Directory: | ../../../ffmpeg/ |
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File: | src/libavcodec/adx.c |
Date: | 2022-07-04 00:18:54 |
Exec | Total | Coverage | |
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Lines: | 25 | 35 | 71.4% |
Branches: | 14 | 28 | 50.0% |
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1 | /* | ||
2 | * Copyright (c) 2011 Justin Ruggles | ||
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 "libavutil/common.h" | ||
22 | #include "libavutil/intreadwrite.h" | ||
23 | #include "libavutil/mathematics.h" | ||
24 | #include "adx.h" | ||
25 | |||
26 | 3 | void ff_adx_calculate_coeffs(int cutoff, int sample_rate, int bits, int *coeff) | |
27 | { | ||
28 | double a, b, c; | ||
29 | |||
30 | 3 | a = M_SQRT2 - cos(2.0 * M_PI * cutoff / sample_rate); | |
31 | 3 | b = M_SQRT2 - 1.0; | |
32 | 3 | c = (a - sqrt((a + b) * (a - b))) / b; | |
33 | |||
34 | 3 | coeff[0] = lrintf(c * 2.0 * (1 << bits)); | |
35 | 3 | coeff[1] = lrintf(-(c * c) * (1 << bits)); | |
36 | 3 | } | |
37 | |||
38 | 2 | int ff_adx_decode_header(AVCodecContext *avctx, const uint8_t *buf, | |
39 | int bufsize, int *header_size, int *coeff) | ||
40 | { | ||
41 | int offset, cutoff, channels; | ||
42 | |||
43 |
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2 | if (bufsize < 24) |
44 | ✗ | return AVERROR_INVALIDDATA; | |
45 | |||
46 |
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2 | if (AV_RB16(buf) != 0x8000) |
47 | ✗ | return AVERROR_INVALIDDATA; | |
48 | 2 | offset = AV_RB16(buf + 2) + 4; | |
49 | |||
50 | /* if copyright string is within the provided data, validate it */ | ||
51 |
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2 | if (bufsize >= offset && offset >= 6 && memcmp(buf + offset - 6, "(c)CRI", 6)) |
52 | ✗ | return AVERROR_INVALIDDATA; | |
53 | |||
54 | /* check for encoding=3 block_size=18, sample_size=4 */ | ||
55 |
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2 | if (buf[4] != 3 || buf[5] != 18 || buf[6] != 4) { |
56 | ✗ | avpriv_request_sample(avctx, "Support for this ADX format"); | |
57 | ✗ | return AVERROR_PATCHWELCOME; | |
58 | } | ||
59 | |||
60 | /* channels */ | ||
61 | 2 | channels = buf[7]; | |
62 |
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2 | if (channels <= 0 || channels > 2) |
63 | ✗ | return AVERROR_INVALIDDATA; | |
64 | |||
65 |
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2 | if (avctx->ch_layout.nb_channels != channels) { |
66 | ✗ | av_channel_layout_uninit(&avctx->ch_layout); | |
67 | ✗ | avctx->ch_layout.order = AV_CHANNEL_ORDER_UNSPEC; | |
68 | ✗ | avctx->ch_layout.nb_channels = channels; | |
69 | } | ||
70 | |||
71 | /* sample rate */ | ||
72 | 2 | avctx->sample_rate = AV_RB32(buf + 8); | |
73 |
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2 | if (avctx->sample_rate < 1 || |
74 |
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2 | avctx->sample_rate > INT_MAX / (channels * BLOCK_SIZE * 8)) |
75 | ✗ | return AVERROR_INVALIDDATA; | |
76 | |||
77 | /* bit rate */ | ||
78 | 2 | avctx->bit_rate = avctx->sample_rate * channels * BLOCK_SIZE * 8 / BLOCK_SAMPLES; | |
79 | |||
80 | /* LPC coefficients */ | ||
81 |
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2 | if (coeff) { |
82 | 2 | cutoff = AV_RB16(buf + 16); | |
83 | 2 | ff_adx_calculate_coeffs(cutoff, avctx->sample_rate, COEFF_BITS, coeff); | |
84 | } | ||
85 | |||
86 | 2 | *header_size = offset; | |
87 | 2 | return 0; | |
88 | } | ||
89 |