Erroneous VP6 Encoding

You have to know that I get a little nervous when I encounter something like this in my general web surfing– a video on the Amazon product page for 3D Dot Heroes:

Did I just encounter a particularly glaring Flash Player bug in the wild? Fortunately (w.r.t. my work load at my day job), I determined that there might be something wrong with the actual video encoding since I downloaded the corresponding .flv file and ran it through an independent VP6 decoder (provided by FFmpeg through VLC).

So what might be wrong with this video, class? I think this logo shot provides an exquisite insight into the problem:

This makes it pretty clear where the Y (grey part), U (blue part) and V (red part) planes begin (the green part shows where Y, U, and V components are all 0). It’s puzzling to think that this would be the encoder’s doing but it’s difficult to pin this on a particular decoder since I tried 2 different implementations.

One thought on “Erroneous VP6 Encoding

  1. Reimar

    They might be using raw YV12 in an intermediate step and gave a too small height value to the encoder.
    One of the reasons why I’m always in favour of using some proper container or at least yuv4mpeg.

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