*sampling*and

*sample precision*with data compression.

Sampling is a data reduction or quantization. It is independent of compression.

Precision of each sample is also a separate issue.

So first, how many samples are being taken, and second, what is the precision of each sample?

Sampling:

Sampling is sort-of related to resolution. You can have an image that is a set resolution, but there might not be discrete data for each pixel of that image.

See Adam Wilt's DV FAQ Pix on sampling and Charles Poynton's document on Chroma subsampling notation

Precision:

Precision is directly related to the data-size of each sample.

For example, a 8-bit BMP versus a 16-bit or 24-bit BMP, they are all

**un**compressed. But they have different precision on the sample size. An 8-bit BMP can show significantly fewer colors than a 24-bit BMP, and a 24-bit BMP (because it's 3 bytes per pixel) is 3 times larger than an 8-bit BMP (with only one byte per pixel).

FourCC.org lists common compression formats and sample sizes.

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