I kind of feel like this DirectVideo was a working name for what ended up called DirectShow formally when ActiveMovie was rolled into DirectX after it grew in scope of multiple codecs.

Notice here
https://news.microsoft.com/1996/03/05/microso … f9OLggDr640z.97
That Encarta was mentioned as the user of ActiveMovie, then correlate that to the KB article troubleshooting why DirectVideo does not work that is needed for Encarta. These are all connected to the same thing then.

the3dfxdude wrote on 2024-10-03, 04:23:

I kind of feel like this DirectVideo was a working name for what ended up called DirectShow formally when ActiveMovie was rolled into DirectX after it grew in scope of multiple codecs.

Well, I came to the same conclusion at first; moreover, in old glossaries these two technologies are often described together side-by-side. Like here, for example:

• DirectShow: audio, video, streaming media
• DirectVideo: video (earlier API)

But then I managed to find the official user manual for the Matrox Rainbow Runner - an expansion board for the Matrox Millennium II and Matrox Mystique 220 video cards mentioned above - where both technologies were mentioned literally in opposition to each other:

Problem: Video file playback is jerky (skipping frames)
Cause: If the problem is specific to Matrox MJPEG video files, Microsoft DirectVideo may be enabled. Matrox MJPEG uses DirectShow, not DirectVideo.

There can be no mistake here, because an earlier version of this manual is still available on the official Matrox website (link 1, link 2), where the same text is present, but DirectShow is mentioned under its previous name ActiveMovie.

But I was still lucky enough to find the truth: Q147658 - You Can Improve Video Playback by Using DirectVideo (mirror).
This page answers my question completely. I have no clue why Google doesn't show it for the exact query "directvideo", but Yandex does.
Along with this, I also found this summary with statements that shed some light on the purpose of DirectVideo:

Microsoft DirectX Game Developers SDK […]
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Microsoft DirectX Game Developers SDK

• Game development SDK.
• Home page: http://www.microsoft.com/imedia/
• Based on COM, so you can use it from C or C++.
  <…>
• ActiveMovie is the new movie architecture.
• DirectVideo is Video for Windows on top of DirectX.
• ActiveX Controls will be integrated with DirectX.
• Here is an article about DirectX and Direct3D that's interesting: http://www.3dsite.com/3dsite/cgi/publications … ss/issue28.html
• Here is an article about the relationship between DirectX and Intel's Native Signal Processing: http://upside.master.com/news/atc/9522atc.html

Microsoft Active Movie

• New video interface, competitive with QuickTime.
• Part of the DirectX architecture. Possibly also known as DirectVideo? No -- DirectVideo is the name for Video for Windows on top of DirectX.
• The successor to Video for Windows.

VFW: Microsoft Video for Windows

• Competes with QuickTime from Apple, compared to which it sucks.
• Part of Win32.
• Superceded by Active Movie, the new video interface based on DirectX.
• Ported to DirectX for backwards compatibility, and renamed "Direct Video". This is not the future, used Active Movie instead.

And finally, I found Alex St. John's first-person stories on YouTube, where he talks about DirectVideo:

• The creation stories for DirectVideo, and DirectShow API's and DirectSound (2024-08-15) - unfortunately the sound didn't record so he deleted this video.
• How Playcasting works (2024-08-28)
  » The Saint explains how Playcasting works and recounts the story of how the DirectVideo demo finally persuaded Microsoft that it's media strategy was terrible...

So it's basically a middle layer driver re-architecting, pretty much transparent to us, and usable when you had Win95 and DirectX, and got the graphics vendor update their drivers. The way Alex St John speaks about really speaks to me as it's more than just replacing VFW, that ActiveMovie/DirectShow came to be was just another consequence of needing to fix and port media playing over to DirectDraw too, because they could, and they already solved the problem of good video/sound in DX. Not sure where I had seen DirectVideo when diving into DirectX a while back, but maybe it's in the DDK?

Thanks to Google AI search, I found another description, now a much more detailed one: https://intel-vintage-developer.eu5.org/PC-SU … DEO/DIRECTX.HTM.

How DirectDraw Improves Video Playback When you view a video file on a PC without DirectDraw support, the application playing th […]
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How DirectDraw Improves Video Playback
When you view a video file on a PC without DirectDraw support, the application playing the video (for example, Media Player) sends the data to the operating system's video playback environment, Video for Windows.* Video for Windows in turn sends the data to the Graphics Device Interface, the same interface that draws pixels on the display for nonmultimedia applications such as word processors or spreadsheets. Such applications, however, do not have the same need for speed as a video player does. This is illustrated in Figure 1.
Figure 1. Graphics Applications Without DirectDraw Support <…>

When you view a video file on a PC that has DirectDraw support, the application playing the video (for example, Media Player) sends the data to the operating system's video playback environment, Video for Windows. Video for Windows sends the data to DirectVideo*, which in turn sends it to DirectDraw for manipulation, bypassing the relatively slow Graphics Device Interface. DirectDraw communicates with your graphics card by means of its device drivers, and the graphics card writes the video image to your display. This is illustrated in Figure 2.
Figure 2. Graphics Applications With DirectDraw Support <…>

DirectVideo
As you can see from Figure 2, when you run Video for Windows under Windows 95, DirectVideo is required to connect to DirectDraw. Ordinarily, this connection is made without any action necessary on your part. However, if you are manipulating the drivers for your graphics card (for example, downloading updated ones), you must ensure that the manufacturer also provides the DirectVideo driver dvideo.dll if that graphics card supports DirectDraw.

ActiveMovie*
When Microsoft ships ActiveMovie, it will replace both Video for Windows and DirectVideo, as illustrated in Figure 3.
Figure 3. Graphics Applications With ActiveMovie <…>

How Your Operating System Plays Video Files
PCs that use operating system software only to play video do so as follows:

1. The application sends one frame of the video file to the Indeo video codec.
2. The video frame is held in system memory, where the Indeo video codec uses the Pentium® processor to decompress it. The amount of data grows.
3. The processor next converts the color information from the compact form used by the codec to the RGB form required by the PC monitor. The amount of data grows again.
4. If you ask the application to double the window size, the processor performs the calculations necessary to do so. The amount of data grows yet larger.
5. The resulting large amount of data is sent over the bus to the graphics hardware responsible for writing to the display.

<…> If your graphics card can take advantage of some or all of the capabilities afforded by DirectDraw, however, the process is instead as follows:

1. The application sends one frame of the video file to the Indeo video codec.
2. The codec decompresses the frame in system memory.
3. This relatively small amount of decompressed data is sent over the bus to the memory on the graphics card, transparently to the application.
4. Special, optimized code running on the graphics card converts the color information.
5. If you ask the application to double the window size, special, optimized code running on the graphics card does so.
6. The data is written to the display.

This process is faster in three ways:

• Much less data is sent over the bus, decreasing the time needed to transfer it.
• Color conversion runs faster because the code on the graphics card is especially optimized for the operation.
• Enlarging the window is also faster for the same reason.

Depending on the details of color conversion and video content, the image quality may also improve. <…>

Where to Get DirectVideo and DirectDraw
Support for DirectVideo and DirectDraw are provided in graphics card drivers. Contact your graphics card manufacturer for more information and the latest software support.

The short & sweet way to think of all DirectX/DirectVideo/etc features are that they are all software implemented, but allow hardware drivers from video/sound card makers to override features so that they can be hardware driven for performance and quality.

DirectX/DirectVideo also provide API commands to software/game developers so they don't have to directly target each video/sound card ever made.

Matrox implemented hardware decode for VfW 1.1 (starting from IS-ATHENA), so the way windows implements it is via DirectVideo so that each application doesn't need drivers for each video card.