| ============================================= |
| Sound Blaster Audigy mixer / default DSP code |
| ============================================= |
| |
| This is based on sb-live-mixer.rst. |
| |
| The EMU10K2 chips have a DSP part which can be programmed to support |
| various ways of sample processing, which is described here. |
| (This article does not deal with the overall functionality of the |
| EMU10K2 chips. See the manuals section for further details.) |
| |
| The ALSA driver programs this portion of chip by default code |
| (can be altered later) which offers the following functionality: |
| |
| |
| Digital mixer controls |
| ====================== |
| |
| These controls are built using the DSP instructions. They offer extended |
| functionality. Only the default built-in code in the ALSA driver is described |
| here. Note that the controls work as attenuators: the maximum value is the |
| neutral position leaving the signal unchanged. Note that if the same destination |
| is mentioned in multiple controls, the signal is accumulated and can be clipped |
| (set to maximal or minimal value without checking for overflow). |
| |
| |
| Explanation of used abbreviations: |
| |
| DAC |
| digital to analog converter |
| ADC |
| analog to digital converter |
| I2S |
| one-way three wire serial bus for digital sound by Philips Semiconductors |
| (this standard is used for connecting standalone D/A and A/D converters) |
| LFE |
| low frequency effects (used as subwoofer signal) |
| AC97 |
| a chip containing an analog mixer, D/A and A/D converters |
| IEC958 |
| S/PDIF |
| FX-bus |
| the EMU10K2 chip has an effect bus containing 64 accumulators. |
| Each of the synthesizer voices can feed its output to these accumulators |
| and the DSP microcontroller can operate with the resulting sum. |
| |
| name='PCM Front Playback Volume',index=0 |
| ---------------------------------------- |
| This control is used to attenuate samples from left and right front PCM FX-bus |
| accumulators. ALSA uses accumulators 8 and 9 for left and right front PCM |
| samples for 5.1 playback. The result samples are forwarded to the front speakers. |
| |
| name='PCM Surround Playback Volume',index=0 |
| ------------------------------------------- |
| This control is used to attenuate samples from left and right surround PCM FX-bus |
| accumulators. ALSA uses accumulators 2 and 3 for left and right surround PCM |
| samples for 5.1 playback. The result samples are forwarded to the surround (rear) |
| speakers. |
| |
| name='PCM Side Playback Volume',index=0 |
| --------------------------------------- |
| This control is used to attenuate samples from left and right side PCM FX-bus |
| accumulators. ALSA uses accumulators 14 and 15 for left and right side PCM |
| samples for 7.1 playback. The result samples are forwarded to the side speakers. |
| |
| name='PCM Center Playback Volume',index=0 |
| ----------------------------------------- |
| This control is used to attenuate samples from center PCM FX-bus accumulator. |
| ALSA uses accumulator 6 for center PCM samples for 5.1 playback. The result |
| samples are forwarded to the center speaker. |
| |
| name='PCM LFE Playback Volume',index=0 |
| -------------------------------------- |
| This control is used to attenuate sample for LFE PCM FX-bus accumulator. |
| ALSA uses accumulator 7 for LFE PCM samples for 5.1 playback. The result |
| samples are forwarded to the subwoofer. |
| |
| name='PCM Playback Volume',index=0 |
| ---------------------------------- |
| This control is used to attenuate samples from left and right PCM FX-bus |
| accumulators. ALSA uses accumulators 0 and 1 for left and right PCM samples for |
| stereo playback. The result samples are forwarded to the front speakers. |
| |
| name='PCM Capture Volume',index=0 |
| --------------------------------- |
| This control is used to attenuate samples from left and right PCM FX-bus |
| accumulators. ALSA uses accumulators 0 and 1 for left and right PCM samples for |
| stereo playback. The result is forwarded to the standard capture PCM device. |
| |
| name='Music Playback Volume',index=0 |
| ------------------------------------ |
| This control is used to attenuate samples from left and right MIDI FX-bus |
| accumulators. ALSA uses accumulators 4 and 5 for left and right MIDI samples. |
| The result samples are forwarded to the virtual stereo mixer. |
| |
| name='Music Capture Volume',index=0 |
| ----------------------------------- |
| These controls are used to attenuate samples from left and right MIDI FX-bus |
| accumulator. ALSA uses accumulators 4 and 5 for left and right MIDI samples. |
| The result is forwarded to the standard capture PCM device. |
| |
| name='Mic Playback Volume',index=0 |
| ---------------------------------- |
| This control is used to attenuate samples from left and right Mic input of |
| the AC97 codec. The result samples are forwarded to the virtual stereo mixer. |
| |
| name='Mic Capture Volume',index=0 |
| --------------------------------- |
| This control is used to attenuate samples from left and right Mic input of |
| the AC97 codec. The result is forwarded to the standard capture PCM device. |
| |
| The original samples are also forwarded to the Mic capture PCM device (device 1; |
| 16bit/8KHz mono) without volume control. |
| |
| name='Audigy CD Playback Volume',index=0 |
| ---------------------------------------- |
| This control is used to attenuate samples from left and right IEC958 TTL |
| digital inputs (usually used by a CDROM drive). The result samples are |
| forwarded to the virtual stereo mixer. |
| |
| name='Audigy CD Capture Volume',index=0 |
| --------------------------------------- |
| This control is used to attenuate samples from left and right IEC958 TTL |
| digital inputs (usually used by a CDROM drive). The result is forwarded |
| to the standard capture PCM device. |
| |
| name='IEC958 Optical Playback Volume',index=0 |
| --------------------------------------------- |
| This control is used to attenuate samples from left and right IEC958 optical |
| digital input. The result samples are forwarded to the virtual stereo mixer. |
| |
| name='IEC958 Optical Capture Volume',index=0 |
| -------------------------------------------- |
| This control is used to attenuate samples from left and right IEC958 optical |
| digital inputs. The result is forwarded to the standard capture PCM device. |
| |
| name='Line2 Playback Volume',index=0 |
| ------------------------------------ |
| This control is used to attenuate samples from left and right I2S ADC |
| inputs (on the AudigyDrive). The result samples are forwarded to the virtual |
| stereo mixer. |
| |
| name='Line2 Capture Volume',index=1 |
| ----------------------------------- |
| This control is used to attenuate samples from left and right I2S ADC |
| inputs (on the AudigyDrive). The result is forwarded to the standard capture |
| PCM device. |
| |
| name='Analog Mix Playback Volume',index=0 |
| ----------------------------------------- |
| This control is used to attenuate samples from left and right I2S ADC |
| inputs from Philips ADC. The result samples are forwarded to the virtual |
| stereo mixer. This contains mix from analog sources like CD, Line In, Aux, .... |
| |
| name='Analog Mix Capture Volume',index=1 |
| ---------------------------------------- |
| This control is used to attenuate samples from left and right I2S ADC |
| inputs Philips ADC. The result is forwarded to the standard capture PCM device. |
| |
| name='Aux2 Playback Volume',index=0 |
| ----------------------------------- |
| This control is used to attenuate samples from left and right I2S ADC |
| inputs (on the AudigyDrive). The result samples are forwarded to the virtual |
| stereo mixer. |
| |
| name='Aux2 Capture Volume',index=1 |
| ---------------------------------- |
| This control is used to attenuate samples from left and right I2S ADC |
| inputs (on the AudigyDrive). The result is forwarded to the standard capture |
| PCM device. |
| |
| name='Front Playback Volume',index=0 |
| ------------------------------------ |
| This control is used to attenuate samples from the virtual stereo mixer. |
| The result samples are forwarded to the front speakers. |
| |
| name='Surround Playback Volume',index=0 |
| --------------------------------------- |
| This control is used to attenuate samples from the virtual stereo mixer. |
| The result samples are forwarded to the surround (rear) speakers. |
| |
| name='Side Playback Volume',index=0 |
| ----------------------------------- |
| This control is used to attenuate samples from the virtual stereo mixer. |
| The result samples are forwarded to the side speakers. |
| |
| name='Center Playback Volume',index=0 |
| ------------------------------------- |
| This control is used to attenuate samples from the virtual stereo mixer. |
| The result samples are forwarded to the center speaker. |
| |
| name='LFE Playback Volume',index=0 |
| ---------------------------------- |
| This control is used to attenuate samples from the virtual stereo mixer. |
| The result samples are forwarded to the subwoofer. |
| |
| name='Tone Control - Switch',index=0 |
| ------------------------------------ |
| This control turns the tone control on or off. The samples forwarded to |
| the speaker outputs are affected. |
| |
| name='Tone Control - Bass',index=0 |
| ---------------------------------- |
| This control sets the bass intensity. There is no neutral value!! |
| When the tone control code is activated, the samples are always modified. |
| The closest value to pure signal is 20. |
| |
| name='Tone Control - Treble',index=0 |
| ------------------------------------ |
| This control sets the treble intensity. There is no neutral value!! |
| When the tone control code is activated, the samples are always modified. |
| The closest value to pure signal is 20. |
| |
| name='Master Playback Volume',index=0 |
| ------------------------------------- |
| This control is used to attenuate samples forwarded to the speaker outputs. |
| |
| name='IEC958 Optical Raw Playback Switch',index=0 |
| ------------------------------------------------- |
| If this switch is on, then the samples for the IEC958 (S/PDIF) digital |
| output are taken only from the raw iec958 ALSA PCM device (which uses |
| accumulators 20 and 21 for left and right PCM by default). |
| |
| |
| PCM stream related controls |
| =========================== |
| |
| name='EMU10K1 PCM Volume',index 0-31 |
| ------------------------------------ |
| Channel volume attenuation in range 0-0x1fffd. The middle value (no |
| attenuation) is default. The channel mapping for three values is |
| as follows: |
| |
| * 0 - mono, default 0xffff (no attenuation) |
| * 1 - left, default 0xffff (no attenuation) |
| * 2 - right, default 0xffff (no attenuation) |
| |
| name='EMU10K1 PCM Send Routing',index 0-31 |
| ------------------------------------------ |
| This control specifies the destination - FX-bus accumulators. There are 24 |
| values in this mapping: |
| |
| * 0 - mono, A destination (FX-bus 0-63), default 0 |
| * 1 - mono, B destination (FX-bus 0-63), default 1 |
| * 2 - mono, C destination (FX-bus 0-63), default 2 |
| * 3 - mono, D destination (FX-bus 0-63), default 3 |
| * 4 - mono, E destination (FX-bus 0-63), default 4 |
| * 5 - mono, F destination (FX-bus 0-63), default 5 |
| * 6 - mono, G destination (FX-bus 0-63), default 6 |
| * 7 - mono, H destination (FX-bus 0-63), default 7 |
| * 8 - left, A destination (FX-bus 0-63), default 0 |
| * 9 - left, B destination (FX-bus 0-63), default 1 |
| * 10 - left, C destination (FX-bus 0-63), default 2 |
| * 11 - left, D destination (FX-bus 0-63), default 3 |
| * 12 - left, E destination (FX-bus 0-63), default 4 |
| * 13 - left, F destination (FX-bus 0-63), default 5 |
| * 14 - left, G destination (FX-bus 0-63), default 6 |
| * 15 - left, H destination (FX-bus 0-63), default 7 |
| * 16 - right, A destination (FX-bus 0-63), default 0 |
| * 17 - right, B destination (FX-bus 0-63), default 1 |
| * 18 - right, C destination (FX-bus 0-63), default 2 |
| * 19 - right, D destination (FX-bus 0-63), default 3 |
| * 20 - right, E destination (FX-bus 0-63), default 4 |
| * 21 - right, F destination (FX-bus 0-63), default 5 |
| * 22 - right, G destination (FX-bus 0-63), default 6 |
| * 23 - right, H destination (FX-bus 0-63), default 7 |
| |
| Don't forget that it's illegal to assign a channel to the same FX-bus accumulator |
| more than once (it means 0=0 && 1=0 is an invalid combination). |
| |
| name='EMU10K1 PCM Send Volume',index 0-31 |
| ----------------------------------------- |
| It specifies the attenuation (amount) for given destination in range 0-255. |
| The channel mapping is following: |
| |
| * 0 - mono, A destination attn, default 255 (no attenuation) |
| * 1 - mono, B destination attn, default 255 (no attenuation) |
| * 2 - mono, C destination attn, default 0 (mute) |
| * 3 - mono, D destination attn, default 0 (mute) |
| * 4 - mono, E destination attn, default 0 (mute) |
| * 5 - mono, F destination attn, default 0 (mute) |
| * 6 - mono, G destination attn, default 0 (mute) |
| * 7 - mono, H destination attn, default 0 (mute) |
| * 8 - left, A destination attn, default 255 (no attenuation) |
| * 9 - left, B destination attn, default 0 (mute) |
| * 10 - left, C destination attn, default 0 (mute) |
| * 11 - left, D destination attn, default 0 (mute) |
| * 12 - left, E destination attn, default 0 (mute) |
| * 13 - left, F destination attn, default 0 (mute) |
| * 14 - left, G destination attn, default 0 (mute) |
| * 15 - left, H destination attn, default 0 (mute) |
| * 16 - right, A destination attn, default 0 (mute) |
| * 17 - right, B destination attn, default 255 (no attenuation) |
| * 18 - right, C destination attn, default 0 (mute) |
| * 19 - right, D destination attn, default 0 (mute) |
| * 20 - right, E destination attn, default 0 (mute) |
| * 21 - right, F destination attn, default 0 (mute) |
| * 22 - right, G destination attn, default 0 (mute) |
| * 23 - right, H destination attn, default 0 (mute) |
| |
| |
| |
| MANUALS/PATENTS |
| =============== |
| |
| See sb-live-mixer.rst. |
