Dot name reference on non-scalar structure using Video Reader class

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Townsend 2012-9-24

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评论： Falak Shah 2014-3-19

Hi... I am trying to read in a .wmv. I have basically copied the example from the VideoReader class in the help but I get this error when I run the .m:

Dot name reference on non-scalar structure.

Error in VideoReader/read (line 91)

if( ~isempty(obj.NumberOfFrames) )

Error in vidFile (line 22)

mov(i).cdata = read(Test, i);

mov is a 1xNumberOfFrames struct with objects 'cdata' and 'colormap'. The main issue is number frames it reads before this error is thrown varies.

Please help. I have banged my head against the wall enough...

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回答（1 个）

Ralph Hummeling 2012-9-25

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编辑：Ralph Hummeling 2012-9-25

@Townsend:

I'm afraid you've stumbled upon a bug that persists since R2012a. Matlab sometimes erroneously interprets a scalar structure as being non-scalar when confronted with a getfield operation: S.fieldname

A workaround is to insert an index on the field reference like this: S(1).fieldname

It's ugly but it works. So in your case your code could read: if( ~isempty(obj(1).NumberOfFrames) )