ffmpeg/libavcodec/avs3_parser.c

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/*
* AVS3-P2/IEEE1857.10 video parser.
* Copyright (c) 2020 Zhenyu Wang <wangzhenyu@pkusz.edu.cn>
* Bingjie Han <hanbj@pkusz.edu.cn>
* Huiwen Ren <hwrenx@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avs3.h"
#include "get_bits.h"
#include "parser.h"
static int avs3_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
{
int pic_found = pc->frame_start_found;
uint32_t state = pc->state;
int cur = 0;
if (!pic_found) {
for (; cur < buf_size; ++cur) {
state = (state << 8) | buf[cur];
if (AVS3_ISPIC(buf[cur])){
cur++;
pic_found = 1;
break;
}
}
}
if (pic_found) {
if (!buf_size)
return END_NOT_FOUND;
for (; cur < buf_size; ++cur) {
state = (state << 8) | buf[cur];
if ((state & 0xFFFFFF00) == 0x100 && AVS3_ISUNIT(state & 0xFF)) {
pc->frame_start_found = 0;
pc->state = -1;
return cur - 3;
}
}
}
pc->frame_start_found = pic_found;
pc->state = state;
return END_NOT_FOUND;
}
static void parse_avs3_nal_units(AVCodecParserContext *s, const uint8_t *buf,
int buf_size, AVCodecContext *avctx)
{
if (buf_size < 5) {
return;
}
if (buf[0] == 0x0 && buf[1] == 0x0 && buf[2] == 0x1) {
if (buf[3] == AVS3_SEQ_START_CODE) {
GetBitContext gb;
int profile, ratecode, low_delay;
av_unused int ret = init_get_bits(&gb, buf + 4, 100);
av_assert1(ret >= 0);
s->key_frame = 1;
s->pict_type = AV_PICTURE_TYPE_I;
profile = get_bits(&gb, 8);
// Skip bits: level(8)
// progressive(1)
// field(1)
// library(2)
// resv(1)
// width(14)
// resv(1)
// height(14)
// chroma(2)
// sampe_precision(3)
skip_bits(&gb, 47);
if (profile == AVS3_PROFILE_BASELINE_MAIN10) {
int sample_precision = get_bits(&gb, 3);
if (sample_precision == 1) {
avctx->pix_fmt = AV_PIX_FMT_YUV420P;
} else if (sample_precision == 2) {
avctx->pix_fmt = AV_PIX_FMT_YUV420P10LE;
} else {
avctx->pix_fmt = AV_PIX_FMT_NONE;
}
}
// Skip bits: resv(1)
// aspect(4)
skip_bits(&gb, 5);
ratecode = get_bits(&gb, 4);
// Skip bits: resv(1)
// bitrate_low(18)
// resv(1)
// bitrate_high(12)
skip_bits(&gb, 32);
low_delay = get_bits(&gb, 1);
avctx->has_b_frames = FFMAX(avctx->has_b_frames, !low_delay);
avctx->framerate.num = ff_avs3_frame_rate_tab[ratecode].num;
avctx->framerate.den = ff_avs3_frame_rate_tab[ratecode].den;
s->width = s->coded_width = avctx->width;
s->height = s->coded_height = avctx->height;
av_log(avctx, AV_LOG_DEBUG,
"AVS3 parse seq HDR: profile %d; coded size: %dx%d; frame rate code: %d\n",
profile, avctx->width, avctx->height, ratecode);
} else if (buf[3] == AVS3_INTRA_PIC_START_CODE) {
s->key_frame = 1;
s->pict_type = AV_PICTURE_TYPE_I;
} else if (buf[3] == AVS3_INTER_PIC_START_CODE){
s->key_frame = 0;
if (buf_size > 9) {
int pic_code_type = buf[8] & 0x3;
if (pic_code_type == 1 || pic_code_type == 3) {
s->pict_type = AV_PICTURE_TYPE_P;
} else {
s->pict_type = AV_PICTURE_TYPE_B;
}
}
}
}
}
static int avs3_parse(AVCodecParserContext *s, AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
ParseContext *pc = s->priv_data;
int next;
if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
next = buf_size;
} else {
next = avs3_find_frame_end(pc, buf, buf_size);
if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
*poutbuf = NULL;
*poutbuf_size = 0;
return buf_size;
}
}
parse_avs3_nal_units(s, buf, buf_size, avctx);
*poutbuf = buf;
*poutbuf_size = buf_size;
return next;
}
const AVCodecParser ff_avs3_parser = {
.codec_ids = { AV_CODEC_ID_AVS3 },
.priv_data_size = sizeof(ParseContext),
.parser_parse = avs3_parse,
.parser_close = ff_parse_close,
};