ya here it is and Feipoa posted a pic of the adapter he made. Re: Can watch 1080 on Pentium III?

Pics of the one i made are on the 1st page.
Can watch 1080 on Pentium III?

anyways I had around 40% CPU utilization on a PIII playing game of thrones 1080p h264.

The thing only works in pot player or media player classic home cinema.

These days I just stream videos with UMS on a computer to a android TV or some other device connected to a Big TV. Much better than watching it on a computer imo.

zyga64 wrote on 2022-09-21, 05:09:

This ! https://en.wikipedia.org/wiki/Broadcom_Crystal_HD
You can buy them on ebay for as little as $10.

It ain't worth a damn though. The code for it was removed from all the favorite non-Microsoft third-party media players ages ago, so you can't just pop it in and go watch stuff. You'd have to obtain or compile older versions of the media players to use it.

Save yourself the headache and don't bother with Windows XP for HD decoding. As others have said, you'll manage MPEG2 decoding but that is practically useless unless you plan to convert all your HD sources to MPEG2 and have the storage space for the resulting larger file sizes.

When I upgraded my HTPC for HD playback back in 2007, I installed Vista instead of XP (then later Win 7).

Pretty much all the Radeon HD AGP cards will do H.264 & VC-1 decoding, some of the later ones will not do MPEG2 however. On the Nvidia side you pretty much need an 8000 series card and those are not very common in AGP format, at least I've never come across one. There were even some legacy PCI versions of Radeon HD cards that supported DXVA2 and could be used in systems lacking an AGP slot.

XP is fine for HD video, when you move up to PCIe video cards and a lot of XP Media Center PCs (a sort of HTPC pre-cursor) were using early PCIe GPUs. For TV connectivity though, many people invested in media extenders (media players) that played from network shares or USB storage. If you are bent on keeping what you have, there were some newer, HD video-friendly PCIe Radeons with AGP bridges that can be used on the older systems, made to fill a gap that Nvidia was unable to fill with their own GPUs, but I don't recall the series designation for those.

Hmm XP is not the limitation but AGP is for good smooth 1080p MKV/MP4/h.264 playback. One of my boxes plays 1080p mkv just fine under XP but is a soc775 w/PCIe and 8800GTS.
What about 720p ? If you are watching from some 22-24" monitor good 720p encodes can look nearly as good a 1080p on screen that size and do not need as much resources.....
just rambling 😀

For me personally, I never had any issues with 1080p playback with an AGP card. My first HD-capable HTPC was a Socket 754-based Athlon 64 3200+, with an AGP Radeon HD 2600 (later a HD 3450). It handled 720p, 1080p, MP4/MKV & Blu-Ray disc playback just fine. DXVA wouldn't work with HD-DVD or YouTube playback, but that was more a software issue than a hardware capability one.

I once had a legacy PCI version of the Radeon HD 5450. The card was a load of crap performance-wise, but 1080p playback did at least function on a lowly Athlon XP-based PC, running Windows 7. It wasn't stable and the card itself died after only a few months, so not really recommended 🤣.

I've watched HD content no problem on XP.
XP also supported HDA, high-definition audio, at some point. Until SP3 messed it up.
I guess that's why VMs nolonger support HDA for XP.

Anyway, this is about graphics cards, mainly.
(- Although audio support is related to it, due to DRM and HDMI..)

Back in the 2000s, I quickly switched to PCIe due to the sheer incompatibility of AGP cards.

An PCI card could always be used in any PCI slot, but not so with AGP:
An AGP 1.x card didn't fit in an AGP 8x slot or vice versa. And even if it fit, it could cause a fire due to a voltage mismatch. What a chaos. I do still dislike AGP for that. 😒

zyga64 wrote on 2022-09-21, 05:09:

This ! https://en.wikipedia.org/wiki/Broadcom_Crystal_HD
You can buy them on ebay for as little as $10.

Sounds promising,
I already have a working pcie to pci adapter, but I am not sure how to go from mini pcie to pcie (or directly pci).