1. A data compression method comprising: accessing image data and depth information for pixels of an image; determining a distance from a region of focus for pixels of the image by calculations that use the depth information; controlling a bit rate for compression of the image data in accordance with the distance from the region of focus, such that more bits are used for pixels closer to the region of focus and fewer bits are used for pixels farther from the region of focus; wherein compression includes the steps of transforming the image data from an image domain into coefficients in a transform domain, quantizing the coefficients, and entropy-encoding the quantized coefficients, and wherein controlling the bit rate for compression comprises determining a distance for a pixel in the transform domain based on distances of pixels in the image domain, and wherein determining a distance for a pixel in the transform domain based on distances of pixels in the image domain comprises the steps of: applying an inverse transform to an impulse image with the impulse at the pixel in the transform domain; determining pixels in the inverse-transformed impulse image in the image domain that are non-zero; and assigning the distance for the pixel in the transform domain by choosing a smaller one of distances of determined non-zero pixels in the image domain from the region of focus.