-
Notifications
You must be signed in to change notification settings - Fork 78
/
WaveParser.cs
350 lines (297 loc) · 10.2 KB
/
WaveParser.cs
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
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
// Licensed under the MIT license: https://opensource.org/licenses/MIT
namespace Whisper.net.Wave;
public sealed class WaveParser
{
private readonly Stream waveStream;
private ushort channels;
private uint sampleRate;
private ushort bitsPerSample;
private uint dataChunkSize;
private long dataChunkPosition;
private bool wasInitialized;
public WaveParser(Stream waveStream)
{
this.waveStream = waveStream;
}
public int GetSamplesCount()
{
if (!wasInitialized)
{
Initialize();
}
return (int)(dataChunkSize / 2 / channels);
}
/// <summary>
/// Returns the average samples from all channels.
/// </summary>
/// <returns></returns>
public async Task<float[]> GetAvgSamplesAsync(CancellationToken cancellationToken)
{
if (!wasInitialized)
{
await InitializeAsync();
}
if (channels == 0)
{
throw new InvalidOperationException("Channel count is set to 0");
}
var samplesCount = GetSamplesCount();
var samples = new float[samplesCount];
var buffer = new byte[4096];
var sampleIndex = 0;
int bytesRead;
do
{
bytesRead = await waveStream.ReadAsync(buffer, 0, buffer.Length, cancellationToken);
for (var i = 0; i < bytesRead;)
{
long sampleSum = 0;
for (var currentChannel = 0; currentChannel < channels; currentChannel++)
{
sampleSum += BitConverter.ToInt16(buffer, i);
i += 2;
}
samples[sampleIndex++] = sampleSum / (float)channels / 32768.0f;
}
} while (bytesRead > 0);
return samples;
}
/// <summary>
/// Returns the average samples from all channels.
/// </summary>
/// <returns></returns>
public float[] GetAvgSamples()
{
if (!wasInitialized)
{
Initialize();
}
var reader = GetDataReader();
var samplesCount = GetSamplesCount();
var samples = new float[samplesCount];
for (var i = 0; i < samplesCount; i++)
{
var sampleSum = 0L;
for (var currentChannel = 0; currentChannel < channels; currentChannel++)
{
sampleSum += reader.ReadInt16();
}
samples[i] = (sampleSum / 4) / 32768.0f;
}
return samples;
}
public float[] GetChannelSamples(int channelIndex = 0)
{
if (!wasInitialized)
{
Initialize();
}
var reader = GetDataReader();
var samplesCount = GetSamplesCount();
var samples = new float[samplesCount];
for (var i = 0; i < samplesCount; i++)
{
for (var currentChannel = 0; currentChannel < channels; currentChannel++)
{
if (channelIndex == currentChannel)
{
samples[i] = reader.ReadInt16() / 32768.0f;
}
else
{
_ = reader.ReadInt16();
}
}
}
return samples;
}
private void Initialize()
{
if (wasInitialized)
{
return;
}
var buffer = new byte[36];
//Read RIFF Header
var actualRead = waveStream.Read(buffer, 0, 36);
if (actualRead != 36)
{
throw new CorruptedWaveException("Invalid wave file, the size is too small.");
}
if (buffer[0] != 'R' || buffer[1] != 'I' || buffer[2] != 'F' || buffer[3] != 'F')
{
throw new CorruptedWaveException("Invalid wave file RIFF header.");
}
// Skip FileSize 4 => 8
// Read Wave and Fmt tags
if (buffer[8] != 'W' || buffer[9] != 'A' || buffer[10] != 'V' || buffer[11] != 'E' || buffer[12] != 'f' || buffer[13] != 'm' || buffer[14] != 't' || buffer[15] != ' ')
{
throw new CorruptedWaveException("Invalid wave file header.");
}
// Read Format Chunk Size
var formatChunkSize = BitConverter.ToInt32(buffer, 16);
if (formatChunkSize < 0)
{
throw new CorruptedWaveException("Invalid wave format size.");
}
// Read Format
var format = BitConverter.ToUInt16(buffer, 20);
if (format != 1)
{
throw new CorruptedWaveException("Unsupported wave file");
}
channels = BitConverter.ToUInt16(buffer, 22);
sampleRate = BitConverter.ToUInt32(buffer, 24);
if (sampleRate != 16000)
{
throw new NotSupportedWaveException("Only 16KHz sample rate is supported.");
}
// Skip Average bytes rate 28 => 32
// Skip Block Allign 32 => 34
bitsPerSample = BitConverter.ToUInt16(buffer, 34);
if (bitsPerSample != 16)
{
throw new NotSupportedWaveException("Only 16 bits per sample is supported.");
}
// Until now we have read 16 bytes in format, the rest is cbSize, averageBytesRate, and is ignored for now.
if (formatChunkSize > 16)
{
if (waveStream.CanSeek)
{
waveStream.Seek(formatChunkSize - 16, SeekOrigin.Current);
}
else
{
var restOfBuffer = new byte[formatChunkSize - 16];
waveStream.Read(restOfBuffer, 0, formatChunkSize - 16);
}
}
// Seek data chuunk
// Read chunk name and size
waveStream.Read(buffer, 0, 8);
while (buffer[0] != 'd' || buffer[1] != 'a' || buffer[2] != 't' || buffer[3] != 'a')
{
var chunkSize = BitConverter.ToInt32(buffer, 4);
if (chunkSize < 0)
{
throw new CorruptedWaveException("Invalid wave chunk size.");
}
if (waveStream.CanSeek)
{
waveStream.Seek(chunkSize, SeekOrigin.Current);
}
else
{
var restOfChunk = new byte[chunkSize];
waveStream.Read(restOfChunk, 0, chunkSize);
}
actualRead = waveStream.Read(buffer, 0, 8);
if (actualRead != 8)
{
throw new CorruptedWaveException("Invalid wave chunk size.");
}
}
dataChunkSize = BitConverter.ToUInt32(buffer, 4);
dataChunkPosition = waveStream.Position;
wasInitialized = true;
}
private async Task InitializeAsync()
{
if (wasInitialized)
{
return;
}
var buffer = new byte[36];
var actualRead = waveStream.Read(buffer, 0, 36);
if (actualRead != 36)
{
throw new CorruptedWaveException("Invalid wave file, the size is too small.");
}
//Read RIFF Header
if (buffer[0] != 'R' || buffer[1] != 'I' || buffer[2] != 'F' || buffer[3] != 'F')
{
throw new CorruptedWaveException("Invalid wave file RIFF header.");
}
// Skip FileSize 4 => 8
// Read Wave and Fmt tags
if (buffer[8] != 'W' || buffer[9] != 'A' || buffer[10] != 'V' || buffer[11] != 'E' || buffer[12] != 'f' || buffer[13] != 'm' || buffer[14] != 't' || buffer[15] != ' ')
{
throw new CorruptedWaveException("Invalid wave file header.");
}
// Read Format Chunk Size
var formatChunkSize = BitConverter.ToInt32(buffer, 16);
if (formatChunkSize < 0)
{
throw new CorruptedWaveException("Invalid wave format size.");
}
// Read Format
var format = BitConverter.ToUInt16(buffer, 20);
if (format != 1)
{
throw new CorruptedWaveException("Unsupported wave file");
}
channels = BitConverter.ToUInt16(buffer, 22);
sampleRate = BitConverter.ToUInt32(buffer, 24);
if (sampleRate != 16000)
{
throw new NotSupportedWaveException("Only 16KHz sample rate is supported.");
}
// Skip Average bytes rate 28 => 32
// Skip Block Allign 32 => 34
bitsPerSample = BitConverter.ToUInt16(buffer, 34);
if (bitsPerSample != 16)
{
throw new NotSupportedWaveException("Only 16 bits per sample is supported.");
}
// Until now we have read 16 bytes in format, the rest is cbSize, averageBytesRate, and is ignored for now.
if (formatChunkSize > 16)
{
if (waveStream.CanSeek)
{
waveStream.Seek(formatChunkSize - 16, SeekOrigin.Current);
}
else
{
var restOfBuffer = new byte[formatChunkSize - 16];
await waveStream.ReadAsync(restOfBuffer, 0, formatChunkSize - 16);
}
}
// Seek data chuunk
// Read chunk name and size
await waveStream.ReadAsync(buffer, 0, 8);
while (buffer[0] != 'd' || buffer[1] != 'a' || buffer[2] != 't' || buffer[3] != 'a')
{
var chunkSize = BitConverter.ToInt32(buffer, 4);
if (chunkSize < 0)
{
throw new CorruptedWaveException("Invalid wave chunk size.");
}
if (waveStream.CanSeek)
{
waveStream.Seek(chunkSize, SeekOrigin.Current);
}
else
{
var restOfChunk = new byte[chunkSize];
await waveStream.ReadAsync(restOfChunk, 0, chunkSize);
}
actualRead = await waveStream.ReadAsync(buffer, 0, 8);
if (actualRead != 8)
{
throw new CorruptedWaveException("Invalid wave chunk size.");
}
}
dataChunkSize = BitConverter.ToUInt32(buffer, 4);
dataChunkPosition = waveStream.Position;
wasInitialized = true;
}
private BinaryReader GetDataReader()
{
var reader = new BinaryReader(waveStream);
if (waveStream.Position != dataChunkPosition)
{
waveStream.Seek(dataChunkPosition, SeekOrigin.Begin);
}
return reader;
}
}