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If I'm watching a DVD, how many [inverse?] descrete cosine transforms per second is my computer performing?

If I'm understanding this correctly, DVD video uses MPEG 2, which is basically MPEG 1 but with only one possible resolution and frame rate. [Also interlaced, because legacy.]

I'm by no means an expert in this area, but I got the impression MPEG 1 works similarly to JPEG, in that you transform to a luminance-chrominance colour-space [rather than RGB], split the image into 8x8 pixel blocks, perform a DCT on each block, and then truncate the resulting frequency coefficients based on what you think the audience won't notice.

Since all DVDs use the exact same resolution and framerate, I guess that means that theoretically you can put a hard number on exactly how many DCTs per second you need to do to play one. Does anybody have that number?

MathematicalOrchid
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1 Answers1

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DVD is typically either: 720x480i @ 60 fields/second or 720x576i @ 50 fields/second

4:2:0 means that there are two color (difference) pixels per 4 luma pixels.

MPEG-2 use 8x8 DCTs AFAIK.

720x240x60x(3/2)/(8x8)= 243000 DCT/second

720x288x50x(3/2)/(8x8)= 243000 DCT/second

Knut Inge
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