# 3.3.8.2.1.1 Performing the First Progressive Pass

For the first pass, the data received is sent to the RLGR
entropy decoder to produce the progressively quantized coefficients **DecProgQ**.

For each element being decoded, except elements in the LL
band, the sign is recorded (positive, negative, or zero). This tri-state
(referred to as **Sign**) is used for successive upgrade passes.

**Sign** = -1 if **DecProgQ-NonLL** < 0

**Sign** = 0 if **DecProgQ-NonLL** = 0

**Sign** = 1 if **DecProgQ-NonLL** > 0

The LL3 deltas MUST be summed up to produce the LL3 elements, even if the tile is not an original tile (section 3.1.8.1.2).

**DecProgQ-LL**[0] = **DecProgQ-LL-Deltas**[0]

**DecProgQ-LL**[idx+1] = **DecProgQ-LL**[idx] + **DecProgQ-LL-Deltas**[idx+1]

Elements in all the bands are dequantized.

**DecDwtQ-NonLL**, **DecDwtQ-LL** = **DecProgQ** * **PQF**

**DecDwtQ** is the data that MUST be de-quantized and
inverse DWT transformed to produce the image pixels.

If the tile is a difference tile (section 3.1.8.1.2), then
the progressively quantized coefficients are simply added to the **DecDwtQ**
elements:

**DecDwtQ** = **DecDwtQ** + **DecProgQ** * **PQF**