2010/8/5 Sebastian H. <vand2@xxxxxx> > Hello Raymond > > >> I've been working on Alsamixer-Qt4 lately and compiled > >> the changes into a new release version 0.4.0. > > > > 1) au8830 Equalizer > > you can find the screenshot of the equalizer ( gnome volume control) and > the > > correct implementation of the equalizer of the vortexcontrol and python > > version of the equalizer > > > > the asound.state of au8830 > > > > https://bugtrack.alsa-project.org/alsa-bug/view.php?id=3678 > > Ok, I tried to figure out how this relates to alsamixer-qt4 (since I > don't have the sound card). > > Please correct me if I'm wrong. > > The "EQ Peaks" Simple Mixer Element has more channels than the 9 > channels described in the snd_mixer_selem_channel_id_t enum. > ( SND_MIXER_SCHN_FRONT_LEFT up to SND_MIXER_SCHN_REAR_CENTER ). > EQ Peaks is a volatile control without write access (i.e. you cannot use slider since you cannot modify the value ) which provide the peak of 10 bands (31Hz, 63Hz, 125Hz, 250Hz, 500Hz, 1Kz, 2Kz, 4Kz, 8Kz , 16Kz) stereo channels of the au8830's hardware equalizer , ( one stereo vu-meters at each band ) The values are ordered by left channel of 10 bands followed by right channel of 10 bands control.12 { comment.access read comment.type INTEGER comment.count 20 comment.range '0 - 32767' iface MIXER name 'EQ Peaks' value.0 1 value.1 1 value.2 0 value.3 0 value.4 1 value.5 1 value.6 1 value.7 1 value.8 0 value.9 0 value.10 1 value.11 1 value.12 0 value.13 0 value.14 0 value.15 0 value.16 1 value.17 1 value.18 0 value.19 0 } EQ enable switch control the output of DSP pass through/bypass the equalizer , so your application can based on the on/off state of the switch to start/stop a timer which read the value from EQ peak control and display on 10 stereo vu-meters at regular time intervals There are also 10 stereo volume controls to control gain/atten of 10 bands of the hardware equalizer if your application are unable to display EQ peaks , it is better to skip this "EQ peaks" control with count =20 or simple mixer control with 20 channels All the EQ controls appear on capture side is a bug of alsa-lib or the driver , either change the name of those "EQ xx" controls to "EQ xx Playback" in the driver or add "EQ" to the definition of the controls name Simple mixer control 'EQ Peaks',0 Capabilities: volume Playback channels: Front Left - Front Right - Rear Left - Rear Right - Front Center - Woofer - Side Left - Side Right - Rear Center - ? - ? - ? - ? - ? - ? - ? - ? - ? - ? - ? Capture channels: Front Left - Front Right - Rear Left - Rear Right - Front Center - Woofer - Side Left - Side Right - Rear Center - ? - ? - ? - ? - ? - ? - ? - ? - ? - ? - ? Limits: 0 - 32767 Front Left: 0 [0%] Front Right: 0 [0%] Rear Left: 0 [0%] Rear Right: 0 [0%] Front Center: 0 [0%] Woofer: 0 [0%] Side Left: 0 [0%] Side Right: 0 [0%] Rear Center: 0 [0%] ?: 0 [0%] ?: 0 [0%] ?: 0 [0%] ?: 0 [0%] ?: 0 [0%] ?: 0 [0%] ?: 0 [0%] ?: 0 [0%] ?: 0 [0%] ?: 0 [0%] ?: 0 [0%] > > http://www.alsa-project.org/alsa-doc/alsa-lib/group___simple_mixer.html#g9cb8437b2f92d168c43e4da2c667e823 > > Alsamixer-Qt4 currently can only show these 9 channels - in the channels > mixer dialog - which is not sufficient. > > I did not find a function like snd_mixer_selem_playback_channels > which would return the number of channels. > So to find out how many channels there actually are I would have to do > something like this > > int num_playback = 0; > for ( int ii=0; ii < 1024; ++ii ) { > if ( snd_mixer_selem_has_playback_channel ( elem, ii ) ) { > num_playback += 1; > } else { > break; > } > } > > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
