1/*
2 * Copyright (C) 2017 foo86
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#include "get_bits.h"
22#include "put_bits.h"
23#include "dolby_e.h"
24
25static const uint8_t nb_programs_tab[MAX_PROG_CONF + 1] = {
26    2, 3, 2, 3, 4, 5, 4, 5, 6, 7, 8, 1, 2, 3, 3, 4, 5, 6, 1, 2, 3, 4, 1, 1
27};
28
29static const uint8_t nb_channels_tab[MAX_PROG_CONF + 1] = {
30    8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 6, 6, 6, 6, 6, 6, 6, 4, 4, 4, 4, 8, 8
31};
32
33static const uint16_t sample_rate_tab[16] = {
34    0, 42965, 43008, 44800, 53706, 53760
35};
36
37static int skip_input(DBEContext *s, int nb_words)
38{
39    if (nb_words > s->input_size) {
40        return AVERROR_INVALIDDATA;
41    }
42
43    s->input      += nb_words * s->word_bytes;
44    s->input_size -= nb_words;
45    return 0;
46}
47
48static int parse_key(DBEContext *s)
49{
50    if (s->key_present) {
51        const uint8_t *key = s->input;
52        int      ret = skip_input(s, 1);
53        if (ret < 0)
54            return ret;
55        return AV_RB24(key) >> 24 - s->word_bits;
56    }
57    return 0;
58}
59
60int ff_dolby_e_convert_input(DBEContext *s, int nb_words, int key)
61{
62    const uint8_t *src = s->input;
63    uint8_t *dst = s->buffer;
64    PutBitContext pb;
65    int i;
66
67    av_assert0(nb_words <= 1024u);
68
69    if (nb_words > s->input_size) {
70        if (s->avctx)
71            av_log(s->avctx, AV_LOG_ERROR, "Packet too short\n");
72        return AVERROR_INVALIDDATA;
73    }
74
75    switch (s->word_bits) {
76    case 16:
77        for (i = 0; i < nb_words; i++, src += 2, dst += 2)
78            AV_WB16(dst, AV_RB16(src) ^ key);
79        break;
80    case 20:
81        init_put_bits(&pb, s->buffer, sizeof(s->buffer));
82        for (i = 0; i < nb_words; i++, src += 3)
83            put_bits(&pb, 20, AV_RB24(src) >> 4 ^ key);
84        flush_put_bits(&pb);
85        break;
86    case 24:
87        for (i = 0; i < nb_words; i++, src += 3, dst += 3)
88            AV_WB24(dst, AV_RB24(src) ^ key);
89        break;
90    default:
91        av_assert0(0);
92    }
93
94    return init_get_bits(&s->gb, s->buffer, nb_words * s->word_bits);
95}
96
97int ff_dolby_e_parse_header(DBEContext *s, const uint8_t *buf, int buf_size)
98{
99    DolbyEHeaderInfo *const header = &s->metadata;
100    int hdr, ret, key, mtd_size;
101
102    if (buf_size < 3)
103        return AVERROR_INVALIDDATA;
104
105    hdr = AV_RB24(buf);
106    if ((hdr & 0xfffffe) == 0x7888e) {
107        s->word_bits = 24;
108    } else if ((hdr & 0xffffe0) == 0x788e0) {
109        s->word_bits = 20;
110    } else if ((hdr & 0xfffe00) == 0x78e00) {
111        s->word_bits = 16;
112    } else {
113        if (s->avctx)
114            av_log(s->avctx, AV_LOG_ERROR, "Invalid frame header\n");
115        return AVERROR_INVALIDDATA;
116    }
117
118    s->word_bytes  = s->word_bits + 7 >> 3;
119    s->input       = buf + s->word_bytes;
120    s->input_size  = buf_size / s->word_bytes - 1;
121    s->key_present = hdr >> 24 - s->word_bits & 1;
122
123    if ((key = parse_key(s)) < 0)
124        return key;
125    if ((ret = ff_dolby_e_convert_input(s, 1, key)) < 0)
126        return ret;
127
128    skip_bits(&s->gb, 4);
129    mtd_size = get_bits(&s->gb, 10);
130    if (!mtd_size) {
131        if (s->avctx)
132            av_log(s->avctx, AV_LOG_ERROR, "Invalid metadata size\n");
133        return AVERROR_INVALIDDATA;
134    }
135
136    if ((ret = ff_dolby_e_convert_input(s, mtd_size, key)) < 0)
137        return ret;
138
139    skip_bits(&s->gb, 14);
140    header->prog_conf = get_bits(&s->gb, 6);
141    if (header->prog_conf > MAX_PROG_CONF) {
142        if (s->avctx)
143            av_log(s->avctx, AV_LOG_ERROR, "Invalid program configuration\n");
144        return AVERROR_INVALIDDATA;
145    }
146
147    header->nb_channels = nb_channels_tab[header->prog_conf];
148    header->nb_programs = nb_programs_tab[header->prog_conf];
149
150    header->fr_code      = get_bits(&s->gb, 4);
151    header->fr_code_orig = get_bits(&s->gb, 4);
152    if (!(header->sample_rate = sample_rate_tab[header->fr_code]) ||
153        !sample_rate_tab[header->fr_code_orig]) {
154        if (s->avctx)
155            av_log(s->avctx, AV_LOG_ERROR, "Invalid frame rate code\n");
156        return AVERROR_INVALIDDATA;
157    }
158
159    skip_bits_long(&s->gb, 88);
160    for (int i = 0; i < header->nb_channels; i++)
161        header->ch_size[i] = get_bits(&s->gb, 10);
162    header->mtd_ext_size = get_bits(&s->gb, 8);
163    header->meter_size   = get_bits(&s->gb, 8);
164
165    skip_bits_long(&s->gb, 10 * header->nb_programs);
166    for (int i = 0; i < header->nb_channels; i++) {
167        header->rev_id[i]     = get_bits(&s->gb,  4);
168        skip_bits1(&s->gb);
169        header->begin_gain[i] = get_bits(&s->gb, 10);
170        header->end_gain[i]   = get_bits(&s->gb, 10);
171    }
172
173    if (get_bits_left(&s->gb) < 0) {
174        if (s->avctx)
175            av_log(s->avctx, AV_LOG_ERROR, "Read past end of metadata\n");
176        return AVERROR_INVALIDDATA;
177    }
178
179    return skip_input(s, mtd_size + 1);
180}
181