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#include "get_bits.h"
28
29typedef struct DCAParseContext {
30    ParseContext pc;
31    uint32_t lastmarker;
32    int size;
33    int framesize;
34    int hd_pos;
35} DCAParseContext;
36
37#define IS_MARKER(state, i, buf, buf_size) \
38 ((state == DCA_MARKER_14B_LE && (i < buf_size-2) && (buf[i+1] & 0xF0) == 0xF0 && buf[i+2] == 0x07) \
39 || (state == DCA_MARKER_14B_BE && (i < buf_size-2) && buf[i+1] == 0x07 && (buf[i+2] & 0xF0) == 0xF0) \
40 || state == DCA_MARKER_RAW_LE || state == DCA_MARKER_RAW_BE || state == DCA_HD_MARKER)
41
42/**
43 * Find the end of the current frame in the bitstream.
44 * @return the position of the first byte of the next frame, or -1
45 */
46static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf,
47                              int buf_size)
48{
49    int start_found, i;
50    uint32_t state;
51    ParseContext *pc = &pc1->pc;
52
53    start_found = pc->frame_start_found;
54    state = pc->state;
55
56    i = 0;
57    if (!start_found) {
58        for (i = 0; i < buf_size; i++) {
59            state = (state << 8) | buf[i];
60            if (IS_MARKER(state, i, buf, buf_size)) {
61                if (!pc1->lastmarker || state == pc1->lastmarker || pc1->lastmarker == DCA_HD_MARKER) {
62                    start_found = 1;
63                    pc1->lastmarker = state;
64                    i++;
65                    break;
66                }
67            }
68        }
69    }
70    if (start_found) {
71        for (; i < buf_size; i++) {
72            pc1->size++;
73            state = (state << 8) | buf[i];
74            if (state == DCA_HD_MARKER && !pc1->hd_pos)
75                pc1->hd_pos = pc1->size;
76            if (IS_MARKER(state, i, buf, buf_size) && (state == pc1->lastmarker || pc1->lastmarker == DCA_HD_MARKER)) {
77                if(pc1->framesize > pc1->size)
78                    continue;
79                pc->frame_start_found = 0;
80                pc->state = -1;
81                pc1->size = 0;
82                return i - 3;
83            }
84        }
85    }
86    pc->frame_start_found = start_found;
87    pc->state = state;
88    return END_NOT_FOUND;
89}
90
91static av_cold int dca_parse_init(AVCodecParserContext * s)
92{
93    DCAParseContext *pc1 = s->priv_data;
94
95    pc1->lastmarker = 0;
96    return 0;
97}
98
99static int dca_parse_params(const uint8_t *buf, int buf_size, int *duration,
100                            int *sample_rate, int *framesize)
101{
102    GetBitContext gb;
103    uint8_t hdr[12 + FF_INPUT_BUFFER_PADDING_SIZE] = { 0 };
104    int ret, sample_blocks, sr_code;
105
106    if (buf_size < 12)
107        return AVERROR_INVALIDDATA;
108
109    if ((ret = ff_dca_convert_bitstream(buf, 12, hdr, 12)) < 0)
110        return ret;
111
112    init_get_bits(&gb, hdr, 96);
113
114    skip_bits_long(&gb, 39);
115    sample_blocks = get_bits(&gb, 7) + 1;
116    if (sample_blocks < 8)
117        return AVERROR_INVALIDDATA;
118    *duration = 256 * (sample_blocks / 8);
119
120    *framesize = get_bits(&gb, 14) + 1;
121    if (*framesize < 95)
122        return AVERROR_INVALIDDATA;
123
124    skip_bits(&gb, 6);
125    sr_code = get_bits(&gb, 4);
126    *sample_rate = avpriv_dca_sample_rates[sr_code];
127    if (*sample_rate == 0)
128        return AVERROR_INVALIDDATA;
129
130    return 0;
131}
132
133static int dca_parse(AVCodecParserContext * s,
134                     AVCodecContext * avctx,
135                     const uint8_t ** poutbuf, int *poutbuf_size,
136                     const uint8_t * buf, int buf_size)
137{
138    DCAParseContext *pc1 = s->priv_data;
139    ParseContext *pc = &pc1->pc;
140    int next, duration, sample_rate;
141
142    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
143        next = buf_size;
144    } else {
145        next = dca_find_frame_end(pc1, buf, buf_size);
146
147        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
148            *poutbuf = NULL;
149            *poutbuf_size = 0;
150            return buf_size;
151        }
152    }
153
154    /* read the duration and sample rate from the frame header */
155    if (!dca_parse_params(buf, buf_size, &duration, &sample_rate, &pc1->framesize)) {
156        s->duration = duration;
157        avctx->sample_rate = sample_rate;
158    } else
159        s->duration = 0;
160
161    *poutbuf = buf;
162    *poutbuf_size = buf_size;
163    return next;
164}
165
166AVCodecParser ff_dca_parser = {
167    .codec_ids      = { AV_CODEC_ID_DTS },
168    .priv_data_size = sizeof(DCAParseContext),
169    .parser_init    = dca_parse_init,
170    .parser_parse   = dca_parse,
171    .parser_close   = ff_parse_close,
172};
173