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/**
26 * @file libavcodec/dca_parser.c
27 */
28
29#include "parser.h"
30#include "dca.h"
31
32typedef struct DCAParseContext {
33    ParseContext pc;
34    uint32_t lastmarker;
35    int size;
36    int framesize;
37    int hd_pos;
38} DCAParseContext;
39
40#define IS_MARKER(state, i, buf, buf_size) \
41 ((state == DCA_MARKER_14B_LE && (i < buf_size-2) && (buf[i+1] & 0xF0) == 0xF0 && buf[i+2] == 0x07) \
42 || (state == DCA_MARKER_14B_BE && (i < buf_size-2) && buf[i+1] == 0x07 && (buf[i+2] & 0xF0) == 0xF0) \
43 || state == DCA_MARKER_RAW_LE || state == DCA_MARKER_RAW_BE)
44
45/**
46 * finds the end of the current frame in the bitstream.
47 * @return the position of the first byte of the next frame, or -1
48 */
49static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf,
50                              int buf_size)
51{
52    int start_found, i;
53    uint32_t state;
54    ParseContext *pc = &pc1->pc;
55
56    start_found = pc->frame_start_found;
57    state = pc->state;
58
59    i = 0;
60    if (!start_found) {
61        for (i = 0; i < buf_size; i++) {
62            state = (state << 8) | buf[i];
63            if (IS_MARKER(state, i, buf, buf_size)) {
64                if (pc1->lastmarker && state == pc1->lastmarker) {
65                    start_found = 1;
66                    break;
67                } else if (!pc1->lastmarker) {
68                    start_found = 1;
69                    pc1->lastmarker = state;
70                    break;
71                }
72            }
73        }
74    }
75    if (start_found) {
76        for (; i < buf_size; i++) {
77            pc1->size++;
78            state = (state << 8) | buf[i];
79            if (state == DCA_HD_MARKER && !pc1->hd_pos)
80                pc1->hd_pos = pc1->size;
81            if (state == pc1->lastmarker && IS_MARKER(state, i, buf, buf_size)) {
82                if(pc1->framesize > pc1->size)
83                    continue;
84                if(!pc1->framesize){
85                    pc1->framesize = pc1->hd_pos ? pc1->hd_pos : pc1->size;
86                }
87                pc->frame_start_found = 0;
88                pc->state = -1;
89                pc1->size = 0;
90                return i - 3;
91            }
92        }
93    }
94    pc->frame_start_found = start_found;
95    pc->state = state;
96    return END_NOT_FOUND;
97}
98
99static av_cold int dca_parse_init(AVCodecParserContext * s)
100{
101    DCAParseContext *pc1 = s->priv_data;
102
103    pc1->lastmarker = 0;
104    return 0;
105}
106
107static int dca_parse(AVCodecParserContext * s,
108                     AVCodecContext * avctx,
109                     const uint8_t ** poutbuf, int *poutbuf_size,
110                     const uint8_t * buf, int buf_size)
111{
112    DCAParseContext *pc1 = s->priv_data;
113    ParseContext *pc = &pc1->pc;
114    int next;
115
116    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
117        next = buf_size;
118    } else {
119        next = dca_find_frame_end(pc1, buf, buf_size);
120
121        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
122            *poutbuf = NULL;
123            *poutbuf_size = 0;
124            return buf_size;
125        }
126    }
127    *poutbuf = buf;
128    *poutbuf_size = buf_size;
129    return next;
130}
131
132AVCodecParser dca_parser = {
133    {CODEC_ID_DTS},
134    sizeof(DCAParseContext),
135    dca_parse_init,
136    dca_parse,
137    ff_parse_close,
138};
139