Repo created

TMessagesProj/jni/voip/webrtc/common_audio/wav_header.cc

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+/*
+ *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Based on the WAV file format documentation at
+// https://ccrma.stanford.edu/courses/422/projects/WaveFormat/ and
+// http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/WAVE.html
+
+#include "common_audio/wav_header.h"
+
+#include <cstring>
+#include <limits>
+#include <string>
+
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/sanitizer.h"
+#include "rtc_base/system/arch.h"
+
+namespace webrtc {
+namespace {
+
+#ifndef WEBRTC_ARCH_LITTLE_ENDIAN
+#error "Code not working properly for big endian platforms."
+#endif
+
+#pragma pack(2)
+struct ChunkHeader {
+  uint32_t ID;
+  uint32_t Size;
+};
+static_assert(sizeof(ChunkHeader) == 8, "ChunkHeader size");
+
+#pragma pack(2)
+struct RiffHeader {
+  ChunkHeader header;
+  uint32_t Format;
+};
+static_assert(sizeof(RiffHeader) == sizeof(ChunkHeader) + 4, "RiffHeader size");
+
+// We can't nest this definition in WavHeader, because VS2013 gives an error
+// on sizeof(WavHeader::fmt): "error C2070: 'unknown': illegal sizeof operand".
+#pragma pack(2)
+struct FmtPcmSubchunk {
+  ChunkHeader header;
+  uint16_t AudioFormat;
+  uint16_t NumChannels;
+  uint32_t SampleRate;
+  uint32_t ByteRate;
+  uint16_t BlockAlign;
+  uint16_t BitsPerSample;
+};
+static_assert(sizeof(FmtPcmSubchunk) == 24, "FmtPcmSubchunk size");
+const uint32_t kFmtPcmSubchunkSize =
+    sizeof(FmtPcmSubchunk) - sizeof(ChunkHeader);
+
+// Pack struct to avoid additional padding bytes.
+#pragma pack(2)
+struct FmtIeeeFloatSubchunk {
+  ChunkHeader header;
+  uint16_t AudioFormat;
+  uint16_t NumChannels;
+  uint32_t SampleRate;
+  uint32_t ByteRate;
+  uint16_t BlockAlign;
+  uint16_t BitsPerSample;
+  uint16_t ExtensionSize;
+};
+static_assert(sizeof(FmtIeeeFloatSubchunk) == 26, "FmtIeeeFloatSubchunk size");
+const uint32_t kFmtIeeeFloatSubchunkSize =
+    sizeof(FmtIeeeFloatSubchunk) - sizeof(ChunkHeader);
+
+// Simple PCM wav header. It does not include chunks that are not essential to
+// read audio samples.
+#pragma pack(2)
+struct WavHeaderPcm {
+  RiffHeader riff;
+  FmtPcmSubchunk fmt;
+  struct {
+    ChunkHeader header;
+  } data;
+};
+static_assert(sizeof(WavHeaderPcm) == kPcmWavHeaderSize,
+              "no padding in header");
+
+// IEEE Float Wav header, includes extra chunks necessary for proper non-PCM
+// WAV implementation.
+#pragma pack(2)
+struct WavHeaderIeeeFloat {
+  RiffHeader riff;
+  FmtIeeeFloatSubchunk fmt;
+  struct {
+    ChunkHeader header;
+    uint32_t SampleLength;
+  } fact;
+  struct {
+    ChunkHeader header;
+  } data;
+};
+static_assert(sizeof(WavHeaderIeeeFloat) == kIeeeFloatWavHeaderSize,
+              "no padding in header");
+
+uint32_t PackFourCC(char a, char b, char c, char d) {
+  uint32_t packed_value =
+      static_cast<uint32_t>(a) | static_cast<uint32_t>(b) << 8 |
+      static_cast<uint32_t>(c) << 16 | static_cast<uint32_t>(d) << 24;
+  return packed_value;
+}
+
+std::string ReadFourCC(uint32_t x) {
+  return std::string(reinterpret_cast<char*>(&x), 4);
+}
+
+uint16_t MapWavFormatToHeaderField(WavFormat format) {
+  switch (format) {
+    case WavFormat::kWavFormatPcm:
+      return 1;
+    case WavFormat::kWavFormatIeeeFloat:
+      return 3;
+    case WavFormat::kWavFormatALaw:
+      return 6;
+    case WavFormat::kWavFormatMuLaw:
+      return 7;
+  }
+  RTC_CHECK_NOTREACHED();
+}
+
+WavFormat MapHeaderFieldToWavFormat(uint16_t format_header_value) {
+  if (format_header_value == 1) {
+    return WavFormat::kWavFormatPcm;
+  }
+  if (format_header_value == 3) {
+    return WavFormat::kWavFormatIeeeFloat;
+  }
+
+  RTC_CHECK(false) << "Unsupported WAV format";
+}
+
+uint32_t RiffChunkSize(size_t bytes_in_payload, size_t header_size) {
+  return static_cast<uint32_t>(bytes_in_payload + header_size -
+                               sizeof(ChunkHeader));
+}
+
+uint32_t ByteRate(size_t num_channels,
+                  int sample_rate,
+                  size_t bytes_per_sample) {
+  return static_cast<uint32_t>(num_channels * sample_rate * bytes_per_sample);
+}
+
+uint16_t BlockAlign(size_t num_channels, size_t bytes_per_sample) {
+  return static_cast<uint16_t>(num_channels * bytes_per_sample);
+}
+
+// Finds a chunk having the sought ID. If found, then `readable` points to the
+// first byte of the sought chunk data. If not found, the end of the file is
+// reached.
+bool FindWaveChunk(ChunkHeader* chunk_header,
+                   WavHeaderReader* readable,
+                   const std::string sought_chunk_id) {
+  RTC_DCHECK_EQ(sought_chunk_id.size(), 4);
+  while (true) {
+    if (readable->Read(chunk_header, sizeof(*chunk_header)) !=
+        sizeof(*chunk_header))
+      return false;  // EOF.
+    if (ReadFourCC(chunk_header->ID) == sought_chunk_id)
+      return true;  // Sought chunk found.
+    // Ignore current chunk by skipping its payload.
+    if (!readable->SeekForward(chunk_header->Size))
+      return false;  // EOF or error.
+  }
+}
+
+bool ReadFmtChunkData(FmtPcmSubchunk* fmt_subchunk, WavHeaderReader* readable) {
+  // Reads "fmt " chunk payload.
+  if (readable->Read(&(fmt_subchunk->AudioFormat), kFmtPcmSubchunkSize) !=
+      kFmtPcmSubchunkSize)
+    return false;
+  const uint32_t fmt_size = fmt_subchunk->header.Size;
+  if (fmt_size != kFmtPcmSubchunkSize) {
+    // There is an optional two-byte extension field permitted to be present
+    // with PCM, but which must be zero.
+    int16_t ext_size;
+    if (kFmtPcmSubchunkSize + sizeof(ext_size) != fmt_size)
+      return false;
+    if (readable->Read(&ext_size, sizeof(ext_size)) != sizeof(ext_size))
+      return false;
+    if (ext_size != 0)
+      return false;
+  }
+  return true;
+}
+
+void WritePcmWavHeader(size_t num_channels,
+                       int sample_rate,
+                       size_t bytes_per_sample,
+                       size_t num_samples,
+                       uint8_t* buf,
+                       size_t* header_size) {
+  RTC_CHECK(buf);
+  RTC_CHECK(header_size);
+  *header_size = kPcmWavHeaderSize;
+  auto header = rtc::MsanUninitialized<WavHeaderPcm>({});
+  const size_t bytes_in_payload = bytes_per_sample * num_samples;
+
+  header.riff.header.ID = PackFourCC('R', 'I', 'F', 'F');
+  header.riff.header.Size = RiffChunkSize(bytes_in_payload, *header_size);
+  header.riff.Format = PackFourCC('W', 'A', 'V', 'E');
+  header.fmt.header.ID = PackFourCC('f', 'm', 't', ' ');
+  header.fmt.header.Size = kFmtPcmSubchunkSize;
+  header.fmt.AudioFormat = MapWavFormatToHeaderField(WavFormat::kWavFormatPcm);
+  header.fmt.NumChannels = static_cast<uint16_t>(num_channels);
+  header.fmt.SampleRate = sample_rate;
+  header.fmt.ByteRate = ByteRate(num_channels, sample_rate, bytes_per_sample);
+  header.fmt.BlockAlign = BlockAlign(num_channels, bytes_per_sample);
+  header.fmt.BitsPerSample = static_cast<uint16_t>(8 * bytes_per_sample);
+  header.data.header.ID = PackFourCC('d', 'a', 't', 'a');
+  header.data.header.Size = static_cast<uint32_t>(bytes_in_payload);
+
+  // Do an extra copy rather than writing everything to buf directly, since buf
+  // might not be correctly aligned.
+  memcpy(buf, &header, *header_size);
+}
+
+void WriteIeeeFloatWavHeader(size_t num_channels,
+                             int sample_rate,
+                             size_t bytes_per_sample,
+                             size_t num_samples,
+                             uint8_t* buf,
+                             size_t* header_size) {
+  RTC_CHECK(buf);
+  RTC_CHECK(header_size);
+  *header_size = kIeeeFloatWavHeaderSize;
+  auto header = rtc::MsanUninitialized<WavHeaderIeeeFloat>({});
+  const size_t bytes_in_payload = bytes_per_sample * num_samples;
+
+  header.riff.header.ID = PackFourCC('R', 'I', 'F', 'F');
+  header.riff.header.Size = RiffChunkSize(bytes_in_payload, *header_size);
+  header.riff.Format = PackFourCC('W', 'A', 'V', 'E');
+  header.fmt.header.ID = PackFourCC('f', 'm', 't', ' ');
+  header.fmt.header.Size = kFmtIeeeFloatSubchunkSize;
+  header.fmt.AudioFormat =
+      MapWavFormatToHeaderField(WavFormat::kWavFormatIeeeFloat);
+  header.fmt.NumChannels = static_cast<uint16_t>(num_channels);
+  header.fmt.SampleRate = sample_rate;
+  header.fmt.ByteRate = ByteRate(num_channels, sample_rate, bytes_per_sample);
+  header.fmt.BlockAlign = BlockAlign(num_channels, bytes_per_sample);
+  header.fmt.BitsPerSample = static_cast<uint16_t>(8 * bytes_per_sample);
+  header.fmt.ExtensionSize = 0;
+  header.fact.header.ID = PackFourCC('f', 'a', 'c', 't');
+  header.fact.header.Size = 4;
+  header.fact.SampleLength = static_cast<uint32_t>(num_channels * num_samples);
+  header.data.header.ID = PackFourCC('d', 'a', 't', 'a');
+  header.data.header.Size = static_cast<uint32_t>(bytes_in_payload);
+
+  // Do an extra copy rather than writing everything to buf directly, since buf
+  // might not be correctly aligned.
+  memcpy(buf, &header, *header_size);
+}
+
+// Returns the number of bytes per sample for the format.
+size_t GetFormatBytesPerSample(WavFormat format) {
+  switch (format) {
+    case WavFormat::kWavFormatPcm:
+      // Other values may be OK, but for now we're conservative.
+      return 2;
+    case WavFormat::kWavFormatALaw:
+    case WavFormat::kWavFormatMuLaw:
+      return 1;
+    case WavFormat::kWavFormatIeeeFloat:
+      return 4;
+  }
+  RTC_CHECK_NOTREACHED();
+}
+
+bool CheckWavParameters(size_t num_channels,
+                        int sample_rate,
+                        WavFormat format,
+                        size_t bytes_per_sample,
+                        size_t num_samples) {
+  // num_channels, sample_rate, and bytes_per_sample must be positive, must fit
+  // in their respective fields, and their product must fit in the 32-bit
+  // ByteRate field.
+  if (num_channels == 0 || sample_rate <= 0 || bytes_per_sample == 0)
+    return false;
+  if (static_cast<uint64_t>(sample_rate) > std::numeric_limits<uint32_t>::max())
+    return false;
+  if (num_channels > std::numeric_limits<uint16_t>::max())
+    return false;
+  if (static_cast<uint64_t>(bytes_per_sample) * 8 >
+      std::numeric_limits<uint16_t>::max())
+    return false;
+  if (static_cast<uint64_t>(sample_rate) * num_channels * bytes_per_sample >
+      std::numeric_limits<uint32_t>::max())
+    return false;
+
+  // format and bytes_per_sample must agree.
+  switch (format) {
+    case WavFormat::kWavFormatPcm:
+      // Other values may be OK, but for now we're conservative:
+      if (bytes_per_sample != 1 && bytes_per_sample != 2)
+        return false;
+      break;
+    case WavFormat::kWavFormatALaw:
+    case WavFormat::kWavFormatMuLaw:
+      if (bytes_per_sample != 1)
+        return false;
+      break;
+    case WavFormat::kWavFormatIeeeFloat:
+      if (bytes_per_sample != 4)
+        return false;
+      break;
+    default:
+      return false;
+  }
+
+  // The number of bytes in the file, not counting the first ChunkHeader, must
+  // be less than 2^32; otherwise, the ChunkSize field overflows.
+  const size_t header_size = kPcmWavHeaderSize - sizeof(ChunkHeader);
+  const size_t max_samples =
+      (std::numeric_limits<uint32_t>::max() - header_size) / bytes_per_sample;
+  if (num_samples > max_samples)
+    return false;
+
+  // Each channel must have the same number of samples.
+  if (num_samples % num_channels != 0)
+    return false;
+
+  return true;
+}
+
+}  // namespace
+
+bool CheckWavParameters(size_t num_channels,
+                        int sample_rate,
+                        WavFormat format,
+                        size_t num_samples) {
+  return CheckWavParameters(num_channels, sample_rate, format,
+                            GetFormatBytesPerSample(format), num_samples);
+}
+
+void WriteWavHeader(size_t num_channels,
+                    int sample_rate,
+                    WavFormat format,
+                    size_t num_samples,
+                    uint8_t* buf,
+                    size_t* header_size) {
+  RTC_CHECK(buf);
+  RTC_CHECK(header_size);
+
+  const size_t bytes_per_sample = GetFormatBytesPerSample(format);
+  RTC_CHECK(CheckWavParameters(num_channels, sample_rate, format,
+                               bytes_per_sample, num_samples));
+  if (format == WavFormat::kWavFormatPcm) {
+    WritePcmWavHeader(num_channels, sample_rate, bytes_per_sample, num_samples,
+                      buf, header_size);
+  } else {
+    RTC_CHECK_EQ(format, WavFormat::kWavFormatIeeeFloat);
+    WriteIeeeFloatWavHeader(num_channels, sample_rate, bytes_per_sample,
+                            num_samples, buf, header_size);
+  }
+}
+
+bool ReadWavHeader(WavHeaderReader* readable,
+                   size_t* num_channels,
+                   int* sample_rate,
+                   WavFormat* format,
+                   size_t* bytes_per_sample,
+                   size_t* num_samples,
+                   int64_t* data_start_pos) {
+  // Read using the PCM header, even though it might be float Wav file
+  auto header = rtc::MsanUninitialized<WavHeaderPcm>({});
+
+  // Read RIFF chunk.
+  if (readable->Read(&header.riff, sizeof(header.riff)) != sizeof(header.riff))
+    return false;
+  if (ReadFourCC(header.riff.header.ID) != "RIFF")
+    return false;
+  if (ReadFourCC(header.riff.Format) != "WAVE")
+    return false;
+
+  // Find "fmt " and "data" chunks. While the official Wave file specification
+  // does not put requirements on the chunks order, it is uncommon to find the
+  // "data" chunk before the "fmt " one. The code below fails if this is not the
+  // case.
+  if (!FindWaveChunk(&header.fmt.header, readable, "fmt ")) {
+    RTC_LOG(LS_ERROR) << "Cannot find 'fmt ' chunk.";
+    return false;
+  }
+  if (!ReadFmtChunkData(&header.fmt, readable)) {
+    RTC_LOG(LS_ERROR) << "Cannot read 'fmt ' chunk.";
+    return false;
+  }
+  if (!FindWaveChunk(&header.data.header, readable, "data")) {
+    RTC_LOG(LS_ERROR) << "Cannot find 'data' chunk.";
+    return false;
+  }
+
+  // Parse needed fields.
+  *format = MapHeaderFieldToWavFormat(header.fmt.AudioFormat);
+  *num_channels = header.fmt.NumChannels;
+  *sample_rate = header.fmt.SampleRate;
+  *bytes_per_sample = header.fmt.BitsPerSample / 8;
+  const size_t bytes_in_payload = header.data.header.Size;
+  if (*bytes_per_sample == 0)
+    return false;
+  *num_samples = bytes_in_payload / *bytes_per_sample;
+
+  const size_t header_size = *format == WavFormat::kWavFormatPcm
+                                 ? kPcmWavHeaderSize
+                                 : kIeeeFloatWavHeaderSize;
+
+  if (header.riff.header.Size < RiffChunkSize(bytes_in_payload, header_size))
+    return false;
+  if (header.fmt.ByteRate !=
+      ByteRate(*num_channels, *sample_rate, *bytes_per_sample))
+    return false;
+  if (header.fmt.BlockAlign != BlockAlign(*num_channels, *bytes_per_sample))
+    return false;
+
+  if (!CheckWavParameters(*num_channels, *sample_rate, *format,
+                          *bytes_per_sample, *num_samples)) {
+    return false;
+  }
+
+  *data_start_pos = readable->GetPosition();
+  return true;
+}
+
+}  // namespace webrtc