// 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>
/*
* Size of the tempory buffer allocated when printing reference lists. The
* output will be truncated if the size is too small.
*/
static const int tmp_str_size = 1024;
/**
* v4l2_h264_init_reflist_builder() - Initialize a P/B0/B1 reference list
* builder
*
* @b: the builder context to initialize
* @dec_params: decode 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_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 = dec_params->frame_num;
memset(b, 0, sizeof(*b));
if (!(dec_params->flags & V4L2_H264_DECODE_PARAM_FLAG_FIELD_PIC)) {
b->cur_pic_order_count = min(dec_params->bottom_field_order_cnt,
dec_params->top_field_order_cnt);
b->cur_pic_fields = V4L2_H264_FRAME_REF;
} else if (dec_params->flags & V4L2_H264_DECODE_PARAM_FLAG_BOTTOM_FIELD) {
b->cur_pic_order_count = dec_params->bottom_field_order_cnt;
b->cur_pic_fields = V4L2_H264_BOTTOM_FIELD_REF;
} else {
b->cur_pic_order_count = dec_params->top_field_order_cnt;
b->cur_pic_fields = V4L2_H264_TOP_FIELD_REF;
}
for (i = 0; i < V4L2_H264_NUM_DPB_ENTRIES; i++) {
if (!(dpb[i].flags & V4L2_H264_DPB_ENTRY_FLAG_ACTIVE))
continue;
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.
* For long term references, frame_num is set to
* long_term_frame_idx which requires no wrapping.
*/
if (!b->refs[i].longterm && 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;
b->refs[i].top_field_order_cnt = dpb[i].top_field_order_cnt;
b->refs[i].bottom_field_order_cnt = dpb[i].bottom_field_order_cnt;
if (b->cur_pic_fields == V4L2_H264_FRAME_REF) {
u8 fields = V4L2_H264_FRAME_REF;
b->unordered_reflist[b->num_valid].index = i;
b->unordered_reflist[b->num_valid].fields = fields;
b->num_valid++;
continue;
}
if (dpb[i].fields & V4L2_H264_TOP_FIELD_REF) {
u8 fields = V4L2_H264_TOP_FIELD_REF;
b->unordered_reflist[b->num_valid].index = i;
b->unordered_reflist[b->num_valid].fields = fields;
b->num_valid++;
}
if (dpb[i].fields & V4L2_H264_BOTTOM_FIELD_REF) {
u8 fields = V4L2_H264_BOTTOM_FIELD_REF;
b->unordered_reflist[b->num_valid].index = i;
b->unordered_reflist[b->num_valid].fields = fields;
b->num_valid++;
}
}
for (i = b->num_valid; i < ARRAY_SIZE(b->unordered_reflist); i++)
b->unordered_reflist[i].index = i;
}
EXPORT_SYMBOL_GPL(v4l2_h264_init_reflist_builder);
static s32 v4l2_h264_get_poc(const struct v4l2_h264_reflist_builder *b,
const struct v4l2_h264_reference *ref)
{
switch (ref->fields) {
case V4L2_H264_FRAME_REF:
return min(b->refs[ref->index].top_field_order_cnt,
b->refs[ref->index].bottom_field_order_cnt);
case V4L2_H264_TOP_FIELD_REF:
return b->refs[ref->index].top_field_order_cnt;
case V4L2_H264_BOTTOM_FIELD_REF:
return b->refs[ref->index].bottom_field_order_cnt;
}
/* not reached */
return 0;
}
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 = ((struct v4l2_h264_reference *)ptra)->index;
idxb = ((struct v4l2_h264_reference *)ptrb)->index;
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;
}
/*
* For frames, short term pics are in descending pic num order and long
* term ones in ascending order. For fields, the same direction is used
* but with frame_num (wrapped). For frames, the value of pic_num and
* frame_num are the same (see formula (8-28) and (8-29)). For this
* reason we can use frame_num only and share this function between
* frames and fields reflist.
*/
if (!builder->refs[idxa].longterm)
return builder->refs[idxb].frame_num <
builder->refs[idxa].frame_num ?
-1 : 1;
return builder->refs[idxa].frame_num < builder->refs[idxb].frame_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 = ((struct v4l2_h264_reference *)ptra)->index;
idxb = ((struct v4l2_h264_reference *)ptrb)->index;
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 frame num order. */
if (builder->refs[idxa].longterm)
return builder->refs[idxa].frame_num <
builder->refs[idxb].frame_num ?
-1 : 1;
poca = v4l2_h264_get_poc(builder, ptra);
pocb = v4l2_h264_get_poc(builder, ptrb);
/*
* 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 = ((struct v4l2_h264_reference *)ptra)->index;
idxb = ((struct v4l2_h264_reference *)ptrb)->index;
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 frame num order. */
if (builder->refs[idxa].longterm)
return builder->refs[idxa].frame_num <
builder->refs[idxb].frame_num ?
-1 : 1;
poca = v4l2_h264_get_poc(builder, ptra);
pocb = v4l2_h264_get_poc(builder, ptrb);
/*
* 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;
}
/*
* The references need to be reordered so that references are alternating
* between top and bottom field references starting with the current picture
* parity. This has to be done for short term and long term references
* separately.
*/
static void reorder_field_reflist(const struct v4l2_h264_reflist_builder *b,
struct v4l2_h264_reference *reflist)
{
struct v4l2_h264_reference tmplist[V4L2_H264_REF_LIST_LEN];
u8 lt, i = 0, j = 0, k = 0;
memcpy(tmplist, reflist, sizeof(tmplist[0]) * b->num_valid);
for (lt = 0; lt <= 1; lt++) {
do {
for (; i < b->num_valid && b->refs[tmplist[i].index].longterm == lt; i++) {
if (tmplist[i].fields == b->cur_pic_fields) {
reflist[k++] = tmplist[i++];
break;
}
}
for (; j < b->num_valid && b->refs[tmplist[j].index].longterm == lt; j++) {
if (tmplist[j].fields != b->cur_pic_fields) {
reflist[k++] = tmplist[j++];
break;
}
}
} while ((i < b->num_valid && b->refs[tmplist[i].index].longterm == lt) ||
(j < b->num_valid && b->refs[tmplist[j].index].longterm == lt));
}
}
static char ref_type_to_char(u8 ref_type)
{
switch (ref_type) {
case V4L2_H264_FRAME_REF:
return 'f';
case V4L2_H264_TOP_FIELD_REF:
return 't';
case V4L2_H264_BOTTOM_FIELD_REF:
return 'b';
}
return '?';
}
static const char *format_ref_list_p(const struct v4l2_h264_reflist_builder *builder,
struct v4l2_h264_reference *reflist,
char **out_str)
{
int n = 0, i;
*out_str = kmalloc(tmp_str_size, GFP_KERNEL);
if (!(*out_str))
return NULL;
n += snprintf(*out_str + n, tmp_str_size - n, "|");
for (i = 0; i < builder->num_valid; i++) {
/* this is pic_num for frame and frame_num (wrapped) for field,
* but for frame pic_num is equal to frame_num (wrapped).
*/
int frame_num = builder->refs[reflist[i].index].frame_num;
bool longterm = builder->refs[reflist[i].index].longterm;
n += scnprintf(*out_str + n, tmp_str_size - n, "%i%c%c|",
frame_num, longterm ? 'l' : 's',
ref_type_to_char(reflist[i].fields));
}
return *out_str;
}
static void print_ref_list_p(const struct v4l2_h264_reflist_builder *builder,
struct v4l2_h264_reference *reflist)
{
char *buf = NULL;
pr_debug("ref_pic_list_p (cur_poc %u%c) %s\n",
builder->cur_pic_order_count,
ref_type_to_char(builder->cur_pic_fields),
format_ref_list_p(builder, reflist, &buf));
kfree(buf);
}
static const char *format_ref_list_b(const struct v4l2_h264_reflist_builder *builder,
struct v4l2_h264_reference *reflist,
char **out_str)
{
int n = 0, i;
*out_str = kmalloc(tmp_str_size, GFP_KERNEL);
if (!(*out_str))
return NULL;
n += snprintf(*out_str + n, tmp_str_size - n, "|");
for (i = 0; i < builder->num_valid; i++) {
int frame_num = builder->refs[reflist[i].index].frame_num;
u32 poc = v4l2_h264_get_poc(builder, reflist + i);
bool longterm = builder->refs[reflist[i].index].longterm;
n += scnprintf(*out_str + n, tmp_str_size - n, "%i%c%c|",
longterm ? frame_num : poc,
longterm ? 'l' : 's',
ref_type_to_char(reflist[i].fields));
}
return *out_str;
}
static void print_ref_list_b(const struct v4l2_h264_reflist_builder *builder,
struct v4l2_h264_reference *reflist, u8 list_num)
{
char *buf = NULL;
pr_debug("ref_pic_list_b%u (cur_poc %u%c) %s",
list_num, builder->cur_pic_order_count,
ref_type_to_char(builder->cur_pic_fields),
format_ref_list_b(builder, reflist, &buf));
kfree(buf);
}
/**
* v4l2_h264_build_p_ref_list() - Build the P reference list
*
* @builder: reference list builder context
* @reflist: 32 sized array used to store the P reference list. Each entry
* is a v4l2_h264_reference structure
*
* 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,
struct v4l2_h264_reference *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);
if (builder->cur_pic_fields != V4L2_H264_FRAME_REF)
reorder_field_reflist(builder, reflist);
print_ref_list_p(builder, reflist);
}
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: 32 sized array used to store the B0 reference list. Each entry
* is a v4l2_h264_reference structure
* @b1_reflist: 32 sized array used to store the B1 reference list. Each entry
* is a v4l2_h264_reference structure
*
* 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,
struct v4l2_h264_reference *b0_reflist,
struct v4l2_h264_reference *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->cur_pic_fields != V4L2_H264_FRAME_REF) {
reorder_field_reflist(builder, b0_reflist);
reorder_field_reflist(builder, b1_reflist);
}
if (builder->num_valid > 1 &&
!memcmp(b1_reflist, b0_reflist, builder->num_valid))
swap(b1_reflist[0], b1_reflist[1]);
print_ref_list_b(builder, b0_reflist, 0);
print_ref_list_b(builder, 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>");
