Source code

Revision control

Other Tools

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "ADTSDemuxer.h"
#include "TimeUnits.h"
#include "VideoUtils.h"
#include "mozilla/UniquePtr.h"
#include <inttypes.h>
extern mozilla::LazyLogModule gMediaDemuxerLog;
#define ADTSLOG(msg, ...) \
DDMOZ_LOG(gMediaDemuxerLog, LogLevel::Debug, msg, ##__VA_ARGS__)
#define ADTSLOGV(msg, ...) \
DDMOZ_LOG(gMediaDemuxerLog, LogLevel::Verbose, msg, ##__VA_ARGS__)
namespace mozilla {
namespace adts {
// adts::FrameHeader - Holds the ADTS frame header and its parsing
// state.
//
// ADTS Frame Structure
//
// 11111111 1111BCCD EEFFFFGH HHIJKLMM MMMMMMMM MMMOOOOO OOOOOOPP(QQQQQQQQ
// QQQQQQQQ)
//
// Header consists of 7 or 9 bytes(without or with CRC).
// Letter Length(bits) Description
// { sync } 12 syncword 0xFFF, all bits must be 1
// B 1 MPEG Version: 0 for MPEG-4, 1 for MPEG-2
// C 2 Layer: always 0
// D 1 protection absent, Warning, set to 1 if there is no
// CRC and 0 if there is CRC
// E 2 profile, the MPEG-4 Audio Object Type minus 1
// F 4 MPEG-4 Sampling Frequency Index (15 is forbidden)
// H 3 MPEG-4 Channel Configuration (in the case of 0, the
// channel configuration is sent via an in-band PCE)
// M 13 frame length, this value must include 7 or 9 bytes of
// header length: FrameLength =
// (ProtectionAbsent == 1 ? 7 : 9) + size(AACFrame)
// O 11 Buffer fullness
// P 2 Number of AAC frames(RDBs) in ADTS frame minus 1, for
// maximum compatibility always use 1 AAC frame per ADTS
// frame
// Q 16 CRC if protection absent is 0
class FrameHeader {
public:
uint32_t mFrameLength;
uint32_t mSampleRate;
uint32_t mSamples;
uint32_t mChannels;
uint8_t mObjectType;
uint8_t mSamplingIndex;
uint8_t mChannelConfig;
uint8_t mNumAACFrames;
bool mHaveCrc;
// Returns whether aPtr matches a valid ADTS header sync marker
static bool MatchesSync(const uint8_t* aPtr) {
return aPtr[0] == 0xFF && (aPtr[1] & 0xF6) == 0xF0;
}
FrameHeader() { Reset(); }
// Header size
size_t HeaderSize() const { return (mHaveCrc) ? 9 : 7; }
bool IsValid() const { return mFrameLength > 0; }
// Resets the state to allow for a new parsing session.
void Reset() { PodZero(this); }
// Returns whether the byte creates a valid sequence up to this point.
bool Parse(const uint8_t* aPtr) {
const uint8_t* p = aPtr;
if (!MatchesSync(p)) {
return false;
}
// AAC has 1024 samples per frame per channel.
mSamples = 1024;
mHaveCrc = !(p[1] & 0x01);
mObjectType = ((p[2] & 0xC0) >> 6) + 1;
mSamplingIndex = (p[2] & 0x3C) >> 2;
mChannelConfig = (p[2] & 0x01) << 2 | (p[3] & 0xC0) >> 6;
mFrameLength =
(p[3] & 0x03) << 11 | (p[4] & 0xFF) << 3 | (p[5] & 0xE0) >> 5;
mNumAACFrames = (p[6] & 0x03) + 1;
static const int32_t SAMPLE_RATES[16] = {96000, 88200, 64000, 48000, 44100,
32000, 24000, 22050, 16000, 12000,
11025, 8000, 7350};
mSampleRate = SAMPLE_RATES[mSamplingIndex];
MOZ_ASSERT(mChannelConfig < 8);
mChannels = (mChannelConfig == 7) ? 8 : mChannelConfig;
return true;
}
};
// adts::Frame - Frame meta container used to parse and hold a frame
// header and side info.
class Frame {
public:
Frame() : mOffset(0), mHeader() {}
int64_t Offset() const { return mOffset; }
size_t Length() const {
// TODO: If fields are zero'd when invalid, this check wouldn't be
// necessary.
if (!mHeader.IsValid()) {
return 0;
}
return mHeader.mFrameLength;
}
// Returns the offset to the start of frame's raw data.
int64_t PayloadOffset() const { return mOffset + mHeader.HeaderSize(); }
// Returns the length of the frame's raw data (excluding the header) in bytes.
size_t PayloadLength() const {
// TODO: If fields are zero'd when invalid, this check wouldn't be
// necessary.
if (!mHeader.IsValid()) {
return 0;
}
return mHeader.mFrameLength - mHeader.HeaderSize();
}
// Returns the parsed frame header.
const FrameHeader& Header() const { return mHeader; }
bool IsValid() const { return mHeader.IsValid(); }
// Resets the frame header and data.
void Reset() {
mHeader.Reset();
mOffset = 0;
}
// Returns whether the valid
bool Parse(int64_t aOffset, const uint8_t* aStart, const uint8_t* aEnd) {
MOZ_ASSERT(aStart && aEnd);
bool found = false;
const uint8_t* ptr = aStart;
// Require at least 7 bytes of data at the end of the buffer for the minimum
// ADTS frame header.
while (ptr < aEnd - 7 && !found) {
found = mHeader.Parse(ptr);
ptr++;
}
mOffset = aOffset + (ptr - aStart) - 1;
return found;
}
private:
// The offset to the start of the header.
int64_t mOffset;
// The currently parsed frame header.
FrameHeader mHeader;
};
class FrameParser {
public:
// Returns the currently parsed frame. Reset via Reset or EndFrameSession.
const Frame& CurrentFrame() const { return mFrame; }
// Returns the first parsed frame. Reset via Reset.
const Frame& FirstFrame() const { return mFirstFrame; }
// Resets the parser. Don't use between frames as first frame data is reset.
void Reset() {
EndFrameSession();
mFirstFrame.Reset();
}
// Clear the last parsed frame to allow for next frame parsing, i.e.:
// - sets PrevFrame to CurrentFrame
// - resets the CurrentFrame
// - resets ID3Header if no valid header was parsed yet
void EndFrameSession() { mFrame.Reset(); }
// Parses contents of given ByteReader for a valid frame header and returns
// true if one was found. After returning, the variable passed to
// 'aBytesToSkip' holds the amount of bytes to be skipped (if any) in order to
// jump across a large ID3v2 tag spanning multiple buffers.
bool Parse(int64_t aOffset, const uint8_t* aStart, const uint8_t* aEnd) {
const bool found = mFrame.Parse(aOffset, aStart, aEnd);
if (mFrame.Length() && !mFirstFrame.Length()) {
mFirstFrame = mFrame;
}
return found;
}
private:
// We keep the first parsed frame around for static info access, the
// previously parsed frame for debugging and the currently parsed frame.
Frame mFirstFrame;
Frame mFrame;
};
// Initialize the AAC AudioSpecificConfig.
// Only handles two-byte version for AAC-LC.
static void InitAudioSpecificConfig(const Frame& frame,
MediaByteBuffer* aBuffer) {
const FrameHeader& header = frame.Header();
MOZ_ASSERT(header.IsValid());
int audioObjectType = header.mObjectType;
int samplingFrequencyIndex = header.mSamplingIndex;
int channelConfig = header.mChannelConfig;
uint8_t asc[2];
asc[0] = (audioObjectType & 0x1F) << 3 | (samplingFrequencyIndex & 0x0E) >> 1;
asc[1] = (samplingFrequencyIndex & 0x01) << 7 | (channelConfig & 0x0F) << 3;
aBuffer->AppendElements(asc, 2);
}
} // namespace adts
using media::TimeUnit;
// ADTSDemuxer
ADTSDemuxer::ADTSDemuxer(MediaResource* aSource) : mSource(aSource) {
DDLINKCHILD("source", aSource);
}
bool ADTSDemuxer::InitInternal() {
if (!mTrackDemuxer) {
mTrackDemuxer = new ADTSTrackDemuxer(mSource);
DDLINKCHILD("track demuxer", mTrackDemuxer.get());
}
return mTrackDemuxer->Init();
}
RefPtr<ADTSDemuxer::InitPromise> ADTSDemuxer::Init() {
if (!InitInternal()) {
ADTSLOG("Init() failure: waiting for data");
return InitPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_METADATA_ERR,
__func__);
}
ADTSLOG("Init() successful");
return InitPromise::CreateAndResolve(NS_OK, __func__);
}
uint32_t ADTSDemuxer::GetNumberTracks(TrackInfo::TrackType aType) const {
return (aType == TrackInfo::kAudioTrack) ? 1 : 0;
}
already_AddRefed<MediaTrackDemuxer> ADTSDemuxer::GetTrackDemuxer(
TrackInfo::TrackType aType, uint32_t aTrackNumber) {
if (!mTrackDemuxer) {
return nullptr;
}
return RefPtr<ADTSTrackDemuxer>(mTrackDemuxer).forget();
}
bool ADTSDemuxer::IsSeekable() const {
int64_t length = mSource->GetLength();
if (length > -1) return true;
return false;
}
// ADTSTrackDemuxer
ADTSTrackDemuxer::ADTSTrackDemuxer(MediaResource* aSource)
: mSource(aSource),
mParser(new adts::FrameParser()),
mOffset(0),
mNumParsedFrames(0),
mFrameIndex(0),
mTotalFrameLen(0),
mSamplesPerFrame(0),
mSamplesPerSecond(0),
mChannels(0) {
DDLINKCHILD("source", aSource);
Reset();
}
ADTSTrackDemuxer::~ADTSTrackDemuxer() { delete mParser; }
bool ADTSTrackDemuxer::Init() {
FastSeek(TimeUnit::Zero());
// Read the first frame to fetch sample rate and other meta data.
RefPtr<MediaRawData> frame(GetNextFrame(FindNextFrame(true)));
ADTSLOG("Init StreamLength()=%" PRId64 " first-frame-found=%d",
StreamLength(), !!frame);
if (!frame) {
return false;
}
// Rewind back to the stream begin to avoid dropping the first frame.
FastSeek(TimeUnit::Zero());
if (!mSamplesPerSecond) {
return false;
}
if (!mInfo) {
mInfo = MakeUnique<AudioInfo>();
}
mInfo->mRate = mSamplesPerSecond;
mInfo->mChannels = mChannels;
mInfo->mBitDepth = 16;
mInfo->mDuration = Duration();
// AAC Specific information
mInfo->mMimeType = "audio/mp4a-latm";
// Configure AAC codec-specific values.
// For AAC, mProfile and mExtendedProfile contain the audioObjectType from
// Table 1.3 -- Audio Profile definition, ISO/IEC 14496-3. Eg. 2 == AAC LC
mInfo->mProfile = mInfo->mExtendedProfile =
mParser->FirstFrame().Header().mObjectType;
InitAudioSpecificConfig(mParser->FirstFrame(), mInfo->mCodecSpecificConfig);
ADTSLOG("Init mInfo={mRate=%u mChannels=%u mBitDepth=%u mDuration=%" PRId64
"}",
mInfo->mRate, mInfo->mChannels, mInfo->mBitDepth,
mInfo->mDuration.ToMicroseconds());
// AAC encoder delay is by default 2112 audio frames.
// See
// So we always seek 2112 frames prior the seeking point.
mPreRoll = TimeUnit::FromMicroseconds(2112 * 1000000ULL / mSamplesPerSecond);
return mChannels;
}
UniquePtr<TrackInfo> ADTSTrackDemuxer::GetInfo() const {
return mInfo->Clone();
}
RefPtr<ADTSTrackDemuxer::SeekPromise> ADTSTrackDemuxer::Seek(
const TimeUnit& aTime) {
// Efficiently seek to the position.
const TimeUnit time = aTime > mPreRoll ? aTime - mPreRoll : TimeUnit::Zero();
FastSeek(time);
// Correct seek position by scanning the next frames.
const TimeUnit seekTime = ScanUntil(time);
return SeekPromise::CreateAndResolve(seekTime, __func__);
}
TimeUnit ADTSTrackDemuxer::FastSeek(const TimeUnit& aTime) {
ADTSLOG("FastSeek(%" PRId64 ") avgFrameLen=%f mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mOffset=%" PRIu64,
aTime.ToMicroseconds(), AverageFrameLength(), mNumParsedFrames,
mFrameIndex, mOffset);
const int64_t firstFrameOffset = mParser->FirstFrame().Offset();
if (!aTime.ToMicroseconds()) {
// Quick seek to the beginning of the stream.
mOffset = firstFrameOffset;
} else if (AverageFrameLength() > 0) {
mOffset =
firstFrameOffset + FrameIndexFromTime(aTime) * AverageFrameLength();
}
if (mOffset > firstFrameOffset && StreamLength() > 0) {
mOffset = std::min(StreamLength() - 1, mOffset);
}
mFrameIndex = FrameIndexFromOffset(mOffset);
mParser->EndFrameSession();
ADTSLOG("FastSeek End avgFrameLen=%f mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mFirstFrameOffset=%" PRIu64
" mOffset=%" PRIu64 " SL=%" PRIu64 "",
AverageFrameLength(), mNumParsedFrames, mFrameIndex, firstFrameOffset,
mOffset, StreamLength());
return Duration(mFrameIndex);
}
TimeUnit ADTSTrackDemuxer::ScanUntil(const TimeUnit& aTime) {
ADTSLOG("ScanUntil(%" PRId64 ") avgFrameLen=%f mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mOffset=%" PRIu64,
aTime.ToMicroseconds(), AverageFrameLength(), mNumParsedFrames,
mFrameIndex, mOffset);
if (!aTime.ToMicroseconds()) {
return FastSeek(aTime);
}
if (Duration(mFrameIndex) > aTime) {
FastSeek(aTime);
}
while (SkipNextFrame(FindNextFrame()) && Duration(mFrameIndex + 1) < aTime) {
ADTSLOGV("ScanUntil* avgFrameLen=%f mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mOffset=%" PRIu64 " Duration=%" PRId64,
AverageFrameLength(), mNumParsedFrames, mFrameIndex, mOffset,
Duration(mFrameIndex + 1).ToMicroseconds());
}
ADTSLOG("ScanUntil End avgFrameLen=%f mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mOffset=%" PRIu64,
AverageFrameLength(), mNumParsedFrames, mFrameIndex, mOffset);
return Duration(mFrameIndex);
}
RefPtr<ADTSTrackDemuxer::SamplesPromise> ADTSTrackDemuxer::GetSamples(
int32_t aNumSamples) {
ADTSLOGV("GetSamples(%d) Begin mOffset=%" PRIu64 " mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mTotalFrameLen=%" PRIu64
" mSamplesPerFrame=%d "
"mSamplesPerSecond=%d mChannels=%d",
aNumSamples, mOffset, mNumParsedFrames, mFrameIndex, mTotalFrameLen,
mSamplesPerFrame, mSamplesPerSecond, mChannels);
MOZ_ASSERT(aNumSamples);
RefPtr<SamplesHolder> frames = new SamplesHolder();
while (aNumSamples--) {
RefPtr<MediaRawData> frame(GetNextFrame(FindNextFrame()));
if (!frame) break;
frames->AppendSample(frame);
}
ADTSLOGV(
"GetSamples() End mSamples.Size()=%zu aNumSamples=%d mOffset=%" PRIu64
" mNumParsedFrames=%" PRIu64 " mFrameIndex=%" PRId64
" mTotalFrameLen=%" PRIu64
" mSamplesPerFrame=%d mSamplesPerSecond=%d "
"mChannels=%d",
frames->GetSamples().Length(), aNumSamples, mOffset, mNumParsedFrames,
mFrameIndex, mTotalFrameLen, mSamplesPerFrame, mSamplesPerSecond,
mChannels);
if (frames->GetSamples().IsEmpty()) {
return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_END_OF_STREAM,
__func__);
}
return SamplesPromise::CreateAndResolve(frames, __func__);
}
void ADTSTrackDemuxer::Reset() {
ADTSLOG("Reset()");
MOZ_ASSERT(mParser);
if (mParser) {
mParser->Reset();
}
FastSeek(TimeUnit::Zero());
}
RefPtr<ADTSTrackDemuxer::SkipAccessPointPromise>
ADTSTrackDemuxer::SkipToNextRandomAccessPoint(const TimeUnit& aTimeThreshold) {
// Will not be called for audio-only resources.
return SkipAccessPointPromise::CreateAndReject(
SkipFailureHolder(NS_ERROR_DOM_MEDIA_DEMUXER_ERR, 0), __func__);
}
int64_t ADTSTrackDemuxer::GetResourceOffset() const { return mOffset; }
media::TimeIntervals ADTSTrackDemuxer::GetBuffered() {
auto duration = Duration();
if (!duration.IsPositive()) {
return media::TimeIntervals();
}
AutoPinned<MediaResource> stream(mSource.GetResource());
return GetEstimatedBufferedTimeRanges(stream, duration.ToMicroseconds());
}
int64_t ADTSTrackDemuxer::StreamLength() const { return mSource.GetLength(); }
TimeUnit ADTSTrackDemuxer::Duration() const {
if (!mNumParsedFrames) {
return TimeUnit::FromMicroseconds(-1);
}
const int64_t streamLen = StreamLength();
if (streamLen < 0) {
// Unknown length, we can't estimate duration.
return TimeUnit::FromMicroseconds(-1);
}
const int64_t firstFrameOffset = mParser->FirstFrame().Offset();
int64_t numFrames = (streamLen - firstFrameOffset) / AverageFrameLength();
return Duration(numFrames);
}
TimeUnit ADTSTrackDemuxer::Duration(int64_t aNumFrames) const {
if (!mSamplesPerSecond) {
return TimeUnit::FromMicroseconds(-1);
}
return FramesToTimeUnit(aNumFrames * mSamplesPerFrame, mSamplesPerSecond);
}
const adts::Frame& ADTSTrackDemuxer::FindNextFrame(
bool findFirstFrame /*= false*/) {
static const int BUFFER_SIZE = 4096;
static const int MAX_SKIPPED_BYTES = 10 * BUFFER_SIZE;
ADTSLOGV("FindNext() Begin mOffset=%" PRIu64 " mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mTotalFrameLen=%" PRIu64
" mSamplesPerFrame=%d mSamplesPerSecond=%d mChannels=%d",
mOffset, mNumParsedFrames, mFrameIndex, mTotalFrameLen,
mSamplesPerFrame, mSamplesPerSecond, mChannels);
uint8_t buffer[BUFFER_SIZE];
int32_t read = 0;
bool foundFrame = false;
int64_t frameHeaderOffset = mOffset;
// Prepare the parser for the next frame parsing session.
mParser->EndFrameSession();
// Check whether we've found a valid ADTS frame.
while (!foundFrame) {
if ((read = Read(buffer, frameHeaderOffset, BUFFER_SIZE)) == 0) {
ADTSLOG("FindNext() EOS without a frame");
break;
}
if (frameHeaderOffset - mOffset > MAX_SKIPPED_BYTES) {
ADTSLOG("FindNext() exceeded MAX_SKIPPED_BYTES without a frame");
break;
}
const adts::Frame& currentFrame = mParser->CurrentFrame();
foundFrame = mParser->Parse(frameHeaderOffset, buffer, buffer + read);
if (findFirstFrame && foundFrame) {
// Check for sync marker after the found frame, since it's
// possible to find sync marker in AAC data. If sync marker
// exists after the current frame then we've found a frame
// header.
int64_t nextFrameHeaderOffset =
currentFrame.Offset() + currentFrame.Length();
int32_t read = Read(buffer, nextFrameHeaderOffset, 2);
if (read != 2 || !adts::FrameHeader::MatchesSync(buffer)) {
frameHeaderOffset = currentFrame.Offset() + 1;
mParser->Reset();
foundFrame = false;
continue;
}
}
if (foundFrame) {
break;
}
// Minimum header size is 7 bytes.
int64_t advance = read - 7;
// Check for offset overflow.
if (frameHeaderOffset + advance <= frameHeaderOffset) {
break;
}
frameHeaderOffset += advance;
}
if (!foundFrame || !mParser->CurrentFrame().Length()) {
ADTSLOG(
"FindNext() Exit foundFrame=%d mParser->CurrentFrame().Length()=%zu ",
foundFrame, mParser->CurrentFrame().Length());
mParser->Reset();
return mParser->CurrentFrame();
}
ADTSLOGV("FindNext() End mOffset=%" PRIu64 " mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " frameHeaderOffset=%" PRId64
" mTotalFrameLen=%" PRIu64
" mSamplesPerFrame=%d mSamplesPerSecond=%d"
" mChannels=%d",
mOffset, mNumParsedFrames, mFrameIndex, frameHeaderOffset,
mTotalFrameLen, mSamplesPerFrame, mSamplesPerSecond, mChannels);
return mParser->CurrentFrame();
}
bool ADTSTrackDemuxer::SkipNextFrame(const adts::Frame& aFrame) {
if (!mNumParsedFrames || !aFrame.Length()) {
RefPtr<MediaRawData> frame(GetNextFrame(aFrame));
return frame;
}
UpdateState(aFrame);
ADTSLOGV("SkipNext() End mOffset=%" PRIu64 " mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mTotalFrameLen=%" PRIu64
" mSamplesPerFrame=%d mSamplesPerSecond=%d mChannels=%d",
mOffset, mNumParsedFrames, mFrameIndex, mTotalFrameLen,
mSamplesPerFrame, mSamplesPerSecond, mChannels);
return true;
}
already_AddRefed<MediaRawData> ADTSTrackDemuxer::GetNextFrame(
const adts::Frame& aFrame) {
ADTSLOG("GetNext() Begin({mOffset=%" PRId64
" HeaderSize()=%zu"
" Length()=%zu})",
aFrame.Offset(), aFrame.Header().HeaderSize(),
aFrame.PayloadLength());
if (!aFrame.IsValid()) return nullptr;
const int64_t offset = aFrame.PayloadOffset();
const uint32_t length = aFrame.PayloadLength();
RefPtr<MediaRawData> frame = new MediaRawData();
frame->mOffset = offset;
UniquePtr<MediaRawDataWriter> frameWriter(frame->CreateWriter());
if (!frameWriter->SetSize(length)) {
ADTSLOG("GetNext() Exit failed to allocated media buffer");
return nullptr;
}
const uint32_t read = Read(frameWriter->Data(), offset, length);
if (read != length) {
ADTSLOG("GetNext() Exit read=%u frame->Size()=%zu", read, frame->Size());
return nullptr;
}
UpdateState(aFrame);
frame->mTime = Duration(mFrameIndex - 1);
frame->mDuration = Duration(1);
frame->mTimecode = frame->mTime;
frame->mKeyframe = true;
MOZ_ASSERT(!frame->mTime.IsNegative());
MOZ_ASSERT(frame->mDuration.IsPositive());
ADTSLOGV("GetNext() End mOffset=%" PRIu64 " mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mTotalFrameLen=%" PRIu64
" mSamplesPerFrame=%d mSamplesPerSecond=%d mChannels=%d",
mOffset, mNumParsedFrames, mFrameIndex, mTotalFrameLen,
mSamplesPerFrame, mSamplesPerSecond, mChannels);
return frame.forget();
}
int64_t ADTSTrackDemuxer::FrameIndexFromOffset(int64_t aOffset) const {
int64_t frameIndex = 0;
if (AverageFrameLength() > 0) {
frameIndex =
(aOffset - mParser->FirstFrame().Offset()) / AverageFrameLength();
}
ADTSLOGV("FrameIndexFromOffset(%" PRId64 ") -> %" PRId64, aOffset,
frameIndex);
return std::max<int64_t>(0, frameIndex);
}
int64_t ADTSTrackDemuxer::FrameIndexFromTime(const TimeUnit& aTime) const {
int64_t frameIndex = 0;
if (mSamplesPerSecond > 0 && mSamplesPerFrame > 0) {
frameIndex = aTime.ToSeconds() * mSamplesPerSecond / mSamplesPerFrame - 1;
}
ADTSLOGV("FrameIndexFromOffset(%fs) -> %" PRId64, aTime.ToSeconds(),
frameIndex);
return std::max<int64_t>(0, frameIndex);
}
void ADTSTrackDemuxer::UpdateState(const adts::Frame& aFrame) {
int32_t frameLength = aFrame.Length();
// Prevent overflow.
if (mTotalFrameLen + frameLength < mTotalFrameLen) {
// These variables have a linear dependency and are only used to derive the
// average frame length.
mTotalFrameLen /= 2;
mNumParsedFrames /= 2;
}
// Full frame parsed, move offset to its end.
mOffset = aFrame.Offset() + frameLength;
mTotalFrameLen += frameLength;
if (!mSamplesPerFrame) {
const adts::FrameHeader& header = aFrame.Header();
mSamplesPerFrame = header.mSamples;
mSamplesPerSecond = header.mSampleRate;
mChannels = header.mChannels;
}
++mNumParsedFrames;
++mFrameIndex;
MOZ_ASSERT(mFrameIndex > 0);
}
int32_t ADTSTrackDemuxer::Read(uint8_t* aBuffer, int64_t aOffset,
int32_t aSize) {
ADTSLOGV("ADTSTrackDemuxer::Read(%p %" PRId64 " %d)", aBuffer, aOffset,
aSize);
const int64_t streamLen = StreamLength();
if (mInfo && streamLen > 0) {
// Prevent blocking reads after successful initialization.
aSize = std::min<int64_t>(aSize, streamLen - aOffset);
}
uint32_t read = 0;
ADTSLOGV("ADTSTrackDemuxer::Read -> ReadAt(%d)", aSize);
const nsresult rv = mSource.ReadAt(aOffset, reinterpret_cast<char*>(aBuffer),
static_cast<uint32_t>(aSize), &read);
NS_ENSURE_SUCCESS(rv, 0);
return static_cast<int32_t>(read);
}
double ADTSTrackDemuxer::AverageFrameLength() const {
if (mNumParsedFrames) {
return static_cast<double>(mTotalFrameLen) / mNumParsedFrames;
}
return 0.0;
}
/* static */
bool ADTSDemuxer::ADTSSniffer(const uint8_t* aData, const uint32_t aLength) {
if (aLength < 7) {
return false;
}
if (!adts::FrameHeader::MatchesSync(aData)) {
return false;
}
auto parser = MakeUnique<adts::FrameParser>();
if (!parser->Parse(0, aData, aData + aLength)) {
return false;
}
const adts::Frame& currentFrame = parser->CurrentFrame();
// Check for sync marker after the found frame, since it's
// possible to find sync marker in AAC data. If sync marker
// exists after the current frame then we've found a frame
// header.
int64_t nextFrameHeaderOffset = currentFrame.Offset() + currentFrame.Length();
return int64_t(aLength) > nextFrameHeaderOffset &&
aLength - nextFrameHeaderOffset >= 2 &&
adts::FrameHeader::MatchesSync(aData + nextFrameHeaderOffset);
}
} // namespace mozilla