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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* 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
#include "MP3Demuxer.h"
#include <algorithm>
#include <inttypes.h>
#include <limits>
#include "ByteWriter.h"
#include "TimeUnits.h"
#include "VideoUtils.h"
#include "mozilla/Assertions.h"
extern mozilla::LazyLogModule gMediaDemuxerLog;
#define MP3LOG(msg, ...) \
DDMOZ_LOG(gMediaDemuxerLog, LogLevel::Debug, msg, ##__VA_ARGS__)
#define MP3LOGV(msg, ...) \
DDMOZ_LOG(gMediaDemuxerLog, LogLevel::Verbose, msg, ##__VA_ARGS__)
using mozilla::media::TimeInterval;
using mozilla::media::TimeIntervals;
using mozilla::media::TimeUnit;
namespace mozilla {
// MP3Demuxer
MP3Demuxer::MP3Demuxer(MediaResource* aSource) : mSource(aSource) {
DDLINKCHILD("source", aSource);
}
bool MP3Demuxer::InitInternal() {
if (!mTrackDemuxer) {
mTrackDemuxer = new MP3TrackDemuxer(mSource);
DDLINKCHILD("track demuxer", mTrackDemuxer.get());
}
return mTrackDemuxer->Init();
}
RefPtr<MP3Demuxer::InitPromise> MP3Demuxer::Init() {
if (!InitInternal()) {
MP3LOG("MP3Demuxer::Init() failure: waiting for data");
return InitPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_METADATA_ERR,
__func__);
}
MP3LOG("MP3Demuxer::Init() successful");
return InitPromise::CreateAndResolve(NS_OK, __func__);
}
uint32_t MP3Demuxer::GetNumberTracks(TrackInfo::TrackType aType) const {
return aType == TrackInfo::kAudioTrack ? 1u : 0u;
}
already_AddRefed<MediaTrackDemuxer> MP3Demuxer::GetTrackDemuxer(
TrackInfo::TrackType aType, uint32_t aTrackNumber) {
if (!mTrackDemuxer) {
return nullptr;
}
return RefPtr<MP3TrackDemuxer>(mTrackDemuxer).forget();
}
bool MP3Demuxer::IsSeekable() const { return true; }
void MP3Demuxer::NotifyDataArrived() {
NS_WARNING("Unimplemented function NotifyDataArrived");
MP3LOGV("NotifyDataArrived()");
}
void MP3Demuxer::NotifyDataRemoved() {
NS_WARNING("Unimplemented function NotifyDataRemoved");
MP3LOGV("NotifyDataRemoved()");
}
// MP3TrackDemuxer
MP3TrackDemuxer::MP3TrackDemuxer(MediaResource* aSource)
: mSource(aSource),
mFrameLock(false),
mOffset(0),
mFirstFrameOffset(0),
mNumParsedFrames(0),
mFrameIndex(0),
mTotalFrameLen(0),
mSamplesPerFrame(0),
mSamplesPerSecond(0),
mChannels(0) {
DDLINKCHILD("source", aSource);
Reset();
}
bool MP3TrackDemuxer::Init() {
Reset();
FastSeek(TimeUnit());
// Read the first frame to fetch sample rate and other meta data.
RefPtr<MediaRawData> frame(GetNextFrame(FindFirstFrame()));
MP3LOG("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());
if (!mInfo) {
mInfo = MakeUnique<AudioInfo>();
}
mInfo->mRate = mSamplesPerSecond;
mInfo->mChannels = mChannels;
mInfo->mBitDepth = 16;
mInfo->mMimeType = "audio/mpeg";
mInfo->mDuration = Duration().valueOr(TimeUnit::FromInfinity());
MP3LOG("Init mInfo={mRate=%d mChannels=%d mBitDepth=%d mDuration=%s (%lfs)}",
mInfo->mRate, mInfo->mChannels, mInfo->mBitDepth,
mInfo->mDuration.ToString().get(), mInfo->mDuration.ToSeconds());
return mSamplesPerSecond && mChannels;
}
media::TimeUnit MP3TrackDemuxer::SeekPosition() const {
TimeUnit pos = Duration(mFrameIndex);
auto duration = Duration();
if (duration) {
pos = std::min(*duration, pos);
}
return pos;
}
const FrameParser::Frame& MP3TrackDemuxer::LastFrame() const {
return mParser.PrevFrame();
}
RefPtr<MediaRawData> MP3TrackDemuxer::DemuxSample() {
return GetNextFrame(FindNextFrame());
}
const ID3Parser::ID3Header& MP3TrackDemuxer::ID3Header() const {
return mParser.ID3Header();
}
const FrameParser::VBRHeader& MP3TrackDemuxer::VBRInfo() const {
return mParser.VBRInfo();
}
UniquePtr<TrackInfo> MP3TrackDemuxer::GetInfo() const { return mInfo->Clone(); }
RefPtr<MP3TrackDemuxer::SeekPromise> MP3TrackDemuxer::Seek(
const TimeUnit& aTime) {
mRemainingEncoderPadding = AssertedCast<int32_t>(mEncoderPadding);
// Efficiently seek to the position.
FastSeek(aTime);
// Correct seek position by scanning the next frames.
const TimeUnit seekTime = ScanUntil(aTime);
return SeekPromise::CreateAndResolve(seekTime, __func__);
}
TimeUnit MP3TrackDemuxer::FastSeek(const TimeUnit& aTime) {
MP3LOG("FastSeek(%" PRId64 ") avgFrameLen=%f mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mOffset=%" PRIu64,
aTime.ToMicroseconds(), AverageFrameLength(), mNumParsedFrames,
mFrameIndex, mOffset);
const auto& vbr = mParser.VBRInfo();
if (aTime.IsZero()) {
// Quick seek to the beginning of the stream.
mFrameIndex = 0;
} else if (vbr.IsTOCPresent() && Duration() &&
*Duration() != TimeUnit::Zero()) {
// Use TOC for more precise seeking.
mFrameIndex = FrameIndexFromOffset(vbr.Offset(aTime, Duration().value()));
} else if (AverageFrameLength() > 0) {
mFrameIndex = FrameIndexFromTime(aTime);
}
mOffset = OffsetFromFrameIndex(mFrameIndex);
if (mOffset > mFirstFrameOffset && StreamLength() > 0) {
mOffset = std::min(StreamLength() - 1, mOffset);
}
mParser.EndFrameSession();
MP3LOG("FastSeek End TOC=%d avgFrameLen=%f mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mFirstFrameOffset=%" PRId64
" mOffset=%" PRIu64 " SL=%" PRId64 " NumBytes=%u",
vbr.IsTOCPresent(), AverageFrameLength(), mNumParsedFrames,
mFrameIndex, mFirstFrameOffset, mOffset, StreamLength(),
vbr.NumBytes().valueOr(0));
return Duration(mFrameIndex);
}
TimeUnit MP3TrackDemuxer::ScanUntil(const TimeUnit& aTime) {
MP3LOG("ScanUntil(%" PRId64 ") avgFrameLen=%f mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mOffset=%" PRIu64,
aTime.ToMicroseconds(), AverageFrameLength(), mNumParsedFrames,
mFrameIndex, mOffset);
if (aTime.IsZero()) {
return FastSeek(aTime);
}
if (Duration(mFrameIndex) > aTime) {
// We've seeked past the target time, rewind back a little to correct it.
const int64_t rewind = aTime.ToMicroseconds() / 100;
FastSeek(aTime - TimeUnit::FromMicroseconds(rewind));
}
if (Duration(mFrameIndex + 1) > aTime) {
return SeekPosition();
}
MediaByteRange nextRange = FindNextFrame();
while (SkipNextFrame(nextRange) && Duration(mFrameIndex + 1) < aTime) {
nextRange = FindNextFrame();
MP3LOGV("ScanUntil* avgFrameLen=%f mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mOffset=%" PRIu64 " Duration=%" PRId64,
AverageFrameLength(), mNumParsedFrames, mFrameIndex, mOffset,
Duration(mFrameIndex + 1).ToMicroseconds());
}
MP3LOG("ScanUntil End avgFrameLen=%f mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mOffset=%" PRIu64,
AverageFrameLength(), mNumParsedFrames, mFrameIndex, mOffset);
return SeekPosition();
}
RefPtr<MP3TrackDemuxer::SamplesPromise> MP3TrackDemuxer::GetSamples(
int32_t aNumSamples) {
MP3LOGV("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(NS_ERROR_DOM_MEDIA_DEMUXER_ERR,
__func__);
}
RefPtr<SamplesHolder> frames = new SamplesHolder();
while (aNumSamples--) {
RefPtr<MediaRawData> frame(GetNextFrame(FindNextFrame()));
if (!frame) {
break;
}
if (!frame->HasValidTime()) {
return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_DEMUXER_ERR,
__func__);
}
frames->AppendSample(frame);
}
MP3LOGV("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 MP3TrackDemuxer::Reset() {
MP3LOG("Reset()");
FastSeek(TimeUnit());
mParser.Reset();
}
RefPtr<MP3TrackDemuxer::SkipAccessPointPromise>
MP3TrackDemuxer::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 MP3TrackDemuxer::GetResourceOffset() const { return mOffset; }
TimeIntervals MP3TrackDemuxer::GetBuffered() {
AutoPinned<MediaResource> stream(mSource.GetResource());
TimeIntervals buffered;
if (Duration() && stream->IsDataCachedToEndOfResource(0)) {
// Special case completely cached files. This also handles local files.
buffered += TimeInterval(TimeUnit(), *Duration());
MP3LOGV("buffered = [[%" PRId64 ", %" PRId64 "]]",
TimeUnit().ToMicroseconds(), Duration()->ToMicroseconds());
return buffered;
}
MediaByteRangeSet ranges;
nsresult rv = stream->GetCachedRanges(ranges);
NS_ENSURE_SUCCESS(rv, buffered);
for (const auto& range : ranges) {
if (range.IsEmpty()) {
continue;
}
TimeUnit start = Duration(FrameIndexFromOffset(range.mStart));
TimeUnit end = Duration(FrameIndexFromOffset(range.mEnd));
MP3LOGV("buffered += [%" PRId64 ", %" PRId64 "]", start.ToMicroseconds(),
end.ToMicroseconds());
buffered += TimeInterval(start, end);
}
// If the number of frames reported by the header is valid,
// the duration calculated from it is the maximal duration.
if (ValidNumAudioFrames() && Duration()) {
TimeInterval duration = TimeInterval(TimeUnit(), *Duration());
return buffered.Intersection(duration);
}
return buffered;
}
int64_t MP3TrackDemuxer::StreamLength() const { return mSource.GetLength(); }
media::NullableTimeUnit NothingIfNegative(TimeUnit aDuration) {
if (aDuration.IsNegative()) {
return Nothing();
}
return Some(aDuration);
}
media::NullableTimeUnit MP3TrackDemuxer::Duration() const {
if (!mNumParsedFrames) {
return Nothing();
}
int64_t numFrames = 0;
const auto numAudioFrames = ValidNumAudioFrames();
if (numAudioFrames) {
// VBR headers don't include the VBR header frame.
numFrames = numAudioFrames.value() + 1;
return NothingIfNegative(Duration(numFrames) -
(EncoderDelay() + Padding()));
}
const int64_t streamLen = StreamLength();
if (streamLen < 0) { // Live streams.
// Unknown length, we can't estimate duration.
return Nothing();
}
// We can't early return when streamLen < 0 before checking numAudioFrames
// since some live radio will give an opening remark before playing music
// and the duration of the opening talk can be calculated by numAudioFrames.
int64_t size = streamLen - mFirstFrameOffset;
MOZ_ASSERT(size);
if (mParser.ID3v1MetadataFound() && size > 128) {
size -= 128;
}
// If it's CBR, calculate the duration by bitrate.
if (!mParser.VBRInfo().IsValid()) {
const uint32_t bitrate = mParser.CurrentFrame().Header().Bitrate();
return NothingIfNegative(
media::TimeUnit::FromSeconds(static_cast<double>(size) * 8 / bitrate));
}
if (AverageFrameLength() > 0) {
numFrames = std::lround(AssertedCast<double>(size) / AverageFrameLength());
}
return NothingIfNegative(Duration(numFrames) - (EncoderDelay() + Padding()));
}
TimeUnit MP3TrackDemuxer::Duration(int64_t aNumFrames) const {
if (!mSamplesPerSecond) {
return TimeUnit::Invalid();
}
const int64_t frameCount = aNumFrames * mSamplesPerFrame;
return TimeUnit(frameCount, mSamplesPerSecond);
}
MediaByteRange MP3TrackDemuxer::FindFirstFrame() {
// We attempt to find multiple successive frames to avoid locking onto a false
// positive if we're fed a stream that has been cut mid-frame.
// For compatibility reasons we have to use the same frame count as Chrome,
// since some web sites actually use a file that short to test our playback
// capabilities.
static const int MIN_SUCCESSIVE_FRAMES = 3;
mFrameLock = false;
MediaByteRange candidateFrame = FindNextFrame();
int numSuccFrames = candidateFrame.Length() > 0;
MediaByteRange currentFrame = candidateFrame;
MP3LOGV("FindFirst() first candidate frame: mOffset=%" PRIu64
" Length()=%" PRIu64,
candidateFrame.mStart, candidateFrame.Length());
while (candidateFrame.Length()) {
mParser.EndFrameSession();
mOffset = currentFrame.mEnd;
const MediaByteRange prevFrame = currentFrame;
// FindNextFrame() here will only return frames consistent with our
// candidate frame.
currentFrame = FindNextFrame();
numSuccFrames += currentFrame.Length() > 0;
// Multiple successive false positives, which wouldn't be caught by the
// consistency checks alone, can be detected by wrong alignment (non-zero
// gap between frames).
const int64_t frameSeparation = currentFrame.mStart - prevFrame.mEnd;
if (!currentFrame.Length() || frameSeparation != 0) {
MP3LOGV(
"FindFirst() not enough successive frames detected, "
"rejecting candidate frame: successiveFrames=%d, last "
"Length()=%" PRIu64 ", last frameSeparation=%" PRId64,
numSuccFrames, currentFrame.Length(), frameSeparation);
mParser.ResetFrameData();
mOffset = candidateFrame.mStart + 1;
candidateFrame = FindNextFrame();
numSuccFrames = candidateFrame.Length() > 0;
currentFrame = candidateFrame;
MP3LOGV("FindFirst() new candidate frame: mOffset=%" PRIu64
" Length()=%" PRIu64,
candidateFrame.mStart, candidateFrame.Length());
} else if (numSuccFrames >= MIN_SUCCESSIVE_FRAMES) {
MP3LOG(
"FindFirst() accepting candidate frame: "
"successiveFrames=%d",
numSuccFrames);
mFrameLock = true;
return candidateFrame;
} else if (prevFrame.mStart == mParser.TotalID3HeaderSize() &&
currentFrame.mEnd == StreamLength()) {
// We accept streams with only two frames if both frames are valid. This
// is to handle very short files and provide parity with Chrome. See
// with a trailing tag, but as of writing we lack infrastructure to
// handle such tags.
MP3LOG(
"FindFirst() accepting candidate frame for short stream: "
"successiveFrames=%d",
numSuccFrames);
mFrameLock = true;
return candidateFrame;
}
}
MP3LOG("FindFirst() no suitable first frame found");
return candidateFrame;
}
static bool VerifyFrameConsistency(const FrameParser::Frame& aFrame1,
const FrameParser::Frame& aFrame2) {
const auto& h1 = aFrame1.Header();
const auto& h2 = aFrame2.Header();
return h1.IsValid() && h2.IsValid() && h1.Layer() == h2.Layer() &&
h1.SlotSize() == h2.SlotSize() &&
h1.SamplesPerFrame() == h2.SamplesPerFrame() &&
h1.Channels() == h2.Channels() && h1.SampleRate() == h2.SampleRate() &&
h1.RawVersion() == h2.RawVersion() &&
h1.RawProtection() == h2.RawProtection();
}
MediaByteRange MP3TrackDemuxer::FindNextFrame() {
static const int BUFFER_SIZE = 64;
static const uint32_t MAX_SKIPPABLE_BYTES = 1024 * BUFFER_SIZE;
MP3LOGV("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];
uint32_t read = 0;
bool foundFrame = false;
int64_t frameHeaderOffset = 0;
int64_t startOffset = mOffset;
const bool searchingForID3 = !mParser.ID3Header().HasSizeBeenSet();
// Check whether we've found a valid MPEG frame.
while (!foundFrame) {
// How many bytes we can go without finding a valid MPEG frame
// (effectively rounded up to the next full buffer size multiple, as we
// only check this before reading the next set of data into the buffer).
// This default value of 0 will be used during testing whether we're being
// fed a valid stream, which shouldn't have any gaps between frames.
uint32_t maxSkippableBytes = 0;
if (!mParser.FirstFrame().Length()) {
// We're looking for the first valid frame. A well-formed file should
// have its first frame header right at the start (skipping an ID3 tag
// if necessary), but in order to support files that might have been
// improperly cut, we search the first few kB for a frame header.
maxSkippableBytes = MAX_SKIPPABLE_BYTES;
// Since we're counting the skipped bytes from the offset we started
// this parsing session with, we need to discount the ID3 tag size only
// if we were looking for one during the current frame parsing session.
if (searchingForID3) {
maxSkippableBytes += mParser.TotalID3HeaderSize();
}
} else if (mFrameLock) {
// We've found a valid MPEG stream, so don't impose any limits
// to allow skipping corrupted data until we hit EOS.
maxSkippableBytes = std::numeric_limits<uint32_t>::max();
}
if ((mOffset - startOffset > maxSkippableBytes) ||
(read = Read(buffer, mOffset, BUFFER_SIZE)) == 0) {
MP3LOG(
"FindNext() EOS or exceeded maxSkippeableBytes without a frame "
"(read: %d)",
read);
// This is not a valid MPEG audio stream or we've reached EOS, give up.
break;
}
BufferReader reader(buffer, read);
uint32_t bytesToSkip = 0;
auto res = mParser.Parse(&reader, &bytesToSkip);
foundFrame = res.unwrapOr(false);
int64_t readerOffset = static_cast<int64_t>(reader.Offset());
frameHeaderOffset = mOffset + readerOffset - FrameParser::FrameHeader::SIZE;
// If we've found neither an MPEG frame header nor an ID3v2 tag,
// the reader shouldn't have any bytes remaining.
MOZ_ASSERT(foundFrame || bytesToSkip || !reader.Remaining());
if (foundFrame && mParser.FirstFrame().Length() &&
!VerifyFrameConsistency(mParser.FirstFrame(), mParser.CurrentFrame())) {
MP3LOG("Skipping frame");
// We've likely hit a false-positive, ignore it and proceed with the
// search for the next valid frame.
foundFrame = false;
mOffset = frameHeaderOffset + 1;
mParser.EndFrameSession();
} else {
// Advance mOffset by the amount of bytes read and if necessary,
// skip an ID3v2 tag which stretches beyond the current buffer.
NS_ENSURE_TRUE(mOffset + read + bytesToSkip > mOffset,
MediaByteRange(0, 0));
mOffset += static_cast<int64_t>(read + bytesToSkip);
}
}
if (StreamLength() != -1) {
mEOS = frameHeaderOffset + mParser.CurrentFrame().Length() + BUFFER_SIZE >
StreamLength();
}
if (!foundFrame || !mParser.CurrentFrame().Length()) {
MP3LOG("FindNext() Exit foundFrame=%d mParser.CurrentFrame().Length()=%d ",
foundFrame, mParser.CurrentFrame().Length());
return {0, 0};
}
MP3LOGV("FindNext() End mOffset=%" PRIu64 " mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " frameHeaderOffset=%" PRId64
" mTotalFrameLen=%" PRIu64
" mSamplesPerFrame=%d mSamplesPerSecond=%d"
" mChannels=%d, mEOS=%s",
mOffset, mNumParsedFrames, mFrameIndex, frameHeaderOffset,
mTotalFrameLen, mSamplesPerFrame, mSamplesPerSecond, mChannels,
mEOS ? "true" : "false");
return {frameHeaderOffset,
frameHeaderOffset + mParser.CurrentFrame().Length()};
}
bool MP3TrackDemuxer::SkipNextFrame(const MediaByteRange& aRange) {
if (!mNumParsedFrames || !aRange.Length()) {
// We can't skip the first frame, since it could contain VBR headers.
RefPtr<MediaRawData> frame(GetNextFrame(aRange));
return frame;
}
UpdateState(aRange);
MP3LOGV("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;
}
media::TimeUnit MP3TrackDemuxer::EncoderDelay() const {
return media::TimeUnit(mEncoderDelay, mSamplesPerSecond);
}
uint32_t MP3TrackDemuxer::EncoderDelayFrames() const { return mEncoderDelay; }
media::TimeUnit MP3TrackDemuxer::Padding() const {
return media::TimeUnit(mEncoderPadding, mSamplesPerSecond);
}
uint32_t MP3TrackDemuxer::PaddingFrames() const { return mEncoderPadding; }
already_AddRefed<MediaRawData> MP3TrackDemuxer::GetNextFrame(
const MediaByteRange& aRange) {
MP3LOG("GetNext() Begin({mStart=%" PRId64 " Length()=%" PRId64 "})",
aRange.mStart, aRange.Length());
if (!aRange.Length()) {
return nullptr;
}
RefPtr<MediaRawData> frame = new MediaRawData();
frame->mOffset = aRange.mStart;
UniquePtr<MediaRawDataWriter> frameWriter(frame->CreateWriter());
if (!frameWriter->SetSize(static_cast<size_t>(aRange.Length()))) {
MP3LOG("GetNext() Exit failed to allocated media buffer");
return nullptr;
}
const uint32_t read =
Read(frameWriter->Data(), frame->mOffset, frame->Size());
if (read != aRange.Length()) {
MP3LOG("GetNext() Exit read=%u frame->Size()=%zu", read, frame->Size());
return nullptr;
}
UpdateState(aRange);
if (mNumParsedFrames == 1) {
// First frame parsed, let's read VBR info if available.
BufferReader reader(frame->Data(), frame->Size());
mFirstFrameOffset = frame->mOffset;
if (mParser.ParseVBRHeader(&reader)) {
// Parsing was successful
if (mParser.VBRInfo().Type() == FrameParser::VBRHeader::XING) {
MP3LOG("XING header present, skipping encoder delay (%u frames)",
mParser.VBRInfo().EncoderDelay());
mEncoderDelay = mParser.VBRInfo().EncoderDelay();
mEncoderPadding = mParser.VBRInfo().EncoderPadding();
// Padding is encoded as a 12-bit unsigned number so this is fine.
mRemainingEncoderPadding = AssertedCast<int32_t>(mEncoderPadding);
if (mEncoderDelay == 0) {
// Skip the VBR frame + the decoder delay, that is always 529 frames
// in practice for the decoder we're using.
mEncoderDelay = mSamplesPerFrame + 529;
MP3LOG(
"No explicit delay present in vbr header, delay is assumed to be "
"%u frames\n",
mEncoderDelay);
}
} else if (mParser.VBRInfo().Type() == FrameParser::VBRHeader::VBRI) {
MP3LOG("VBRI header present, skipping encoder delay (%u frames)",
mParser.VBRInfo().EncoderDelay());
mEncoderDelay = mParser.VBRInfo().EncoderDelay();
}
}
}
TimeUnit rawPts = Duration(mFrameIndex - 1) - EncoderDelay();
TimeUnit rawDuration = Duration(1);
TimeUnit rawEnd = rawPts + rawDuration;
frame->mTime = std::max(TimeUnit::Zero(mSamplesPerSecond), rawPts);
frame->mDuration = Duration(1);
frame->mTimecode = frame->mTime;
frame->mKeyframe = true;
frame->mEOS = mEOS;
// Handle decoder delay. A packet must be trimmed if its pts, adjusted for
// decoder delay, is negative. A packet can be trimmed entirely.
if (rawPts.IsNegative()) {
frame->mDuration =
std::max(TimeUnit::Zero(mSamplesPerSecond), rawEnd - frame->mTime);
}
// It's possible to create an mp3 file that has a padding value that somehow
// spans multiple packets. In that case the duration is probably known,
// because it's probably a VBR file with a XING header (that has a duration
// field). Use the duration to be able to set the correct duration on
// packets that aren't the last one.
// For most files, the padding is less than a packet, it's simply substracted.
if (mParser.VBRInfo().Type() == FrameParser::VBRHeader::XING &&
mRemainingEncoderPadding > 0 &&
frame->GetEndTime() > Duration().valueOr(TimeUnit::FromInfinity())) {
TimeUnit duration = Duration().value();
TimeUnit inPaddingZone = frame->GetEndTime() - duration;
TimeUnit originalEnd = frame->GetEndTime();
TimeUnit originalPts = frame->mTime;
frame->mDuration -= inPaddingZone;
// Packet is entirely padding and will be completely discarded by the
// decoder.
if (frame->mDuration.IsNegative()) {
frame->mDuration = TimeUnit::Zero(mSamplesPerSecond);
}
int32_t paddingFrames =
AssertedCast<int32_t>(inPaddingZone.ToTicksAtRate(mSamplesPerSecond));
if (mRemainingEncoderPadding >= paddingFrames) {
mRemainingEncoderPadding -= paddingFrames;
} else {
mRemainingEncoderPadding = 0;
}
MP3LOG("Trimming [%s, %s] to [%s,%s] (padding) (stream duration: %s)",
originalPts.ToString().get(), originalEnd.ToString().get(),
frame->mTime.ToString().get(), frame->GetEndTime().ToString().get(),
duration.ToString().get());
} else if (frame->mEOS &&
mRemainingEncoderPadding <=
frame->mDuration.ToTicksAtRate(mSamplesPerSecond)) {
frame->mDuration -= TimeUnit(mRemainingEncoderPadding, mSamplesPerSecond);
MOZ_ASSERT(frame->mDuration.IsPositiveOrZero());
MP3LOG("Trimming last packet %s to [%s,%s]", Padding().ToString().get(),
frame->mTime.ToString().get(), frame->GetEndTime().ToString().get());
}
MP3LOGV("GetNext() End mOffset=%" PRIu64 " mNumParsedFrames=%" PRIu64
" mFrameIndex=%" PRId64 " mTotalFrameLen=%" PRIu64
" mSamplesPerFrame=%d mSamplesPerSecond=%d mChannels=%d, mEOS=%s",
mOffset, mNumParsedFrames, mFrameIndex, mTotalFrameLen,
mSamplesPerFrame, mSamplesPerSecond, mChannels,
mEOS ? "true" : "false");
// It's possible for the duration of a frame to be zero if the frame is to be
// trimmed entirely because it's fully comprised of decoder delay samples.
// This is common at the beginning of an stream.
MOZ_ASSERT(frame->mDuration.IsPositiveOrZero());
MP3LOG("Packet demuxed: pts [%s, %s] (duration: %s)",
frame->mTime.ToString().get(), frame->GetEndTime().ToString().get(),
frame->mDuration.ToString().get());
// Indicate original packet information to trim after decoding.
if (frame->mDuration != rawDuration) {
frame->mOriginalPresentationWindow = Some(TimeInterval{rawPts, rawEnd});
MP3LOG("Total packet time excluding trimming: [%s, %s]",
rawPts.ToString().get(), rawEnd.ToString().get());
}
return frame.forget();
}
int64_t MP3TrackDemuxer::OffsetFromFrameIndex(int64_t aFrameIndex) const {
int64_t offset = 0;
const auto& vbr = mParser.VBRInfo();
if (vbr.IsComplete()) {
offset = mFirstFrameOffset + aFrameIndex * vbr.NumBytes().value() /
vbr.NumAudioFrames().value();
} else if (AverageFrameLength() > 0) {
offset = mFirstFrameOffset +
AssertedCast<int64_t>(static_cast<float>(aFrameIndex) *
AverageFrameLength());
}
MP3LOGV("OffsetFromFrameIndex(%" PRId64 ") -> %" PRId64, aFrameIndex, offset);
return std::max<int64_t>(mFirstFrameOffset, offset);
}
int64_t MP3TrackDemuxer::FrameIndexFromOffset(int64_t aOffset) const {
int64_t frameIndex = 0;
const auto& vbr = mParser.VBRInfo();
if (vbr.IsComplete()) {
frameIndex =
AssertedCast<int64_t>(static_cast<float>(aOffset - mFirstFrameOffset) /
static_cast<float>(vbr.NumBytes().value()) *
static_cast<float>(vbr.NumAudioFrames().value()));
frameIndex = std::min<int64_t>(vbr.NumAudioFrames().value(), frameIndex);
} else if (AverageFrameLength() > 0) {
frameIndex = AssertedCast<int64_t>(
static_cast<float>(aOffset - mFirstFrameOffset) / AverageFrameLength());
}
MP3LOGV("FrameIndexFromOffset(%" PRId64 ") -> %" PRId64, aOffset, frameIndex);
return std::max<int64_t>(0, frameIndex);
}
int64_t MP3TrackDemuxer::FrameIndexFromTime(
const media::TimeUnit& aTime) const {
int64_t frameIndex = 0;
if (mSamplesPerSecond > 0 && mSamplesPerFrame > 0) {
frameIndex = AssertedCast<int64_t>(
aTime.ToSeconds() * mSamplesPerSecond / mSamplesPerFrame - 1);
}
MP3LOGV("FrameIndexFromOffset(%fs) -> %" PRId64, aTime.ToSeconds(),
frameIndex);
return std::max<int64_t>(0, frameIndex);
}
void MP3TrackDemuxer::UpdateState(const MediaByteRange& aRange) {
// Prevent overflow.
if (mTotalFrameLen + aRange.Length() < 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 = aRange.mEnd;
mTotalFrameLen += aRange.Length();
if (!mSamplesPerFrame) {
mSamplesPerFrame = mParser.CurrentFrame().Header().SamplesPerFrame();
mSamplesPerSecond = mParser.CurrentFrame().Header().SampleRate();
mChannels = mParser.CurrentFrame().Header().Channels();
}
++mNumParsedFrames;
++mFrameIndex;
MOZ_ASSERT(mFrameIndex > 0);
// Prepare the parser for the next frame parsing session.
mParser.EndFrameSession();
}
uint32_t MP3TrackDemuxer::Read(uint8_t* aBuffer, int64_t aOffset,
uint32_t aSize) {
MP3LOGV("MP3TrackDemuxer::Read(%p %" PRId64 " %d)", aBuffer, aOffset, aSize);
const int64_t streamLen = StreamLength();
if (mInfo && streamLen > 0) {
// Prevent blocking reads after successful initialization.
int64_t max = streamLen > aOffset ? streamLen - aOffset : 0;
aSize = std::min<int64_t>(aSize, max);
}
uint32_t read = 0;
MP3LOGV("MP3TrackDemuxer::Read -> ReadAt(%u)", aSize);
const nsresult rv = mSource.ReadAt(aOffset, reinterpret_cast<char*>(aBuffer),
static_cast<uint32_t>(aSize), &read);
NS_ENSURE_SUCCESS(rv, 0);
return read;
}
double MP3TrackDemuxer::AverageFrameLength() const {
if (mNumParsedFrames) {
return static_cast<double>(mTotalFrameLen) /
static_cast<double>(mNumParsedFrames);
}
const auto& vbr = mParser.VBRInfo();
if (vbr.IsComplete() && vbr.NumAudioFrames().value() + 1) {
return static_cast<double>(vbr.NumBytes().value()) /
(vbr.NumAudioFrames().value() + 1);
}
return 0.0;
}
Maybe<uint32_t> MP3TrackDemuxer::ValidNumAudioFrames() const {
return mParser.VBRInfo().IsValid() &&
mParser.VBRInfo().NumAudioFrames().valueOr(0) + 1 > 1
? mParser.VBRInfo().NumAudioFrames()
: Nothing();
}
} // namespace mozilla
#undef MP3LOG
#undef MP3LOGV