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