FFmpeg4/libavcodec/dvd_nav_parser.c

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2023-07-02 12:20:28 +00:00
/*
* DVD navigation block parser for FFmpeg
* Copyright (c) 2013 The FFmpeg Project
*
* 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 "avcodec.h"
#include "get_bits.h"
#include "parser.h"
#define PCI_SIZE 980
#define DSI_SIZE 1018
/* parser definition */
typedef struct DVDNavParseContext {
uint32_t lba;
uint8_t buffer[PCI_SIZE+DSI_SIZE];
int copied;
} DVDNavParseContext;
static av_cold int dvd_nav_parse_init(AVCodecParserContext *s)
{
DVDNavParseContext *pc = s->priv_data;
pc->lba = 0xFFFFFFFF;
pc->copied = 0;
return 0;
}
static int dvd_nav_parse(AVCodecParserContext *s,
AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
DVDNavParseContext *pc1 = s->priv_data;
int lastPacket = 0;
int valid = 0;
s->pict_type = AV_PICTURE_TYPE_NONE;
avctx->time_base.num = 1;
avctx->time_base.den = 90000;
if (buf && buf_size) {
switch(buf[0]) {
case 0x00:
if (buf_size == PCI_SIZE) {
/* PCI */
uint32_t lba = AV_RB32(&buf[0x01]);
uint32_t startpts = AV_RB32(&buf[0x0D]);
uint32_t endpts = AV_RB32(&buf[0x11]);
if (endpts > startpts) {
pc1->lba = lba;
s->pts = (int64_t)startpts;
s->duration = endpts - startpts;
memcpy(pc1->buffer, buf, PCI_SIZE);
pc1->copied = PCI_SIZE;
valid = 1;
}
}
break;
case 0x01:
if ((buf_size == DSI_SIZE) && (pc1->copied == PCI_SIZE)) {
/* DSI */
uint32_t lba = AV_RB32(&buf[0x05]);
if (lba == pc1->lba) {
memcpy(pc1->buffer + pc1->copied, buf, DSI_SIZE);
lastPacket = 1;
valid = 1;
}
}
break;
}
}
if (!valid || lastPacket) {
pc1->copied = 0;
pc1->lba = 0xFFFFFFFF;
}
if (lastPacket) {
*poutbuf = pc1->buffer;
*poutbuf_size = sizeof(pc1->buffer);
} else {
*poutbuf = NULL;
*poutbuf_size = 0;
}
return buf_size;
}
AVCodecParser ff_dvd_nav_parser = {
.codec_ids = { AV_CODEC_ID_DVD_NAV },
.priv_data_size = sizeof(DVDNavParseContext),
.parser_init = dvd_nav_parse_init,
.parser_parse = dvd_nav_parse,
};