src/add-ons/kernel/drivers/audio/echo/generic/CMtcSync.h

   1 // ****************************************************************************
   2 //
   3 //              CMtcSync.h
   4 //
   5 //              Include file for interfacing with the CMtcSync class.
   6 //
   7 //              This class manages syncing to MIDI time code.
   8 //
   9 //              Set editor tabs to 3 for your viewing pleasure.
  10 //
  11 // ----------------------------------------------------------------------------
  12 //
  13 // This file is part of Echo Digital Audio's generic driver library.
  14 // Copyright Echo Digital Audio Corporation (c) 1998 - 2005
  15 // All rights reserved
  16 // www.echoaudio.com
  17 //
  18 // This library is free software; you can redistribute it and/or
  19 // modify it under the terms of the GNU Lesser General Public
  20 // License as published by the Free Software Foundation; either
  21 // version 2.1 of the License, or (at your option) any later version.
  22 //
  23 // This library is distributed in the hope that it will be useful,
  24 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  25 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  26 // Lesser General Public License for more details.
  27 //
  28 // You should have received a copy of the GNU Lesser General Public
  29 // License along with this library; if not, write to the Free Software
  30 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  31 //
  32 // ****************************************************************************
  33
  34 //      Prevent problems with multiple includes
  35 #ifndef _MTCQUEUEOBJECT_
  36 #define _MTCQUEUEOBJECT_
  37
  38 typedef struct tMTC_DATA
  39 {
  40         DWORD   dwData;                 // DWORD here wastes memory, but is easier to debug...
  41         DWORD dwTimestamp;      // Timestamp in terms of the DSP sample count
  42 } MTC_DATA;
  43
  44
  45 //
  46 //      CMtcSync
  47 //
  48 class CMtcSync
  49 {
  50 public:
  51         //
  52         //      Construction/destruction
  53         //
  54         CMtcSync( CEchoGals *pEG );
  55         ~CMtcSync();
  56
  57         //
  58         // Methods used to store MTC data & timestamps
  59         //
  60         void StoreTimestampHigh(DWORD dwData);
  61         void StoreTimestampLow(DWORD dwData);
  62         void StoreMtcData(DWORD dwData);
  63
  64         //
  65         // Call this to process the MTC data and adjust the sample rate
  66         //
  67         void Sync();
  68
  69         //
  70         //      Reset the state of things
  71         //
  72         void Reset();
  73
  74         //
  75         //  Overload new & delete so memory for this object is allocated from non-paged memory.
  76         //
  77         PVOID operator new( size_t Size );
  78         VOID  operator delete( PVOID pVoid );
  79
  80 protected:
  81
  82         enum    // Quarter-frame message types
  83         {
  84                 MTC_QF_FRAME_LSN = 0,
  85                 MTC_QF_FRAME_MSN,
  86                 MTC_QF_SECOND_LSN,
  87                 MTC_QF_SECOND_MSN,
  88                 MTC_QF_MINUTE_LSN,
  89                 MTC_QF_MINUTE_MSN,
  90                 MTC_QF_HOUR_LSN,
  91                 MTC_QF_HOUR_MSN,
  92
  93                 MTC_TOLERANCE           = 64,
  94                 MTC_DAMPING                     = 98 * 0x1000 / 100,    // 95% in 12 bit fixed point
  95
  96                 MAX_DFRAME_SYNC_COUNT   = 4096,
  97
  98                 DAMPING_RATIO_LIMIT_LOW  = 4096 - 16,
  99                 DAMPING_RATIO_LIMIT_HIGH = 4096 + 16
 100         };
 101
 102         //
 103         //      Midi buffer management
 104         //
 105         MTC_DATA        m_Buffer[ ECHO_MTC_QUEUE_SZ ];
 106         DWORD                   m_dwFill;
 107         DWORD                   m_dwDrain;
 108
 109         //
 110         // State information
 111         //
 112         DWORD                   m_dwBaseSampleRate;
 113
 114         DWORD                   m_dwLastDframeTimestamp;        // Timestamp of last double frame
 115                                                                                                                 // in units of samples
 116
 117         DWORD                   m_iSamplesPerDframe;
 118         DWORD                   m_dwFramesPerSec;
 119
 120         DWORD                   m_dwLastDframe;                         // Last doubleframe number
 121         DWORD                   m_dwCurrentDframe;                      // Doubleframe number currently being assembled
 122                                                                                                                 // from MTC data bytes
 123
 124         DWORD                   m_iNumDframesSynced;                    // How many frames have elapsed since the
 125                                                                                                                 // last sample rate adjustment
 126
 127         INT32                   m_iNumSamplesSynced;                    // Sum of all actual timestamp deltas since
 128                                                                                                                 // last sample rate adjustment
 129         DWORD                   m_dwNextQfType;
 130
 131         DWORD                   m_dwTemp;
 132
 133         //
 134         // Other stuff
 135         //
 136         CEchoGals       *m_pEG;
 137
 138         friend class CMidiInQ;
 139
 140 };              // class CMtcSync
 141
 142 typedef CMtcSync * PCMtcSync;
 143
 144 #endif
 145
 146 // *** CMtcSync.H ***