mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2024-12-22 15:23:11 +00:00
127 lines
3.6 KiB
C
127 lines
3.6 KiB
C
/*
|
|
* DCA parser
|
|
* Copyright (C) 2004 Gildas Bazin
|
|
* Copyright (C) 2004 Benjamin Zores
|
|
* Copyright (C) 2006 Benjamin Larsson
|
|
* Copyright (C) 2007 Konstantin Shishkov
|
|
*
|
|
* 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
|
|
*/
|
|
|
|
/**
|
|
* @file dca_parser.c
|
|
*/
|
|
|
|
#include "parser.h"
|
|
#include "dca.h"
|
|
|
|
typedef struct DCAParseContext {
|
|
ParseContext pc;
|
|
uint32_t lastmarker;
|
|
} DCAParseContext;
|
|
|
|
#define IS_MARKER(state, i, buf, buf_size) \
|
|
((state == DCA_MARKER_14B_LE && (i < buf_size-2) && (buf[i+1] & 0xF0) == 0xF0 && buf[i+2] == 0x07) \
|
|
|| (state == DCA_MARKER_14B_BE && (i < buf_size-2) && buf[i+1] == 0x07 && (buf[i+2] & 0xF0) == 0xF0) \
|
|
|| state == DCA_MARKER_RAW_LE || state == DCA_MARKER_RAW_BE)
|
|
|
|
/**
|
|
* finds the end of the current frame in the bitstream.
|
|
* @return the position of the first byte of the next frame, or -1
|
|
*/
|
|
static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf,
|
|
int buf_size)
|
|
{
|
|
int start_found, i;
|
|
uint32_t state;
|
|
ParseContext *pc = &pc1->pc;
|
|
|
|
start_found = pc->frame_start_found;
|
|
state = pc->state;
|
|
|
|
i = 0;
|
|
if (!start_found) {
|
|
for (i = 0; i < buf_size; i++) {
|
|
state = (state << 8) | buf[i];
|
|
if (IS_MARKER(state, i, buf, buf_size)) {
|
|
if (pc1->lastmarker && state == pc1->lastmarker) {
|
|
start_found = 1;
|
|
break;
|
|
} else if (!pc1->lastmarker) {
|
|
start_found = 1;
|
|
pc1->lastmarker = state;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if (start_found) {
|
|
for (; i < buf_size; i++) {
|
|
state = (state << 8) | buf[i];
|
|
if (state == pc1->lastmarker && IS_MARKER(state, i, buf, buf_size)) {
|
|
pc->frame_start_found = 0;
|
|
pc->state = -1;
|
|
return i - 3;
|
|
}
|
|
}
|
|
}
|
|
pc->frame_start_found = start_found;
|
|
pc->state = state;
|
|
return END_NOT_FOUND;
|
|
}
|
|
|
|
static int dca_parse_init(AVCodecParserContext * s)
|
|
{
|
|
DCAParseContext *pc1 = s->priv_data;
|
|
|
|
pc1->lastmarker = 0;
|
|
return 0;
|
|
}
|
|
|
|
static int dca_parse(AVCodecParserContext * s,
|
|
AVCodecContext * avctx,
|
|
const uint8_t ** poutbuf, int *poutbuf_size,
|
|
const uint8_t * buf, int buf_size)
|
|
{
|
|
DCAParseContext *pc1 = s->priv_data;
|
|
ParseContext *pc = &pc1->pc;
|
|
int next;
|
|
|
|
if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
|
|
next = buf_size;
|
|
} else {
|
|
next = dca_find_frame_end(pc1, buf, buf_size);
|
|
|
|
if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
|
|
*poutbuf = NULL;
|
|
*poutbuf_size = 0;
|
|
return buf_size;
|
|
}
|
|
}
|
|
*poutbuf = buf;
|
|
*poutbuf_size = buf_size;
|
|
return next;
|
|
}
|
|
|
|
AVCodecParser dca_parser = {
|
|
{CODEC_ID_DTS},
|
|
sizeof(DCAParseContext),
|
|
dca_parse_init,
|
|
dca_parse,
|
|
ff_parse_close,
|
|
};
|