/*

    File:       ComponentVideoPayload.h

    Contains:   Declaration of ComponentVideoPayload datatype and its operations

    Copyright:  © 1997-1999 by Apple Computer Inc. all rights reserved.

    X-Sample-YUV-422-v0 Payload Format

    -----------------------------------------------------------------

                         1                   2                   3

     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

    +-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+

    |D|                      Description Seed                       |

    +-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+

    |                        Offset                         |  MBZ  |

    +-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+

    :                      Payload Description                      :

    +-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+

    :                          Image Data                           :

    +-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+

    D - 1 bit

        Set if, and only if, Payload Description is present.

    Description Seed - 31 bits

        A payload description seed that increments cyclically

        whenever the payload description changes.

    Offset - 28 bits

        Positive offset from the start of the current frame to the

        start of image data contained in this payload as counted in

        32-bit words. Multiply by 4 to compute the offset in octets.

    MBZ - 4 bits

        Reserved.  Must be zero.

    Payload Description - described below

        Present if, and only if, the D bit is set.

    Image Data - 0 or more 32-bit words

        YUV 4:2:2 encoded image data.  Might be omitted if Payload

        Description is present.

    Payload Description Format

    -----------------------------------------------------------------

                         1                   2                   3

     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

    +-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+

    | Z |            Width            |            Height           |

    +-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+

    Z - 2 bits

        Reserved.  Must be zero.

    Width - 15 bits

        Positive integer specifying width of current frame in pixels.

    Height - 15 bits

        Positive integer specifying height of current frame in pixels.

*/

#ifndef __COMPONENTVIDEOPAYLOAD__

#define __COMPONENTVIDEOPAYLOAD__

/* ---------------------------------------------------------------------------

 *      H E A D E R S

 * ---------------------------------------------------------------------------

 */

#include <MacTypes.h>

/* ---------------------------------------------------------------------------

 *      C O N S T A N T S

 * ---------------------------------------------------------------------------

 */

enum

{

    kComponentVideoPayloadFixedHeaderWordCount  = 2,

    kComponentVideoPayloadDescriptionWordCount  = 1

};

/* ---------------------------------------------------------------------------

 *      D A T A T Y P E S

 * ---------------------------------------------------------------------------

 *

 *  The ComponentVideoPayload structure represents the payload format defined

 *  above.  Unfortunately, the position of bit fields in C data structures is

 *  implementation-dependent, so the data structure cannot declare individual

 *  fields of the payload format.

 *

 */

typedef struct

{

    UInt32  itsFixedHeader[ kComponentVideoPayloadFixedHeaderWordCount ];

    union

    {

        UInt32  itsDescription[ kComponentVideoPayloadDescriptionWordCount ];

        UInt32  itsImageData[ 1 ];

    };

} ComponentVideoPayload;

/* ---------------------------------------------------------------------------

 *      P R O T O T Y P E S

 * ---------------------------------------------------------------------------

 *

 *  These functions get and set fields of the ComponentVideoPayload.  Some

 *  functions affect multiple fields, and some functions expect or return

 *  values that differ from the representation encoded in the payload:

 *

 *      ComponentVideoPayloadSetOffset()

 *      ComponentVideoPayloadOffset()           These functions expect or

 *                                              return the offset in octets,

 *                                              not 32-bit words

 *

 *      ComponentVideoPayloadSetDescription()   This function implicitly sets

 *                                              the description flag (D) field

 *                                              if inWidth and inHeight are

 *                                              both non-zero.  If inWidth or

 *                                              inHeight is zero, this

 *                                              function clears the

 *                                              description flag, but does not

 *                                              modify the Width or Height

 *                                              fields in the given

 *                                              ComponentPayloadDescription.

 *      

 *      ComponentVideoPayloadCopyDescription()  This function copies the

 *                                              description flag (D) and

 *                                              Description Seed fields as

 *                                              well as the Payload

 *                                              Description field.

 */

UInt32

ComponentVideoPayloadDescriptionSeedLimit(

    void );

ComponentVideoPayload *

ComponentVideoPayloadInitialize(

    ComponentVideoPayload *     inPayload,

    UInt16                      inWidth,

    UInt16                      inHeight );

UInt32

ComponentVideoPayloadSetOffset(

    ComponentVideoPayload *     inPayload,

    UInt32                      inOffset );

UInt32

ComponentVideoPayloadSetDescription(

    ComponentVideoPayload *     inPayload,

    UInt16                      inWidth,

    UInt16                      inHeight );

UInt32

ComponentVideoPayloadCopyDescription(

    ComponentVideoPayload *         inTargetPayload,

    const ComponentVideoPayload *   inSourcePayload );

Boolean

ComponentVideoPayloadHasDescription(

    const ComponentVideoPayload *   inPayload );

UInt32

ComponentVideoPayloadDescriptionSeed(

    const ComponentVideoPayload *   inPayload );

UInt32

ComponentVideoPayloadOffset(

    const ComponentVideoPayload *   inPayload );

UInt16

ComponentVideoPayloadWidth(

    const ComponentVideoPayload *   inPayload );

UInt16

ComponentVideoPayloadHeight(

    const ComponentVideoPayload *   inPayload );

#endif /* __COMPONENTVIDEOPAYLOAD__ */