Isn't the overlay surface a feature to save CPU or memory transfer cycles, so you could compensate by putting it in a faster system? The feature may also depend on VRAM capacity, and maybe they optimized it for miro graphics cards.

well, it's only a 2mb trio64v2/dx, but the driver is saying that my card supports overlay surface for best performance or something. and they had a compatibility list including a bunch of 2mb trio and virge cards. but i guess i can look if i have something compatible with more memory.

it might be a dc30plus actually, it's a bit ambiguous with all the variants they sold under that name, with different cards for pc/mac. another interesting thing is, i've seen it mentioned that it may be possible to get uncompressed video out of this card, and a driver setting also suggests that.

Back in the day I used for BT878 based cards the version of Windows movie maker that came with Windows Me and a little later I started using VirtualDub to capture VHS and compress using DivX or Xvid (https://www.virtualdub.org/index.html), I was surprised to see that it is still easy to find.
I know the DC30 is older, but maybe VirtualDub works.

Unless you want a genuine experience I'd say forget overlay surfaces on 2 MB cards and period correct Windows 9x systems. The card looks to have drivers for up to Windows XP and be supported by Video4Linux in Linux, so it might work on all machines with a PCI slot, and may well work in a VM if your motherboard supports passthrough, then you have all the system speed it needs. Just a gut feeling but I doubt you would've been doing crisp 60 FPS 640 x 480 capture on a home computer in 1997.

if you translate this, they say it works about as good in a p100 as in a ppro 200, it's just that slower bus speeds will drag it down. and the latest driver basically needs 64mb minimum, it's setting vcache to a fixed 16mb. SCSI > IDE too obviously.

Have you tried capturing without overlay/preview enabled ?

auron wrote on 2025-02-17, 20:13:

if you translate this, they say it works about as good in a p100 as in a ppro 200, it's just that slower bus speeds will drag it down. and the latest driver basically needs 64mb minimum, it's setting vcache to a fixed 16mb. SCSI > IDE too obviously.

I'd say forget the overlays, just move up to a faster system as needed and do all frame handling on the CPU. That is if you plan to use it for capture's sake. If you just want to mess around with it on an old computer then maybe get a miro ViRGE and see how they pair up.

auron wrote on 2025-02-17, 03:52:

i'm not sure how much interest there is here in old capture cards, but i'm currently testing a DC30 from 1997 and have run into […]
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i'm not sure how much interest there is here in old capture cards, but i'm currently testing a DC30 from 1997 and have run into some limitations with both the miro/pinnacle software and vidcap32 that the latest driver for 9x comes with. i have already swapped my matrox millennium, because it did not support the "overlay surface" feature that this card wants for best performance; otherwise, it will revert to a slower "primary surface" instead to show the capture feed. i replaced this with some newer trio64 variant which according to the included test supports overlay surface - at least when the desktop resolution is set to 800x600 or higher.

the main problem is that despite the readme mentioning that with overlay surface the capture feed can be scaled to certain sizes, that does not seem to be possible with either software. i'm usually going with vidcap32 because its UI at least makes some sort of sense unlike that miro software. with 640x480 on the trio card, one of the vidcap32 setting windows mentions using primary surface, while with 800x600 nothing is mentioned there. doesn't really seem to make a difference, in fact 640x480 is the only way to get the viewport to be at least a little bit bigger. it's not clear to me why they mention scaling in the readme if it's not exposed in either of the supplied tools.

or, to be more specific - with a certain option on, making the window smaller will downscale the capture feed instead of cropping, but it won't upscale when enlarging the window. what i'd want at the minimum is least a 2x integer upscale, and ideally proper pixel aspect ratio control as well, beyond that simple CCIR 601 toggle. with this trio card, the miro settings mention a min scale of 1/max scale of 9.9 at a resolution of 384x288, whatever that's exactly supposed to refer to.

the other issue is, 60 fps capture should be theoretically possible in low-res from what i've read, but vidcap32 will just drop half the frames and the miro program won't accept that value. the documentation is saying that it can do 60 fields per second at 640x480 or 30 fields per second in 320x240 - again, seems much like a software side limitation. finally, the capture feed always exhibits some tearing which would be great to avoid, but i'd imagine this is why the video passthrough on the card exists.

is there any kind of software that can work with this card, ideally under 9x, while addressing these issues? i've already looked at amcap which is supposed to be much like vidcap32, but didn't recognize the card, and pinnacle 7 didn't seem to mention any proper scaling options in its documentation.

The 640x480 capture at 60 fields per second is likely from capturing from both fields and sampling 640 times per line.

The 320x240 capture at 30 fields per second is likely from capturing only one field (either the odd or the even one) and sampling 320 times per line.

I doubt there is anything fancy happening in software (driver) on 1997 timeframe machines.

Are you capturing in MJPEG using the DC30's hardware encoder?

darry wrote on 2025-02-17, 20:20:

Have you tried capturing without overlay/preview enabled ?

no, but i've already acknowledged that using the passthrough would be the way to go when capturing game footage. input lag is actually somewhat acceptable, maybe 2 frames, but i'd imagine that enabling vsync in some newer capture program would not help this.

vvbee wrote on 2025-02-18, 03:46:

I'd say forget the overlays, just move up to a faster system as needed and do all frame handling on the CPU. That is if you plan to use it for capture's sake. If you just want to mess around with it on an old computer then maybe get a miro ViRGE and see how they pair up.

i'm trying to get a feel right now for what is possible with period correct software before possibly testing it on a more modern setup later. FWIW, at least short 320x240 videos were captured fine on a p133 even with an IDE drive that's way slower than what they benchmarked with. it comes with an HDD benchmark that gives a maximum recommended bitrate.

i'm not sure why you make the point that the card is basically unusable unless you move to an XP machine or something, because it probably was used for serious editing at the time and their requirements had to hold some water. i don't see why a high-spec 1997 build capturing to a dedicated SCSI drive wouldn't be able to max this card out. my card maxes out at 6100 kb/s (so i guess it's not the plus variant) and the fastest drives in that benchmark reach that speed.

darry wrote on 2025-02-18, 03:49:

The 640x480 capture at 60 fields per second is likely from capturing from both fields and sampling 640 times per line. […]
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The 640x480 capture at 60 fields per second is likely from capturing from both fields and sampling 640 times per line.

The 320x240 capture at 30 fields per second is likely from capturing only one field (either the odd or the even one) and sampling 320 times per line.

I doubt there is anything fancy happening in software (driver) on 1997 timeframe machines.

Are you capturing in MJPEG using the DC30's hardware encoder?

yes, i've not even tried to get uncompressed RGB out of this yet. incidentally, the rainbow runner manual mentions that being possible as well so it looks like that really was a thing at the time.

another limitation i've noticed is the smaller the resolution, the more limited the bitrate. not sure if that's a limitation on the hardware side, but that's another reason to capture in 640x240 over 320x240 (and rescale in post if nothing else).

and again, scaling is literally mentioned in the readme and driver panel, which is the reason why i expected it to work without having to hunt for different software.

i've also briefly looked into virtualdub, using the last version for win95 (1.6.19), but unlike wincap32 i'm not seeing any DC30-related settings so not sure yet how this would work. didn't seem to have any scaling settings for the capture feed either, only a bunch of filter options.

A miro ViRGE driver readme mentions this:

Important hint for DC30 and PCTV users: ======================================= The recent introduction of Microsoft DirectX tec […]
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Important hint for DC30 and PCTV users:
=======================================
The recent introduction of Microsoft DirectX technology has made it
possible to use the free memory of a graphics board for an overlay by
transferring the video data directly via the PCI bus. In addition,
DirectX introduces many new functions which are especially suited for
computer games.

New technologies, however, may also lead to problems. On some earlier
systems the combination of DirectX-3, the optimized miro drivers, and
the DC30 board may cause trouble.
For this reason, miro has decided to offer two driver concepts:
the optimized ones and drivers which have been especially designed for
Digital Video applications.
For this reason digital Video users (DC20, DC30, PCTV) will find a
special Digital Video driver version in the \Disksets\DVEDRV\ directory
on the installation CD.

of the cards listed on the site i have the elsa victory erazor (riva 128) and was looking to test it with this, but the card is acting up badly - hangs the system about 10 seconds into booting windows, before i can even install the driver, and sometimes shows artifacts. the card is in mint condition, too...

edit: actually it's the victory 3d they listed, but whatever. with the way prices are these days i'm not looking to pick up a virge just for this. might still test something else but most PCI video cards i have will be too old for this.

so i've put in a 4mb ati rage ii+ now and for this, the driver likewise says that overlay is supported, this time with "min=1.0, max=10000.0", with the same size of 384x288. as with the other card, if i uncheck this box, it's saying that without overlay it may not be able to stretch the feed to window size. the results with this card in wincap32 were exactly the same as with the other one.

however virtualdub does work with the DC30, just had to click capture to avi first. it exposes all the DC30 driver settings as well and will stretch the feed to window size, even almost fullscreen when turning off the info panel on the right. just viewing the feed incurs almost no load on the p133, as it should be. i really don't understand what problem the other tools had with this.

any type of filters or vsync don't seem to work though, at least when viewing the feed, or may only work with certain other settings. and unlike wincap32, cropping from the DC30 panel doesn't work. also, anything else than MJPEG is a no here, as is 60fps apparently. it will put out 60fps files that are probably just framedoubled. so 60 fps may only be possible with some post trickery. also, 640x240 capture looks quite a bit worse than 320x240 with 240p sources for some reason, as the interlacing artifacts become much more noticeable here. so despite being able to capture in single field mode, this doesn't make it recognize 240p as such, which was to be expected. 320x240 captures do come out alright for what it is at the maximum 1500 kb/s for that though, this is probably above the quality that youtube offered originally.

edit: after more testing with virtualdub, the cropping from the miro panel works fine, it just wasn't apparent because the stretch to window option needs to be toggled for this to show. it's actually the virtualdub internal cropping that doesn't work. two other advantages in virtualdub over wincap32 are being able to start/stop a capture via hotkey and sequential filenames - really must-have features. however i've noticed that virtualdub is a bit heavier in terms of RAM usage, maybe 10-20 mb, though perfectly understandable as it's 10 years newer.

Since it's supported in Video4Linux I'd just write my own software for it. In fact I already did that with another retro capture card and it worked a treat. The key is to do everything on the CPU, then you have maximum speed, maximum compatibility, and maximum feature set.

i don't know if this would be worth the effort, because there will be newer solutions that will be easier to use and probably outperform this. this is just composite/s-video after all where cheap USB framegrabbers have been commonplace for a long time.

for one, it's still not clear whether it's even possible to get uncompressed video out of this. on the other hand, a comparison of this with other solutions from the time would be interesting. besides expensive cards with a ton of chips like this, at the same time there were the bt848/bt878 cheap single-chip solutions relying on software encoding instead. so i guess a slow system is where something like the DC30 would really have an edge.

I have a Kona LHE (not the Plus) with the breakout box (KLBOX).
https://www.bhphotovideo.com/c/product/408186 … D_SD_Video.html

https://www.bhphotovideo.com/c/product/400818 … x_Breakout.html
These are (or at least were, not sure about now) dirt cheap on the second hand market and work at least up to and including Windows 10. They handle standard definition interlaced video and up to 1080i over a variety of inputs and in a variety of codecs (including uncompressed 422 YCbCr )

The Kona LHE works with Mac and PC actually. I have a couple versions (they came in PCIE and PCI-X) and mine has the breakout cable which was more common?

The cheap frame grabbers lost sync with sound on longer grabs and USB ones kinda sucked.

Unknown_K wrote on 2025-02-20, 05:17:

The Kona LHE works with Mac and PC actually. I have a couple versions (they came in PCIE and PCI-X) and mine has the breakout cable which was more common?

The cheap frame grabbers lost sync with sound on longer grabs and USB ones kinda sucked.

The KLBOX add-on is still dirt cheap, though make sure you get one with the proper cable. I got my KLBOX separately (with the cable).

IUVCR was my capture software solution back in the day. Nowadays, I use the Kona capture app with the Kona LHE and Virtualdub2 with everything else.

I have a Matrox RT.X2 setup that came in recently I want to test.