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/*
* 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
*/
#include "parser.h"
#include "dca.h"
typedef struct DCAParseContext {
ParseContext pc;
uint32_t lastmarker;
int size;
int framesize;
int hd_pos;
} 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 || state == DCA_HD_MARKER)
/**
* 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 || pc1->lastmarker == DCA_HD_MARKER) {
start_found = 1;
pc1->lastmarker = state;
break;
}
}
}
}
if (start_found) {
for (; i < buf_size; i++) {
pc1->size++;
state = (state << 8) | buf[i];
if (state == DCA_HD_MARKER && !pc1->hd_pos)
pc1->hd_pos = pc1->size;
if (IS_MARKER(state, i, buf, buf_size) && (state == pc1->lastmarker || pc1->lastmarker == DCA_HD_MARKER)) {
if(pc1->framesize > pc1->size)
continue;
// We have to check that we really read a full frame here, and that it isn't a pure HD frame, because their size is not constant.
if(!pc1->framesize && state == pc1->lastmarker && state != DCA_HD_MARKER){
pc1->framesize = pc1->hd_pos ? pc1->hd_pos : pc1->size;
}
pc->frame_start_found = 0;
pc->state = -1;
pc1->size = 0;
return i - 3;
}
}
}
pc->frame_start_found = start_found;
pc->state = state;
return END_NOT_FOUND;
}
static av_cold 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 ff_dca_parser = {
{CODEC_ID_DTS},
sizeof(DCAParseContext),
dca_parse_init,
dca_parse,
ff_parse_close,
};
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