Expression Encoder - Limitations for file Dimension - min size of 64 * 64 and must be a multiple of 4?

Question

I receive error messages when attempting to encode files in Expression Encoder when the file width or height is not a multiple of four, or is smaller than 64. I have been able to find very little in the documentation / web searches on this, and nothing that explains what settings may cause / alleviate these limitations. I assume it has something to do with the underlying data type.

Error Message: Invalid Width Specified. The value must be an integer between 64 - and 4096 and be a multiple of 4.

Can anyone provide further details on why / what settings can be manipulated to change this behavior: I.E. quality, compression etc.

Answer 1

After posting on several MS sites, I recieved this response from Microsoft should it be of assistance.

The WMSDK, our main dependency to encode WMV, has those limitations. Note that those limits were also enforced in WME.

Are you trying to encode something smaller than 64 pixels wide or tall? If so, I suggest you letterbox. Current VC-1 or H.264 profiles do not support 4096 width, so the limit is already over what you can accomplish with our supported output format.

That would leave the "divisible by 4" limitation, which I would suggest you simply either letterbox or slightly crop the other way to get around that limit. Not only the "divisible by 4" limit is required by the WMSDK, but it also helps during encoding (macroblock size) and decoding (no scanline padding necessary).