1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * V4L2 JPEG helpers header 4 * 5 * Copyright (C) 2019 Pengutronix, Philipp Zabel <kernel@pengutronix.de> 6 * 7 * For reference, see JPEG ITU-T.81 (ISO/IEC 10918-1) 8 */ 9 10#ifndef _V4L2_JPEG_H 11#define _V4L2_JPEG_H 12 13#include <linux/v4l2-controls.h> 14 15#define V4L2_JPEG_MAX_COMPONENTS 4 16#define V4L2_JPEG_MAX_TABLES 4 17 18/** 19 * struct v4l2_jpeg_reference - reference into the JPEG buffer 20 * @start: pointer to the start of the referenced segment or table 21 * @length: size of the referenced segment or table 22 * 23 * Wnen referencing marker segments, start points right after the marker code, 24 * and length is the size of the segment parameters, excluding the marker code. 25 */ 26struct v4l2_jpeg_reference { 27 u8 *start; 28 size_t length; 29}; 30 31/* B.2.2 Frame header syntax */ 32 33/** 34 * struct v4l2_jpeg_frame_component_spec - frame component-specification 35 * @component_identifier: C[i] 36 * @horizontal_sampling_factor: H[i] 37 * @vertical_sampling_factor: V[i] 38 * @quantization_table_selector: quantization table destination selector Tq[i] 39 */ 40struct v4l2_jpeg_frame_component_spec { 41 u8 component_identifier; 42 u8 horizontal_sampling_factor; 43 u8 vertical_sampling_factor; 44 u8 quantization_table_selector; 45}; 46 47/** 48 * struct v4l2_jpeg_frame_header - JPEG frame header 49 * @height: Y 50 * @width: X 51 * @precision: P 52 * @num_components: Nf 53 * @component: component-specification, see v4l2_jpeg_frame_component_spec 54 * @subsampling: decoded subsampling from component-specification 55 */ 56struct v4l2_jpeg_frame_header { 57 u16 height; 58 u16 width; 59 u8 precision; 60 u8 num_components; 61 struct v4l2_jpeg_frame_component_spec component[V4L2_JPEG_MAX_COMPONENTS]; 62 enum v4l2_jpeg_chroma_subsampling subsampling; 63}; 64 65/* B.2.3 Scan header syntax */ 66 67/** 68 * struct v4l2_jpeg_scan_component_spec - scan component-specification 69 * @component_selector: Cs[j] 70 * @dc_entropy_coding_table_selector: Td[j] 71 * @ac_entropy_coding_table_selector: Ta[j] 72 */ 73struct v4l2_jpeg_scan_component_spec { 74 u8 component_selector; 75 u8 dc_entropy_coding_table_selector; 76 u8 ac_entropy_coding_table_selector; 77}; 78 79/** 80 * struct v4l2_jpeg_scan_header - JPEG scan header 81 * @num_components: Ns 82 * @component: component-specification, see v4l2_jpeg_scan_component_spec 83 */ 84struct v4l2_jpeg_scan_header { 85 u8 num_components; /* Ns */ 86 struct v4l2_jpeg_scan_component_spec component[V4L2_JPEG_MAX_COMPONENTS]; 87 /* Ss, Se, Ah, and Al are not used by any driver */ 88}; 89 90/** 91 * enum v4l2_jpeg_app14_tf - APP14 transform flag 92 * According to Rec. ITU-T T.872 (06/2012) 6.5.3 93 * APP14 segment is for color encoding, it contains a transform flag, 94 * which may have values of 0, 1 and 2 and are interpreted as follows: 95 * @V4L2_JPEG_APP14_TF_CMYK_RGB: CMYK for images encoded with four components 96 * RGB for images encoded with three components 97 * @V4L2_JPEG_APP14_TF_YCBCR: an image encoded with three components using YCbCr 98 * @V4L2_JPEG_APP14_TF_YCCK: an image encoded with four components using YCCK 99 * @V4L2_JPEG_APP14_TF_UNKNOWN: indicate app14 is not present 100 */ 101enum v4l2_jpeg_app14_tf { 102 V4L2_JPEG_APP14_TF_CMYK_RGB = 0, 103 V4L2_JPEG_APP14_TF_YCBCR = 1, 104 V4L2_JPEG_APP14_TF_YCCK = 2, 105 V4L2_JPEG_APP14_TF_UNKNOWN = -1, 106}; 107 108/** 109 * struct v4l2_jpeg_header - parsed JPEG header 110 * @sof: pointer to frame header and size 111 * @sos: pointer to scan header and size 112 * @num_dht: number of entries in @dht 113 * @dht: pointers to huffman tables and sizes 114 * @num_dqt: number of entries in @dqt 115 * @dqt: pointers to quantization tables and sizes 116 * @frame: parsed frame header 117 * @scan: pointer to parsed scan header, optional 118 * @quantization_tables: references to four quantization tables, optional 119 * @huffman_tables: references to four Huffman tables in DC0, DC1, AC0, AC1 120 * order, optional 121 * @restart_interval: number of MCU per restart interval, Ri 122 * @ecs_offset: buffer offset in bytes to the entropy coded segment 123 * @app14_tf: transform flag from app14 data 124 * 125 * When this structure is passed to v4l2_jpeg_parse_header, the optional scan, 126 * quantization_tables, and huffman_tables pointers must be initialized to NULL 127 * or point at valid memory. 128 */ 129struct v4l2_jpeg_header { 130 struct v4l2_jpeg_reference sof; 131 struct v4l2_jpeg_reference sos; 132 unsigned int num_dht; 133 struct v4l2_jpeg_reference dht[V4L2_JPEG_MAX_TABLES]; 134 unsigned int num_dqt; 135 struct v4l2_jpeg_reference dqt[V4L2_JPEG_MAX_TABLES]; 136 137 struct v4l2_jpeg_frame_header frame; 138 struct v4l2_jpeg_scan_header *scan; 139 struct v4l2_jpeg_reference *quantization_tables; 140 struct v4l2_jpeg_reference *huffman_tables; 141 u16 restart_interval; 142 size_t ecs_offset; 143 enum v4l2_jpeg_app14_tf app14_tf; 144}; 145 146int v4l2_jpeg_parse_header(void *buf, size_t len, struct v4l2_jpeg_header *out); 147 148int v4l2_jpeg_parse_frame_header(void *buf, size_t len, 149 struct v4l2_jpeg_frame_header *frame_header); 150int v4l2_jpeg_parse_scan_header(void *buf, size_t len, 151 struct v4l2_jpeg_scan_header *scan_header); 152int v4l2_jpeg_parse_quantization_tables(void *buf, size_t len, u8 precision, 153 struct v4l2_jpeg_reference *q_tables); 154int v4l2_jpeg_parse_huffman_tables(void *buf, size_t len, 155 struct v4l2_jpeg_reference *huffman_tables); 156 157#endif 158