1 CRAS = ChromeOS Audio Server 2 3 Directories 4 src/server - the source for the sound server 5 src/libcras - client library for interacting with cras 6 src/common - files common to both the server and library 7 src/tests - tests for cras and libcras 8 9 Building from source: 10 ./git_prepare.sh 11 ./configure 12 make 13 sudo make install 14 15 --------------------- 16 Configuration: 17 --------------------- 18 19 Device Blacklisting: 20 -------------------- 21 Blacklist of certain USB output device(s) is possible by modifying the config 22 file /etc/cras/device_blacklist. 23 24 The format of this file is as follows: 25 26 [USB_Outputs] 27 <vendor_id>_<product_id>_<checksum>_<device_index> = 1 28 29 Where vendor_id and product id are the USB identifiers for the card to 30 blacklist. The checksum is the output of "cksum" command applied to the 31 sysfs "descriptors" file of the device. The device index specifies the 32 index of the output device in the card to blacklist. This is a bool 33 parameter, so '= 1' enables the option. 34 35 Example, blacklisting the non-functional output device reported by the C-Media 36 based CAD-u1 mic: 37 38 [USB_Outputs] 39 0d8c_0008_00000000_0 = 1 40 41 Card Configuration: 42 ------------------- 43 There can be a config file for each sound alsa card on the system. This file 44 lives in /etc/cras/. The file should be named with the card name returned by 45 ALSA, the string in the second set of '[]' in the aplay -l output. The ini file 46 has the following format. 47 48 [<output-node-name>] ; Name of the mixer control for this output. 49 <config-option> = <config-value> 50 51 output-node-name can be speficied in a few ways to link with the real node: 52 UCM device name - The name string following the SectionDevice label in UCM 53 config, i.e. HiFi.conf 54 Jack name - Name of the mixer control for mixer jack, or the gpio jack name 55 listed by 'evtest' command. 56 Mixer control name - e.g. "Headphone" or "Speaker", listed by 57 'amixer scontrols' command. 58 59 Note that an output node matches to the output-node-name label in card config by 60 priorty ordered above. For example if a node has UCM device, it will first 61 search the config file for the UCM device name. When not found, jack name will 62 be used for searching, and lastly the mixer output control name. 63 64 config-option can be the following: 65 volume_curve - The type of volume curve, "simple_step" or "explicit". 66 Options valid and mandatory when volume_curve = simple_step: 67 max_volume - The maximum volume for this output specified in dBFS * 100. 68 volume_step - Number of dB per volume 'tick' specified in dBFS * 100. 69 Options valid and mandatory when volume_curve = explicit: 70 dB_at_N - The value in dB*100 that should be used for the volume at step 71 "N". There must be one of these for each setting from N=0 to 100 72 inclusive. 73 74 75 Example: 76 This example configures the Headphones to have a max volume of -3dBFS with a 77 step size of 0.75dBFS and the Speaker to have the curve specified by the steps 78 given, which is a 1dBFS per step curve from max = +0.5dBFS to min = -99.5dBFS 79 (volume step 10 is -89.5dBFS). 80 81 [Headphone] 82 volume_curve = simple_step 83 volume_step = 75 84 max_volume = -300 85 [Speaker] 86 volume_curve = explicit 87 dB_at_0 = -9950 88 dB_at_1 = -9850 89 dB_at_2 = -9750 90 dB_at_3 = -9650 91 dB_at_4 = -9550 92 dB_at_5 = -9450 93 dB_at_6 = -9350 94 dB_at_7 = -9250 95 dB_at_8 = -9150 96 dB_at_9 = -9050 97 dB_at_10 = -8950 98 dB_at_11 = -8850 99 dB_at_12 = -8750 100 dB_at_13 = -8650 101 dB_at_14 = -8550 102 dB_at_15 = -8450 103 dB_at_16 = -8350 104 dB_at_17 = -8250 105 dB_at_18 = -8150 106 dB_at_19 = -8050 107 dB_at_20 = -7950 108 dB_at_21 = -7850 109 dB_at_22 = -7750 110 dB_at_23 = -7650 111 dB_at_24 = -7550 112 dB_at_25 = -7450 113 dB_at_26 = -7350 114 dB_at_27 = -7250 115 dB_at_28 = -7150 116 dB_at_29 = -7050 117 dB_at_30 = -6950 118 dB_at_31 = -6850 119 dB_at_32 = -6750 120 dB_at_33 = -6650 121 dB_at_34 = -6550 122 dB_at_35 = -6450 123 dB_at_36 = -6350 124 dB_at_37 = -6250 125 dB_at_38 = -6150 126 dB_at_39 = -6050 127 dB_at_40 = -5950 128 dB_at_41 = -5850 129 dB_at_42 = -5750 130 dB_at_43 = -5650 131 dB_at_44 = -5550 132 dB_at_45 = -5450 133 dB_at_46 = -5350 134 dB_at_47 = -5250 135 dB_at_48 = -5150 136 dB_at_49 = -5050 137 dB_at_50 = -4950 138 dB_at_51 = -4850 139 dB_at_52 = -4750 140 dB_at_53 = -4650 141 dB_at_54 = -4550 142 dB_at_55 = -4450 143 dB_at_56 = -4350 144 dB_at_57 = -4250 145 dB_at_58 = -4150 146 dB_at_59 = -4050 147 dB_at_60 = -3950 148 dB_at_61 = -3850 149 dB_at_62 = -3750 150 dB_at_63 = -3650 151 dB_at_64 = -3550 152 dB_at_65 = -3450 153 dB_at_66 = -3350 154 dB_at_67 = -3250 155 dB_at_68 = -3150 156 dB_at_69 = -3050 157 dB_at_70 = -2950 158 dB_at_71 = -2850 159 dB_at_72 = -2750 160 dB_at_73 = -2650 161 dB_at_74 = -2550 162 dB_at_75 = -2450 163 dB_at_76 = -2350 164 dB_at_77 = -2250 165 dB_at_78 = -2150 166 dB_at_79 = -2050 167 dB_at_80 = -1950 168 dB_at_81 = -1850 169 dB_at_82 = -1750 170 dB_at_83 = -1650 171 dB_at_84 = -1550 172 dB_at_85 = -1450 173 dB_at_86 = -1350 174 dB_at_87 = -1250 175 dB_at_88 = -1150 176 dB_at_89 = -1050 177 dB_at_90 = -950 178 dB_at_91 = -850 179 dB_at_92 = -750 180 dB_at_93 = -650 181 dB_at_94 = -550 182 dB_at_95 = -450 183 dB_at_96 = -350 184 dB_at_97 = -250 185 dB_at_98 = -150 186 dB_at_99 = -50 187 dB_at_100 = 50 188
