/*

* Copyright (c) 2010 Ixonos Plc.

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - Initial contribution

*

* Contributors:

* Ixonos Plc

*

* Description:  

* Header for VOL header parser.

*

*/

#ifndef __VEDVOLREADER_H__

#define __VEDVOLREADER_H__

//  INCLUDES

#include <e32base.h>

#include <e32std.h>

#include <vedcommon.h>

// DATA TYPES

/**

 * Structure for the Video Object Layer header data

 */ 

struct TVolHeader

    {

    TInt iProfileLevelId;     // Indicates the Level Id (0,1,2,3,4,8 or 9) of the Simple

                              // Profile the Video Object conforms to

    TInt iVoPriority;         // Priority assigned to the Video Object 

                              // a value between 1(lowest)-7(highest).

                              // If not in the bitstream, set to zero

    TInt iVoId;               // id of the Video Object 

    TInt iVolId;              // id of the Video Object Layer 

    TInt iRandomAccessibleVol;// set to 1 if all the VOPs in the stream are I-VOP.

    TInt iPixelAspectRatio;   // see MPEG-4 visual spec. pp. 71

    TInt iTimeIncrementResolution;

                              // Resolution to interpret the time_increment 

                              // fields in the VOP headers 

    TInt iLumWidth;           // Frame width of the Y component in pixels 

    TInt iLumHeight;          // Frame height of the Y component in pixels 

    TUint8 iErrorResDisable;  // Flag ON if no resynchronization markers are

                              // used inside frames. 

                              // When OFF it doesn't mean they ARE used.

    TUint8 iDataPartitioned;  // Flag indicating if data partitioning inside 

                              // a VP is used or not.

    TUint8 iReversibleVlc;    // flag indicating the usage of reversible 

                              // VLC codes

    // the following parameters concern the input video signal,

    // see MPEG-4 visual spec. pp. 66-70, and "Note" in viddemux_mpeg.c 

    // Not used in the current implementatnion.

    TInt iVideoFormat;

    TInt iVideoRange;

    TInt iColourPrimaries;    

    TInt iTransferCharacteristics;

    TInt iMatrixCoefficients;

    // the following parameters are used in the Video Buffering Verifier

    // (Annex D) to monitor the input bit buffer, complexity, memory buffer

    // used in the decoding process. The conformance of a stream can be checked

    // using these parameters. 

    // Not used in the current implementatnion. 

    TUint32 iBitRate;

    TUint32 iVbvBufferSize;

    TUint32 iVbvOccupancy;

    HBufC8* iUserData;        // User Data if available

    };

// CLASS DECLARATION

/**

 * A class for parsing the Video Object Layer header

 */

class CVedVolReader : public CBase

    {

public:

    /**

     * Two-phased constructor.

     */

    IMPORT_C static CVedVolReader* NewL();

    /**

     * Destructor.

     */

    virtual ~CVedVolReader();

    /**

     * Parses given Video Object Layer header

     * @param aData Buffer from where to parse the header

     * @return error code

     */

    IMPORT_C TInt ParseVolHeaderL(TDesC8& aData);

    /**

     * Returns the time increment resolution that was read from the VOL header

     * @return time increment resolution

     */    

    IMPORT_C TInt TimeIncrementResolution() const;

    /**

     * Returns the width of the video that was read from the VOL header

     * @return width

     */  

    IMPORT_C TInt Width() const;

    /**

     * Returns the height of the video that was read from the VOL header

     * @return height

     */  

    IMPORT_C TInt Height() const;

    /**

     * Returns the Level Id of the Simple Profile the Video Object conforms to

     * @return profile level Id

     */  

    IMPORT_C TInt ProfileLevelId() const;

    /**

     * Returns the bitstream mode of the video

     * @return bitstream mode

     */  

    IMPORT_C TVedVideoBitstreamMode BitstreamMode() const;

    /**

     * Returns the size of the VOL header

     * @return size of the header

     */  

    IMPORT_C TInt HeaderSize() const;

private:

    /**

     * Structure for internal buffer of the header sequence

     */

    struct TSeqHeaderBuffer

        {

        TDesC8& iData;           // The actual data of the buffer

        TInt    iGetIndex;       // Index of getting from the buffer 

        TInt    iBitInOctet;	 // Bit index in the buffer

        TSeqHeaderBuffer(TDesC8& aData, TInt aGetIndex, TInt aBitInOctet) :

            iData(aData), iGetIndex(aGetIndex), iBitInOctet(aBitInOctet) {}

        };

    /**

     * C++ default constructor.

     */

    CVedVolReader();

    /**

     * By default Symbian OS constructor is private.

     */

    void ConstructL();

    /**

     * Reads requested bits from given buffer

     * @param aBuffer Buffer from where to read the bits

     * @param aNumBits Amount of bits to read

     * @param aFlush Discard the bits that were read

     * @return The bits that were read

     */

    TUint32 ReadSeqHeaderBits(TSeqHeaderBuffer& aBuffer, TInt aNumBits, TBool aFlush);

    /**

     * Reads user data from given buffer

     * @param aBuffer Buffer from where to read the user data

     */

    void ReadUserDataL(TSeqHeaderBuffer& aBuffer);

    /**

     * Checks what is the bit stream mode the video

     * @param aErd Flag error resilience disable used

     * @param aDp Flag data partitioned used

     * @param aRvlc Flag reversible vlc used

     * @return The bit stream mode

     */

    TVedVideoBitstreamMode CheckBitstreamMode(TUint8 aErd, TUint8 aDp, TUint8 aRvlc);

private:

    // Member variables

    static const TInt KMaxUserDataLength;       // The maximum allocated memory for 

                                                // user data (UD). Only this much of the UD

                                                // from the bitstream is stored

    static const TUint8 KMsbMask[8];            // Mask for extracting the needed bits

    static const TUint8 KLsbMask[9];

    TVolHeader iHeader;                         // For storing the header data

    TVedVideoBitstreamMode iBitstreamMode;

    TInt iHeaderSize;

    };

#endif // __VEDVOLREADER_H__