It looks like when speaking about video cards supported, only few lines were written about tested few cards.. The driver listed in that page which seems to be a long source of info about the card, are often gone.. some drivers can be found but not the player for example and I'm not sure it might depend also on the Revision of the PCB card and when released. But I'll do more tests on the driver side which requires much patience. The CT7160 seems like a good similar card but different chip (Luxsonor LS 220); I never had it but I might test it in future. Anyway @ 1024x768 (beside the desktop colors palette) the fullscreen (only) frame quality is really high now, I'd say on the same level of the other best 2000 solutions only missing some more options to tweak the hw decoding. Also the sw player GUI doesn't feel the best (general gui speed, etc..) but at last some good result and better than the Voodoo3 test I did for sure. I'll test other video cards too to see if the different connector setting and features might improves or not (as explained in your manual each card supported a different connector setting (on the left of the columns) and that's another factor too as suspected before).

Some update: I uninstalled the Riva 128 to test different cards but I suspect the Mystique 220 PCI, the only good time correct PCI card I've got, probably might not have a compatible feature connector but it could be similar to the Millennium that somewhere I read having possibly an output feature connector if I understood it correctly and anyway even testing it didn't work with any resolution or color depth not even the same of the Riva 128. So I decided for a different test config, the 440BX AGP board with a P2-350 cpu and a Matrox G450 16MB SGRAM AGP, a 1999 card I know but probably one of the best VGA output imho and reading about the G400 specs the feature connectors should have a classic VIP/VIM port so theorically compatible (at least the G400, I suppose they share mostly the same layout) (Edit: I don't think it's a compatible feature connector). Using again the Opti 925 ISA sound card (good card I wasn't expecting).

Update 2: after trying the G450 16MB with its good vga quality unfortunately it doesn't work. With latest Ravisent driver every video mode seems unsupported. With older Dell package having late 1998 Quadrant branded drivers/app seems to start at first with a confused mostly green image but stays without any video (black screen) all the time with the sound as usual running in background. No mode seems supported but it's like it try but doesn't seems to find a way to deal with the vga feature connector. It's really difficult to understand this, I try the older G400 16MB and see if it solve something. Maybe later I might try the older Matrox drivers if I find them to see if it might need the original CD installation version, more time correct than the 2002 one. And by the way, on the G400 info around it seems specified the chip compatibility. Decoding is anyway working even if not visible, the DVD movie tested is the same that ran on the Riva128 and obviously genuine original commercial disc (even time correct dvd disc Matrix (1999)) and the decoder card had free drivers/sw app. I might try restarting from the original vga installation disk.

With the G4x0 older installation disc same problems; I wonder if these vga had a different connector logic so this vga test end here. I switch to a Rage Pro "Turbo" AGP card that has what was called ATi Multimedia Channel as a Feature connector and before even installing it I'm trying an old diagnostic Cinemaster/Dell floppy software found on their website that start at boot to test the PCI card with a great amount of detailed tests to check if functional but not only, EEPROM, microcode, even memory test of the decoder PCI card and of course the compatibility of the video card. This same software was tried booting with the G450 and it couldn't pass the vga detect test, probably not a good compatibility sign suggesting a more time correct vga, instead the Rage Pro is perfectly detected. While I'm writing this the floppy diagnostic sw is still testing the card with a "decompression memory test" similar to a sort of memtest.

Update: tests passed. The diagnostic specific card sw doesn't just check if the mpeg decoder card is installed but test each PCB's component to make sure it works and in msdos. Now the Win mpeg decoder driver remains a problem. As said various brands drivers/cards/rev released mostly lost, some OEM too and I suspect not all the cards have the same firmware so a theory might be the sw player/drivers better works with the correct driver and not just the last one as usual. From an early Win test with OEM late 1998 drivers/player, the DVD seems to finally display again even on this config (EDIT) with any resolutions but if I set "Full screen" or change the default window size it display the "Unsupported video mode" message; it looks like with the last Rage Pro 2002 drivers it works but "only" in the default downscaled window size not leaving many possibilities to resize the frame buffer window. Interesting the "AMC-feature connector" and the Rage Pro seems to process the input data in a better quality as expected for the aliasing problem seen on the Riva 128. So the vga chip does elaborate the frame buffered data (not just send it to the output) improving or not, sign that any card might work it in a different way and results with these old hardware mpeg decoders. Really too bad last drivers works only in window mode, even when changing resolutions/colors. It doesn't seems in this config to make much difference the monitor settings strangely.

Update 2: As suspected the last rage pro driver might have problems with the AMC connector compatibility; with an older time correct ati driver the mpeg card software now works full screen / any windowed playback size.

Update 3: I'm using the .2560 ATi drivers and while it works I'd say the full screen video quality is high, is not better than the 430VX/P-233/Riva 128@fullscreen. It's a feeling but while certainly a good and stable mpeg decoding output as inteded to be by any of these ancient PC-DVD kit solutions, compared to the previous combination with the Riva 128 (on the same LCD old 4:3 monitor), the window mode quality now improved totally but when upscaled full screen is on the same level and not better even with 32bit resolution, possibly felt even a bit lower (it's difficult to compare by memory it's a feeling). Still both far better than any Voodoo3 card usually used to test this even myself when tried in the past but from this vga card I was expecting to see a better video output considering it did improve the windowed mode for sure.

Update 4: This 440BX mainboard seems to have problems with reading L2 cache of the Pentium II cpus. I don't know the reason but as suggested on this forum it might be a slot problem and I don't think I can fix it. I'll try using the Pentium III on this even if I don't like not-time correct configs but I'll probably use again the 430VX and so I'll need a PCI better card to test and I'll get a Rage Pro I suppose. Cause if the Diamond Riva128 had anyway its problems the only cards left time correct and with high quality ramdac/output would be some alternative ones I'm not sure which are supported by the mpeg decoder itself. Cause it might be that the decoder "talk" to the video card to choose the right feature connector setting but when many of these cards were OEM oriented I suppose not all the video card were supported that easily.

Finally I got some big improvements from this sort of useless time/patience consuming test of this old mpeg decoder card. Reinstalled anything but upgraded directly to Win ME and then installed the >latest< drivers/app package that never worked, still using the Rage Pro Turbo 8MB SGRAM AGP with some .2611 driver I've found. I don't even know which driver is this but it doesn't come with control panel or not automatically installed but I still didn't trust to install the final 2002 driver considering the previous tests. Anyway I suppose cause the Win ME installation the mpeg decoder card DOES work with latest driver finally in this config. And I suppose for the newer sw player engine and optimized hw decoder drivers the fullscreen video quality improved, immediately visible and that's what I was expecting using an ATi card only as output device but still the frame buffer processing differs imho from card to card. This is for sure the best test result until now. 1024x768 60Hz 32bit desktop but I suppose resolutions shouldn't be anymore a problem at least with the ATi cards. No errors seen but the vga driver is not certified so I'm going to look for another Win ME oriented driver. The mpeg decoder card offload totally the cpu work and it's like 2% CPU during playback on a early Pentium III. Next test might be the Matrox solution again but I suppose that's difficult if the diagnostic tool of the card fail to detect it.

I'll do more tests of course and I think I'll still try again the 430VX board with the P-233 MMX and the heavy Win ME o.s. but at the end I'd not suggest using these 90's PC DVD solutions of course since when video cards began to accelerate 60 to 80% of the decoding task (but still not that usual in the early 2000's) but from a test point of view even if they need much patience to make them work and when they do, the hardware decoders cards had some positive points like very high quality decoding and cpu free constant speed playback. Like most add-in card using the "feature connector" wasn't easy to configure and it might probably not even work on some chipsets and probably only few vga cards. But even if they had a very short lifetime these cards still seems to convince as a consumer 90's/early 2000 product, if only they would've been more compatible with optimized softwares. Anyway I know now why Sigma Designs and Creative went for the external vga cable concept to overcome all the problems I tested but at the cost that when LCD became popular that analog solution wasn't mitigated anymore by the CRT tech so they did change the concept at last again until mpeg decoders card had no sense anymore. That's it for now. Other users that tested hw mpeg decoders cards in the past I hope found this test interesting and anyway the '3dfx only' idea I was also convinced for this card is confirmed not a limitation. The Voodoo3 config I tested had surely more problems than the ATi card and much less quality but still it would need many more tests with those cards too. But for sure it did work with some other vga brands; only there're quite many factors that seems involved like similar cards anyway.. it's not like the Dxr3 PCI card was easy to configure sometimes. 😀

386SX wrote on 2022-01-21, 20:00:

Finally I got some big improvements from this sort of useless time/patience consuming test of this old mpeg decoder card. Reinstalled anything but upgraded directly to Win ME and then installed the >latest< drivers/app package that never worked, still using the Rage Pro Turbo 8MB SGRAM AGP with some .2611 driver I've found. I don't even know which driver is this but it doesn't come with control panel or not automatically installed but I still didn't trust to install the final 2002 driver considering the previous tests. Anyway I suppose cause the Win ME installation the mpeg decoder card DOES work with latest driver finally in this config. And I suppose for the newer sw player engine and optimized hw decoder drivers the fullscreen video quality improved, immediately visible and that's what I was expecting using an ATi card only as output device but still the frame buffer processing differs imho from card to card. This is for sure the best test result until now. 1024x768 60Hz 32bit desktop but I suppose resolutions shouldn't be anymore a problem at least with the ATi cards. No errors seen but the vga driver is not certified so I'm going to look for another Win ME oriented driver. The mpeg decoder card offload totally the cpu work and it's like 2% CPU during playback on a early Pentium III. Next test might be the Matrox solution again but I suppose that's difficult if the diagnostic tool of the card fail to detect it.

I'll do more tests of course and I think I'll still try again the 430VX board with the P-233 MMX and the heavy Win ME o.s. but at the end I'd not suggest using these 90's PC DVD solutions of course since when video cards began to accelerate 60 to 80% of the decoding task (but still not that usual in the early 2000's) but from a test point of view even if they need much patience to make them work and when they do, the hardware decoders cards had some positive points like very high quality decoding and cpu free constant speed playback. Like most add-in card using the "feature connector" wasn't easy to configure and it might probably not even work on some chipsets and probably only few vga cards. But even if they had a very short lifetime these cards still seems to convince as a consumer 90's/early 2000 product, if only they would've been more compatible with optimized softwares. Anyway I know now why Sigma Designs and Creative went for the external vga cable concept to overcome all the problems I tested but at the cost that when LCD became popular that analog solution wasn't mitigated anymore by the CRT tech so they did change the concept at last again until mpeg decoders card had no sense anymore. That's it for now. Other users that tested hw mpeg decoders cards in the past I hope found this test interesting and anyway the '3dfx only' idea I was also convinced for this card is confirmed not a limitation. The Voodoo3 config I tested had surely more problems than the ATi card and much less quality but still it would need many more tests with those cards too. But for sure it did work with some other vga brands; only there're quite many factors that seems involved like similar cards anyway.. it's not like the Dxr3 PCI card was easy to configure sometimes. 😀

ATI Rage Pro driver 5.40.1 is the most compatible as for me

https://gona.mactar.hu/ATI3DCIF/drivers/rpro_540-1b02f.zip

That's the same driver version I've tested above and for the ravisent sw player it works as said perfectly but seems like a sort of upgrade package, it didn't install the control panel and not certified for Win ME. I wonder how that version compare to the .2632 or .2647 ATi drivers (?). For my previous retrogaming test the final 2002 driver improved a lot OpenGL but broke something in some games and as tested can't work in Win 98 and this decoder card (but might work in Win ME who knows.. that might be another test but I suppose in the 2002 the feature connector optimization was the last priority considering back then not even installed on the video card PCB).

It installs control panels in Display preferences, but they can be visible only if your locale is set to English (check it in Win98).

It looks like going for higher W98 version drivers, has problems with the feature connector again for some reasons even on Win ME. While the .2611 (but also the Win ME original disc driver) do work equally, newer drivers did change something here. Probably with/after the Rage 128 Pro this function wasn't supported/tested much and in fact it wasn't installed anymore too on the PCBs. For the G4x0 video cards I suppose I'll not do more tests, the diagnostic tool not detecting the vga wasn't a good sign and It might be that these video cards with their feature connectors had possibly not the same standard or the decoder itself wasn't designed for it. I even tried oldest drivers/video bios and same problems. I'll read some technical info about it cause I'd not like the idea this specific decoder might break or something if their pinout might differ at least theorically.

Update: the Riva128 ZX 8MB ompared to the 256 colors requirement of the original 4MB version, can run the DVD up to the desktop 16bit colors and 1024x768 but the windowed mode seems mostly broken, it doesn't notice the usual unsupported mode message but the window is like divided in multiple frames. But full screen mode works good enough even if I can confirm compared to the Rage Pro (when it works with some of the many drivers) the ATi results have better video quality; the Riva128 has more fullscreen aliasing even if still good (same monitor and 1024x768/16bit). I suppose the frame buffered image get processed in a different way even if the decoding task is done completely by the decoder but still the vga chip as said take care of the final output. There're some possible options in the register that might be changed if only I knew which values does what, some lines called "Riva128Compatibility" or things like "DoubleBufferingOnly". I tried set them to 1 but seems like nothing changed with the Riva128 card. Those values aren't anywhere in the software options and might be related to the video card mpeg acceleration only when without the hw mpeg card.
Update 2: it seems the Win ME installation resulted in the best test results until now with final decoder drivers and Rage Pro card but some vga driver only. I've configured again the 430VX chipset config with the P-MMX 233 and again the Riva 128 PCI config, and it seems like in Win ME (reinstalled there too) it doesn't work anymore as it did before on W98 and older OEM sw/drivers (Unsupported video mode etc..). Not even at 256 desktop colors both with default Win ME drivers (2000) or the latest 3.37 ones (1999). While installing older decoder drivers and sw player make it work again. I'll test soon the Rage Pro in the PCI bus, I suppose I'll get the high quality results already seen before and with those latest decoder drivers/sw that might be oriented for that video card serie more than others compared to the older versions.

Final thoughts would be that to make these mpeg 90's "accelerator" work, seems to be better use their manual suggested video cards only and not easy anyway depending on multiple factors. IMHO I'd not simply try "any" other video card easily cause there's a possibility the feature connector might be proprietary, having different pinout or simply not supported by the add-in card depending on the decoder design or optimized mostly for those few video cards. But on the positive side if everything worked the slow cpus (Pentium to Pentium II/K6-2 period) passed from 95% to 5% cpu usage with high quality results in the correct configuration. And the video card choice make quite a difference in the final result quality. We could say none of the similar PCI cards had an easy life: whatever the design was, they had to solve not easy compatibility problems or quality problems if used the analog overlay logic and both depending on the vga anyway. Probably the last decoder generations that separated the video card output from the decoder output logic driving itself the monitor was a good design but loosing the windowed mode it needed two monitor or a single-task logic (desktop or dvd) and at the end it had sense the video cards included that task completely at the mostly similar high quality without all those problems.

Creative PC-DVD Inlay CT7160 and Apple MPEG2 accellerator for ATI Rage 128 Mac Edition (as I suspect, all accelerators connected via various Feature Connector options) at a resolution not higher than 1152x864 give a very decent picture quality, and at a screen resolution of 1280x1024 and higher, the picture goes in pixels, it feels like 320x240

It's interesting. Anyway I suppose the Rage 128 might be one the latest cards rarely supporting these mpeg accelerators (while I've not tested it with this decoder so I can't suggest it); even if the "Feature Connector" were installed a bit later on some more advanced vga I'd not got too far expecting it to work cause it should better to check before the specific vga PCB connector logic and if the drivers were still supporting with the same compatibility of the older cards these add-in solutions. Even in the specific Cinemaster sw player help page, there's written the AMC (only) connector beside this should be intended to be compatible with the old VFC standards but that page suggested in that way the Ati Multimedia Channel as a "requirement" and probably I might suppose the solution was optimized on it.. while it might work with others but I'd not simply try without searching tech info about the vga PCB connector logic.
For example Millennium and later cards seems having a different connector logic imho and probably only intended for their upgrade multimedia modules. So I'd stay time correct as a requirement, only the vga tested and suggested on the last manuals revision and imho at least for the decoder I'm testing, the ATi Rage Pro seems like one of the last card compatible, having a good frame buffer video processing both windowed and full screen. I suppose but I didn't test it that later cards by ATi might (!) still support this decoder (maybe even better who knows), still I've many doubts about it considering newer drivers seems to stop even the Rage Pro compatibility with this decoder from some tests for example the ones after the .2611 we talked about. Or maybe I was not lucky with my tests but I think I have more or less understood why sometimes the card works and in different config combinations it doesn't; anyway "feature connector" I understood doesn't mean much cause there were different standards, port management drivers, decoders compatibility by their design, decoder chip compatibility itself, vga chip compatibility and PCB layout choice, drivers compatibility, sw player compatibility, o.s... etc... and before anything elsa being sure both connector pinout were intended to be connected or not.

You would need driver support to use the feature connector. If my memory serves, it's basically 8-16bit bus plus some signalling. The display engine keeps a bit of memory to the side, which it fills up with data from that bus, and then shows that in an overlay (an extra layer on the display). All this needs to be set up correctly on the display engine side, and then both the display card and the decoder card need to talk to eachother about what format is being sent, and then some other overhead.

Given the vintage of this hw, there very likely was no semi-standard way for both drivers to communicate, so each display card driver would have to add specific support for specific versions of drivers of the decoder chip families. You are lucky if you get anything at all working.

My collection only has S3 Scenics either directly attached, or graphics card specific daughterboards, or Tseng vipers directly connected, but i have never been brave enough to play with those.

I think it was needed a strong driver support/testing on both connector sides to support different standards and to understand which standard be used in any config combinations/brands/chips. For example a decoder chip might have supported all the standards but the final PCB needed to be designed for a wide compatibility. I imagine that in the early 90's the add-in cards just like these ones, specified which video cards were suggested/tested while the others might work or not or even being proprietary sometimes might have a different pinout and that might have been a bigger problem. So with different standards, different port management drivers, different add-in cards too, drivers, maybe a problem of costs/design to have a wide compatibility; multimedia solutions were probably (for the home consumer they were oriented for) a very thin market and already at the early Pentium II times MPEG2 acceleration wasn't far from possible thanks to newer vga chips helping it. Much similar to the early 3D accelerators, standards, games, add-in cards designs (Voodoo vs PowerVR design for example), at the end all included in single chip. But 3D acceleration in general was a much more interesting consumer offer while multimedia PC-DVD home theatre solution was not. I'm testing also that the software decoder engines choice was just as important and often resulted in very high quality frames beside the "high end CPU" needed for it and each sw player resulted in much different quality even if not hw accelerated. What I do like of these hardware accelerators but also early dvd hw assisted sw players, is that they did that specific task without heavy post-processing logics to try (and fail) to "improve" pixel sharpness or things like that often seen in later software/home dvd players. The video/audio source was processed in some smart hardware logic but mantaining the original frames quality they had to work with improving it if possible on an hardware level but without expecting miracles.

Anyway until now with this card, the ATi Rage Pro (with older drivers as said above) choice resulted the better and it seems like the vga chip still process data for downscaling/upscaling frames changing the final quality. I've tested the Rage Pro PCI and confirmed the previous test even on the 430VX mainboard. The cpu usage is around 10% on the P-MMX 233 and the quality in this setup is at the top of those times. Dxr3 and H+ cards were great hardwares but depending on the card revision, vga, monitor, the results were great but clearly limited if the monitor was the main output. Software decoders anyway improved at the same time cpu became more powerful. Some time correct sw players had similar high pixel quality and at the end a much easier solution. Vga decoding offload helped a lot but I'm not sure anymore like in the past that improved so much the quality (but the speed) and much more depended on which software decoder was used instead.
The last test I might try in future to have a final opinion of this multimedia product, is some early Rage 128 or Rage 128 Pro having still the AMC feature connector, if they would work or not. After some driver release it seems even the Rage Pro AMC compatibility wasn't as good as before, more or less after the 2000 drivers. So it might be with some doubts that those last Rage 128 cards might work (or not) with some early driver version and the last would benefit a lot on the VGA output quality improved imho on the Rage 128 Pro (also higher ramdac etc..) and maybe also a more advanced frame buffer processing.