Undocumented(?) limitation constraints for H264 encoding

Hello,

I am trying to understand why an MSMF H264 encoding session is refused for some not-so large image sizes.

For instance, 1280x1024 is accepted, but not 1024x1280. So my assumption that the bitrate could be a problem is wrong in that case.

Perhaps the problem is in MSMF, H264 or even MPEG4/AVI containers ?

I wonder if there is any documentation I should take into account about limitations regarding a mix of

-current profile

-estimated bitrate

-frame widht and height

-framerate

-kind of container

Here is a minimal sample code to exhibit the problem. Did I miss some parameters ? My goal is to encode videos ~4096x4096, even with very low framerate, with maximum quality, preferably on Windows 7 (that unfortunately does not support High profile)

https://chachatelier.fr/temp/TestMFTH264.zip

Typically my output :

IsWindows7OrGreater : 1
IsWindows7SP1OrGreater : 1
IsWindows8OrGreater : 0
IsWindows8Point1OrGreater : 0
IsWindows10OrGreater : 0
initalizing MSMF...
============================================
(1024x1024)@1 fps, eAVEncH264VProfile_Base
estimated bitRate = 71 kbps
        OK
============================================
(1024x1024)@5 fps, eAVEncH264VProfile_Base
estimated bitRate = 358 kbps
        OK
============================================
(1280x1024)@1 fps, eAVEncH264VProfile_Base
estimated bitRate = 89 kbps
        OK
============================================
(1280x1024)@5 fps, eAVEncH264VProfile_Base
estimated bitRate = 448 kbps
        OK
============================================
(1024x1280)@1 fps, eAVEncH264VProfile_Base
estimated bitRate = 89 kbps
        errorMessage unknown for code <0xc00d36b4>
        UNSUPPORTED
============================================
(1024x1280)@5 fps, eAVEncH264VProfile_Base
estimated bitRate = 448 kbps
        errorMessage unknown for code <0xc00d36b4>
        UNSUPPORTED
============================================
(1280x1280)@1 fps, eAVEncH264VProfile_Base
estimated bitRate = 112 kbps
        errorMessage unknown for code <0xc00d36b4>
        UNSUPPORTED
============================================
(1280x1280)@5 fps, eAVEncH264VProfile_Base
estimated bitRate = 560 kbps
        errorMessage unknown for code <0xc00d36b4>
        UNSUPPORTED
============================================
(1024x1024)@1 fps, eAVEncH264VProfile_Main
estimated bitRate = 143 kbps
        OK
============================================
(1024x1024)@5 fps, eAVEncH264VProfile_Main
estimated bitRate = 716 kbps
        OK
============================================
(1280x1024)@1 fps, eAVEncH264VProfile_Main
estimated bitRate = 179 kbps
        OK
============================================
(1280x1024)@5 fps, eAVEncH264VProfile_Main
estimated bitRate = 896 kbps
        OK
============================================
(1024x1280)@1 fps, eAVEncH264VProfile_Main
estimated bitRate = 179 kbps
        errorMessage unknown for code <0xc00d36b4>
        UNSUPPORTED
============================================
(1024x1280)@5 fps, eAVEncH264VProfile_Main
estimated bitRate = 896 kbps
        errorMessage unknown for code <0xc00d36b4>
        UNSUPPORTED
============================================
(1280x1280)@1 fps, eAVEncH264VProfile_Main
estimated bitRate = 224 kbps
        errorMessage unknown for code <0xc00d36b4>
        UNSUPPORTED
============================================
(1280x1280)@5 fps, eAVEncH264VProfile_Main
estimated bitRate = 1120 kbps
        errorMessage unknown for code <0xc00d36b4>
        UNSUPPORTED
============================================
(1024x1024)@1 fps, eAVEncH264VProfile_High
        skip unsupported profile under this version of Windows
============================================
(1024x1024)@5 fps, eAVEncH264VProfile_High
        skip unsupported profile under this version of Windows
============================================
(1280x1024)@1 fps, eAVEncH264VProfile_High
        skip unsupported profile under this version of Windows
============================================
(1280x1024)@5 fps, eAVEncH264VProfile_High
        skip unsupported profile under this version of Windows
============================================
(1024x1280)@1 fps, eAVEncH264VProfile_High
        skip unsupported profile under this version of Windows
============================================
(1024x1280)@5 fps, eAVEncH264VProfile_High
        skip unsupported profile under this version of Windows
============================================
(1280x1280)@1 fps, eAVEncH264VProfile_High
        skip unsupported profile under this version of Windows
============================================
(1280x1280)@5 fps, eAVEncH264VProfile_High
        skip unsupported profile under this version of Windows
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