include/media/v4l2-h264.h

   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.pic_order_count: reference picture order count
  19  * @refs.frame_num: reference frame number
  20  * @refs.pic_num: reference picture 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  * @unordered_reflist: unordered list of references. Will be used to generate
  25  *                     ordered P/B0/B1 lists
  26  * @num_valid: number of valid references in the refs array
  27  *
  28  * This object stores the context of the P/B0/B1 reference list builder.
  29  * This procedure is described in section '8.2.4 Decoding process for reference
  30  * picture lists construction' of the H264 spec.
  31  */
  32 struct v4l2_h264_reflist_builder {
  33         struct {
  34                 s32 pic_order_count;
  35                 int frame_num;
  36                 u32 pic_num;
  37                 u16 longterm : 1;
  38         } refs[V4L2_H264_NUM_DPB_ENTRIES];
  39         s32 cur_pic_order_count;
  40         u8 unordered_reflist[V4L2_H264_NUM_DPB_ENTRIES];
  41         u8 num_valid;
  42 };
  43
  44 void
  45 v4l2_h264_init_reflist_builder(struct v4l2_h264_reflist_builder *b,
  46                 const struct v4l2_ctrl_h264_decode_params *dec_params,
  47                 const struct v4l2_ctrl_h264_sps *sps,
  48                 const struct v4l2_h264_dpb_entry dpb[V4L2_H264_NUM_DPB_ENTRIES]);
  49
  50 /**
  51  * v4l2_h264_build_b_ref_lists() - Build the B0/B1 reference lists
  52  *
  53  * @builder: reference list builder context
  54  * @b0_reflist: 16-bytes array used to store the B0 reference list. Each entry
  55  *              is an index in the DPB
  56  * @b1_reflist: 16-bytes array used to store the B1 reference list. Each entry
  57  *              is an index in the DPB
  58  *
  59  * This functions builds the B0/B1 reference lists. This procedure is described
  60  * in section '8.2.4 Decoding process for reference picture lists construction'
  61  * of the H264 spec. This function can be used by H264 decoder drivers that
  62  * need to pass B0/B1 reference lists to the hardware.
  63  */
  64 void
  65 v4l2_h264_build_b_ref_lists(const struct v4l2_h264_reflist_builder *builder,
  66                             u8 *b0_reflist, u8 *b1_reflist);
  67
  68 /**
  69  * v4l2_h264_build_b_ref_lists() - Build the P reference list
  70  *
  71  * @builder: reference list builder context
  72  * @p_reflist: 16-bytes array used to store the P reference list. Each entry
  73  *             is an index in the DPB
  74  *
  75  * This functions builds the P reference lists. This procedure is describe in
  76  * section '8.2.4 Decoding process for reference picture lists construction'
  77  * of the H264 spec. This function can be used by H264 decoder drivers that
  78  * need to pass a P reference list to the hardware.
  79  */
  80 void
  81 v4l2_h264_build_p_ref_list(const struct v4l2_h264_reflist_builder *builder,
  82                            u8 *reflist);
  83
  84 #endif /* _MEDIA_V4L2_H264_H */