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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 * struct v4l2_jpeg_header - parsed JPEG header
92 * @sof: pointer to frame header and size
93 * @sos: pointer to scan header and size
94 * @dht: pointers to huffman tables and sizes
95 * @dqt: pointers to quantization tables and sizes
96 * @frame: parsed frame header
97 * @scan: pointer to parsed scan header, optional
98 * @quantization_tables: references to four quantization tables, optional
99 * @huffman_tables: references to four Huffman tables in DC0, DC1, AC0, AC1
100 * order, optional
101 * @restart_interval: number of MCU per restart interval, Ri
102 * @ecs_offset: buffer offset in bytes to the entropy coded segment
103 *
104 * When this structure is passed to v4l2_jpeg_parse_header, the optional scan,
105 * quantization_tables, and huffman_tables pointers must be initialized to NULL
106 * or point at valid memory.
107 */
108struct v4l2_jpeg_header {
109 struct v4l2_jpeg_reference sof;
110 struct v4l2_jpeg_reference sos;
111 unsigned int num_dht;
112 struct v4l2_jpeg_reference dht[V4L2_JPEG_MAX_TABLES];
113 unsigned int num_dqt;
114 struct v4l2_jpeg_reference dqt[V4L2_JPEG_MAX_TABLES];
115
116 struct v4l2_jpeg_frame_header frame;
117 struct v4l2_jpeg_scan_header *scan;
118 struct v4l2_jpeg_reference *quantization_tables;
119 struct v4l2_jpeg_reference *huffman_tables;
120 u16 restart_interval;
121 size_t ecs_offset;
122};
123
124int v4l2_jpeg_parse_header(void *buf, size_t len, struct v4l2_jpeg_header *out);
125
126int v4l2_jpeg_parse_frame_header(void *buf, size_t len,
127 struct v4l2_jpeg_frame_header *frame_header);
128int v4l2_jpeg_parse_scan_header(void *buf, size_t len,
129 struct v4l2_jpeg_scan_header *scan_header);
130int v4l2_jpeg_parse_quantization_tables(void *buf, size_t len, u8 precision,
131 struct v4l2_jpeg_reference *q_tables);
132int v4l2_jpeg_parse_huffman_tables(void *buf, size_t len,
133 struct v4l2_jpeg_reference *huffman_tables);
134
135#endif
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