/* SPDX-License-Identifier: LGPL-2.1+ */ /* * Copyright 2016 Tom aan de Wiel * Copyright 2018 Cisco Systems, Inc. and/or its affiliates. All rights reserved. */ #ifndef CODEC_FWHT_H #define CODEC_FWHT_H #include <linux/types.h> #include <linux/bitops.h> #include <asm/byteorder.h> /* * The compressed format consists of a fwht_cframe_hdr struct followed by the * compressed frame data. The header contains the size of that data. * Each Y, Cb and Cr plane is compressed separately. If the compressed * size of each plane becomes larger than the uncompressed size, then * that plane is stored uncompressed and the corresponding bit is set * in the flags field of the header. * * Each compressed plane consists of macroblocks and each macroblock * is run-length-encoded. Each macroblock starts with a 16 bit value. * Bit 15 indicates if this is a P-coded macroblock (1) or not (0). * P-coded macroblocks contain a delta against the previous frame. * * Bits 1-12 contain a number. If non-zero, then this same macroblock * repeats that number of times. This results in a high degree of * compression for generated images like colorbars. * * Following this macroblock header the MB coefficients are run-length * encoded: the top 12 bits contain the coefficient, the bottom 4 bits * tell how many times this coefficient occurs. The value 0xf indicates * that the remainder of the macroblock should be filled with zeroes. * * All 16 and 32 bit values are stored in big-endian (network) order. * * Each fwht_cframe_hdr starts with an 8 byte magic header that is * guaranteed not to occur in the compressed frame data. This header * can be used to sync to the next frame. * * This codec uses the Fast Walsh Hadamard Transform. Tom aan de Wiel * developed this as part of a university project, specifically for use * with this driver. His project report can be found here: * * https://hverkuil.home.xs4all.nl/fwht.pdf */ /* * This is a sequence of 8 bytes with the low 4 bits set to 0xf. * * This sequence cannot occur in the encoded data * * Note that these two magic values are symmetrical so endian issues here. */ #define FWHT_MAGIC1 … #define FWHT_MAGIC2 … /* * A macro to calculate the needed padding in order to make sure * both luma and chroma components resolutions are rounded up to * a multiple of 8 */ #define vic_round_dim(dim, div) … struct fwht_cframe_hdr { … }; struct fwht_cframe { … }; struct fwht_raw_frame { … }; #define FWHT_FRAME_PCODED … #define FWHT_FRAME_UNENCODED … #define FWHT_LUMA_UNENCODED … #define FWHT_CB_UNENCODED … #define FWHT_CR_UNENCODED … #define FWHT_ALPHA_UNENCODED … u32 fwht_encode_frame(struct fwht_raw_frame *frm, struct fwht_raw_frame *ref_frm, struct fwht_cframe *cf, bool is_intra, bool next_is_intra, unsigned int width, unsigned int height, unsigned int stride, unsigned int chroma_stride); bool fwht_decode_frame(struct fwht_cframe *cf, u32 hdr_flags, unsigned int components_num, unsigned int width, unsigned int height, const struct fwht_raw_frame *ref, unsigned int ref_stride, unsigned int ref_chroma_stride, struct fwht_raw_frame *dst, unsigned int dst_stride, unsigned int dst_chroma_stride); #endif
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