JPEG processing engine for low profile systems

1. A method for indexing minimum coded units (MCUs) in a Joint Photographic Expert Group (JPEG) bit stream on an as needed basis, comprising:

receiving a request for an i th MCU in the bit stream;

determining if the i th MCU precedes a last indexed MCU in the bit stream, wherein the last indexed MCU is a last MCU in the bit stream that has a bit offset from a start of the bit stream stored in an index; and

if the i th MCU does not precede the last indexed MCU in the bit stream:

entropy decoding a plurality of the MCUs up to and including the i th MCU in the bit stream, but without going beyond the i th MCU, to determine their corresponding bit offsets from the start of the bit stream; and

indexing the plurality of the MCUs by saving their corresponding bit offsets in the index.

2. The method of claim 1 , wherein:

said entropy decoding a plurality of the MCUs up to and including the i th MCU in the bit stream further comprises determining a plurality of DC coefficients of the plurality of the MCUs; and

said indexing the plurality of the MCUs further comprises saving the plurality of DC coefficients in the index.

3. The method of claim 2 , further comprising:

if the MCU precedes the last indexed MCU in the bit stream:

reading the index to determine the bit offset of the i th MCU; and

entropy decoding the i th MCU starting at the bit offset in the bit stream.