src/third_party/webrtc/common_audio/wav_writer.cc

   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 #include "webrtc/common_audio/wav_writer.h"
  12
  13 #include <algorithm>
  14 #include <cstdio>
  15 #include <limits>
  16
  17 #include "webrtc/base/checks.h"
  18 #include "webrtc/common_audio/include/audio_util.h"
  19 #include "webrtc/common_audio/wav_header.h"
  20
  21 namespace webrtc {
  22
  23 // We write 16-bit PCM WAV files.
  24 static const WavFormat kWavFormat = kWavFormatPcm;
  25 static const int kBytesPerSample = 2;
  26
  27 WavFile::WavFile(const std::string& filename, int sample_rate, int num_channels)
  28     : sample_rate_(sample_rate),
  29       num_channels_(num_channels),
  30       num_samples_(0),
  31       file_handle_(fopen(filename.c_str(), "wb")) {
  32   CHECK(file_handle_);
  33   CHECK(CheckWavParameters(num_channels_,
  34                            sample_rate_,
  35                            kWavFormat,
  36                            kBytesPerSample,
  37                            num_samples_));
  38
  39   // Write a blank placeholder header, since we need to know the total number
  40   // of samples before we can fill in the real data.
  41   static const uint8_t blank_header[kWavHeaderSize] = {0};
  42   CHECK_EQ(1u, fwrite(blank_header, kWavHeaderSize, 1, file_handle_));
  43 }
  44
  45 WavFile::~WavFile() {
  46   Close();
  47 }
  48
  49 void WavFile::WriteSamples(const int16_t* samples, size_t num_samples) {
  50 #ifndef WEBRTC_ARCH_LITTLE_ENDIAN
  51 #error "Need to convert samples to little-endian when writing to WAV file"
  52 #endif
  53   const size_t written =
  54       fwrite(samples, sizeof(*samples), num_samples, file_handle_);
  55   CHECK_EQ(num_samples, written);
  56   num_samples_ += static_cast<uint32_t>(written);
  57   CHECK(written <= std::numeric_limits<uint32_t>::max() ||
  58         num_samples_ >= written);  // detect uint32_t overflow
  59   CHECK(CheckWavParameters(num_channels_,
  60                            sample_rate_,
  61                            kWavFormat,
  62                            kBytesPerSample,
  63                            num_samples_));
  64 }
  65
  66 void WavFile::WriteSamples(const float* samples, size_t num_samples) {
  67   static const size_t kChunksize = 4096 / sizeof(uint16_t);
  68   for (size_t i = 0; i < num_samples; i += kChunksize) {
  69     int16_t isamples[kChunksize];
  70     const size_t chunk = std::min(kChunksize, num_samples - i);
  71     RoundToInt16(samples + i, chunk, isamples);
  72     WriteSamples(isamples, chunk);
  73   }
  74 }
  75
  76 void WavFile::Close() {
  77   CHECK_EQ(0, fseek(file_handle_, 0, SEEK_SET));
  78   uint8_t header[kWavHeaderSize];
  79   WriteWavHeader(header, num_channels_, sample_rate_, kWavFormat,
  80                  kBytesPerSample, num_samples_);
  81   CHECK_EQ(1u, fwrite(header, kWavHeaderSize, 1, file_handle_));
  82   CHECK_EQ(0, fclose(file_handle_));
  83   file_handle_ = NULL;
  84 }
  85
  86 }  // namespace webrtc
  87
  88 rtc_WavFile* rtc_WavOpen(const char* filename,
  89                          int sample_rate,
  90                          int num_channels) {
  91   return reinterpret_cast<rtc_WavFile*>(
  92       new webrtc::WavFile(filename, sample_rate, num_channels));
  93 }
  94
  95 void rtc_WavClose(rtc_WavFile* wf) {
  96   delete reinterpret_cast<webrtc::WavFile*>(wf);
  97 }
  98
  99 void rtc_WavWriteSamples(rtc_WavFile* wf,
 100                          const float* samples,
 101                          size_t num_samples) {
 102   reinterpret_cast<webrtc::WavFile*>(wf)->WriteSamples(samples, num_samples);
 103 }
 104
 105 int rtc_WavSampleRate(const rtc_WavFile* wf) {
 106   return reinterpret_cast<const webrtc::WavFile*>(wf)->sample_rate();
 107 }
 108
 109 int rtc_WavNumChannels(const rtc_WavFile* wf) {
 110   return reinterpret_cast<const webrtc::WavFile*>(wf)->num_channels();
 111 }
 112
 113 uint32_t rtc_WavNumSamples(const rtc_WavFile* wf) {
 114   return reinterpret_cast<const webrtc::WavFile*>(wf)->num_samples();
 115 }