Chroma Upsampling Error (11/23/2008 9:44 am)
Filed under: Computers
Perhaps because I'm colorblind, or perhaps just because I tend to notice small things like this, I've often noticed DVDs will often have jaggy lines around red objects. In the past I've always chalked it up to an artifact of how MPEG compression works, but this old article points out it's actually a bug with MPEG decoders.
This brings up an issue I remember running across at a company I worked at. Inside of the company, they had a term, "giblets", that I haven't seen used in the industry at wide. It basically refers to bits of code that are copied from somewhere else, complex enough to potentially have subtle bugs or security issues. The big problem with giblets is that they don't get much review, and if the original author updates them, there's no way to update everyone's that using them.
It seems to me the MPEG decoding issue I mention is a good example of this. It's apparently long since been known about, but DVD manufactures are beginning to fix the issue in players. Of course, here it's a small issue, one you may have never noticed, but I've seen this sort of thing in a lot of development of Windows applications. Sample code is used from the web to do some routine task, and the person copying it doesn't understand it well enough or simply doesn't bother to review it in detail enough, to understand it's not bug free. The end result is harmless sample code ends up causing bugs in a lot of applications, and all sorts of fun when those bugs are security issues.
