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/* 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 0x4f4f4f4f
#define FWHT_MAGIC2 0xffffffff
#define FWHT_VERSION 1
/* Set if this is an interlaced format */
#define FWHT_FL_IS_INTERLACED BIT(0)
/* Set if this is a bottom-first (NTSC) interlaced format */
#define FWHT_FL_IS_BOTTOM_FIRST BIT(1)
/* Set if each 'frame' contains just one field */
#define FWHT_FL_IS_ALTERNATE BIT(2)
/*
* If FWHT_FL_IS_ALTERNATE was set, then this is set if this
* 'frame' is the bottom field, else it is the top field.
*/
#define FWHT_FL_IS_BOTTOM_FIELD BIT(3)
/* Set if this frame is uncompressed */
#define FWHT_FL_LUMA_IS_UNCOMPRESSED BIT(4)
#define FWHT_FL_CB_IS_UNCOMPRESSED BIT(5)
#define FWHT_FL_CR_IS_UNCOMPRESSED BIT(6)
#define FWHT_FL_CHROMA_FULL_HEIGHT BIT(7)
#define FWHT_FL_CHROMA_FULL_WIDTH BIT(8)
struct fwht_cframe_hdr {
u32 magic1;
u32 magic2;
__be32 version;
__be32 width, height;
__be32 flags;
__be32 colorspace;
__be32 xfer_func;
__be32 ycbcr_enc;
__be32 quantization;
__be32 size;
};
struct fwht_cframe {
unsigned int width, height;
u16 i_frame_qp;
u16 p_frame_qp;
__be16 *rlc_data;
s16 coeffs[8 * 8];
s16 de_coeffs[8 * 8];
s16 de_fwht[8 * 8];
u32 size;
};
struct fwht_raw_frame {
unsigned int width, height;
unsigned int width_div;
unsigned int height_div;
unsigned int luma_step;
unsigned int chroma_step;
u8 *luma, *cb, *cr;
};
#define FWHT_FRAME_PCODED BIT(0)
#define FWHT_FRAME_UNENCODED BIT(1)
#define FWHT_LUMA_UNENCODED BIT(2)
#define FWHT_CB_UNENCODED BIT(3)
#define FWHT_CR_UNENCODED BIT(4)
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);
void fwht_decode_frame(struct fwht_cframe *cf, struct fwht_raw_frame *ref,
u32 hdr_flags);
#endif
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