C++ TimeUnit类代码示例

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.ToMicroseconds()) {
    return FastSeek(aTime);
  }

  if (Duration(mFrameIndex) > aTime) {
    FastSeek(aTime);
  }

  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();
}

bool
MediaSourceDecoder::CanPlayThrough()
{
  MOZ_ASSERT(NS_IsMainThread());

  if (NextFrameBufferedStatus() == MediaDecoderOwner::NEXT_FRAME_UNAVAILABLE) {
    return false;
  }

  if (IsNaN(mMediaSource->Duration())) {
    // Don't have any data yet.
    return false;
  }
  TimeUnit duration = TimeUnit::FromSeconds(mMediaSource->Duration());
  TimeUnit currentPosition = TimeUnit::FromMicroseconds(CurrentPosition());
  if (duration.IsInfinite()) {
    // We can't make an informed decision and just assume that it's a live stream
    return true;
  } else if (duration <= currentPosition) {
    return true;
  }
  // If we have data up to the mediasource's duration or 30s ahead, we can
  // assume that we can play without interruption.
  TimeUnit timeAhead =
    std::min(duration, currentPosition + TimeUnit::FromSeconds(30));
  TimeInterval interval(currentPosition,
                        timeAhead,
                        MediaSourceDemuxer::EOS_FUZZ);
  return GetBuffered().Contains(ClampIntervalToEnd(interval));
}

	// TODO: USE idx INSTEAD OF size_t
    size_t getElapsed()
    {
	/*!
	* Returns elapsed time as number of ticks of TimeUnits
	* Elapsed time can mean 2 different things:
	* 
	* 1. 	If TickCounter is running, elapsed time is measured between starTime
	* 	and now.
	* 2. 	If TickCounter is not running (i.e. it is stopped), elapsed time
	* 	is measured between startTime and stopTime.
	*/
      
		// DIFFERENCE BETWEEN THE TWO "TIMEPOINTS" MUST BE CAST TO
		// A "DURATION" USING THE std::chrono::duration_cast 
		TimeUnit duration;
	
		// CASE 1 - TickCounter IS RUNNING, USE CURRENT TIME
		if (isRunning)
		{
			duration = std::chrono::duration_cast <TimeUnit> 
			( std::chrono::high_resolution_clock::now() - startTime );
		}
		// CASE 2 - NOT RUNNING, USE stopTime
		else
		{
			duration = std::chrono::duration_cast<TimeUnit> 
			(stopTime - startTime);
		}
		// CAST TO TICK COUNT
		return static_cast <size_t> ( duration.count() );
    }

TimeUnit
MP3TrackDemuxer::FastSeek(TimeUnit aTime) {
  MP3DEMUXER_LOG("FastSeek(%" PRId64 ") avgFrameLen=%f mNumParsedFrames=%" PRIu64
                 " mFrameIndex=%" PRId64 " mOffset=%" PRIu64,
                 aTime, AverageFrameLength(), mNumParsedFrames, mFrameIndex,
                 mOffset);

  if (!aTime.ToMicroseconds()) {
    // Quick seek to the beginning of the stream.
    mOffset = mFirstFrameOffset;
    mFrameIndex = 0;
    mParser.EndFrameSession();
    return TimeUnit();
  }

  if (!mSamplesPerFrame || !mNumParsedFrames) {
    return TimeUnit::FromMicroseconds(-1);
  }

  const int64_t numFrames = aTime.ToSeconds() *
                            mSamplesPerSecond / mSamplesPerFrame;
  mOffset = mFirstFrameOffset + numFrames * AverageFrameLength();
  mFrameIndex = numFrames;

  MP3DEMUXER_LOG("FastSeek mSamplesPerSecond=%d mSamplesPerFrame=%d "
                 "numFrames=%" PRId64,
                 mSamplesPerSecond, mSamplesPerFrame, numFrames);

  mParser.EndFrameSession();

  return Duration(mFrameIndex);
}

TimeIntervals
MP3TrackDemuxer::GetBuffered() {
  AutoPinned<MediaResource> stream(mSource.GetResource());
  TimeIntervals buffered;

  if (Duration() > TimeUnit() && 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);
  }

  return buffered;
}

TEST(MP4Demuxer, GetNextKeyframe)
{
  RefPtr<MP4DemuxerBinding> binding = new MP4DemuxerBinding("gizmo-frag.mp4");

  binding->RunTestAndWait([binding]() {
    // Insert a [0,end] buffered range, to simulate Moof's being buffered
    // via MSE.
    auto len = binding->resource->GetLength();
    binding->resource->MockAddBufferedRange(0, len);

    // gizmp-frag has two keyframes; one at dts=cts=0, and another at
    // dts=cts=1000000. Verify we get expected results.
    TimeUnit time;
    binding->mVideoTrack =
        binding->mDemuxer->GetTrackDemuxer(TrackInfo::kVideoTrack, 0);
    binding->mVideoTrack->Reset();
    binding->mVideoTrack->GetNextRandomAccessPoint(&time);
    EXPECT_EQ(time.ToMicroseconds(), 0);
    binding->mVideoTrack->GetSamples()->Then(
        binding->mTaskQueue, __func__,
        [binding]() {
          TimeUnit time;
          binding->mVideoTrack->GetNextRandomAccessPoint(&time);
          EXPECT_EQ(time.ToMicroseconds(), 1000000);
          binding->mTaskQueue->BeginShutdown();
        },
        DO_FAIL);
  });
}

TimeUnit
MP3TrackDemuxer::FastSeek(const TimeUnit& aTime) {
  MP3LOG("FastSeek(%" PRId64 ") avgFrameLen=%f mNumParsedFrames=%" PRIu64
         " mFrameIndex=%" PRId64 " mOffset=%" PRIu64,
         aTime, AverageFrameLength(), mNumParsedFrames, mFrameIndex, mOffset);

  const auto& vbr = mParser.VBRInfo();
  if (!aTime.ToMicroseconds()) {
    // Quick seek to the beginning of the stream.
    mFrameIndex = 0;
  } else if (vbr.IsTOCPresent()) {
    // Use TOC for more precise seeking.
    const float durationFrac = static_cast<float>(aTime.ToMicroseconds()) /
                                                  Duration().ToMicroseconds();
    mFrameIndex = FrameIndexFromOffset(vbr.Offset(durationFrac));
  } 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=%llu mOffset=%" PRIu64
         " SL=%llu NumBytes=%u",
         vbr.IsTOCPresent(), AverageFrameLength(), mNumParsedFrames, mFrameIndex,
         mFirstFrameOffset, mOffset, StreamLength(), vbr.NumBytes().valueOr(0));

  return Duration(mFrameIndex);
}

already_AddRefed<MediaByteBuffer>
SourceBuffer::PrepareAppend(const uint8_t* aData, uint32_t aLength, ErrorResult& aRv)
{
    typedef SourceBufferContentManager::EvictDataResult Result;

    if (!IsAttached() || mUpdating) {
        aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
        return nullptr;
    }
    if (mMediaSource->ReadyState() == MediaSourceReadyState::Ended) {
        mMediaSource->SetReadyState(MediaSourceReadyState::Open);
    }

    // Eviction uses a byte threshold. If the buffer is greater than the
    // number of bytes then data is evicted. The time range for this
    // eviction is reported back to the media source. It will then
    // evict data before that range across all SourceBuffers it knows
    // about.
    // TODO: Make the eviction threshold smaller for audio-only streams.
    // TODO: Drive evictions off memory pressure notifications.
    // TODO: Consider a global eviction threshold  rather than per TrackBuffer.
    TimeUnit newBufferStartTime;
    // Attempt to evict the amount of data we are about to add by lowering the
    // threshold.
    uint32_t toEvict =
        (mEvictionThreshold > aLength) ? mEvictionThreshold - aLength : aLength;
    Result evicted =
        mContentManager->EvictData(TimeUnit::FromSeconds(mMediaSource->GetDecoder()->GetCurrentTime()),
                                   toEvict, &newBufferStartTime);
    if (evicted == Result::DATA_EVICTED) {
        MSE_DEBUG("AppendData Evict; current buffered start=%f",
                  GetBufferedStart());

        // We notify that we've evicted from the time range 0 through to
        // the current start point.
        mMediaSource->NotifyEvicted(0.0, newBufferStartTime.ToSeconds());
    }

    // See if we have enough free space to append our new data.
    // As we can only evict once we have playable data, we must give a chance
    // to the DASH player to provide a complete media segment.
    if (aLength > mEvictionThreshold || evicted == Result::BUFFER_FULL ||
            ((!mIsUsingFormatReader &&
              mContentManager->GetSize() > mEvictionThreshold - aLength) &&
             evicted != Result::CANT_EVICT)) {
        aRv.Throw(NS_ERROR_DOM_QUOTA_EXCEEDED_ERR);
        return nullptr;
    }

    nsRefPtr<MediaByteBuffer> data = new MediaByteBuffer();
    if (!data->AppendElements(aData, aLength, fallible)) {
        aRv.Throw(NS_ERROR_DOM_QUOTA_EXCEEDED_ERR);
        return nullptr;
    }
    return data.forget();
}

TimeIntervals
MP3TrackDemuxer::GetBuffered() {
  TimeUnit duration = Duration();

  if (duration <= TimeUnit()) {
    return TimeIntervals();
  }
  AutoPinned<MediaResource> stream(mSource.GetResource());
  return GetEstimatedBufferedTimeRanges(stream, duration.ToMicroseconds());
}

TimeUnit AudioSink::GetEndTime() const {
  int64_t written;
  {
    MonitorAutoLock mon(mMonitor);
    written = mWritten;
  }
  TimeUnit played = FramesToTimeUnit(written, mOutputRate) + mStartTime;
  if (!played.IsValid()) {
    NS_WARNING("Int overflow calculating audio end time");
    return TimeUnit::Zero();
  }
  // As we may be resampling, rounding errors may occur. Ensure we never get
  // past the original end time.
  return std::min(mLastEndTime, played);
}

TimeUnit
AudioSink::GetEndTime() const
{
  int64_t written;
  {
    MonitorAutoLock mon(mMonitor);
    written = mWritten;
  }
  TimeUnit played = FramesToTimeUnit(written, mOutputRate) + mStartTime;
  if (!played.IsValid()) {
    NS_WARNING("Int overflow calculating audio end time");
    return TimeUnit::Zero();
  }
  return played;
}

  nsresult PostOutput(BufferInfo::Param aInfo, MediaFormat::Param aFormat,
                      const TimeUnit& aDuration) override
  {
    RefPtr<layers::Image> img =
      new SurfaceTextureImage(mSurfaceTexture.get(), mConfig.mDisplay,
                              gl::OriginPos::BottomLeft);

    nsresult rv;
    int32_t flags;
    NS_ENSURE_SUCCESS(rv = aInfo->Flags(&flags), rv);

    bool isSync = !!(flags & MediaCodec::BUFFER_FLAG_SYNC_FRAME);

    int32_t offset;
    NS_ENSURE_SUCCESS(rv = aInfo->Offset(&offset), rv);

    int64_t presentationTimeUs;
    NS_ENSURE_SUCCESS(rv = aInfo->PresentationTimeUs(&presentationTimeUs), rv);

    RefPtr<VideoData> v =
      VideoData::CreateFromImage(mConfig,
                                 mImageContainer,
                                 offset,
                                 presentationTimeUs,
                                 aDuration.ToMicroseconds(),
                                 img,
                                 isSync,
                                 presentationTimeUs,
                                 gfx::IntRect(0, 0,
                                              mConfig.mDisplay.width,
                                              mConfig.mDisplay.height));
    INVOKE_CALLBACK(Output, v);
    return NS_OK;
  }

static void
WriteVideoToMediaStream(MediaStream* aStream,
                        layers::Image* aImage,
                        const TimeUnit& aEnd,
                        const TimeUnit& aStart,
                        const mozilla::gfx::IntSize& aIntrinsicSize,
                        const TimeStamp& aTimeStamp,
                        VideoSegment* aOutput,
                        const PrincipalHandle& aPrincipalHandle)
{
  RefPtr<layers::Image> image = aImage;
  auto end = aStream->MicrosecondsToStreamTimeRoundDown(aEnd.ToMicroseconds());
  auto start = aStream->MicrosecondsToStreamTimeRoundDown(aStart.ToMicroseconds());
  StreamTime duration = end - start;
  aOutput->AppendFrame(image.forget(), duration, aIntrinsicSize,
                       aPrincipalHandle, false, aTimeStamp);
}

STEPEntity *
TimeUnit::Create(STEPWrapper *sw, SDAI_Application_instance *sse) {
    Factory::OBJECTS::iterator i;
    if ((i = Factory::FindObject(sse->STEPfile_id)) == Factory::objects.end()) {
	TimeUnit *object = new TimeUnit(sw,sse->STEPfile_id);

	Factory::AddObject(object);

	if (!object->Load(sw, sse)) {
	    std::cerr << CLASSNAME << ":Error loading class in ::Create() method." << std::endl;
	    delete object;
	    return NULL;
	}
	return static_cast<STEPEntity *>(object);
    } else {
	return (*i).second;
    }
}

	inline TimeStamp(TimeUnit unit, double dec)
		: _unit(unit)
	{
		dec = std::max(0.0, dec);
		dec = std::min(double(std::numeric_limits<uint32_t>::max()), dec);
		double       integral;
		const double fractional = modf(dec, &integral);
		_ticks    = integral;
		_subticks = fractional * unit.ppt();
	}