Line-Following-Robot/Input/Externals/raspicam-master/dependencies/mmal/mmal_clock.h

/*
Copyright (c) 2012, Broadcom Europe Ltd
All rights reserved.

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    * Neither the name of the copyright holder nor the
      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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*/


#ifndef MMAL_CLOCK_H
#define MMAL_CLOCK_H

#include "vcos/vcos.h"
#include "mmal_types.h"
#include "mmal_common.h"
#include <cassert>
/** \defgroup MmalClock Clock Framework
 * The MMAL clock framework provides scheduling facilities to the rest of
 * MMAL.
 *
 * The framework consists mainly of clock ports and a clock module. Client
 * applications and components interact directly with clock ports, while
 * the clock module is only used internally by clock ports.
 *
 * Clock ports ensure that the local media-time for each component is
 * synchronised across all components. This is done by passing buffers between
 * clock ports which contain clock-specific data.
 *
 * One clock port will normally act as the reference clock for the rest of the
 * system. This is usually chosen to be the clock port of the audio render
 * component, but is configurable by the client and could potentially be any
 * other clock port (or even the client application itself).
 *
 * Components that are responsible for timed delivery of frames, do so by
 * registering callback requests for a particular time-stamp with the clock
 * port. These requests are scheduled using the clock module which maintains
 * an internal media-time.
 *
 * The clock framework also provides the ability to perform playback at different
 * speeds. This is achieved with a clock scale factor which determines the speed
 * at which the media-time advances relative to real-time, with:
 *   scale = 1.0 -> normal playback speed
 *   scale = 0   -> playback paused
 *   scale > 1.0 -> fast-forward
 *   scale < 1.0 -> slow motion
 */

/** Clock event magic */
#define MMAL_CLOCK_EVENT_MAGIC               MMAL_FOURCC('C','K','L','M')

/** Clock reference update */
#define MMAL_CLOCK_EVENT_REFERENCE           MMAL_FOURCC('C','R','E','F')

/** Clock state update */
#define MMAL_CLOCK_EVENT_ACTIVE              MMAL_FOURCC('C','A','C','T')

/** Clock scale update */
#define MMAL_CLOCK_EVENT_SCALE               MMAL_FOURCC('C','S','C','A')

/** Clock media-time update */
#define MMAL_CLOCK_EVENT_TIME                MMAL_FOURCC('C','T','I','M')

/** Clock update threshold */
#define MMAL_CLOCK_EVENT_UPDATE_THRESHOLD    MMAL_FOURCC('C','U','T','H')

/** Clock discontinuity threshold */
#define MMAL_CLOCK_EVENT_DISCONT_THRESHOLD   MMAL_FOURCC('C','D','T','H')

/** Clock request threshold */
#define MMAL_CLOCK_EVENT_REQUEST_THRESHOLD   MMAL_FOURCC('C','R','T','H')

/** Buffer statistics */
#define MMAL_CLOCK_EVENT_INPUT_BUFFER_INFO   MMAL_FOURCC('C','I','B','I')
#define MMAL_CLOCK_EVENT_OUTPUT_BUFFER_INFO  MMAL_FOURCC('C','O','B','I')

/** Clock latency setting */
#define MMAL_CLOCK_EVENT_LATENCY             MMAL_FOURCC('C','L','A','T')

/** Clock event not valid */
#define MMAL_CLOCK_EVENT_INVALID   0


/** Thresholds used when updating a clock's media-time */
typedef struct MMAL_CLOCK_UPDATE_THRESHOLD_T
{
   /** Time differences below this threshold are ignored (microseconds) */
   int64_t threshold_lower;

   /** Time differences above this threshold reset media-time (microseconds) */
   int64_t threshold_upper;
} MMAL_CLOCK_UPDATE_THRESHOLD_T;

/** Threshold for detecting a discontinuity in media-time */
typedef struct MMAL_CLOCK_DISCONT_THRESHOLD_T
{
   /** Threshold after which backward jumps in media-time are treated as a
    * discontinuity (microseconds) */
   int64_t threshold;

   /** Duration in microseconds for which a discontinuity applies (wall-time) */
   int64_t duration;
} MMAL_CLOCK_DISCONT_THRESHOLD_T;

/** Threshold applied to client callback requests */
typedef struct MMAL_CLOCK_REQUEST_THRESHOLD_T
{
   /** Frames with a media-time difference (compared to current media-time)
    * above this threshold are dropped (microseconds) */
   int64_t threshold;

   /** Enable/disable the request threshold */
   MMAL_BOOL_T threshold_enable;
} MMAL_CLOCK_REQUEST_THRESHOLD_T;

/** Structure for passing buffer information to a clock port */
typedef struct MMAL_CLOCK_BUFFER_INFO_T
{
   int64_t time_stamp;
   uint32_t arrival_time;
} MMAL_CLOCK_BUFFER_INFO_T;

/** Clock latency settings used by the clock component */
typedef struct MMAL_CLOCK_LATENCY_T
{
   int64_t target;            /**< target latency (microseconds) */
   int64_t attack_period;     /**< duration of one attack period (microseconds) */
   int64_t attack_rate;       /**< amount by which media-time will be adjusted
                                   every attack_period (microseconds) */
} MMAL_CLOCK_LATENCY_T;

/** Clock event used to pass data between clock ports and a client. */
typedef struct MMAL_CLOCK_EVENT_T
{
   /** 4cc event id */
   uint32_t id;

   /** 4cc event magic */
   uint32_t magic;

   /** buffer associated with this event (can be NULL) */
   struct MMAL_BUFFER_HEADER_T *buffer;

   /** pad to 64-bit boundary */
   uint32_t padding0;

   /** additional event data (type-specific) */
   union
   {
      /** used either for clock reference or clock state */
      MMAL_BOOL_T enable;

      /** new clock scale */
      MMAL_RATIONAL_T scale;

      /** new media-time */
      int64_t media_time;

      /** media-time update threshold */
      MMAL_CLOCK_UPDATE_THRESHOLD_T update_threshold;

      /** media-time discontinuity threshold */
      MMAL_CLOCK_DISCONT_THRESHOLD_T discont_threshold;

      /** client callback request threshold */
      MMAL_CLOCK_REQUEST_THRESHOLD_T request_threshold;

      /** input/output buffer information */
      MMAL_CLOCK_BUFFER_INFO_T buffer;

      /** clock latency setting */
      MMAL_CLOCK_LATENCY_T latency;
   } data;

   /** pad to 64-bit boundary */
   uint64_t padding1;
} MMAL_CLOCK_EVENT_T;

/* Make sure MMAL_CLOCK_EVENT_T will preserve 64-bit alignment */
static_assert(!(sizeof(MMAL_CLOCK_EVENT_T) & 0x7),"mmal error");

#define MMAL_CLOCK_EVENT_INIT(id) { id, MMAL_CLOCK_EVENT_MAGIC, NULL, 0, {0}, 0 }

#endif /* MMAL_CLOCK_H */