1 /*
2 * Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
11 #ifndef COMMON_AUDIO_WAV_HEADER_H_
12 #define COMMON_AUDIO_WAV_HEADER_H_
13
14 #include <stddef.h>
15 #include <stdint.h>
16 #include <algorithm>
17
18 #include "rtc_base/checks.h"
19
20 namespace webrtc {
21
22 // Interface providing header reading functionality.
23 class WavHeaderReader {
24 public:
25 // Returns the number of bytes read.
26 virtual size_t Read(void* buf, size_t num_bytes) = 0;
27 virtual bool SeekForward(uint32_t num_bytes) = 0;
28 virtual ~WavHeaderReader() = default;
29 virtual int64_t GetPosition() = 0;
30 };
31
32 // Possible WAV formats.
33 enum class WavFormat {
34 kWavFormatPcm = 1, // PCM, each sample of size bytes_per_sample.
35 kWavFormatIeeeFloat = 3, // IEEE float.
36 kWavFormatALaw = 6, // 8-bit ITU-T G.711 A-law.
37 kWavFormatMuLaw = 7, // 8-bit ITU-T G.711 mu-law.
38 };
39
40 // Header sizes for supported WAV formats.
41 constexpr size_t kPcmWavHeaderSize = 44;
42 constexpr size_t kIeeeFloatWavHeaderSize = 58;
43
44 // Returns the size of the WAV header for the specified format.
WavHeaderSize(WavFormat format)45 constexpr size_t WavHeaderSize(WavFormat format) {
46 if (format == WavFormat::kWavFormatPcm) {
47 return kPcmWavHeaderSize;
48 }
49 RTC_CHECK_EQ(format, WavFormat::kWavFormatIeeeFloat);
50 return kIeeeFloatWavHeaderSize;
51 }
52
53 // Returns the maximum size of the supported WAV formats.
MaxWavHeaderSize()54 constexpr size_t MaxWavHeaderSize() {
55 return std::max(WavHeaderSize(WavFormat::kWavFormatPcm),
56 WavHeaderSize(WavFormat::kWavFormatIeeeFloat));
57 }
58
59 // Return true if the given parameters will make a well-formed WAV header.
60 bool CheckWavParameters(size_t num_channels,
61 int sample_rate,
62 WavFormat format,
63 size_t num_samples);
64
65 // Write a kWavHeaderSize bytes long WAV header to buf. The payload that
66 // follows the header is supposed to have the specified number of interleaved
67 // channels and contain the specified total number of samples of the specified
68 // type. The size of the header is returned in header_size. CHECKs the input
69 // parameters for validity.
70 void WriteWavHeader(size_t num_channels,
71 int sample_rate,
72 WavFormat format,
73 size_t num_samples,
74 uint8_t* buf,
75 size_t* header_size);
76
77 // Read a WAV header from an implemented WavHeaderReader and parse the values
78 // into the provided output parameters. WavHeaderReader is used because the
79 // header can be variably sized. Returns false if the header is invalid.
80 bool ReadWavHeader(WavHeaderReader* readable,
81 size_t* num_channels,
82 int* sample_rate,
83 WavFormat* format,
84 size_t* bytes_per_sample,
85 size_t* num_samples,
86 int64_t* data_start_pos);
87
88 } // namespace webrtc
89
90 #endif // COMMON_AUDIO_WAV_HEADER_H_
91