1 | Ticket 4804 is an enhancement to MythTV to provide a pre-amp feature. This is |
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2 | |
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3 | From: Erik Hovland <erik@hovland.org> |
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4 | |
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5 | the first step towards having native ReplayGain support in MythMusic. |
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6 | --- |
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7 | |
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8 | mythtv/libs/libmyth/audiooutput.h | 15 ++++ |
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9 | mythtv/libs/libmyth/audiooutputbase.cpp | 120 +++++++++++++++++++++++++++++++ |
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10 | mythtv/libs/libmyth/audiooutputbase.h | 22 +++++- |
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11 | 3 files changed, 155 insertions(+), 2 deletions(-) |
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12 | |
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13 | |
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14 | diff --git a/mythtv/libs/libmyth/audiooutput.h b/mythtv/libs/libmyth/audiooutput.h |
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15 | index e89147c..e3014c4 100644 |
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16 | --- a/mythtv/libs/libmyth/audiooutput.h |
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17 | +++ b/mythtv/libs/libmyth/audiooutput.h |
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18 | @@ -33,6 +33,21 @@ class MPUBLIC AudioOutput : public VolumeBase, public OutputListeners |
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19 | virtual void SetStretchFactor(float factor); |
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20 | virtual float GetStretchFactor(void) const { return 1.0f; } |
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21 | |
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22 | + // For software pre-amplification. |
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23 | + virtual bool IsPreAmpEnabled() const { return false; } |
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24 | + virtual void SetPreAmp(bool enabled) { return; } |
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25 | + virtual void EnablePreAmp() { return; } |
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26 | + virtual void DisablePreAmp() { return; } |
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27 | + virtual void SetPreAmpGain(float gain) { return; } |
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28 | + virtual void SetPreAmpFactor(float factor) { return; } |
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29 | + virtual float GetPreAmpGain() const { return 0.0; } |
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30 | + virtual float GetPreAmpFactor() const { return 1.0; } |
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31 | + virtual void ResetClippingMonitor() { return; } |
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32 | + virtual bool HasClippingOccurred() const { return false; } |
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33 | + virtual float GetMaxOutput() const { return 1.0; } |
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34 | + virtual float GetMaxClipFreePreAmpGain() const { return 0.0; } |
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35 | + virtual float GetMaxClipFreePreAmpFactor() const { return 1.0; } |
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36 | + |
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37 | // do AddSamples calls block? |
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38 | virtual void SetBlocking(bool blocking) = 0; |
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39 | |
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40 | diff --git a/mythtv/libs/libmyth/audiooutputbase.cpp b/mythtv/libs/libmyth/audiooutputbase.cpp |
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41 | index 6db02f2..c71d2ad 100644 |
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42 | --- a/mythtv/libs/libmyth/audiooutputbase.cpp |
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43 | +++ b/mythtv/libs/libmyth/audiooutputbase.cpp |
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44 | @@ -44,6 +44,9 @@ AudioOutputBase::AudioOutputBase(const AudioSettings &settings) : |
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45 | need_resampler(false), |
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46 | |
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47 | src_ctx(NULL), |
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48 | + |
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49 | + pre_amp_enabled(false), pre_amp_factor(1.0), |
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50 | + pre_amp_max_output(0.0), |
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51 | |
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52 | pSoundStretch(NULL), |
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53 | encoder(NULL), |
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54 | @@ -790,6 +793,36 @@ bool AudioOutputBase::AddSamples(char *buffers[], int samples, |
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55 | return true; |
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56 | } |
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57 | |
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58 | +#define __APPLY_PRE_AMP(TYPE,MIN,MAX) \ |
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59 | +{ \ |
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60 | + TYPE *buf = (TYPE *)buffer; \ |
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61 | + for ( int i = 0; i < samples; ++i ) \ |
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62 | + { \ |
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63 | + float f = (float)buf[i] / (float)MAX; \ |
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64 | + f *= pre_amp_factor; \ |
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65 | + float a = abs(f); \ |
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66 | + if ( a > pre_amp_max_output ) pre_amp_max_output = a; \ |
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67 | + if ( f >= 1.0 ) buf[i] = MAX; \ |
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68 | + else if ( f <= -1.0 ) buf[i] = MIN; \ |
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69 | + else buf[i] = (TYPE)round(f*MAX); \ |
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70 | + } \ |
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71 | +} |
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72 | + |
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73 | +void AudioOutputBase::ApplyPreAmp(void *buffer, int samples, int sample_bytes) |
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74 | +{ |
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75 | + if ( !pre_amp_enabled ) return; |
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76 | + // NOTE: This only handles 1, 2 or 4 byte samples. |
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77 | + if ( sample_bytes == 4 ) |
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78 | + __APPLY_PRE_AMP(int,INT_MIN,INT_MAX) |
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79 | + else if ( sample_bytes == 2 ) |
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80 | + __APPLY_PRE_AMP(short,SHRT_MIN,SHRT_MAX) |
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81 | + else if ( sample_bytes == 1 ) |
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82 | + __APPLY_PRE_AMP(char,CHAR_MIN,CHAR_MAX) |
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83 | + |
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84 | + return; |
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85 | +} |
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86 | +#undef __APPLY_PRE_AMP |
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87 | + |
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88 | bool AudioOutputBase::AddSamples(char *buffer, int samples, long long timecode) |
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89 | { |
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90 | // NOTE: This function is not threadsafe |
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91 | @@ -928,6 +961,17 @@ void AudioOutputBase::_AddSamples(void *buffer, bool interleaved, int samples, |
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92 | int audio_bytes = audio_bits / 8; |
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93 | int org_waud = waud; |
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94 | |
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95 | + if ( interleaved ) |
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96 | + // Apply to the single buffer if we're interleaved. |
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97 | + ApplyPreAmp(buffer,samples*source_audio_channels,audio_bytes); |
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98 | + else |
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99 | + { |
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100 | + // Otherwise, apply to each channel individually. |
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101 | + void **bufs = (void**)buffer; |
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102 | + for ( int i = 0; i < source_audio_channels; ++i ) |
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103 | + ApplyPreAmp(bufs[i],samples,audio_bytes); |
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104 | + } |
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105 | + |
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106 | int afree = audiofree(false); |
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107 | |
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108 | int abps = (encoder) ? |
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109 | @@ -1408,5 +1452,79 @@ int AudioOutputBase::readOutputData(unsigned char*, int) |
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110 | return 0; |
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111 | } |
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112 | |
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113 | -/* vim: set expandtab tabstop=4 shiftwidth=4: */ |
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114 | +bool AudioOutputBase::IsPreAmpEnabled() const |
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115 | +{ |
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116 | + return pre_amp_enabled; |
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117 | +} |
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118 | + |
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119 | +void AudioOutputBase::SetPreAmp(bool enabled) |
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120 | +{ |
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121 | + pre_amp_enabled = enabled; |
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122 | + return; |
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123 | +} |
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124 | + |
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125 | +void AudioOutputBase::EnablePreAmp() |
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126 | +{ |
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127 | + pre_amp_enabled = true; |
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128 | + return; |
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129 | +} |
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130 | + |
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131 | +void AudioOutputBase::DisablePreAmp() |
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132 | +{ |
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133 | + pre_amp_enabled = false; |
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134 | + return; |
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135 | +} |
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136 | + |
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137 | +void AudioOutputBase::SetPreAmpGain(float gain) |
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138 | +{ |
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139 | + pre_amp_factor = pow(10.0,gain/20.0); |
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140 | + return; |
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141 | +} |
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142 | |
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143 | +void AudioOutputBase::SetPreAmpFactor(float factor) |
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144 | +{ |
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145 | + if ( factor >= 0 ) pre_amp_factor = factor; |
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146 | + return; |
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147 | +} |
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148 | + |
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149 | +float AudioOutputBase::GetPreAmpGain() const |
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150 | +{ |
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151 | + if ( pre_amp_factor <= 0 ) return -1.0*numeric_limits<float>::max(); |
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152 | + return 20.0*log(pre_amp_factor)/log(10.0); |
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153 | +} |
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154 | + |
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155 | +float AudioOutputBase::GetPreAmpFactor() const |
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156 | +{ |
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157 | + return pre_amp_factor; |
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158 | +} |
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159 | + |
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160 | +void AudioOutputBase::ResetClippingMonitor() |
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161 | +{ |
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162 | + pre_amp_max_output = 0.0; |
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163 | + return; |
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164 | +} |
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165 | + |
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166 | +bool AudioOutputBase::HasClippingOccurred() const |
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167 | +{ |
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168 | + return pre_amp_max_output > 1.0; |
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169 | +} |
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170 | + |
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171 | +float AudioOutputBase::GetMaxOutput() const |
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172 | +{ |
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173 | + return pre_amp_max_output; |
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174 | +} |
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175 | + |
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176 | +float AudioOutputBase::GetMaxClipFreePreAmpGain() const |
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177 | +{ |
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178 | + float max_factor = GetMaxClipFreePreAmpFactor(); |
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179 | + if ( max_factor <= 0 ) return -1.0*numeric_limits<float>::max(); |
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180 | + return 20.0*log(max_factor)/log(10.0); |
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181 | +} |
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182 | + |
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183 | +float AudioOutputBase::GetMaxClipFreePreAmpFactor() const |
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184 | +{ |
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185 | + if ( pre_amp_max_output == 0 ) return numeric_limits<float>::max(); |
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186 | + return pre_amp_factor / pre_amp_max_output; |
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187 | +} |
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188 | + |
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189 | +/* vim: set expandtab tabstop=4 shiftwidth=4: */ |
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190 | diff --git a/mythtv/libs/libmyth/audiooutputbase.h b/mythtv/libs/libmyth/audiooutputbase.h |
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191 | index 8d9e86b..1732d97 100644 |
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192 | --- a/mythtv/libs/libmyth/audiooutputbase.h |
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193 | +++ b/mythtv/libs/libmyth/audiooutputbase.h |
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194 | @@ -71,8 +71,22 @@ class AudioOutputBase : public AudioOutput, public QThread |
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195 | |
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196 | virtual void GetBufferStatus(uint &fill, uint &total); |
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197 | |
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198 | - // Only really used by the AudioOutputNULL object |
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199 | + // For software pre-amplification. |
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200 | + virtual bool IsPreAmpEnabled() const; |
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201 | + virtual void SetPreAmp(bool enabled); |
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202 | + virtual void EnablePreAmp(); |
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203 | + virtual void DisablePreAmp(); |
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204 | + virtual void SetPreAmpGain(float gain); |
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205 | + virtual void SetPreAmpFactor(float factor); |
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206 | + virtual float GetPreAmpGain() const; |
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207 | + virtual float GetPreAmpFactor() const; |
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208 | + virtual void ResetClippingMonitor(); |
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209 | + virtual bool HasClippingOccurred() const; |
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210 | + virtual float GetMaxOutput() const; |
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211 | + virtual float GetMaxClipFreePreAmpGain() const; |
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212 | + virtual float GetMaxClipFreePreAmpFactor() const; |
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213 | |
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214 | + // Only really used by the AudioOutputNULL object |
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215 | virtual void bufferOutputData(bool y){ buffer_output_data_for_use = y; } |
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216 | virtual int readOutputData(unsigned char *read_buffer, int max_length); |
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217 | |
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218 | @@ -100,6 +114,7 @@ class AudioOutputBase : public AudioOutput, public QThread |
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219 | |
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220 | int GetAudioData(unsigned char *buffer, int buf_size, bool fill_buffer); |
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221 | |
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222 | + void ApplyPreAmp(void *buffer, int samples, int sample_bytes); |
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223 | void _AddSamples(void *buffer, bool interleaved, int samples, long long timecode); |
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224 | |
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225 | void OutputAudioLoop(void); |
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226 | @@ -165,6 +180,11 @@ class AudioOutputBase : public AudioOutput, public QThread |
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227 | bool need_resampler; |
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228 | SRC_STATE *src_ctx; |
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229 | |
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230 | + // pre-amplification |
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231 | + bool pre_amp_enabled; |
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232 | + float pre_amp_factor; |
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233 | + float pre_amp_max_output; |
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234 | + |
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235 | // timestretch |
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236 | soundtouch::SoundTouch *pSoundStretch; |
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237 | AudioOutputDigitalEncoder *encoder; |
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