can not connect to DV video decoder using MEDIASUBTYPE_YUY2

Question

Hello,

I try to write a 64bits DirectShow Transform Filter that i want to connect to a "DV Video Decoder" using the subtype MEDIASUBTYPE_YUY2, unfortunately without success. The only Subtype for wich the connection works is MEDIASUBTYPE_RGB24, and even with this subtype an "AVI Decompressor" filter is inserted (because of Intelligent connect). However the "DV Video Decoder" can output this subtype MEDIASUBTYPE_YUY2.

Someone has an idea?

regards, Pascal

Answer 1

Hello,

I found the reason why the MEDIASUBTYPE_YUY2 was not accepted. The input pin, which is created thru a class CDeinterlaceInputPin inherited from CTransformInputPin, specifies a ALLOCATOR_PROPERTIES::cBuffers value greater than 1 after a call to its GetAllocatorRequirements() method. The next call to the GetAllocator() method of CTransformInputPin return without error, but the next call to NotifyAllocator() of CTransformInputPin gives a Actual.cBuffers value of 1 when the media subtype is MEDIASUBTYPE_YUY2 and this method considers this situation as an error. If i specify the cBuffers value = 1, then the connection works, but not the rest of the filter. With the MEDIASUBTYPE_RGB24 there is no problem.

So my question becomes, why the IMemAllocator transmitted in the NotifyAllocator() method of my CDeinterlaceInputPin() always give a ALLOCATOR_PROPERTIES::cBuffers of 1 for MEDIASUBTYPE_YUY2 (and not for MEDIASUBTYPE_RGB24 which is however more demanding)?

regards

Answer 2

Hi,

in fact this not only with MEDIASUBTYPE_YUY2 subtype that the DV Video Decoder does not accept ALLOCATOR_PROPERTIES::cBuffers value greater than 1. But with the MEDIASUBTYPE_RGB24, an AVI Decompressor filter is inserted (with intelligent connect) that accept ALLOCATOR_PROPERTIES::cBuffers greater than 1 with the MEDIASUBTYPE_RGB24 (but not with MEDIASUBTYPE_YUY2 ). Below the 2 graphs showing what happens when ALLOCATOR_PROPERTIES::cBuffers=1

and when ALLOCATOR_PROPERTIES::cBuffers>1

After that, i can connect the ouptut of my filter to a VMR9 renderer with MEDIASUBTYPE_RGB24 (however thru a Color space concerter filter), but not with MEDIASUBTYPE_YUY2, but perhaps i should create another post.
Regards

Answer 3

Hi,

I'm back on this issue.
I foundthe reason why i could not connect the VMR9 render with the MEDIASUBTYPE_YUY2. It was because in the DecideBufferSize() method of my filter, i specified a cbAlign property different than 1 (but this is not a problem with MEDIASUBTYPE_RGB24 ).

then other problems with MEDIASUBTYPE_YUY2, but i will submit another Question if needed.

regards