1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * Helper functions for H264 codecs.
4 *
5 * Copyright (c) 2019 Collabora, Ltd.
6 *
7 * Author: Boris Brezillon <boris.brezillon@collabora.com>
8 */
9
10 #ifndef _MEDIA_V4L2_H264_H
11 #define _MEDIA_V4L2_H264_H
12
13 #include <media/v4l2-ctrls.h>
14
15 /**
16 * struct v4l2_h264_reflist_builder - Reference list builder object
17 *
18 * @refs.top_field_order_cnt: top field order count
19 * @refs.bottom_field_order_cnt: bottom field order count
20 * @refs.frame_num: reference frame number
21 * @refs.longterm: set to true for a long term reference
22 * @refs: array of references
23 * @cur_pic_order_count: picture order count of the frame being decoded
24 * @cur_pic_fields: fields present in the frame being decoded
25 * @unordered_reflist: unordered list of references. Will be used to generate
26 * ordered P/B0/B1 lists
27 * @num_valid: number of valid references in the refs array
28 *
29 * This object stores the context of the P/B0/B1 reference list builder.
30 * This procedure is described in section '8.2.4 Decoding process for reference
31 * picture lists construction' of the H264 spec.
32 */
33 struct v4l2_h264_reflist_builder {
34 struct {
35 s32 top_field_order_cnt;
36 s32 bottom_field_order_cnt;
37 int frame_num;
38 u16 longterm : 1;
39 } refs[V4L2_H264_NUM_DPB_ENTRIES];
40
41 s32 cur_pic_order_count;
42 u8 cur_pic_fields;
43
44 struct v4l2_h264_reference unordered_reflist[V4L2_H264_REF_LIST_LEN];
45 u8 num_valid;
46 };
47
48 void
49 v4l2_h264_init_reflist_builder(struct v4l2_h264_reflist_builder *b,
50 const struct v4l2_ctrl_h264_decode_params *dec_params,
51 const struct v4l2_ctrl_h264_sps *sps,
52 const struct v4l2_h264_dpb_entry dpb[V4L2_H264_NUM_DPB_ENTRIES]);
53
54 /**
55 * v4l2_h264_build_b_ref_lists() - Build the B0/B1 reference lists
56 *
57 * @builder: reference list builder context
58 * @b0_reflist: 32 sized array used to store the B0 reference list. Each entry
59 * is a v4l2_h264_reference structure
60 * @b1_reflist: 32 sized array used to store the B1 reference list. Each entry
61 * is a v4l2_h264_reference structure
62 *
63 * This functions builds the B0/B1 reference lists. This procedure is described
64 * in section '8.2.4 Decoding process for reference picture lists construction'
65 * of the H264 spec. This function can be used by H264 decoder drivers that
66 * need to pass B0/B1 reference lists to the hardware.
67 */
68 void
69 v4l2_h264_build_b_ref_lists(const struct v4l2_h264_reflist_builder *builder,
70 struct v4l2_h264_reference *b0_reflist,
71 struct v4l2_h264_reference *b1_reflist);
72
73 /**
74 * v4l2_h264_build_p_ref_list() - Build the P reference list
75 *
76 * @builder: reference list builder context
77 * @reflist: 32 sized array used to store the P reference list. Each entry
78 * is a v4l2_h264_reference structure
79 *
80 * This functions builds the P reference lists. This procedure is describe in
81 * section '8.2.4 Decoding process for reference picture lists construction'
82 * of the H264 spec. This function can be used by H264 decoder drivers that
83 * need to pass a P reference list to the hardware.
84 */
85 void
86 v4l2_h264_build_p_ref_list(const struct v4l2_h264_reflist_builder *builder,
87 struct v4l2_h264_reference *reflist);
88
89 #endif /* _MEDIA_V4L2_H264_H */
90
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