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gecko-dev/dom/media/ADTSDemuxer.cpp

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/* -*- 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 <inttypes.h>
#include "nsAutoPtr.h"
#include "VideoUtils.h"
#include "TimeUnits.h"
#include "prenv.h"
#ifdef PR_LOGGING
mozilla::LazyLogModule gADTSDemuxerLog("ADTSDemuxer");
#define ADTSLOG(msg, ...) \
MOZ_LOG(gADTSDemuxerLog, LogLevel::Debug, ("ADTSDemuxer " msg, ##__VA_ARGS__))
#define ADTSLOGV(msg, ...) \
MOZ_LOG(gADTSDemuxerLog, LogLevel::Verbose, ("ADTSDemuxer " msg, ##__VA_ARGS__))
#else
#define ADTSLOG(msg, ...) do {} while (false)
#define ADTSLOGV(msg, ...) do {} while (false)
#endif
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, uint8_t* aStart, uint8_t* aEnd) {
MOZ_ASSERT(aStart && aEnd);
bool found = false;
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, uint8_t* aStart, 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;
};
// Return the AAC Profile Level Indication based upon sample rate and channels
// Information based upon table 1.10 from ISO/IEC 14496-3:2005(E)
static int8_t
ProfileLevelIndication(const Frame& frame)
{
const FrameHeader& header = frame.Header();
MOZ_ASSERT(header.IsValid());
if (!header.IsValid()) {
return 0;
}
const int channels = header.mChannels;
const int sampleRate = header.mSampleRate;
if (channels <= 2) {
if (sampleRate <= 24000) {
// AAC Profile L1
return 0x28;
}
else if (sampleRate <= 48000) {
// AAC Profile L2
return 0x29;
}
}
else if (channels <= 5) {
if (sampleRate <= 48000) {
// AAC Profile L4
return 0x2A;
}
else if (sampleRate <= 96000) {
// AAC Profile L5
return 0x2B;
}
}
// TODO: Should this be 0xFE for 'no audio profile specified'?
return 0;
}
// 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
// ADTSDemuxer
ADTSDemuxer::ADTSDemuxer(MediaResource* aSource)
: mSource(aSource)
{}
bool
ADTSDemuxer::InitInternal()
{
if (!mTrackDemuxer) {
mTrackDemuxer = new ADTSTrackDemuxer(mSource);
}
return mTrackDemuxer->Init();
}
RefPtr<ADTSDemuxer::InitPromise>
ADTSDemuxer::Init()
{
if (!InitInternal()) {
ADTSLOG("Init() failure: waiting for data");
return InitPromise::CreateAndReject(
DemuxerFailureReason::DEMUXER_ERROR, __func__);
}
ADTSLOG("Init() successful");
return InitPromise::CreateAndResolve(NS_OK, __func__);
}
bool
ADTSDemuxer::HasTrackType(TrackInfo::TrackType aType) const
{
return aType == TrackInfo::kAudioTrack;
}
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)
{
Reset();
}
ADTSTrackDemuxer::~ADTSTrackDemuxer()
{
delete mParser;
mParser = nullptr;
}
bool
ADTSTrackDemuxer::Init()
{
FastSeek(media::TimeUnit());
// 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(media::TimeUnit());
if (!mInfo) {
mInfo = MakeUnique<AudioInfo>();
}
mInfo->mRate = mSamplesPerSecond;
mInfo->mChannels = mChannels;
mInfo->mBitDepth = 16;
mInfo->mDuration = Duration().ToMicroseconds();
// AAC Specific information
mInfo->mMimeType = "audio/mp4a-latm";
// Configure AAC codec-specific values.
// According to
// https://msdn.microsoft.com/en-us/library/windows/desktop/dd742784%28v=vs.85%29.aspx,
// wAudioProfileLevelIndication, which is passed mInfo->mProfile, is
// a value from Table 1.12 -- audioProfileLevelIndication values, ISO/IEC 14496-3.
mInfo->mProfile = ProfileLevelIndication(mParser->FirstFrame());
// For AAC, mExtendedProfile contains the audioObjectType from Table
// 1.3 -- Audio Profile definition, ISO/IEC 14496-3. Eg. 2 == AAC LC
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);
return mSamplesPerSecond && mChannels;
}
UniquePtr<TrackInfo>
ADTSTrackDemuxer::GetInfo() const
{
return mInfo->Clone();
}
RefPtr<ADTSTrackDemuxer::SeekPromise>
ADTSTrackDemuxer::Seek(media::TimeUnit aTime)
{
// Efficiently seek to the position.
FastSeek(aTime);
// Correct seek position by scanning the next frames.
const media::TimeUnit seekTime = ScanUntil(aTime);
return SeekPromise::CreateAndResolve(seekTime, __func__);
}
media::TimeUnit
ADTSTrackDemuxer::FastSeek(const media::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=%llu mOffset=%" PRIu64
" SL=%llu",
AverageFrameLength(), mNumParsedFrames, mFrameIndex,
firstFrameOffset, mOffset, StreamLength());
return Duration(mFrameIndex);
}
media::TimeUnit
ADTSTrackDemuxer::ScanUntil(const media::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);
if (!aNumSamples) {
return SamplesPromise::CreateAndReject(
DemuxerFailureReason::DEMUXER_ERROR, __func__);
}
RefPtr<SamplesHolder> frames = new SamplesHolder();
while (aNumSamples--) {
RefPtr<MediaRawData> frame(GetNextFrame(FindNextFrame()));
if (!frame)
break;
frames->mSamples.AppendElement(frame);
}
ADTSLOGV("GetSamples() End mSamples.Size()=%d aNumSamples=%d mOffset=%" PRIu64
" mNumParsedFrames=%" PRIu64 " mFrameIndex=%" PRId64
" mTotalFrameLen=%" PRIu64 " mSamplesPerFrame=%d mSamplesPerSecond=%d "
"mChannels=%d",
frames->mSamples.Length(), aNumSamples, mOffset, mNumParsedFrames,
mFrameIndex, mTotalFrameLen, mSamplesPerFrame, mSamplesPerSecond,
mChannels);
if (frames->mSamples.IsEmpty()) {
return SamplesPromise::CreateAndReject(
DemuxerFailureReason::END_OF_STREAM, __func__);
}
return SamplesPromise::CreateAndResolve(frames, __func__);
}
void
ADTSTrackDemuxer::Reset()
{
ADTSLOG("Reset()");
MOZ_ASSERT(mParser);
if (mParser) {
mParser->Reset();
}
FastSeek(media::TimeUnit());
}
RefPtr<ADTSTrackDemuxer::SkipAccessPointPromise>
ADTSTrackDemuxer::SkipToNextRandomAccessPoint(media::TimeUnit aTimeThreshold)
{
// Will not be called for audio-only resources.
return SkipAccessPointPromise::CreateAndReject(
SkipFailureHolder(DemuxerFailureReason::DEMUXER_ERROR, 0), __func__);
}
int64_t
ADTSTrackDemuxer::GetResourceOffset() const
{
return mOffset;
}
media::TimeIntervals
ADTSTrackDemuxer::GetBuffered()
{
media::TimeUnit duration = Duration();
if (duration <= media::TimeUnit()) {
return media::TimeIntervals();
}
AutoPinned<MediaResource> stream(mSource.GetResource());
return GetEstimatedBufferedTimeRanges(stream, duration.ToMicroseconds());
}
int64_t
ADTSTrackDemuxer::StreamLength() const
{
return mSource.GetLength();
}
media::TimeUnit
ADTSTrackDemuxer::Duration() const
{
if (!mNumParsedFrames) {
return media::TimeUnit::FromMicroseconds(-1);
}
const int64_t streamLen = StreamLength();
if (streamLen < 0) {
// Unknown length, we can't estimate duration.
return media::TimeUnit::FromMicroseconds(-1);
}
const int64_t firstFrameOffset = mParser->FirstFrame().Offset();
int64_t numFrames = (streamLen - firstFrameOffset) / AverageFrameLength();
return Duration(numFrames);
}
media::TimeUnit
ADTSTrackDemuxer::Duration(int64_t aNumFrames) const
{
if (!mSamplesPerSecond) {
return media::TimeUnit::FromMicroseconds(-1);
}
const double usPerFrame = USECS_PER_S * mSamplesPerFrame / mSamplesPerSecond;
return media::TimeUnit::FromMicroseconds(aNumFrames * usPerFrame);
}
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()=%d ",
foundFrame, mParser->CurrentFrame().Length());
mParser->Reset();
return mParser->CurrentFrame();
}
ADTSLOGV("FindNext() End mOffset=%" PRIu64 " mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " frameHeaderOffset=%d"
" 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()=%d Length()=%d})",
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;
nsAutoPtr<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()=%u", read, frame->Size());
return nullptr;
}
UpdateState(aFrame);
frame->mTime = Duration(mFrameIndex - 1).ToMicroseconds();
frame->mDuration = Duration(1).ToMicroseconds();
frame->mTimecode = frame->mTime;
frame->mKeyframe = true;
MOZ_ASSERT(frame->mTime >= 0);
MOZ_ASSERT(frame->mDuration > 0);
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 media::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;
}
} // namespace mozilla
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