1/*
2 * DCA parser
3 * Copyright (C) 2004 Gildas Bazin
4 * Copyright (C) 2004 Benjamin Zores
5 * Copyright (C) 2006 Benjamin Larsson
6 * Copyright (C) 2007 Konstantin Shishkov
7 *
8 * This file is part of FFmpeg.
9 *
10 * FFmpeg is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
14 *
15 * FFmpeg is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18 * Lesser General Public License for more details.
19 *
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with FFmpeg; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25#include "parser.h"
26#include "dca.h"
27
28typedef struct DCAParseContext {
29    ParseContext pc;
30    uint32_t lastmarker;
31    int size;
32    int framesize;
33    int hd_pos;
34} DCAParseContext;
35
36#define IS_MARKER(state, i, buf, buf_size) \
37 ((state == DCA_MARKER_14B_LE && (i < buf_size-2) && (buf[i+1] & 0xF0) == 0xF0 && buf[i+2] == 0x07) \
38 || (state == DCA_MARKER_14B_BE && (i < buf_size-2) && buf[i+1] == 0x07 && (buf[i+2] & 0xF0) == 0xF0) \
39 || state == DCA_MARKER_RAW_LE || state == DCA_MARKER_RAW_BE)
40
41/**
42 * finds the end of the current frame in the bitstream.
43 * @return the position of the first byte of the next frame, or -1
44 */
45static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf,
46                              int buf_size)
47{
48    int start_found, i;
49    uint32_t state;
50    ParseContext *pc = &pc1->pc;
51
52    start_found = pc->frame_start_found;
53    state = pc->state;
54
55    i = 0;
56    if (!start_found) {
57        for (i = 0; i < buf_size; i++) {
58            state = (state << 8) | buf[i];
59            if (IS_MARKER(state, i, buf, buf_size)) {
60                if (pc1->lastmarker && state == pc1->lastmarker) {
61                    start_found = 1;
62                    break;
63                } else if (!pc1->lastmarker) {
64                    start_found = 1;
65                    pc1->lastmarker = state;
66                    break;
67                }
68            }
69        }
70    }
71    if (start_found) {
72        for (; i < buf_size; i++) {
73            pc1->size++;
74            state = (state << 8) | buf[i];
75            if (state == DCA_HD_MARKER && !pc1->hd_pos)
76                pc1->hd_pos = pc1->size;
77            if (state == pc1->lastmarker && IS_MARKER(state, i, buf, buf_size)) {
78                if(pc1->framesize > pc1->size)
79                    continue;
80                if(!pc1->framesize){
81                    pc1->framesize = pc1->hd_pos ? pc1->hd_pos : pc1->size;
82                }
83                pc->frame_start_found = 0;
84                pc->state = -1;
85                pc1->size = 0;
86                return i - 3;
87            }
88        }
89    }
90    pc->frame_start_found = start_found;
91    pc->state = state;
92    return END_NOT_FOUND;
93}
94
95static av_cold int dca_parse_init(AVCodecParserContext * s)
96{
97    DCAParseContext *pc1 = s->priv_data;
98
99    pc1->lastmarker = 0;
100    return 0;
101}
102
103static int dca_parse(AVCodecParserContext * s,
104                     AVCodecContext * avctx,
105                     const uint8_t ** poutbuf, int *poutbuf_size,
106                     const uint8_t * buf, int buf_size)
107{
108    DCAParseContext *pc1 = s->priv_data;
109    ParseContext *pc = &pc1->pc;
110    int next;
111
112    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
113        next = buf_size;
114    } else {
115        next = dca_find_frame_end(pc1, buf, buf_size);
116
117        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
118            *poutbuf = NULL;
119            *poutbuf_size = 0;
120            return buf_size;
121        }
122    }
123    *poutbuf = buf;
124    *poutbuf_size = buf_size;
125    return next;
126}
127
128AVCodecParser dca_parser = {
129    {CODEC_ID_DTS},
130    sizeof(DCAParseContext),
131    dca_parse_init,
132    dca_parse,
133    ff_parse_close,
134};
135