bool
WaveReader::LoadFormatChunk(uint32_t aChunkSize)
{
uint32_t rate, channels, frameSize, sampleFormat;
char waveFormat[WAVE_FORMAT_CHUNK_SIZE];
const char* p = waveFormat;
// RIFF chunks are always word (two byte) aligned.
MOZ_ASSERT(mDecoder->GetResource()->Tell() % 2 == 0,
"LoadFormatChunk called with unaligned resource");
if (!ReadAll(waveFormat, sizeof(waveFormat))) {
return false;
}
static_assert(sizeof(uint16_t) +
sizeof(uint16_t) +
sizeof(uint32_t) +
4 +
sizeof(uint16_t) +
sizeof(uint16_t) <= sizeof(waveFormat),
"Reads would overflow waveFormat buffer.");
if (ReadUint16LE(&p) != WAVE_FORMAT_ENCODING_PCM) {
NS_WARNING("WAVE is not uncompressed PCM, compressed encodings are not supported");
return false;
}
channels = ReadUint16LE(&p);
rate = ReadUint32LE(&p);
// Skip over average bytes per second field.
p += 4;
frameSize = ReadUint16LE(&p);
sampleFormat = ReadUint16LE(&p);
// PCM encoded WAVEs are not expected to have an extended "format" chunk,
// but I have found WAVEs that have a extended "format" chunk with an
// extension size of 0 bytes. Be polite and handle this rather than
// considering the file invalid. This code skips any extension of the
// "format" chunk.
if (aChunkSize > WAVE_FORMAT_CHUNK_SIZE) {
char extLength[2];
const char* p = extLength;
if (!ReadAll(extLength, sizeof(extLength))) {
return false;
}
static_assert(sizeof(uint16_t) <= sizeof(extLength),
"Reads would overflow extLength buffer.");
uint16_t extra = ReadUint16LE(&p);
if (aChunkSize - (WAVE_FORMAT_CHUNK_SIZE + 2) != extra) {
NS_WARNING("Invalid extended format chunk size");
return false;
}
extra += extra % 2;
if (extra > 0) {
static_assert(UINT16_MAX + (UINT16_MAX % 2) < UINT_MAX / sizeof(char),
"chunkExtension array too large for iterator.");
nsAutoArrayPtr<char> chunkExtension(new char[extra]);
if (!ReadAll(chunkExtension.get(), extra)) {
return false;
}
}
}
// RIFF chunks are always word (two byte) aligned.
MOZ_ASSERT(mDecoder->GetResource()->Tell() % 2 == 0,
"LoadFormatChunk left resource unaligned");
// Make sure metadata is fairly sane. The rate check is fairly arbitrary,
// but the channels check is intentionally limited to mono or stereo
// when the media is intended for direct playback because that's what the
// audio backend currently supports.
unsigned int actualFrameSize = (sampleFormat == 8 ? 1 : 2) * channels;
if (rate < 100 || rate > 96000 ||
(((channels < 1 || channels > MAX_CHANNELS) ||
(frameSize != 1 && frameSize != 2 && frameSize != 4)) &&
!mIgnoreAudioOutputFormat) ||
(sampleFormat != 8 && sampleFormat != 16) ||
frameSize != actualFrameSize) {
NS_WARNING("Invalid WAVE metadata");
return false;
}
ReentrantMonitorAutoEnter monitor(mDecoder->GetReentrantMonitor());
mSampleRate = rate;
mChannels = channels;
mFrameSize = frameSize;
if (sampleFormat == 8) {
mSampleFormat = FORMAT_U8;
} else {
mSampleFormat = FORMAT_S16;
}
return true;
}
bool
WaveReader::LoadFormatChunk()
{
uint32_t fmtSize, rate, channels, frameSize, sampleFormat;
char waveFormat[WAVE_FORMAT_CHUNK_SIZE];
const char* p = waveFormat;
// RIFF chunks are always word (two byte) aligned.
NS_ABORT_IF_FALSE(mDecoder->GetResource()->Tell() % 2 == 0,
"LoadFormatChunk called with unaligned resource");
// The "format" chunk may not directly follow the "riff" chunk, so skip
// over any intermediate chunks.
if (!ScanForwardUntil(FRMT_CHUNK_MAGIC, &fmtSize)) {
return false;
}
if (!ReadAll(waveFormat, sizeof(waveFormat))) {
return false;
}
PR_STATIC_ASSERT(sizeof(uint16_t) +
sizeof(uint16_t) +
sizeof(uint32_t) +
4 +
sizeof(uint16_t) +
sizeof(uint16_t) <= sizeof(waveFormat));
if (ReadUint16LE(&p) != WAVE_FORMAT_ENCODING_PCM) {
NS_WARNING("WAVE is not uncompressed PCM, compressed encodings are not supported");
return false;
}
channels = ReadUint16LE(&p);
rate = ReadUint32LE(&p);
// Skip over average bytes per second field.
p += 4;
frameSize = ReadUint16LE(&p);
sampleFormat = ReadUint16LE(&p);
// PCM encoded WAVEs are not expected to have an extended "format" chunk,
// but I have found WAVEs that have a extended "format" chunk with an
// extension size of 0 bytes. Be polite and handle this rather than
// considering the file invalid. This code skips any extension of the
// "format" chunk.
if (fmtSize > WAVE_FORMAT_CHUNK_SIZE) {
char extLength[2];
const char* p = extLength;
if (!ReadAll(extLength, sizeof(extLength))) {
return false;
}
PR_STATIC_ASSERT(sizeof(uint16_t) <= sizeof(extLength));
uint16_t extra = ReadUint16LE(&p);
if (fmtSize - (WAVE_FORMAT_CHUNK_SIZE + 2) != extra) {
NS_WARNING("Invalid extended format chunk size");
return false;
}
extra += extra % 2;
if (extra > 0) {
PR_STATIC_ASSERT(UINT16_MAX + (UINT16_MAX % 2) < UINT_MAX / sizeof(char));
nsAutoArrayPtr<char> chunkExtension(new char[extra]);
if (!ReadAll(chunkExtension.get(), extra)) {
return false;
}
}
}
// RIFF chunks are always word (two byte) aligned.
NS_ABORT_IF_FALSE(mDecoder->GetResource()->Tell() % 2 == 0,
"LoadFormatChunk left resource unaligned");
// Make sure metadata is fairly sane. The rate check is fairly arbitrary,
// but the channels check is intentionally limited to mono or stereo
// because that's what the audio backend currently supports.
unsigned int actualFrameSize = sampleFormat == 8 ? 1 : 2 * channels;
if (rate < 100 || rate > 96000 ||
channels < 1 || channels > MAX_CHANNELS ||
(frameSize != 1 && frameSize != 2 && frameSize != 4) ||
(sampleFormat != 8 && sampleFormat != 16) ||
frameSize != actualFrameSize) {
NS_WARNING("Invalid WAVE metadata");
return false;
}
ReentrantMonitorAutoEnter monitor(mDecoder->GetReentrantMonitor());
mSampleRate = rate;
mChannels = channels;
mFrameSize = frameSize;
if (sampleFormat == 8) {
mSampleFormat = FORMAT_U8;
} else {
mSampleFormat = FORMAT_S16;
}
return true;
}
