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// SPDX-License-Identifier: GPL-2.0
/*
* V4L2 H264 helpers.
*
* Copyright (C) 2019 Collabora, Ltd.
*
* Author: Boris Brezillon <boris.brezillon@collabora.com>
*/
#include <linux/module.h>
#include <linux/sort.h>
#include <media/v4l2-h264.h>
/**
* v4l2_h264_init_reflist_builder() - Initialize a P/B0/B1 reference list
* builder
*
* @b: the builder context to initialize
* @dec_params: decode parameters control
* @slice_params: first slice parameters control
* @sps: SPS control
* @dpb: DPB to use when creating the reference list
*/
void
v4l2_h264_init_reflist_builder(struct v4l2_h264_reflist_builder *b,
const struct v4l2_ctrl_h264_decode_params *dec_params,
const struct v4l2_ctrl_h264_slice_params *slice_params,
const struct v4l2_ctrl_h264_sps *sps,
const struct v4l2_h264_dpb_entry dpb[V4L2_H264_NUM_DPB_ENTRIES])
{
int cur_frame_num, max_frame_num;
unsigned int i;
max_frame_num = 1 << (sps->log2_max_frame_num_minus4 + 4);
cur_frame_num = slice_params->frame_num;
memset(b, 0, sizeof(*b));
if (!(slice_params->flags & V4L2_H264_SLICE_FLAG_FIELD_PIC))
b->cur_pic_order_count = min(dec_params->bottom_field_order_cnt,
dec_params->top_field_order_cnt);
else if (slice_params->flags & V4L2_H264_SLICE_FLAG_BOTTOM_FIELD)
b->cur_pic_order_count = dec_params->bottom_field_order_cnt;
else
b->cur_pic_order_count = dec_params->top_field_order_cnt;
for (i = 0; i < V4L2_H264_NUM_DPB_ENTRIES; i++) {
u32 pic_order_count;
if (!(dpb[i].flags & V4L2_H264_DPB_ENTRY_FLAG_ACTIVE))
continue;
b->refs[i].pic_num = dpb[i].pic_num;
if (dpb[i].flags & V4L2_H264_DPB_ENTRY_FLAG_LONG_TERM)
b->refs[i].longterm = true;
/*
* Handle frame_num wraparound as described in section
* '8.2.4.1 Decoding process for picture numbers' of the spec.
* TODO: This logic will have to be adjusted when we start
* supporting interlaced content.
*/
if (dpb[i].frame_num > cur_frame_num)
b->refs[i].frame_num = (int)dpb[i].frame_num -
max_frame_num;
else
b->refs[i].frame_num = dpb[i].frame_num;
if (!(dpb[i].flags & V4L2_H264_DPB_ENTRY_FLAG_FIELD))
pic_order_count = min(dpb[i].top_field_order_cnt,
dpb[i].bottom_field_order_cnt);
else if (dpb[i].flags & V4L2_H264_DPB_ENTRY_FLAG_BOTTOM_FIELD)
pic_order_count = dpb[i].bottom_field_order_cnt;
else
pic_order_count = dpb[i].top_field_order_cnt;
b->refs[i].pic_order_count = pic_order_count;
b->unordered_reflist[b->num_valid] = i;
b->num_valid++;
}
for (i = b->num_valid; i < ARRAY_SIZE(b->unordered_reflist); i++)
b->unordered_reflist[i] = i;
}
EXPORT_SYMBOL_GPL(v4l2_h264_init_reflist_builder);
static int v4l2_h264_p_ref_list_cmp(const void *ptra, const void *ptrb,
const void *data)
{
const struct v4l2_h264_reflist_builder *builder = data;
u8 idxa, idxb;
idxa = *((u8 *)ptra);
idxb = *((u8 *)ptrb);
if (WARN_ON(idxa >= V4L2_H264_NUM_DPB_ENTRIES ||
idxb >= V4L2_H264_NUM_DPB_ENTRIES))
return 1;
if (builder->refs[idxa].longterm != builder->refs[idxb].longterm) {
/* Short term pics first. */
if (!builder->refs[idxa].longterm)
return -1;
else
return 1;
}
/*
* Short term pics in descending pic num order, long term ones in
* ascending order.
*/
if (!builder->refs[idxa].longterm)
return builder->refs[idxb].frame_num <
builder->refs[idxa].frame_num ?
-1 : 1;
return builder->refs[idxa].pic_num < builder->refs[idxb].pic_num ?
-1 : 1;
}
static int v4l2_h264_b0_ref_list_cmp(const void *ptra, const void *ptrb,
const void *data)
{
const struct v4l2_h264_reflist_builder *builder = data;
s32 poca, pocb;
u8 idxa, idxb;
idxa = *((u8 *)ptra);
idxb = *((u8 *)ptrb);
if (WARN_ON(idxa >= V4L2_H264_NUM_DPB_ENTRIES ||
idxb >= V4L2_H264_NUM_DPB_ENTRIES))
return 1;
if (builder->refs[idxa].longterm != builder->refs[idxb].longterm) {
/* Short term pics first. */
if (!builder->refs[idxa].longterm)
return -1;
else
return 1;
}
/* Long term pics in ascending pic num order. */
if (builder->refs[idxa].longterm)
return builder->refs[idxa].pic_num <
builder->refs[idxb].pic_num ?
-1 : 1;
poca = builder->refs[idxa].pic_order_count;
pocb = builder->refs[idxb].pic_order_count;
/*
* Short term pics with POC < cur POC first in POC descending order
* followed by short term pics with POC > cur POC in POC ascending
* order.
*/
if ((poca < builder->cur_pic_order_count) !=
(pocb < builder->cur_pic_order_count))
return poca < pocb ? -1 : 1;
else if (poca < builder->cur_pic_order_count)
return pocb < poca ? -1 : 1;
return poca < pocb ? -1 : 1;
}
static int v4l2_h264_b1_ref_list_cmp(const void *ptra, const void *ptrb,
const void *data)
{
const struct v4l2_h264_reflist_builder *builder = data;
s32 poca, pocb;
u8 idxa, idxb;
idxa = *((u8 *)ptra);
idxb = *((u8 *)ptrb);
if (WARN_ON(idxa >= V4L2_H264_NUM_DPB_ENTRIES ||
idxb >= V4L2_H264_NUM_DPB_ENTRIES))
return 1;
if (builder->refs[idxa].longterm != builder->refs[idxb].longterm) {
/* Short term pics first. */
if (!builder->refs[idxa].longterm)
return -1;
else
return 1;
}
/* Long term pics in ascending pic num order. */
if (builder->refs[idxa].longterm)
return builder->refs[idxa].pic_num <
builder->refs[idxb].pic_num ?
-1 : 1;
poca = builder->refs[idxa].pic_order_count;
pocb = builder->refs[idxb].pic_order_count;
/*
* Short term pics with POC > cur POC first in POC ascending order
* followed by short term pics with POC < cur POC in POC descending
* order.
*/
if ((poca < builder->cur_pic_order_count) !=
(pocb < builder->cur_pic_order_count))
return pocb < poca ? -1 : 1;
else if (poca < builder->cur_pic_order_count)
return pocb < poca ? -1 : 1;
return poca < pocb ? -1 : 1;
}
/**
* v4l2_h264_build_p_ref_list() - Build the P reference list
*
* @builder: reference list builder context
* @reflist: 16-bytes array used to store the P reference list. Each entry
* is an index in the DPB
*
* This functions builds the P reference lists. This procedure is describe in
* section '8.2.4 Decoding process for reference picture lists construction'
* of the H264 spec. This function can be used by H264 decoder drivers that
* need to pass a P reference list to the hardware.
*/
void
v4l2_h264_build_p_ref_list(const struct v4l2_h264_reflist_builder *builder,
u8 *reflist)
{
memcpy(reflist, builder->unordered_reflist,
sizeof(builder->unordered_reflist[0]) * builder->num_valid);
sort_r(reflist, builder->num_valid, sizeof(*reflist),
v4l2_h264_p_ref_list_cmp, NULL, builder);
}
EXPORT_SYMBOL_GPL(v4l2_h264_build_p_ref_list);
/**
* v4l2_h264_build_b_ref_lists() - Build the B0/B1 reference lists
*
* @builder: reference list builder context
* @b0_reflist: 16-bytes array used to store the B0 reference list. Each entry
* is an index in the DPB
* @b1_reflist: 16-bytes array used to store the B1 reference list. Each entry
* is an index in the DPB
*
* This functions builds the B0/B1 reference lists. This procedure is described
* in section '8.2.4 Decoding process for reference picture lists construction'
* of the H264 spec. This function can be used by H264 decoder drivers that
* need to pass B0/B1 reference lists to the hardware.
*/
void
v4l2_h264_build_b_ref_lists(const struct v4l2_h264_reflist_builder *builder,
u8 *b0_reflist, u8 *b1_reflist)
{
memcpy(b0_reflist, builder->unordered_reflist,
sizeof(builder->unordered_reflist[0]) * builder->num_valid);
sort_r(b0_reflist, builder->num_valid, sizeof(*b0_reflist),
v4l2_h264_b0_ref_list_cmp, NULL, builder);
memcpy(b1_reflist, builder->unordered_reflist,
sizeof(builder->unordered_reflist[0]) * builder->num_valid);
sort_r(b1_reflist, builder->num_valid, sizeof(*b1_reflist),
v4l2_h264_b1_ref_list_cmp, NULL, builder);
if (builder->num_valid > 1 &&
!memcmp(b1_reflist, b0_reflist, builder->num_valid))
swap(b1_reflist[0], b1_reflist[1]);
}
EXPORT_SYMBOL_GPL(v4l2_h264_build_b_ref_lists);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("V4L2 H264 Helpers");
MODULE_AUTHOR("Boris Brezillon <boris.brezillon@collabora.com>");
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