path: root/dom/media/encoder/fmp4_muxer/ISOControl.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
/* 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/. */

#ifndef ISOCOMPOSITOR_H_
#define ISOCOMPOSITOR_H_

#include "mozilla/EndianUtils.h"
#include "nsTArray.h"
#include "ISOTrackMetadata.h"
#include "EncodedFrameContainer.h"

namespace mozilla {

class Box;
class ISOControl;

/**
 * This class collects elementary stream data to form a fragment.
 * ISOMediaWriter will check if the data is enough; if yes, the corresponding
 * moof will be created and write to ISOControl.
 * Each audio and video has its own fragment and only one during the whole
 * life cycle, when a fragment is formed in ISOControl, Flush() needs to
 * be called to reset it.
 */
class FragmentBuffer {
public:
  // aTrackType: it could be Audio_Track or Video_Track.
  // aFragDuration: it is the fragment duration. (microsecond per unit)
  //                Audio and video have the same fragment duration.
  FragmentBuffer(uint32_t aTrackType, uint32_t aFragDuration);
  ~FragmentBuffer();

  // Get samples of first fragment, that will swap all the elements in the
  // mFragArray[0] when aFlush = true, and caller is responsible for drop
  // EncodedFrame reference count.
  nsresult GetFirstFragment(nsTArray<RefPtr<EncodedFrame>>& aFragment,
                            bool aFlush = false);

  // Add sample frame to the last element fragment of mFragArray. If sample
  // number is enough, it will append a new fragment element. And the new
  // sample will be added to the new fragment element of mFragArray.
  nsresult AddFrame(EncodedFrame* aFrame);

  // Get total sample size of first complete fragment size.
  uint32_t GetFirstFragmentSampleSize();

  // Get sample number of first complete fragment.
  uint32_t GetFirstFragmentSampleNumber();

  // Check if it accumulates enough frame data.
  // It returns true when data is enough to form a fragment.
  bool HasEnoughData();

  // Called by ISOMediaWriter when TrackEncoder has sent the last frame. The
  // remains frame data will form the last moof and move the state machine to
  // in ISOMediaWriter to last phrase.
  nsresult SetEndOfStream() {
    mEOS = true;
    return  NS_OK;
  }
  bool EOS() { return mEOS; }

  // CSD (codec specific data), it is generated by encoder and the data depends
  // on codec type. This data will be sent as a special frame from encoder to
  // ISOMediaWriter and pass to this class via AddFrame().
  nsresult GetCSD(nsTArray<uint8_t>& aCSD);

  bool HasCSD() { return mCSDFrame; }

  uint32_t GetType() { return mTrackType; }

  void SetLastFragmentLastFrameTime(uint32_t aTime) {
    mLastFrameTimeOfLastFragment = aTime;
  }

  uint32_t GetLastFragmentLastFrameTime() {
    return mLastFrameTimeOfLastFragment;
  }

private:
  uint32_t mTrackType;

  // Fragment duration, microsecond per unit.
  uint32_t mFragDuration;

  // Media start time, microsecond per unit.
  // Together with mFragDuration, mFragmentNumber and EncodedFrame->GetTimeStamp(),
  // when the difference between current frame time and mMediaStartTime is
  // exceeded current fragment ceiling timeframe, that means current fragment has
  // enough data and a new element in mFragArray will be added.
  uint64_t mMediaStartTime;

  // Current fragment number. It will be increase when a new element of
  // mFragArray is created.
  // Note:
  //   It only means the fragment number of current accumulated frames, not
  //   the current 'creating' fragment mFragNum in ISOControl.
  uint32_t mFragmentNumber;

  // The last frame time stamp of last fragment. It is for calculating the
  // play duration of first frame in current fragment. The frame duration is
  // defined as "current frame timestamp - last frame timestamp" here. So it
  // needs to keep the last timestamp of last fragment.
  uint32_t mLastFrameTimeOfLastFragment;

  // Array of fragments, each element has enough samples to form a
  // complete fragment.
  nsTArray<nsTArray<RefPtr<EncodedFrame>>> mFragArray;

  // Codec specific data frame, it will be generated by encoder and send to
  // ISOMediaWriter through WriteEncodedTrack(). The data will be vary depends
  // on codec type.
  RefPtr<EncodedFrame> mCSDFrame;

  // END_OF_STREAM from ContainerWriter
  bool mEOS;
};

/**
 * ISOControl will be carried to each box when box is created. It is the main
 * bridge for box to output stream to ContainerWriter and retrieve information.
 * ISOControl acts 3 different roles:
 * 1. Holds the pointer of audio metadata, video metadata, fragment and
 *    pass them to boxes.
 * 2. Provide the functions to generate the base structure of MP4; they are
 *    GenerateFtyp, GenerateMoov, GenerateMoof, and GenerateMfra.
 * 3. The actually writer used by MuxOperation::Write() in each box. It provides
 *    writing methods for different kind of data; they are Write, WriteArray,
 *    WriteBits...etc.
 */
class ISOControl {

friend class Box;

public:
  ISOControl(uint32_t aMuxingType);
  ~ISOControl();

  nsresult GenerateFtyp();
  nsresult GenerateMoov();
  nsresult GenerateMoof(uint32_t aTrackType);

  // Swap elementary stream pointer to output buffers.
  uint32_t WriteAVData(nsTArray<uint8_t>& aArray);

  uint32_t Write(uint8_t* aBuf, uint32_t aSize);

  uint32_t Write(uint8_t aData);

  template <typename T>
  uint32_t Write(T aData) {
    MOZ_ASSERT(!mBitCount);

    aData = NativeEndian::swapToNetworkOrder(aData);
    Write((uint8_t*)&aData, sizeof(T));
    return sizeof(T);
  }

  template <typename T>
  uint32_t WriteArray(const T &aArray, uint32_t aSize) {
    MOZ_ASSERT(!mBitCount);

    uint32_t size = 0;
    for (uint32_t i = 0; i < aSize; i++) {
      size += Write(aArray[i]);
    }
    return size;
  }

  uint32_t WriteFourCC(const char* aType);

  // Bit writing. Note: it needs to be byte-boundary before using
  // others non-bit writing function.
  uint32_t WriteBits(uint64_t aBits, size_t aNumBits);

  // This is called by GetContainerData and swap all the buffers to aOutputBuffers.
  nsresult GetBufs(nsTArray<nsTArray<uint8_t>>* aOutputBufs);

  // Presentation time in seconds since midnight, Jan. 1, 1904, in UTC time.
  uint32_t GetTime();

  // current fragment number
  uint32_t GetCurFragmentNumber() { return mFragNum; }

  nsresult SetFragment(FragmentBuffer* aFragment);
  FragmentBuffer* GetFragment(uint32_t aType);

  uint32_t GetMuxingType() { return mMuxingType; }

  nsresult SetMetadata(TrackMetadataBase* aTrackMeta);
  nsresult GetAudioMetadata(RefPtr<AudioTrackMetadata>& aAudMeta);
  nsresult GetVideoMetadata(RefPtr<VideoTrackMetadata>& aVidMeta);

  // Track ID is the Metadata index in mMetaArray. It allows only 1 audio
  // track and 1 video track in this muxer. In this muxer, it is prohibt to have
  // mutiple audio track or video track in the same file.
  uint32_t GetTrackID(TrackMetadataBase::MetadataKind aKind);
  uint32_t GetNextTrackID();

  bool HasAudioTrack();
  bool HasVideoTrack();

private:
  uint32_t GetBufPos();
  nsresult FlushBuf();

  // One of value in TYPE_XXX, defined in ISOMediaWriter.
  uint32_t mMuxingType;

  // Audio and video fragments are owned by ISOMediaWriter.
  // They don't need to worry about pointer going stale because ISOMediaWriter's
  // lifetime is longer than ISOControl.
  FragmentBuffer* mAudioFragmentBuffer;
  FragmentBuffer* mVideoFragmentBuffer;

  // Generated fragment number
  uint32_t mFragNum;

  // The (index + 1) will be the track ID.
  nsTArray<RefPtr<TrackMetadataBase>> mMetaArray;

  // Array of output buffers.
  // To save memory usage, audio/video sample will be swapped into a new element
  // of this array.
  //
  // For example,
  //   mOutBuffers[0] --> boxes (allocated by muxer)
  //   mOutBuffers[1] --> video raw data (allocated by encoder)
  //   mOutBuffers[2] --> video raw data (allocated by encoder)
  //   mOutBuffers[3] --> video raw data (allocated by encoder)
  //   mOutBuffers[4] --> boxes (allocated by muxer)
  //   mOutBuffers[5] --> audio raw data (allocated by encoder)
  //   ...etc.
  //
  nsTArray<nsTArray<uint8_t>> mOutBuffers;

  // Accumulate output size from Write().
  uint64_t mOutputSize;

  // Bit writing operation. Note: the mBitCount should be 0 before any
  // byte-boundary writing method be called (Write(uint32_t), Write(uint16_t)...etc);
  // otherwise, there will be assertion on these functions.
  uint8_t mBitCount;
  uint8_t mBit;
};

}
#endif