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View Full Version : VfW / VCM wrapper for DMO codecs?


temporance
29th May 2006, 16:32
It should not be too difficult to write a VfW codec wrapper for DMO codecs such as VC-1. I believe FFVFW did something similar a couple of years ago, wrapping DirectShow decoders into a VfW driver.

It would work like this. You would see, for example, Microsoft's VC-1 listed in VDub's compressors dialog as "Proxy VC-1". When you open this codec, you would have access to encoder configuration via a dumb GUI that interfaces with the codec's properties. When you save in VDub, the "Proxy" codec instantiates the DMO, passes raw video frames to it and gathers encoded bitstream. On decoding, the "Proxy" and DMO object work together in a similar way.

With a little bit of manipluation, B-frames could be handled packed (using VDub's workaround to avoid frame delay) or unpacked.

This could be useful for many here who use VirtualDub and AVI.

Has anyone heard, or considered such a project?

Please no flaming "VfW/AVI is crap", etc. I'm aware of the limitations, just wondered whether others think a DMO wrapper would be an interesting/useful project.

bond
29th May 2006, 17:08
i would prefer m$ releasing their codecs not as dmo, but (additionally) as vfw or directshow :D

zambelli
30th May 2006, 03:57
i would prefer m$ releasing their codecs not as dmo, but (additionally) as vfw or directshow :D
Video for Windows dates back to Windows 3.0 days. Microsoft has moved on 3 times already - DirectShow, Windows Media Format and the newest API - Media Foundation. You can't expect VfW to be supported forever.

As for Microsoft releasing DirectShow codecs... The bridge between DMOs and DirectShow has already been built so there's no point in developing exclusive DirectShow filters when DMOs work just fine with DirectShow.

zambelli
30th May 2006, 04:36
@temporance:
I think it's a good idea, but as you've noted - it could be quite tricky considering VfW's numerous limitations.

Also interesting could be a reverse wrapper: one for making VfW and DirectShow codecs available in WM Format based applications.

bond
30th May 2006, 17:04
As for Microsoft releasing DirectShow codecs... The bridge between DMOs and DirectShow has already been built so there's no point in developing exclusive DirectShow filters when DMOs work just fine with DirectShow.well if you look at the long discussion we had in the other thread you will realise that dmo's sdk doesnt work everywhere (eg windows 2000) and therefore dmos also dont work and therefore releasing a normal directshow filter makes sense

zambelli
30th May 2006, 20:34
well if you look at the long discussion we had in the other thread you will realise that dmo's sdk doesnt work everywhere (eg windows 2000) and therefore dmos also dont work and therefore releasing a normal directshow filter makes sense
I think you're the one who needs to re-read that discussion. I told you that installing the WMF SDK 9.0 runtime will install the necessary DirectShow wrappers that allow DMOs to work under DirectShow. It's been like that since 2000 when Windows Media 7 shipped.
DirectShow didn't ship with Windows 95. Does that mean that nobody should develop DirectShow filters either?

bond
30th May 2006, 20:37
I think you're the one who needs to re-read that discussion. I told you that installing the WMF SDK 9.0 runtime will install the necessary DirectShow wrappers that allow DMOs to work under DirectShow. It's been like that since 2000 when Windows Media 7 shipped.
DirectShow didn't ship with Windows 95. Does that mean that nobody should develop DirectShow filters either?you wrote that the correct performance is only with sdk 9.5 ensured, and this version is only available for winxp

anyways no need to get personal. all i am asking for is that m$ supports its own technologies