1 .. SPDX-License-Identifier: GFDL-1.1-no-invari
2
3 .. _v4l2-pix-fmt-pisp-comp1-rggb:
4 .. _v4l2-pix-fmt-pisp-comp1-grbg:
5 .. _v4l2-pix-fmt-pisp-comp1-gbrg:
6 .. _v4l2-pix-fmt-pisp-comp1-bggr:
7 .. _v4l2-pix-fmt-pisp-comp1-mono:
8 .. _v4l2-pix-fmt-pisp-comp2-rggb:
9 .. _v4l2-pix-fmt-pisp-comp2-grbg:
10 .. _v4l2-pix-fmt-pisp-comp2-gbrg:
11 .. _v4l2-pix-fmt-pisp-comp2-bggr:
12 .. _v4l2-pix-fmt-pisp-comp2-mono:
13
14 **********************************************
15 V4L2_PIX_FMT_PISP_COMP1_RGGB ('PC1R'), V4L2_PI
16 **********************************************
17
18 ==============================================
19 Raspberry Pi PiSP compressed 8-bit Bayer forma
20 ==============================================
21
22 Description
23 ===========
24
25 The Raspberry Pi ISP (PiSP) uses a family of t
26 formats. A black-level offset may be subtracte
27 efficiency; the nominal black level and amount
28 of band. Each scanline is padded to a multiple
29 of 8 horizontally-contiguous pixels is coded u
30
31 Mode 1 uses a quantization and delta-based cod
32 12 significant bits. Mode 2 is a simple sqrt-l
33 chords, preserving up to 12 significant bits.
34 (with 4 chords) and the delta scheme, preservi
35
36 The remainder of this description applies to M
37
38 Each block of 8 pixels is separated into even
39 coded independently by 32-bit words at success
40 The two LS bits of each 32-bit word give its "
41
42 In quantization mode 0, the lowest 321 quantiz
43 FSD/4096 and the remaining levels are successi
44 Quantization modes 1 and 2 use linear quantiza
45 FSD/1024 and FSD/512 respectively. Each of the
46 independently, with rounding to the nearest le
47 In quantization mode 2 where the middle two sa
48 (q1,q2) both in the range [384..511], they are
49 followed by 7 bits for (q2 & 127). Otherwise,
50 0, 1 and 2: a 9-bit field encodes MIN(q1,q2) w
51 [0..511] and a 7-bit field encodes (q2-q1+64)
52
53 Each of the outer samples (q0,q3) is encoded u
54 on its inner neighbour q1 or q2. In quantizati
55 sample has a quantized value in the range [448
56 (q0-384). Otherwise for quantization modes 0,
57 is encoded as (q0-MAX(0,q1-64)). q3 is likewis
58 Each of these values must be in the range [0..
59 of 2, 9, 7, 7, 7 bits respectively are packed
60 to give a 32-bit word with LE byte order.
61
62 Quantization mode 3 has a "7.5-bit" escape, us
63 encodings will fit. Each pixel value is quanti
64 levels, where the lowest 95 levels are multipl
65 remaining levels are multiples of FSD/128 (lev
66 very close to FSD and may require saturating a
67
68 Each pair of quantized pixels (q0,q1) or (q2,q
69 by a 15-bit field: 2816*(q0>>4) + 16*q1 + (q0&
70 Three fields of 2, 15, 15 bits are packed in L
71
72 An implementation of a software decoder of com
73 in `Raspberry Pi camera applications code base
74 <https://github.com/raspberrypi/rpicam-apps/bl
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