WMP11 and resizing plugin (DMO)

Question

Hi!

I try to write resizing plug-in for WMP11 (DMO based) and found next issue: if I return output type in IMediaObject::GetOutputType different from input type (that WMP11 sets by IMediaObject::SetInputType, BITMAPINFOHEADER structure changed), the WMP11 sets same type (that I return as output type) as input type of my DMO (using call to IMediaObject::SetInputType). I get this problem on Vista x64 using x86 WMP11, I know, that WMP11 use IMediaObject in this mode instead using MFxxx interfaces. Is there any workarrounds for this issue?

Regards,
Artyom.

Answer 1

What if you just reject changed media type on your input pin/stream then? It does not look exactly like a problem, perhaps the host attempts to avoid format change.

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http://alax.info/blog/tag/directshow

Answer 2

Thanks for your answer! If I reject changed media type on my input stream, WMP stops playing media. If host attempts to avoid format change, is there any method for changing media format in WMP11?

Answer 3

AFAIK starting with WMP11 DMO's are not allowed to change the media type.  The media type is decided before the DMO is inserted and it should remain in this format.

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www.chrisnet.net

Answer 4

Thanks, Chris! Where I can read about this? Can you help with link? I don't found this info in MSDN. Did you know any method for changing output size from DMO? I see. that my task can be done with custom renderer and second DMO stream with custom media type, but I want to get more right method...

Answer 5

The reason is related to this change that happened in WMP11 for Vista.  I don't see any way to overcome this.

http://blogs.msdn.com/mediasdkstuff/archive/2008/10/17/windows-media-player-does-not-negotiate-media-types-for-dmo-dsp-plug-ins-on-vista.aspx

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www.chrisnet.net

Answer 6

Thank you, Chris! Its sufficient.