Video thumbnail sometimes all black

[ChuckSavage]

So, I'm using something relatively simple to get a thumbnail for a video file. At the moment, if a video uses fade in from black, the thumb is black. Is there a way to advance frame by frame to find a frame that isn't black?

using MagickImage image = new MagickImage(imageFile.FullName); 
image.Thumbnail(ThumbSizeDTO.Size.Width, ThumbSizeDTO.Size.Height);
image.Write(thumb.FullName);

I'm thinking before the image.Write, to resize the thumb to a 1x1 and check for blackness, if too black advance a frame and try again. Though I'm not sure how to step through the movie using MagickImage. I'm not seeing anything like image.AdvanceFrame() or some construct. The only Frame I see is for geometry stuff.

A image.SeekFrame(frame_number) method and a image.FrameCount property might help to create a for loop. Then a call to image.Thumbnail would use the current frame.

[dlemstra]

You will need to use an MagickImageCollection instead to iterate through the frames. But I would advise you to use the MagickReadSettings and set FrameCount to a value to make sure you only read the first x frames. And you could probably also use the Histogram method instead of resizing the image.