun 21, 2011 8:25 am
Contact:

Re: Capturing interlaced / 50Hz video

Post by tricky » Tue Sep 03, 2019 8:44 am

The retro asylum (Iirc) discord group for creating videos for what a system was like recommended the capture HD, but if it does the rates you want, I would have thought the rgb to HDMI with a pi might work best, but then you would still need an HDMI capture option.

User avatar
Richard Russell
Posts: 1040
Joined: Sun Feb 27, 2011 10:35 am
Location: Downham Market, Norfolk
Contact:

Re: Capturing interlaced / 50Hz video

Post by Richard Russell » Tue Sep 03, 2019 10:31 am

dominicbeesley wrote:
Tue Sep 03, 2019 8:30 am
I'd like to be able record my demos to proper interlaced 576i PAL type video for posting up on the net.
Support for "proper interlaced 576i" is limited, in formats suitable for streaming from the net, so one thing you could consider is to de-interlace it to 576p50 (i.e. progressive at 50 fps). Now it's out of patent protection, Martin Weston's excellent deinterlacer (the one preferred by the BBC) is now available as an FFmpeg filter I believe.

Boydie
Posts: 380
Joined: Sat Oct 24, 2015 8:25 am
Location: Sunny Wigan
Contact:

Re: Capturing interlaced / 50Hz video

Post by Boydie » Tue Sep 03, 2019 10:33 am

The Hauppauge Colossus 2 works well but is PCIe and a bit pricey. Software is at least adequate.
They do an external USB version as well.

dominicbeesley
Posts: 918
Joined: Tue Apr 30, 2013 11:16 am
Contact:

Re: Capturing interlaced / 50Hz video

Post by dominicbeesley » Tue Sep 03, 2019 1:29 pm

Thanks all,

Tricky, I'm tempted for the capture HD but not sure it will do what I want - the software gets very mixed reviews and I don't want to waste £80 on something that will get chucked in the junk box, I'd like to see it running in the flesh on an RGB signal - I may just have to go for it.

RR, thanks, yes I was hoping to be able to capture at 25i and de-interlace to 50p. I have interlace turned off usually on the beeb so I guess that is really 288/50p that I want to capture?

Boydie, the Hauppage looks nice but I'm not sure it supports component RGB but I suppose I could feed it composite or S-video at a push. Their homepage doesn't mention win10 support though. Preferably, I'd like it to be something I could use with a laptop too.

D

dominicbeesley
Posts: 918
Joined: Tue Apr 30, 2013 11:16 am
Contact:

Re: Capturing interlaced / 50Hz video

Post by dominicbeesley » Tue Sep 03, 2019 1:31 pm

I've found a relatively cheap Roxio HD on ebay so I'll give that a punt and sell it if its no good! Hopefully it should do 576i and I can take RR's advice and deinterlace.

D

Boydie
Posts: 380
Joined: Sat Oct 24, 2015 8:25 am
Location: Sunny Wigan
Contact:

Re: Capturing interlaced / 50Hz video

Post by Boydie » Tue Sep 03, 2019 2:14 pm

The Hauppauge card does do component apparently (but possibly not composite or s-video, can’t remember what the lead was like).
I’ve only ever used the software with Win 10, so can confirm it works. There is a clash when first installed - something to do with Win10 and cameras iirc, but changing a single config option in windows sorts it.

User avatar
Diminished
Posts: 199
Joined: Fri Dec 08, 2017 9:47 pm
Contact:

Re: Capturing interlaced / 50Hz video

Post by Diminished » Tue Sep 03, 2019 2:43 pm

Standalone consumer DVD recorder?

User avatar
tricky
Posts: 3859
Joined: Tue Jun 21, 2011 8:25 am
Contact:

Re: Capturing interlaced / 50Hz video

Post by tricky » Tue Sep 03, 2019 10:35 pm

I haven't got one yet as I'm not sure that they will do what I want.

dominicbeesley
Posts: 918
Joined: Tue Apr 30, 2013 11:16 am
Contact:

Re: Capturing interlaced / 50Hz video

Post by dominicbeesley » Tue Sep 03, 2019 10:58 pm

I'll report back when I know more!

D

User avatar
Richard Russell
Posts: 1040
Joined: Sun Feb 27, 2011 10:35 am
Location: Downham Market, Norfolk
Contact:

Re: Capturing interlaced / 50Hz video

Post by Richard Russell » Wed Sep 04, 2019 9:46 am

dominicbeesley wrote:
Tue Sep 03, 2019 1:29 pm
I have interlace turned off usually on the beeb so I guess that is really 288/50p that I want to capture?
With interlace turned off it's a non-standard video format so possibly a capture card won't lock to it at all, it will depend on how tolerant it is. I would recommend leaving interlace on and then deinterlacing later, since that effectively doubles the vertical resolution (admittedly only really of value in MODE 7).

dominicbeesley
Posts: 918
Joined: Tue Apr 30, 2013 11:16 am
Contact:

Re: Capturing interlaced / 50Hz video

Post by dominicbeesley » Wed Sep 04, 2019 11:46 am

Noted. Though I suspect the Roxio will tolerate some non-standard behaviour. I seem to remember the Wii does something non-standard with interlace which caused a large screen set we were using to randomly turn on and off its PAL dot-crawl filter (I may be misremembering).

Effectively the games and demos I want to record are 288/50p i.e. we don't want any offset between the two fields...

I'll look forward to playing around with all this. I suspect the de-interlace may make my problems worse i.e. does it shuggle lines horizontally to de-interlace to a 25p frame? What I'd really like is to line double each field to a 50p frame for smooth action.

An example of the best I've managed so far with the phone (not the best cinematography but least flicker/judder). https://youtu.be/SNBGbdUB8TI It's not too bad but looks a lot smoother viewing the CRT.

D

chinnyhill10
Posts: 119
Joined: Mon Apr 27, 2015 7:37 pm
Contact:

Re: Capturing interlaced / 50Hz video

Post by chinnyhill10 » Wed Sep 04, 2019 12:09 pm

You have to deinterlace at some stage and turn it into 50p. Your choice of deinterlacer is down to you. I use a Pioneer DVD recorder to take the RGB, deinterlace it and then it squirts it out as component which I then capture. I could do it as HDMI but I prefer component. Then you upscale if you wish using your software of choice.

I'm sure purists will complain but since I was one of the first people running a channel doing real capture from mulitiple systems I'm quite happy with how it comes out.

User avatar
Richard Russell
Posts: 1040
Joined: Sun Feb 27, 2011 10:35 am
Location: Downham Market, Norfolk
Contact:

Re: Capturing interlaced / 50Hz video

Post by Richard Russell » Wed Sep 04, 2019 1:16 pm

dominicbeesley wrote:
Wed Sep 04, 2019 11:46 am
I suspect the de-interlace may make my problems worse i.e. does it shuggle lines horizontally to de-interlace to a 25p frame?
A deinterlacer shouldn't be doing anything "horizontally"! All good deinterlacers are vertical-temporal filters of some kind; the beauty of Martin Weston's filter is that it is entirely non-adaptive yet achieves a performance at least as good as, if not better than, some adaptive filters that can easily get 'confused'.
What I'd really like is to line double each field to a 50p frame for smooth action.
Indeed. If you're outputting only MODEs 0-6 you want a deinterlacer with no temporal component at all, but just a vertical one.

dominicbeesley
Posts: 918
Joined: Tue Apr 30, 2013 11:16 am
Contact:

Re: Capturing interlaced / 50Hz video

Post by dominicbeesley » Wed Sep 04, 2019 2:25 pm

I was under the impression that some de-interlacers used motion compensation (where it tries to guess the trajectory of moving objects and compensate for this)...something I really don't want. I bow to your superior knowledge though!

D

User avatar
Richard Russell
Posts: 1040
Joined: Sun Feb 27, 2011 10:35 am
Location: Downham Market, Norfolk
Contact:

Re: Capturing interlaced / 50Hz video

Post by Richard Russell » Wed Sep 04, 2019 3:02 pm

dominicbeesley wrote:
Wed Sep 04, 2019 2:25 pm
I was under the impression that some de-interlacers used motion compensation (where it tries to guess the trajectory of moving objects and compensate for this)...something I really don't want.
There are indeed motion-compensated deinterlacers, but as you say these aren't relevant to you. It's probably not helpful to think of the conversion from 288p50 (which is effectively what the Beeb outputs in MODEs 0-6) to 576p50 as 'deinterlacing' at all, because it requires only a vertical filter with no temporal component. This may be as simple as just a 'line doubler', or a more complex vertical filter if aliasing is an issue.

User avatar
BeebMaster
Posts: 2952
Joined: Sun Aug 02, 2009 4:59 pm
Location: Lost in the BeebVault!
Contact:

Re: Capturing interlaced / 50Hz video

Post by BeebMaster » Thu Sep 05, 2019 3:37 pm

I use a JVC DVD recorder (DR-M150) to capture video output from a BBC micro with an RGB to SCART lead, but it's fussy about the DVD formats it supports, and after 9 years it's getting a bit choosy about the actual discs as well, seeming to eat them and make them unusable after only a very few writes. When it does work the output has always been very good, although I don't do much with video, I extract frames to png with ffmpeg for my screenshot picture sets.
Image

dominicbeesley
Posts: 918
Joined: Tue Apr 30, 2013 11:16 am
Contact:

Re: Capturing interlaced / 50Hz video

Post by dominicbeesley » Mon Sep 09, 2019 10:46 am

Thanks beebmaster, I may end up doing that - I've got a couple of cakes of DVDs that need using up!

I got the Roxio HD this weekend - I suspect it will be relegated to the junk box or sold on. I installed the software and started it up...no signal, try another port, a brief flash of something and then....Blue Screen Of Death! :evil: I'll not be trying that on my main computer again!

D

dominicbeesley
Posts: 918
Joined: Tue Apr 30, 2013 11:16 am
Contact:

Re: Capturing interlaced / 50Hz video

Post by dominicbeesley » Tue Sep 10, 2019 10:37 am

I got it going on my laptop and I have been left a little disappointed. It seems to only record at 25fps (there are few settings and most stuff is automatic depending on the signal detected) and does its own de-interlacing which looks good on normal material but on the scrolling moving stuff I'm wanting to record leads to blurriness and it all looking a bit juddery. I see another fpga project coming on - a scan doubler of some sort - any recommendations for video DAC's?

The TCP5150 from TI is cheap and cheerful and would probably "do" or maybe push the boat out on something like the ADV7403 or even the ADV7202 in increasing cost/complexity. I could then double up to 576p using a simple line buffer?

D

User avatar
BeebMaster
Posts: 2952
Joined: Sun Aug 02, 2009 4:59 pm
Location: Lost in the BeebVault!
Contact:

Re: Capturing interlaced / 50Hz video

Post by BeebMaster » Tue Sep 10, 2019 12:00 pm

I could make a test recording from my setup and post it, see if it's up to scratch for you as a possible setup before you invest in any alternatives?

What sort of thing would help - a game running for example?

Actually thinking about it I have all the videos I've ever done, mebbe I could fish something out that already exists.
Image

dominicbeesley
Posts: 918
Joined: Tue Apr 30, 2013 11:16 am
Contact:

Re: Capturing interlaced / 50Hz video

Post by dominicbeesley » Tue Sep 10, 2019 12:36 pm

I very much doubt that the DVD will do what I want (it will probably do the same as the Roxio which is 25fps) I want to produce a scan-doubled 576p/50 when recorded from 576i. Something like defender or the twisted brain demo would maybe show it up.

I'm probably being very picky but I know what I'm after and was hoping that the roxio wouldn't be so "helpful"!

D

User avatar
Richard Russell
Posts: 1040
Joined: Sun Feb 27, 2011 10:35 am
Location: Downham Market, Norfolk
Contact:

Re: Capturing interlaced / 50Hz video

Post by Richard Russell » Tue Sep 10, 2019 1:21 pm

dominicbeesley wrote:
Tue Sep 10, 2019 10:37 am
I see another fpga project coming on - a scan doubler of some sort - any recommendations for video DAC's?
If you can find a capture device that will save the 576i 'properly' (i.e. without attempting to deinterlace or otherwise mangling the video) you can do the conversion to 576p50 downstream, either using something like FFmpeg or writing the code yourself. A 'professional' capture card is likely to have the option of saving the video uncompressed, e.g. in Rec.601 format, which would be ideal. You might want to look at Blackmagic products, for example this, although I cannot personally vouch for its suitability.

dominicbeesley
Posts: 918
Joined: Tue Apr 30, 2013 11:16 am
Contact:

Re: Capturing interlaced / 50Hz video

Post by dominicbeesley » Tue Sep 10, 2019 1:37 pm

Sorry Beebmaster, I posted before I'd finished typing - I meant to say thanks for the offer!

RR, that's what I was hoping the roxio "pro" would do but it only gives the option of 25fps de-interlaced. It will do for now - it's better than the phone and cheap chinese capture device which record at a very jittery 30 or 60fps.

That device looks like it will do it but I'm not sure I want to throw any more money at it until I'm sure. The more I think about it the more I ought to have a go at a scan doubler...maybe with HDMI to boot. I managed to get hdmi working at 576p/50 with my bbc micro fpga clone a few years ago. It should be possible to beat this with careful use of sdram...the blocker on this is that most of the good ADC's seem to be either end-of line or very expensive.

D

SteveBagley
Posts: 220
Joined: Sun Mar 15, 2015 8:44 pm
Contact:

Re: Capturing interlaced / 50Hz video

Post by SteveBagley » Tue Sep 10, 2019 2:40 pm

dominicbeesley wrote:
Tue Sep 10, 2019 1:37 pm
the blocker on this is that most of the good ADC's seem to be either end-of line or very expensive.
You don't need an ADC for the Beeb -- the RGB output is TTL level. I successfully used a cheap USB logic analyser to capture the video in the past.

Steve

dominicbeesley
Posts: 918
Joined: Tue Apr 30, 2013 11:16 am
Contact:

Re: Capturing interlaced / 50Hz video

Post by dominicbeesley » Tue Sep 10, 2019 3:28 pm

You do if it contains a RobC nula!

User avatar
1024MAK
Posts: 9496
Joined: Mon Apr 18, 2011 4:46 pm
Location: Looking forward to summer in Somerset, UK...
Contact:

Re: Capturing interlaced / 50Hz video

Post by 1024MAK » Tue Sep 10, 2019 3:34 pm

Assuming it’s a standard Beeb and not got a custom VideoProc / Video ULA...

Ideally you just need FIVE digital inputs, channels as follows:
  1. Red TTL Video
  2. Green TTL Video
  3. Blue TTL Video
  4. Vertical TTL Sync.
  5. Horizontal TTL Sync
The reason for capturing the separate synchronisation signals, is so that it is easier to process.

Of course if it’s fitted with a VideoNuLA module or other similar analogue video system, then a video ADC is essential :D

Mark

Ahh, cross posted :lol:

SteveBagley
Posts: 220
Joined: Sun Mar 15, 2015 8:44 pm
Contact:

Re: Capturing interlaced / 50Hz video

Post by SteveBagley » Sat Sep 14, 2019 9:08 am

dominicbeesley wrote:
Tue Sep 10, 2019 3:28 pm
You do if it contains a RobC nula!
True -- although then you could just capture the data input into the nULA and implement a nULA emulator in software :)

Steve

dominicbeesley
Posts: 918
Joined: Tue Apr 30, 2013 11:16 am
Contact:

Re: Capturing interlaced / 50Hz video

Post by dominicbeesley » Sat Sep 14, 2019 12:58 pm

I have been seriously considering a hdmi nula...would be cheaper but not sure about all the parents and licences on hdmi or dvi

User avatar
tricky
Posts: 3859
Joined: Tue Jun 21, 2011 8:25 am
Contact:

Re: Capturing interlaced / 50Hz video

Post by tricky » Sat Sep 14, 2019 5:17 pm

I think some of the nula finctionality is already in the pi based version hoglet and co did. You run in a mono mode and the pi does the rest.
I don't remember exactly what is supported.

User avatar
BeebMaster
Posts: 2952
Joined: Sun Aug 02, 2009 4:59 pm
Location: Lost in the BeebVault!
Contact:

Re: Capturing interlaced / 50Hz video

Post by BeebMaster » Wed Sep 25, 2019 9:56 am

I'd like to have a go at running that twisted brain demo (assuming it isn't going to really break my 6845) to see how my bygone old ways of recording Beeb video fare against what others are doing. However I can only find an SSD of the disc image, and I don't have a way of extracting the files from an image - apart from doing it manually with dd which is all right for a single file or two at a push but a bit much for a whole dis{c|k|que}-full{(e|eaux)}.

I've a thing called Linux DFS Explorer, but it doesn't seem to do anything, probably because it isn't installed correctly, which if it involves anything ending in sh or py or beginning with .?><:@{}/make then there's no hope of me doing it.

I thought I once had a RISC OS DFS reader which could work with images but I can't seem to find that.

I must devise a better way of being able to cope with DFS disc images: the only way I can think of doing it is to download the SSD and put it on my RPi4 server then save it from there onto my Econet file server using RISC PC and load it into Station 1's ARM7 RAM and write sectors directly to an actually floppy disc from there, and then load it in Station 114 which is connected to the recorder. PC, Pi, RPC and 2 Masters to do a file transfer sounds a bit much!
Image

Post Reply