nsOggCodecState.h

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/* ***** BEGIN LICENSE BLOCK *****
 * Version: ML 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla code.
 *
 * The Initial Developer of the Original Code is the Mozilla Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2010
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *  Chris Double <chris.double@double.co.nz>
 *  Chris Pearce <chris@pearce.org.nz>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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#if !defined(nsOggCodecState_h_)
#define nsOggCodecState_h_

#include <ogg/ogg.h>
#include <theora/theoradec.h>
#ifdef MOZ_TREMOR
#include <tremor/ivorbiscodec.h>
#else
#include <vorbis/codec.h>
#endif
#include <nsDeque.h>
#include <nsTArray.h>
#include <nsClassHashtable.h>
#include "VideoUtils.h"

// Uncomment the following to validate that we're predicting the number
// of Vorbis samples in each packet correctly.
#define VALIDATE_VORBIS_SAMPLE_CALCULATION
#ifdef  VALIDATE_VORBIS_SAMPLE_CALCULATION
#include <map>
#endif

// Deallocates a packet, used in nsPacketQueue below.
class OggPacketDeallocator : public nsDequeFunctor {
  virtual void* operator() (void* aPacket) {
    ogg_packet* p = static_cast<ogg_packet*>(aPacket);
    delete [] p->packet;
    delete p;
    return nsnull;
  }
};

// A queue of ogg_packets. When we read a page, we extract the page's packets
// and buffer them in the owning stream's nsOggCodecState. This is because
// if we're skipping up to the next keyframe in very large frame sized videos,
// there may be several megabytes of data between keyframes, and the
// ogg_stream_state would end up resizing its buffer every time we added a
// new 4KB page to the bitstream, which kills performance on Windows. This
// also gives us the option to timestamp packets rather than decoded
// frames/samples, reducing the amount of frames/samples we must decode to
// determine start-time at a particular offset, and gives us finer control
// over memory usage.
class nsPacketQueue : private nsDeque {
public:
  nsPacketQueue() : nsDeque(new OggPacketDeallocator()) {}
  ~nsPacketQueue() { Erase(); }
  PRBool IsEmpty() { return nsDeque::GetSize() == 0; }
  void Append(ogg_packet* aPacket);
  ogg_packet* PopFront() { return static_cast<ogg_packet*>(nsDeque::PopFront()); }
  ogg_packet* PeekFront() { return static_cast<ogg_packet*>(nsDeque::PeekFront()); }
  void PushFront(ogg_packet* aPacket) { nsDeque::PushFront(aPacket); }
  void PushBack(ogg_packet* aPacket) { nsDeque::PushFront(aPacket); }
  void Erase() { nsDeque::Erase(); }
};

// Encapsulates the data required for decoding an ogg bitstream and for
// converting granulepos to timestamps.
class nsOggCodecState {
public:
  // Ogg types we know about
  enum CodecType {
    TYPE_VORBIS=0,
    TYPE_THEORA=1,
    TYPE_SKELETON=2,
    TYPE_UNKNOWN=3
  };

  virtual ~nsOggCodecState();
  
  // Factory for creating nsCodecStates. Use instead of constructor.
  // aPage should be a beginning-of-stream page.
  static nsOggCodecState* Create(ogg_page* aPage);
  
  virtual CodecType GetType() { return TYPE_UNKNOWN; }
  
  // Reads a header packet. Returns PR_TRUE when last header has been read.
  virtual PRBool DecodeHeader(ogg_packet* aPacket) {
    return (mDoneReadingHeaders = PR_TRUE);
  }

  // Returns the end time that a granulepos represents.
  virtual PRInt64 Time(PRInt64 granulepos) { return -1; }

  // Returns the start time that a granulepos represents.
  virtual PRInt64 StartTime(PRInt64 granulepos) { return -1; }

  // Initializes the codec state.
  virtual PRBool Init();

  // Returns PR_TRUE when this bitstream has finished reading all its
  // header packets.
  PRBool DoneReadingHeaders() { return mDoneReadingHeaders; }

  // Deactivates the bitstream. Only the primary video and audio bitstreams
  // should be active.
  void Deactivate() {
    mActive = PR_FALSE;
    mDoneReadingHeaders = PR_TRUE;
    Reset();
  }

  // Resets decoding state.
  virtual nsresult Reset();

  // Returns PR_TRUE if the nsOggCodecState thinks this packet is a header
  // packet. Note this does not verify the validity of the header packet,
  // it just guarantees that the packet is marked as a header packet (i.e.
  // it is definintely not a data packet). Do not use this to identify
  // streams, use it to filter header packets from data packets while
  // decoding.
  virtual PRBool IsHeader(ogg_packet* aPacket) { return PR_FALSE; }

  // Returns the next packet in the stream, or nsnull if there are no more
  // packets buffered in the packet queue. More packets can be buffered by
  // inserting one or more pages into the stream by calling PageIn(). The
  // caller is responsible for deleting returned packet's using
  // nsOggCodecState::ReleasePacket(). The packet will have a valid granulepos.
  ogg_packet* PacketOut();

  // Releases the memory used by a cloned packet. Every packet returned by
  // PacketOut() must be free'd using this function.
  static void ReleasePacket(ogg_packet* aPacket);

  // Extracts all packets from the page, and inserts them into the packet
  // queue. They can be extracted by calling PacketOut(). Packets from an
  // inactive stream are not buffered, i.e. this call has no effect for
  // inactive streams. Multiple pages may need to be inserted before
  // PacketOut() starts to return packets, as granulepos may need to be
  // captured.
  virtual nsresult PageIn(ogg_page* aPage);

  // Number of packets read.  
  PRUint64 mPacketCount;

  // Serial number of the bitstream.
  PRUint32 mSerial;

  // Ogg specific state.
  ogg_stream_state mState;

  // Queue of as yet undecoded packets. Packets are guaranteed to have
  // a valid granulepos.
  nsPacketQueue mPackets;

  // Is the bitstream active; whether we're decoding and playing this bitstream.
  PRPackedBool mActive;
  
  // PR_TRUE when all headers packets have been read.
  PRPackedBool mDoneReadingHeaders;

protected:
  // Constructs a new nsOggCodecState. aActive denotes whether the stream is
  // active. For streams of unsupported or unknown types, aActive should be
  // PR_FALSE.
  nsOggCodecState(ogg_page* aBosPage, PRBool aActive);

  // Deallocates all packets stored in mUnstamped, and clears the array.
  void ClearUnstamped();

  // Extracts packets out of mState until a data packet with a non -1
  // granulepos is encountered, or no more packets are readable. Header
  // packets are pushed into the packet queue immediately, and data packets
  // are buffered in mUnstamped. Once a non -1 granulepos packet is read
  // the granulepos of the packets in mUnstamped can be inferred, and they
  // can be pushed over to mPackets. Used by PageIn() implementations in
  // subclasses.
  nsresult PacketOutUntilGranulepos(PRBool& aFoundGranulepos);

  // Temporary buffer in which to store packets while we're reading packets
  // in order to capture granulepos.
  nsTArray<ogg_packet*> mUnstamped;
};

class nsVorbisState : public nsOggCodecState {
public:
  nsVorbisState(ogg_page* aBosPage);
  virtual ~nsVorbisState();

  CodecType GetType() { return TYPE_VORBIS; }
  PRBool DecodeHeader(ogg_packet* aPacket);
  PRInt64 Time(PRInt64 granulepos);
  PRBool Init();
  nsresult Reset();
  PRBool IsHeader(ogg_packet* aPacket);
  nsresult PageIn(ogg_page* aPage); 

  // Returns the end time that a granulepos represents.
  static PRInt64 Time(vorbis_info* aInfo, PRInt64 aGranulePos); 

  vorbis_info mInfo;
  vorbis_comment mComment;
  vorbis_dsp_state mDsp;
  vorbis_block mBlock;

private:

  // Reconstructs the granulepos of Vorbis packets stored in the mUnstamped
  // array.
  nsresult ReconstructVorbisGranulepos();

  // The "block size" of the previously decoded Vorbis packet, or 0 if we've
  // not yet decoded anything. This is used to calculate the number of samples
  // in a Vorbis packet, since each Vorbis packet depends on the previous
  // packet while being decoded.
  long mPrevVorbisBlockSize;

  // Granulepos (end sample) of the last decoded Vorbis packet. This is used
  // to calculate the Vorbis granulepos when we don't find a granulepos to
  // back-propagate from.
  PRInt64 mGranulepos;

#ifdef VALIDATE_VORBIS_SAMPLE_CALCULATION
  // When validating that we've correctly predicted Vorbis packets' number
  // of samples, we store each packet's predicted number of samples in this
  // map, and verify we decode the predicted number of samples.
  std::map<ogg_packet*, long> mVorbisPacketSamples;
#endif

  // Records that aPacket is predicted to have aSamples samples.
  // This function has no effect if VALIDATE_VORBIS_SAMPLE_CALCULATION
  // is not defined.
  void RecordVorbisPacketSamples(ogg_packet* aPacket, long aSamples);

  // Verifies that aPacket has had its number of samples predicted.
  // This function has no effect if VALIDATE_VORBIS_SAMPLE_CALCULATION
  // is not defined.
  void AssertHasRecordedPacketSamples(ogg_packet* aPacket);

public:
  // Asserts that the number of samples predicted for aPacket is aSamples.
  // This function has no effect if VALIDATE_VORBIS_SAMPLE_CALCULATION
  // is not defined.
  void ValidateVorbisPacketSamples(ogg_packet* aPacket, long aSamples);

};

// Returns 1 if the Theora info struct is decoding a media of Theora
// verion (maj,min,sub) or later, otherwise returns 0.
int TheoraVersion(th_info* info,
                  unsigned char maj,
                  unsigned char min,
                  unsigned char sub);

class nsTheoraState : public nsOggCodecState {
public:
  nsTheoraState(ogg_page* aBosPage);
  virtual ~nsTheoraState();

  CodecType GetType() { return TYPE_THEORA; }
  PRBool DecodeHeader(ogg_packet* aPacket);
  PRInt64 Time(PRInt64 granulepos);
  PRInt64 StartTime(PRInt64 granulepos);
  PRBool Init();
  PRBool IsHeader(ogg_packet* aPacket);
  nsresult PageIn(ogg_page* aPage); 

  // Returns the maximum number of microseconds which a keyframe can be offset
  // from any given interframe.
  PRInt64 MaxKeyframeOffset();

  // Returns the end time that a granulepos represents.
  static PRInt64 Time(th_info* aInfo, PRInt64 aGranulePos); 

  th_info mInfo;
  th_comment mComment;
  th_setup_info *mSetup;
  th_dec_ctx* mCtx;

  float mPixelAspectRatio;

private:

  // Reconstructs the granulepos of Theora packets stored in the
  // mUnstamped array. mUnstamped must be filled with consecutive packets from
  // the stream, with the last packet having a known granulepos. Using this
  // known granulepos, and the known frame numbers, we recover the granulepos
  // of all frames in the array. This enables us to determine their timestamps.
  void ReconstructTheoraGranulepos();

};

// Constructs a 32bit version number out of two 16 bit major,minor
// version numbers.
#define SKELETON_VERSION(major, minor) (((major)<<16)|(minor))

class nsSkeletonState : public nsOggCodecState {
public:
  nsSkeletonState(ogg_page* aBosPage);
  ~nsSkeletonState();
  CodecType GetType() { return TYPE_SKELETON; }
  PRBool DecodeHeader(ogg_packet* aPacket);
  PRInt64 Time(PRInt64 granulepos) { return -1; }
  PRBool Init() { return PR_TRUE; }
  PRBool IsHeader(ogg_packet* aPacket) { return PR_TRUE; }

  // Return PR_TRUE if the given time (in milliseconds) is within
  // the presentation time defined in the skeleton track.
  PRBool IsPresentable(PRInt64 aTime) { return aTime >= mPresentationTime; }

  // Stores the offset of the page on which a keyframe starts,
  // and its presentation time.
  class nsKeyPoint {
  public:
    nsKeyPoint()
      : mOffset(PR_INT64_MAX),
        mTime(PR_INT64_MAX) {}

    nsKeyPoint(PRInt64 aOffset, PRInt64 aTime)
      : mOffset(aOffset),
        mTime(aTime) {}

    // Offset from start of segment/link-in-the-chain in bytes.
    PRInt64 mOffset;

    // Presentation time in usecs.
    PRInt64 mTime;

    PRBool IsNull() {
      return mOffset == PR_INT64_MAX &&
             mTime == PR_INT64_MAX;
    }
  };

  // Stores a keyframe's byte-offset, presentation time and the serialno
  // of the stream it belongs to.
  class nsSeekTarget {
  public:
    nsSeekTarget() : mSerial(0) {}
    nsKeyPoint mKeyPoint;
    PRUint32 mSerial;
    PRBool IsNull() {
      return mKeyPoint.IsNull() &&
             mSerial == 0;
    }
  };

  // Determines from the seek index the keyframe which you must seek back to
  // in order to get all keyframes required to render all streams with
  // serialnos in aTracks, at time aTarget.
  nsresult IndexedSeekTarget(PRInt64 aTarget,
                             nsTArray<PRUint32>& aTracks,
                             nsSeekTarget& aResult);

  PRBool HasIndex() const {
    return mIndex.IsInitialized() && mIndex.Count() > 0;
  }

  // Returns the duration of the active tracks in the media, if we have
  // an index. aTracks must be filled with the serialnos of the active tracks.
  // The duration is calculated as the greatest end time of all active tracks,
  // minus the smalled start time of all the active tracks.
  nsresult GetDuration(const nsTArray<PRUint32>& aTracks, PRInt64& aDuration);

private:

  // Decodes an index packet. Returns PR_FALSE on failure.
  PRBool DecodeIndex(ogg_packet* aPacket);

  // Gets the keypoint you must seek to in order to get the keyframe required
  // to render the stream at time aTarget on stream with serial aSerialno.
  nsresult IndexedSeekTargetForTrack(PRUint32 aSerialno,
                                     PRInt64 aTarget,
                                     nsKeyPoint& aResult);

  // Version of the decoded skeleton track, as per the SKELETON_VERSION macro.
  PRUint32 mVersion;

  // Presentation time of the resource in milliseconds
  PRInt64 mPresentationTime;

  // Length of the resource in bytes.
  PRInt64 mLength;

  // Stores the keyframe index and duration information for a particular
  // stream.
  class nsKeyFrameIndex {
  public:

    nsKeyFrameIndex(PRInt64 aStartTime, PRInt64 aEndTime) 
      : mStartTime(aStartTime),
        mEndTime(aEndTime)
    {
      MOZ_COUNT_CTOR(nsKeyFrameIndex);
    }

    ~nsKeyFrameIndex() {
      MOZ_COUNT_DTOR(nsKeyFrameIndex);
    }

    void Add(PRInt64 aOffset, PRInt64 aTimeMs) {
      mKeyPoints.AppendElement(nsKeyPoint(aOffset, aTimeMs));
    }

    const nsKeyPoint& Get(PRUint32 aIndex) const {
      return mKeyPoints[aIndex];
    }

    PRUint32 Length() const {
      return mKeyPoints.Length();
    }

    // Presentation time of the first sample in this stream in usecs.
    const PRInt64 mStartTime;

    // End time of the last sample in this stream in usecs.
    const PRInt64 mEndTime;

  private:
    nsTArray<nsKeyPoint> mKeyPoints;
  };

  // Maps Ogg serialnos to the index-keypoint list.
  nsClassHashtable<nsUint32HashKey, nsKeyFrameIndex> mIndex;
};

#endif