codec-fwht.h

  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