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Diffstat (limited to 'include/media/v4l2-jpeg.h')
| -rw-r--r-- | include/media/v4l2-jpeg.h | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/include/media/v4l2-jpeg.h b/include/media/v4l2-jpeg.h new file mode 100644 index 000000000..2dba843ce --- /dev/null +++ b/include/media/v4l2-jpeg.h @@ -0,0 +1,157 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * V4L2 JPEG helpers header + * + * Copyright (C) 2019 Pengutronix, Philipp Zabel <kernel@pengutronix.de> + * + * For reference, see JPEG ITU-T.81 (ISO/IEC 10918-1) + */ + +#ifndef _V4L2_JPEG_H +#define _V4L2_JPEG_H + +#include <linux/v4l2-controls.h> + +#define V4L2_JPEG_MAX_COMPONENTS 4 +#define V4L2_JPEG_MAX_TABLES 4 + +/** + * struct v4l2_jpeg_reference - reference into the JPEG buffer + * @start: pointer to the start of the referenced segment or table + * @length: size of the referenced segment or table + * + * Wnen referencing marker segments, start points right after the marker code, + * and length is the size of the segment parameters, excluding the marker code. + */ +struct v4l2_jpeg_reference { + u8 *start; + size_t length; +}; + +/* B.2.2 Frame header syntax */ + +/** + * struct v4l2_jpeg_frame_component_spec - frame component-specification + * @component_identifier: C[i] + * @horizontal_sampling_factor: H[i] + * @vertical_sampling_factor: V[i] + * @quantization_table_selector: quantization table destination selector Tq[i] + */ +struct v4l2_jpeg_frame_component_spec { + u8 component_identifier; + u8 horizontal_sampling_factor; + u8 vertical_sampling_factor; + u8 quantization_table_selector; +}; + +/** + * struct v4l2_jpeg_frame_header - JPEG frame header + * @height: Y + * @width: X + * @precision: P + * @num_components: Nf + * @component: component-specification, see v4l2_jpeg_frame_component_spec + * @subsampling: decoded subsampling from component-specification + */ +struct v4l2_jpeg_frame_header { + u16 height; + u16 width; + u8 precision; + u8 num_components; + struct v4l2_jpeg_frame_component_spec component[V4L2_JPEG_MAX_COMPONENTS]; + enum v4l2_jpeg_chroma_subsampling subsampling; +}; + +/* B.2.3 Scan header syntax */ + +/** + * struct v4l2_jpeg_scan_component_spec - scan component-specification + * @component_selector: Cs[j] + * @dc_entropy_coding_table_selector: Td[j] + * @ac_entropy_coding_table_selector: Ta[j] + */ +struct v4l2_jpeg_scan_component_spec { + u8 component_selector; + u8 dc_entropy_coding_table_selector; + u8 ac_entropy_coding_table_selector; +}; + +/** + * struct v4l2_jpeg_scan_header - JPEG scan header + * @num_components: Ns + * @component: component-specification, see v4l2_jpeg_scan_component_spec + */ +struct v4l2_jpeg_scan_header { + u8 num_components; /* Ns */ + struct v4l2_jpeg_scan_component_spec component[V4L2_JPEG_MAX_COMPONENTS]; + /* Ss, Se, Ah, and Al are not used by any driver */ +}; + +/** + * enum v4l2_jpeg_app14_tf - APP14 transform flag + * According to Rec. ITU-T T.872 (06/2012) 6.5.3 + * APP14 segment is for color encoding, it contains a transform flag, + * which may have values of 0, 1 and 2 and are interpreted as follows: + * @V4L2_JPEG_APP14_TF_CMYK_RGB: CMYK for images encoded with four components + * RGB for images encoded with three components + * @V4L2_JPEG_APP14_TF_YCBCR: an image encoded with three components using YCbCr + * @V4L2_JPEG_APP14_TF_YCCK: an image encoded with four components using YCCK + * @V4L2_JPEG_APP14_TF_UNKNOWN: indicate app14 is not present + */ +enum v4l2_jpeg_app14_tf { + V4L2_JPEG_APP14_TF_CMYK_RGB = 0, + V4L2_JPEG_APP14_TF_YCBCR = 1, + V4L2_JPEG_APP14_TF_YCCK = 2, + V4L2_JPEG_APP14_TF_UNKNOWN = -1, +}; + +/** + * struct v4l2_jpeg_header - parsed JPEG header + * @sof: pointer to frame header and size + * @sos: pointer to scan header and size + * @num_dht: number of entries in @dht + * @dht: pointers to huffman tables and sizes + * @num_dqt: number of entries in @dqt + * @dqt: pointers to quantization tables and sizes + * @frame: parsed frame header + * @scan: pointer to parsed scan header, optional + * @quantization_tables: references to four quantization tables, optional + * @huffman_tables: references to four Huffman tables in DC0, DC1, AC0, AC1 + * order, optional + * @restart_interval: number of MCU per restart interval, Ri + * @ecs_offset: buffer offset in bytes to the entropy coded segment + * @app14_tf: transform flag from app14 data + * + * When this structure is passed to v4l2_jpeg_parse_header, the optional scan, + * quantization_tables, and huffman_tables pointers must be initialized to NULL + * or point at valid memory. + */ +struct v4l2_jpeg_header { + struct v4l2_jpeg_reference sof; + struct v4l2_jpeg_reference sos; + unsigned int num_dht; + struct v4l2_jpeg_reference dht[V4L2_JPEG_MAX_TABLES]; + unsigned int num_dqt; + struct v4l2_jpeg_reference dqt[V4L2_JPEG_MAX_TABLES]; + + struct v4l2_jpeg_frame_header frame; + struct v4l2_jpeg_scan_header *scan; + struct v4l2_jpeg_reference *quantization_tables; + struct v4l2_jpeg_reference *huffman_tables; + u16 restart_interval; + size_t ecs_offset; + enum v4l2_jpeg_app14_tf app14_tf; +}; + +int v4l2_jpeg_parse_header(void *buf, size_t len, struct v4l2_jpeg_header *out); + +int v4l2_jpeg_parse_frame_header(void *buf, size_t len, + struct v4l2_jpeg_frame_header *frame_header); +int v4l2_jpeg_parse_scan_header(void *buf, size_t len, + struct v4l2_jpeg_scan_header *scan_header); +int v4l2_jpeg_parse_quantization_tables(void *buf, size_t len, u8 precision, + struct v4l2_jpeg_reference *q_tables); +int v4l2_jpeg_parse_huffman_tables(void *buf, size_t len, + struct v4l2_jpeg_reference *huffman_tables); + +#endif |