Skip to content

Commit

Permalink
Provide endianness converters before writing or after reading WAV
Browse files Browse the repository at this point in the history
  • Loading branch information
@mymedia2
mymedia2 committed Jan 28, 2021
1 parent 6eaebec commit 65f002e
Show file tree
Hide file tree
Showing 2 changed files with 111 additions and 50 deletions.
80 changes: 64 additions & 16 deletions src/common_audio/wav_file.cc
View file
Expand Up @@ -10,6 +10,7 @@

#include "common_audio/wav_file.h"

#include <byteswap.h>
#include <errno.h>

#include <algorithm>
Expand All @@ -34,6 +35,38 @@ bool FormatSupported(WavFormat format) {
format == WavFormat::kWavFormatIeeeFloat;
}

template <typename T>
void TranslateEndianness(T* destination, const T* source, size_t length) {
static_assert(sizeof(T) == 2 || sizeof(T) == 4 || sizeof(T) == 8,
"no converter, use integral types");
if (sizeof(T) == 2) {
const uint16_t* src = reinterpret_cast<const uint16_t*>(source);
uint16_t* dst = reinterpret_cast<uint16_t*>(destination);
for (size_t index = 0; index < length; index++) {
dst[index] = bswap_16(src[index]);
}
}
if (sizeof(T) == 4) {
const uint32_t* src = reinterpret_cast<const uint32_t*>(source);
uint32_t* dst = reinterpret_cast<uint32_t*>(destination);
for (size_t index = 0; index < length; index++) {
dst[index] = bswap_32(src[index]);
}
}
if (sizeof(T) == 8) {
const uint64_t* src = reinterpret_cast<const uint64_t*>(source);
uint64_t* dst = reinterpret_cast<uint64_t*>(destination);
for (size_t index = 0; index < length; index++) {
dst[index] = bswap_64(src[index]);
}
}
}

template <typename T>
void TranslateEndianness(T* buffer, size_t length) {
TranslateEndianness(buffer, buffer, length);
}

// Doesn't take ownership of the file handle and won't close it.
class WavHeaderFileReader : public WavHeaderReader {
public:
Expand Down Expand Up @@ -89,10 +122,6 @@ void WavReader::Reset() {

size_t WavReader::ReadSamples(const size_t num_samples,
int16_t* const samples) {
#ifndef WEBRTC_ARCH_LITTLE_ENDIAN
#error "Need to convert samples to big-endian when reading from WAV file"
#endif

size_t num_samples_left_to_read = num_samples;
size_t next_chunk_start = 0;
while (num_samples_left_to_read > 0 && num_unread_samples_ > 0) {
Expand All @@ -105,6 +134,9 @@ size_t WavReader::ReadSamples(const size_t num_samples,
num_bytes_read = file_.Read(samples_to_convert.data(),
chunk_size * sizeof(samples_to_convert[0]));
num_samples_read = num_bytes_read / sizeof(samples_to_convert[0]);
#ifdef WEBRTC_ARCH_BIG_ENDIAN
TranslateEndianness(samples_to_convert.data(), num_samples_read);
#endif

for (size_t j = 0; j < num_samples_read; ++j) {
samples[next_chunk_start + j] = FloatToS16(samples_to_convert[j]);
Expand All @@ -114,6 +146,10 @@ size_t WavReader::ReadSamples(const size_t num_samples,
num_bytes_read = file_.Read(&samples[next_chunk_start],
chunk_size * sizeof(samples[0]));
num_samples_read = num_bytes_read / sizeof(samples[0]);

#ifdef WEBRTC_ARCH_BIG_ENDIAN
TranslateEndianness(&samples[next_chunk_start], num_samples_read);
#endif
}
RTC_CHECK(num_samples_read == 0 || (num_bytes_read % num_samples_read) == 0)
<< "Corrupt file: file ended in the middle of a sample.";
Expand All @@ -129,10 +165,6 @@ size_t WavReader::ReadSamples(const size_t num_samples,
}

size_t WavReader::ReadSamples(const size_t num_samples, float* const samples) {
#ifndef WEBRTC_ARCH_LITTLE_ENDIAN
#error "Need to convert samples to big-endian when reading from WAV file"
#endif

size_t num_samples_left_to_read = num_samples;
size_t next_chunk_start = 0;
while (num_samples_left_to_read > 0 && num_unread_samples_ > 0) {
Expand All @@ -145,6 +177,9 @@ size_t WavReader::ReadSamples(const size_t num_samples, float* const samples) {
num_bytes_read = file_.Read(samples_to_convert.data(),
chunk_size * sizeof(samples_to_convert[0]));
num_samples_read = num_bytes_read / sizeof(samples_to_convert[0]);
#ifdef WEBRTC_ARCH_BIG_ENDIAN
TranslateEndianness(samples_to_convert.data(), num_samples_read);
#endif

for (size_t j = 0; j < num_samples_read; ++j) {
samples[next_chunk_start + j] =
Expand All @@ -155,6 +190,9 @@ size_t WavReader::ReadSamples(const size_t num_samples, float* const samples) {
num_bytes_read = file_.Read(&samples[next_chunk_start],
chunk_size * sizeof(samples[0]));
num_samples_read = num_bytes_read / sizeof(samples[0]);
#ifdef WEBRTC_ARCH_BIG_ENDIAN
TranslateEndianness(&samples[next_chunk_start], num_samples_read);
#endif

for (size_t j = 0; j < num_samples_read; ++j) {
samples[next_chunk_start + j] =
Expand Down Expand Up @@ -213,24 +251,32 @@ WavWriter::WavWriter(FileWrapper file,
}

void WavWriter::WriteSamples(const int16_t* samples, size_t num_samples) {
#ifndef WEBRTC_ARCH_LITTLE_ENDIAN
#error "Need to convert samples to little-endian when writing to WAV file"
#endif

for (size_t i = 0; i < num_samples; i += kMaxChunksize) {
const size_t num_remaining_samples = num_samples - i;
const size_t num_samples_to_write =
std::min(kMaxChunksize, num_remaining_samples);

if (format_ == WavFormat::kWavFormatPcm) {
#ifndef WEBRTC_ARCH_BIG_ENDIAN
RTC_CHECK(
file_.Write(&samples[i], num_samples_to_write * sizeof(samples[0])));
#else
std::array<int16_t, kMaxChunksize> converted_samples;
TranslateEndianness(converted_samples.data(), &samples[i],
num_samples_to_write);
RTC_CHECK(
file_.Write(converted_samples.data(),
num_samples_to_write * sizeof(converted_samples[0])));
#endif
} else {
RTC_CHECK_EQ(format_, WavFormat::kWavFormatIeeeFloat);
std::array<float, kMaxChunksize> converted_samples;
for (size_t j = 0; j < num_samples_to_write; ++j) {
converted_samples[j] = S16ToFloat(samples[i + j]);
}
#ifdef WEBRTC_ARCH_BIG_ENDIAN
TranslateEndianness(converted_samples.data(), num_samples_to_write);
#endif
RTC_CHECK(
file_.Write(converted_samples.data(),
num_samples_to_write * sizeof(converted_samples[0])));
Expand All @@ -243,10 +289,6 @@ void WavWriter::WriteSamples(const int16_t* samples, size_t num_samples) {
}

void WavWriter::WriteSamples(const float* samples, size_t num_samples) {
#ifndef WEBRTC_ARCH_LITTLE_ENDIAN
#error "Need to convert samples to little-endian when writing to WAV file"
#endif

for (size_t i = 0; i < num_samples; i += kMaxChunksize) {
const size_t num_remaining_samples = num_samples - i;
const size_t num_samples_to_write =
Expand All @@ -257,6 +299,9 @@ void WavWriter::WriteSamples(const float* samples, size_t num_samples) {
for (size_t j = 0; j < num_samples_to_write; ++j) {
converted_samples[j] = FloatS16ToS16(samples[i + j]);
}
#ifdef WEBRTC_ARCH_BIG_ENDIAN
TranslateEndianness(converted_samples.data(), num_samples_to_write);
#endif
RTC_CHECK(
file_.Write(converted_samples.data(),
num_samples_to_write * sizeof(converted_samples[0])));
Expand All @@ -266,6 +311,9 @@ void WavWriter::WriteSamples(const float* samples, size_t num_samples) {
for (size_t j = 0; j < num_samples_to_write; ++j) {
converted_samples[j] = FloatS16ToFloat(samples[i + j]);
}
#ifdef WEBRTC_ARCH_BIG_ENDIAN
TranslateEndianness(converted_samples.data(), num_samples_to_write);
#endif
RTC_CHECK(
file_.Write(converted_samples.data(),
num_samples_to_write * sizeof(converted_samples[0])));
Expand Down
81 changes: 47 additions & 34 deletions src/common_audio/wav_header.cc
View file
Expand Up @@ -14,6 +14,8 @@

#include "common_audio/wav_header.h"

#include <endian.h>

#include <cstring>
#include <limits>
#include <string>
Expand All @@ -26,10 +28,6 @@
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;
Expand Down Expand Up @@ -174,6 +172,8 @@ bool FindWaveChunk(ChunkHeader* chunk_header,
if (readable->Read(chunk_header, sizeof(*chunk_header)) !=
sizeof(*chunk_header))
return false; // EOF.
chunk_header->Size = le32toh(chunk_header->Size);

if (ReadFourCC(chunk_header->ID) == sought_chunk_id)
return true; // Sought chunk found.
// Ignore current chunk by skipping its payload.
Expand All @@ -187,6 +187,13 @@ bool ReadFmtChunkData(FmtPcmSubchunk* fmt_subchunk, WavHeaderReader* readable) {
if (readable->Read(&(fmt_subchunk->AudioFormat), kFmtPcmSubchunkSize) !=
kFmtPcmSubchunkSize)
return false;
fmt_subchunk->AudioFormat = le16toh(fmt_subchunk->AudioFormat);
fmt_subchunk->NumChannels = le16toh(fmt_subchunk->NumChannels);
fmt_subchunk->SampleRate = le32toh(fmt_subchunk->SampleRate);
fmt_subchunk->ByteRate = le32toh(fmt_subchunk->ByteRate);
fmt_subchunk->BlockAlign = le16toh(fmt_subchunk->BlockAlign);
fmt_subchunk->BitsPerSample = le16toh(fmt_subchunk->BitsPerSample);

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
Expand Down Expand Up @@ -214,19 +221,22 @@ void WritePcmWavHeader(size_t num_channels,
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);
header.riff.header.ID = htole32(PackFourCC('R', 'I', 'F', 'F'));
header.riff.header.Size =
htole32(RiffChunkSize(bytes_in_payload, *header_size));
header.riff.Format = htole32(PackFourCC('W', 'A', 'V', 'E'));
header.fmt.header.ID = htole32(PackFourCC('f', 'm', 't', ' '));
header.fmt.header.Size = htole32(kFmtPcmSubchunkSize);
header.fmt.AudioFormat =
htole16(MapWavFormatToHeaderField(WavFormat::kWavFormatPcm));
header.fmt.NumChannels = htole16(num_channels);
header.fmt.SampleRate = htole32(sample_rate);
header.fmt.ByteRate =
htole32(ByteRate(num_channels, sample_rate, bytes_per_sample));
header.fmt.BlockAlign = htole16(BlockAlign(num_channels, bytes_per_sample));
header.fmt.BitsPerSample = htole16(8 * bytes_per_sample);
header.data.header.ID = htole32(PackFourCC('d', 'a', 't', 'a'));
header.data.header.Size = htole32(bytes_in_payload);

// Do an extra copy rather than writing everything to buf directly, since buf
// might not be correctly aligned.
Expand All @@ -245,24 +255,26 @@ void WriteIeeeFloatWavHeader(size_t num_channels,
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.riff.header.ID = htole32(PackFourCC('R', 'I', 'F', 'F'));
header.riff.header.Size =
htole32(RiffChunkSize(bytes_in_payload, *header_size));
header.riff.Format = htole32(PackFourCC('W', 'A', 'V', 'E'));
header.fmt.header.ID = htole32(PackFourCC('f', 'm', 't', ' '));
header.fmt.header.Size = htole32(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);
htole16(MapWavFormatToHeaderField(WavFormat::kWavFormatIeeeFloat));
header.fmt.NumChannels = htole16(num_channels);
header.fmt.SampleRate = htole32(sample_rate);
header.fmt.ByteRate =
htole32(ByteRate(num_channels, sample_rate, bytes_per_sample));
header.fmt.BlockAlign = htole16(BlockAlign(num_channels, bytes_per_sample));
header.fmt.BitsPerSample = htole16(8 * bytes_per_sample);
header.fmt.ExtensionSize = htole16(0);
header.fact.header.ID = htole32(PackFourCC('f', 'a', 'c', 't'));
header.fact.header.Size = htole32(4);
header.fact.SampleLength = htole32(num_channels * num_samples);
header.data.header.ID = htole32(PackFourCC('d', 'a', 't', 'a'));
header.data.header.Size = htole32(bytes_in_payload);

// Do an extra copy rather than writing everything to buf directly, since buf
// might not be correctly aligned.
Expand Down Expand Up @@ -391,6 +403,7 @@ bool ReadWavHeader(WavHeaderReader* readable,
return false;
if (ReadFourCC(header.riff.Format) != "WAVE")
return false;
header.riff.header.Size = le32toh(header.riff.header.Size);

// 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
Expand Down

0 comments on commit 65f002e

Please sign in to comment.