1/* SPDX-License-Identifier: LGPL-2.1+ */
2/*
3 * Copyright 2016 Tom aan de Wiel
4 * Copyright 2018 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
5 */
6
7#ifndef CODEC_FWHT_H
8#define CODEC_FWHT_H
9
10#include <linux/types.h>
11#include <linux/bitops.h>
12#include <asm/byteorder.h>
13
14/*
15 * The compressed format consists of a fwht_cframe_hdr struct followed by the
16 * compressed frame data. The header contains the size of that data.
17 * Each Y, Cb and Cr plane is compressed separately. If the compressed
18 * size of each plane becomes larger than the uncompressed size, then
19 * that plane is stored uncompressed and the corresponding bit is set
20 * in the flags field of the header.
21 *
22 * Each compressed plane consists of macroblocks and each macroblock
23 * is run-length-encoded. Each macroblock starts with a 16 bit value.
24 * Bit 15 indicates if this is a P-coded macroblock (1) or not (0).
25 * P-coded macroblocks contain a delta against the previous frame.
26 *
27 * Bits 1-12 contain a number. If non-zero, then this same macroblock
28 * repeats that number of times. This results in a high degree of
29 * compression for generated images like colorbars.
30 *
31 * Following this macroblock header the MB coefficients are run-length
32 * encoded: the top 12 bits contain the coefficient, the bottom 4 bits
33 * tell how many times this coefficient occurs. The value 0xf indicates
34 * that the remainder of the macroblock should be filled with zeroes.
35 *
36 * All 16 and 32 bit values are stored in big-endian (network) order.
37 *
38 * Each fwht_cframe_hdr starts with an 8 byte magic header that is
39 * guaranteed not to occur in the compressed frame data. This header
40 * can be used to sync to the next frame.
41 *
42 * This codec uses the Fast Walsh Hadamard Transform. Tom aan de Wiel
43 * developed this as part of a university project, specifically for use
44 * with this driver. His project report can be found here:
45 *
46 * https://hverkuil.home.xs4all.nl/fwht.pdf
47 */
48
49/*
50 * This is a sequence of 8 bytes with the low 4 bits set to 0xf.
51 *
52 * This sequence cannot occur in the encoded data
53 *
54 * Note that these two magic values are symmetrical so endian issues here.
55 */
56#define FWHT_MAGIC1 0x4f4f4f4f
57#define FWHT_MAGIC2 0xffffffff
58
59/*
60 * A macro to calculate the needed padding in order to make sure
61 * both luma and chroma components resolutions are rounded up to
62 * a multiple of 8
63 */
64#define vic_round_dim(dim, div) (round_up((dim) / (div), 8) * (div))
65
66struct fwht_cframe_hdr {
67 u32 magic1;
68 u32 magic2;
69 __be32 version;
70 __be32 width, height;
71 __be32 flags;
72 __be32 colorspace;
73 __be32 xfer_func;
74 __be32 ycbcr_enc;
75 __be32 quantization;
76 __be32 size;
77};
78
79struct fwht_cframe {
80 u16 i_frame_qp;
81 u16 p_frame_qp;
82 __be16 *rlc_data;
83 s16 coeffs[8 * 8];
84 s16 de_coeffs[8 * 8];
85 s16 de_fwht[8 * 8];
86 u32 size;
87};
88
89struct fwht_raw_frame {
90 unsigned int width_div;
91 unsigned int height_div;
92 unsigned int luma_alpha_step;
93 unsigned int chroma_step;
94 unsigned int components_num;
95 u8 *buf;
96 u8 *luma, *cb, *cr, *alpha;
97};
98
99#define FWHT_FRAME_PCODED BIT(0)
100#define FWHT_FRAME_UNENCODED BIT(1)
101#define FWHT_LUMA_UNENCODED BIT(2)
102#define FWHT_CB_UNENCODED BIT(3)
103#define FWHT_CR_UNENCODED BIT(4)
104#define FWHT_ALPHA_UNENCODED BIT(5)
105
106u32 fwht_encode_frame(struct fwht_raw_frame *frm,
107 struct fwht_raw_frame *ref_frm,
108 struct fwht_cframe *cf,
109 bool is_intra, bool next_is_intra,
110 unsigned int width, unsigned int height,
111 unsigned int stride, unsigned int chroma_stride);
112bool fwht_decode_frame(struct fwht_cframe *cf, u32 hdr_flags,
113 unsigned int components_num, unsigned int width,
114 unsigned int height, const struct fwht_raw_frame *ref,
115 unsigned int ref_stride, unsigned int ref_chroma_stride,
116 struct fwht_raw_frame *dst, unsigned int dst_stride,
117 unsigned int dst_chroma_stride);
118#endif
119

source code of linux/drivers/media/test-drivers/vicodec/codec-fwht.h