1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
|
/***
This file is part of snapcast
Copyright (C) 2015 Hannes Ellinger
Copyright (C) 2016-2024 Johannes Pohl
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
***/
// prototype/interface header file
#include "opus_decoder.hpp"
// local headers
#include "common/aixlog.hpp"
#include "common/snap_exception.hpp"
namespace decoder
{
#define ID_OPUS 0x4F505553
/// int: Number of samples per channel in the input signal.
/// This must be an Opus frame size for the encoder's sampling rate. For example, at 48 kHz the
/// permitted values are 120, 240, 480, 960, 1920, and 2880.
/// Passing in a duration of less than 10 ms (480 samples at 48 kHz) will prevent the encoder from using the LPC or hybrid modes.
static constexpr int const_max_frame_size = 2880;
static constexpr auto LOG_TAG = "OpusDecoder";
OpusDecoder::OpusDecoder() : Decoder(), dec_(nullptr)
{
pcm_.resize(120);
}
OpusDecoder::~OpusDecoder()
{
if (dec_ != nullptr)
opus_decoder_destroy(dec_);
}
bool OpusDecoder::decode(msg::PcmChunk* chunk)
{
int decoded_frames = 0;
while ((decoded_frames = opus_decode(dec_, reinterpret_cast<unsigned char*>(chunk->payload), chunk->payloadSize, pcm_.data(),
static_cast<int>(pcm_.size()) / sample_format_.channels(), 0)) == OPUS_BUFFER_TOO_SMALL)
{
if (pcm_.size() < const_max_frame_size * sample_format_.channels())
{
pcm_.resize(pcm_.size() * 2);
LOG(DEBUG, LOG_TAG) << "OPUS encoding buffer too small, resizing to " << pcm_.size() / sample_format_.channels() << " samples per channel\n";
}
else
break;
}
if (decoded_frames < 0)
{
LOG(ERROR, LOG_TAG) << "Failed to decode chunk: " << opus_strerror(decoded_frames) << ", IN size: " << chunk->payloadSize
<< ", OUT size: " << pcm_.size() << '\n';
return false;
}
else
{
LOG(TRACE, LOG_TAG) << "Decode chunk: " << decoded_frames << " frames, size: " << chunk->payloadSize
<< " bytes, decoded: " << decoded_frames * sample_format_.frameSize() << " bytes\n";
// copy encoded data to chunk
chunk->payloadSize = decoded_frames * sample_format_.frameSize(); // decoded_frames * sample_format_.channels() * sizeof(opus_int16);
chunk->payload = static_cast<char*>(realloc(chunk->payload, chunk->payloadSize));
memcpy(chunk->payload, reinterpret_cast<char*>(pcm_.data()), chunk->payloadSize);
return true;
}
}
SampleFormat OpusDecoder::setHeader(msg::CodecHeader* chunk)
{
// decode the opus pseudo header
if (chunk->payloadSize < 12)
throw SnapException("OPUS header too small");
// decode the "opus id" magic number, this is our constant part that must match
uint32_t id_opus;
memcpy(&id_opus, chunk->payload, sizeof(id_opus));
if (SWAP_32(id_opus) != ID_OPUS)
throw SnapException("Not an Opus pseudo header");
// decode the sampleformat
uint32_t rate;
memcpy(&rate, chunk->payload + 4, sizeof(rate));
uint16_t bits;
memcpy(&bits, chunk->payload + 8, sizeof(bits));
uint16_t channels;
memcpy(&channels, chunk->payload + 10, sizeof(channels));
sample_format_.setFormat(SWAP_32(rate), SWAP_16(bits), SWAP_16(channels));
LOG(DEBUG, LOG_TAG) << "Opus sampleformat: " << sample_format_.toString() << "\n";
// create the decoder
int error;
dec_ = opus_decoder_create(sample_format_.rate(), sample_format_.channels(), &error);
if (error != 0)
throw SnapException("Failed to initialize Opus decoder: " + std::string(opus_strerror(error)));
return sample_format_;
}
} // namespace decoder
|
