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1 /* |
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2 * Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies). |
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3 * All rights reserved. |
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4 * This component and the accompanying materials are made available |
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5 * under the terms of "Eclipse Public License v1.0" |
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6 * which accompanies this distribution, and is available |
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7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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8 * |
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9 * Initial Contributors: |
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10 * Nokia Corporation - initial contribution. |
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11 * |
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12 * Contributors: |
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13 * |
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14 * Description: |
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15 * |
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16 */ |
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17 |
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18 |
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19 |
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20 |
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21 /** |
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22 @file |
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23 @publishedPartner |
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24 @released |
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25 */ |
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26 |
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27 #ifndef MAUDIOGAINCONTROL_H |
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28 #define MAUDIOGAINCONTROL_H |
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29 |
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30 #include <e32base.h> |
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31 #include <f32file.h> |
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32 #include <a3f/a3fbase.h> |
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33 #include <a3f/maudioprocessingunit.h> |
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34 |
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35 class MAudioGainControlObserver; |
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36 |
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37 |
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38 /** |
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39 * Interface to gain control processing unit. |
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40 * |
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41 * Gain control is used for controlling volume and gain related settings of an audio stream. |
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42 */ |
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43 class MAudioGainControl |
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44 { |
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45 public: |
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46 |
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47 /** |
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48 * Returns the maximum gain the device supports. |
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49 * |
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50 * The maximum gain value depends on the setup of the stream. |
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51 * |
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52 * this is the maximum gain value which can be passed to SetGain(). |
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53 * @param aMaxGain On return, contains the maximum gain value, provided that the returned error code is KErrNone. |
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54 * @return An error code. KErrNone if the maximum gain value is available, otherwise one of the system wide error codes. |
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55 */ |
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56 virtual TInt GetMaxGain(TInt& aMaxGain) const= 0 ; |
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57 |
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58 /** |
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59 * Returns the maximum ramp time that is supported for the associated stream. |
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60 * |
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61 * The maximum ramp time may be different in playback and recording modes, |
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62 * so the value should be checked before setting the ramptime. this function |
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63 * also does not take into account any possible ongoing ramp. |
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64 * |
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65 * this is the maximum ramp time value which can be passed to SetGain(). |
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66 * @param aMaxRampTime On return contains the maximum ramp time. |
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67 * The value is platform and stream setup dependent but is always greater than or equal to zero. |
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68 * @return An error code. KErrNone on success, otherwise one of the system wide error codes. |
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69 */ |
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70 virtual TInt GetMaxRampTime(TTimeIntervalMicroSeconds& aMaxRampTime) const= 0; |
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71 |
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72 /** |
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73 * Requests changes to the audio gain on a channel-by-channel basis. |
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74 |
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75 * Note that the values for each channel are independent of each other. |
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76 * The call is asynchronous in nature, resulting in a GainChanged() |
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77 * callback, and the request is only applied following a successful |
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78 * Commit() cycle. |
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79 * The callback signals the receipt of the SetGain() call from the |
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80 * underlying adaptation, and not (say) the completion of a ramp operation. |
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81 * The actual gains will only change once the associated Audio Stream becomes EActive. |
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82 * If the associated Audio Stream is already EActive |
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83 * then the change will start immediately following the next successful Commit() cycle. |
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84 * MMRC may choose to modify or ignore the requested gains. |
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85 |
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86 * @param aChannels Contains the channels for which the gain should be set and the gain value for those channels. |
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87 * @param aRampOperation How aRampDuration is to be interpreted.(see below) |
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88 * @param aRampDuration Duration in microseconds. |
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89 * @return KErrNone if initially successful. |
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90 * KErrNotSupported if the SetGain() call referred to non-existent channels. |
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91 * KErrArgument if aGain of less than 0 or larger than max gain, the same channel is specified multiple times, |
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92 * or aRampDuration is less than 0 or greater than max ramp duration. |
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93 * KErrA3fUnsupportedRamp if the ramp operation requested is not supported, or the Uid value supplies is unknown. |
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94 * Other system-wide error codes are also possible. |
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95 * These errors could instead by returned as part of the subsequent GainChanged() callback – depending on the a3f adaptation. |
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96 * Also note: the requested parameters are specific to the associated stream. |
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97 * If more than one stream is concurrently active to the same device, |
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98 * it is up to the adaptation to arrange both the device gains the mixer and splitter gains to achieve a similar effect to the several streams being played through separate devices and mixed post-amplification. |
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99 */ |
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100 virtual TInt SetGain(RArray<TAudioChannelGain>& aChannels, TUid aRampOperation, const TTimeIntervalMicroSeconds& aRampDuration)=0; |
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101 |
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102 /** |
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103 * Sets the audio channel gain. |
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104 * |
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105 * By default all channels are set to use same gain value. Note that the |
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106 * values for each channel are independent of each other, meaning that |
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107 * they only control the gain level on which the particular channel is |
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108 * being used and there is no limitation requiring the sum of all channels to be 100. |
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109 * |
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110 * The gain values will be applied once the associated stream is active. |
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111 * if the stream is active while this function is called, then the values |
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112 * are applied immediately. |
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113 * |
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114 * @param aChannels Contains the channels for which the gain should be set and the gain value for those channels. |
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115 * @return An error code. KErrNone on success. |
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116 * KErrNotSupported if gain for unsupported channels is tried to be set. |
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117 * KErrArgument if a value of less than 0 or larger than max gain is tried to be set as gain. |
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118 * Other system wide error codes are also possible. |
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119 */ |
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120 virtual TInt SetGain(RArray<TAudioChannelGain>& aChannels)=0; |
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121 |
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122 /** |
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123 * Returns channel specific gain settings. |
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124 * |
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125 * @param aChannels On return contains current gain settings for each audio channel. |
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126 * @return An error code. KErrNone on success. |
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127 * KErrArgument if the array passed in as a parameter is not empty. |
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128 * KErrOutOfMemory in case of memory exhaustion. |
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129 * Other system wide error codes are also possible. |
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130 */ |
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131 virtual TInt GetGain(RArray<TAudioChannelGain>& aChannels) const= 0; |
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132 |
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133 /** |
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134 * Registers an observer for receiving callbacks. |
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135 * |
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136 * @param aObserver a reference to the observer to register. |
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137 * @return An error code. KErrNone on success, otherwise one of the system wide error codes. |
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138 */ |
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139 virtual TInt RegisterAudioGainControlObserver(MAudioGainControlObserver& aObserver)=0; |
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140 |
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141 /** |
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142 * Unregisters an observer. |
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143 * |
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144 * @param aObserver a reference to observer to unregister. |
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145 */ |
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146 virtual void UnregisterAudioGainControlObserver(MAudioGainControlObserver& aObserver)=0; |
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147 |
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148 }; |
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149 |
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150 #endif // MAUDIOGAINCONTROL_H |