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Documentation / sound / alsa / SB-Live-mixer.txt




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Based on kernel version 3.16. Page generated on 2014-08-06 21:41 EST.

1	
2			Sound Blaster Live mixer / default DSP code
3			===========================================
4	
5	
6	The EMU10K1 chips have a DSP part which can be programmed to support
7	various ways of sample processing, which is described here.
8	(This article does not deal with the overall functionality of the 
9	EMU10K1 chips. See the manuals section for further details.)
10	
11	The ALSA driver programs this portion of chip by default code
12	(can be altered later) which offers the following functionality:
13	
14	
15	1) IEC958 (S/PDIF) raw PCM
16	--------------------------
17	
18	This PCM device (it's the 4th PCM device (index 3!) and first subdevice
19	(index 0) for a given card) allows to forward 48kHz, stereo, 16-bit
20	little endian streams without any modifications to the digital output
21	(coaxial or optical). The universal interface allows the creation of up
22	to 8 raw PCM devices operating at 48kHz, 16-bit little endian. It would
23	be easy to add support for multichannel devices to the current code,
24	but the conversion routines exist only for stereo (2-channel streams)
25	at the time. 
26	
27	Look to tram_poke routines in lowlevel/emu10k1/emufx.c for more details.
28	
29	
30	2) Digital mixer controls
31	-------------------------
32	
33	These controls are built using the DSP instructions. They offer extended
34	functionality. Only the default build-in code in the ALSA driver is described
35	here. Note that the controls work as attenuators: the maximum value is the 
36	neutral position leaving the signal unchanged. Note that if the  same destination 
37	is mentioned in multiple controls, the signal is accumulated and can be wrapped 
38	(set to maximal or minimal value without checking of overflow).
39	
40	
41	Explanation of used abbreviations:
42	
43	DAC    - digital to analog converter
44	ADC    - analog to digital converter
45	I2S    - one-way three wire serial bus for digital sound by Philips Semiconductors
46	         (this standard is used for connecting standalone DAC and ADC converters)
47	LFE    - low frequency effects (subwoofer signal)
48	AC97   - a chip containing an analog mixer, DAC and ADC converters
49	IEC958 - S/PDIF
50	FX-bus - the EMU10K1 chip has an effect bus containing 16 accumulators.
51	         Each of the synthesizer voices can feed its output to these accumulators
52	         and the DSP microcontroller can operate with the resulting sum.
53	
54	
55	name='Wave Playback Volume',index=0
56	
57	This control is used to attenuate samples for left and right PCM FX-bus
58	accumulators. ALSA uses accumulators 0 and 1 for left and right PCM samples.
59	The result samples are forwarded to the front DAC PCM slots of the AC97 codec.
60	
61	name='Wave Surround Playback Volume',index=0
62	
63	This control is used to attenuate samples for left and right PCM FX-bus
64	accumulators. ALSA uses accumulators 0 and 1 for left and right PCM samples.
65	The result samples are forwarded to the rear I2S DACs. These DACs operates
66	separately (they are not inside the AC97 codec).
67	
68	name='Wave Center Playback Volume',index=0
69	
70	This control is used to attenuate samples for left and right PCM FX-bus
71	accumulators. ALSA uses accumulators 0 and 1 for left and right PCM samples.
72	The result is mixed to mono signal (single channel) and forwarded to
73	the ??rear?? right DAC PCM slot of the AC97 codec.
74	
75	name='Wave LFE Playback Volume',index=0
76	
77	This control is used to attenuate samples for left and right PCM FX-bus
78	accumulators. ALSA uses accumulators 0 and 1 for left and right PCM.
79	The result is mixed to mono signal (single channel) and forwarded to
80	the ??rear?? left DAC PCM slot of the AC97 codec.
81	
82	name='Wave Capture Volume',index=0
83	name='Wave Capture Switch',index=0
84	
85	These controls are used to attenuate samples for left and right PCM FX-bus
86	accumulator. ALSA uses accumulators 0 and 1 for left and right PCM.
87	The result is forwarded to the ADC capture FIFO (thus to the standard capture
88	PCM device).
89	
90	name='Synth Playback Volume',index=0
91	
92	This control is used to attenuate samples for left and right MIDI FX-bus
93	accumulators. ALSA uses accumulators 4 and 5 for left and right MIDI samples.
94	The result samples are forwarded to the front DAC PCM slots of the AC97 codec.
95	
96	name='Synth Capture Volume',index=0
97	name='Synth Capture Switch',index=0
98	
99	These controls are used to attenuate samples for left and right MIDI FX-bus
100	accumulator. ALSA uses accumulators 4 and 5 for left and right PCM.
101	The result is forwarded to the ADC capture FIFO (thus to the standard capture
102	PCM device).
103	
104	name='Surround Playback Volume',index=0
105	
106	This control is used to attenuate samples for left and right rear PCM FX-bus
107	accumulators. ALSA uses accumulators 2 and 3 for left and right rear PCM samples.
108	The result samples are forwarded to the rear I2S DACs. These DACs operate
109	separately (they are not inside the AC97 codec).
110	
111	name='Surround Capture Volume',index=0
112	name='Surround Capture Switch',index=0
113	
114	These controls are used to attenuate samples for left and right rear PCM FX-bus
115	accumulators. ALSA uses accumulators 2 and 3 for left and right rear PCM samples.
116	The result is forwarded to the ADC capture FIFO (thus to the standard capture
117	PCM device).
118	
119	name='Center Playback Volume',index=0
120	
121	This control is used to attenuate sample for center PCM FX-bus accumulator.
122	ALSA uses accumulator 6 for center PCM sample. The result sample is forwarded
123	to the ??rear?? right DAC PCM slot of the AC97 codec.
124	
125	name='LFE Playback Volume',index=0
126	
127	This control is used to attenuate sample for center PCM FX-bus accumulator.
128	ALSA uses accumulator 6 for center PCM sample. The result sample is forwarded
129	to the ??rear?? left DAC PCM slot of the AC97 codec.
130	
131	name='AC97 Playback Volume',index=0
132	
133	This control is used to attenuate samples for left and right front ADC PCM slots
134	of the AC97 codec. The result samples are forwarded to the front DAC PCM
135	slots of the AC97 codec.
136	********************************************************************************
137	*** Note: This control should be zero for the standard operations, otherwise ***
138	*** a digital loopback is activated.                                         ***
139	********************************************************************************
140	
141	name='AC97 Capture Volume',index=0
142	
143	This control is used to attenuate samples for left and right front ADC PCM slots
144	of the AC97 codec. The result is forwarded to the ADC capture FIFO (thus to
145	the standard capture PCM device).
146	********************************************************************************
147	*** Note: This control should be 100 (maximal value), otherwise no analog    ***
148	*** inputs of the AC97 codec can be captured (recorded).                     ***
149	********************************************************************************
150	
151	name='IEC958 TTL Playback Volume',index=0
152	
153	This control is used to attenuate samples from left and right IEC958 TTL
154	digital inputs (usually used by a CDROM drive). The result samples are
155	forwarded to the front DAC PCM slots of the AC97 codec.
156	
157	name='IEC958 TTL Capture Volume',index=0
158	
159	This control is used to attenuate samples from left and right IEC958 TTL
160	digital inputs (usually used by a CDROM drive). The result samples are
161	forwarded to the ADC capture FIFO (thus to the standard capture PCM device).
162	
163	name='Zoom Video Playback Volume',index=0
164	
165	This control is used to attenuate samples from left and right zoom video
166	digital inputs (usually used by a CDROM drive). The result samples are
167	forwarded to the front DAC PCM slots of the AC97 codec.
168	
169	name='Zoom Video Capture Volume',index=0
170	
171	This control is used to attenuate samples from left and right zoom video
172	digital inputs (usually used by a CDROM drive). The result samples are
173	forwarded to the ADC capture FIFO (thus to the standard capture PCM device).
174	
175	name='IEC958 LiveDrive Playback Volume',index=0
176	
177	This control is used to attenuate samples from left and right IEC958 optical
178	digital input. The result samples are forwarded to the front DAC PCM slots
179	of the AC97 codec.
180	
181	name='IEC958 LiveDrive Capture Volume',index=0
182	
183	This control is used to attenuate samples from left and right IEC958 optical
184	digital inputs. The result samples are forwarded to the ADC capture FIFO
185	(thus to the standard capture PCM device).
186	
187	name='IEC958 Coaxial Playback Volume',index=0
188	
189	This control is used to attenuate samples from left and right IEC958 coaxial
190	digital inputs. The result samples are forwarded to the front DAC PCM slots
191	of the AC97 codec.
192	
193	name='IEC958 Coaxial Capture Volume',index=0
194	
195	This control is used to attenuate samples from left and right IEC958 coaxial
196	digital inputs. The result samples are forwarded to the ADC capture FIFO
197	(thus to the standard capture PCM device).
198	
199	name='Line LiveDrive Playback Volume',index=0
200	name='Line LiveDrive Playback Volume',index=1
201	
202	This control is used to attenuate samples from left and right I2S ADC
203	inputs (on the LiveDrive). The result samples are forwarded to the front
204	DAC PCM slots of the AC97 codec.
205	
206	name='Line LiveDrive Capture Volume',index=1
207	name='Line LiveDrive Capture Volume',index=1
208	
209	This control is used to attenuate samples from left and right I2S ADC
210	inputs (on the LiveDrive). The result samples are forwarded to the ADC
211	capture FIFO (thus to the standard capture PCM device).
212	
213	name='Tone Control - Switch',index=0
214	
215	This control turns the tone control on or off. The samples for front, rear
216	and center / LFE outputs are affected.
217	
218	name='Tone Control - Bass',index=0
219	
220	This control sets the bass intensity. There is no neutral value!!
221	When the tone control code is activated, the samples are always modified.
222	The closest value to pure signal is 20.
223	
224	name='Tone Control - Treble',index=0
225	
226	This control sets the treble intensity. There is no neutral value!!
227	When the tone control code is activated, the samples are always modified.
228	The closest value to pure signal is 20.
229	
230	name='IEC958 Optical Raw Playback Switch',index=0
231	
232	If this switch is on, then the samples for the IEC958 (S/PDIF) digital
233	output are taken only from the raw FX8010 PCM, otherwise standard front
234	PCM samples are taken.
235	
236	name='Headphone Playback Volume',index=1
237	
238	This control attenuates the samples for the headphone output.
239	
240	name='Headphone Center Playback Switch',index=1
241	
242	If this switch is on, then the sample for the center PCM is put to the
243	left headphone output (useful for SB Live cards without separate center/LFE
244	output).
245	
246	name='Headphone LFE Playback Switch',index=1
247	
248	If this switch is on, then the sample for the center PCM is put to the
249	right headphone output (useful for SB Live cards without separate center/LFE
250	output).
251	
252	
253	3) PCM stream related controls
254	------------------------------
255	
256	name='EMU10K1 PCM Volume',index 0-31
257	
258	Channel volume attenuation in range 0-0xffff. The maximum value (no
259	attenuation) is default. The channel mapping for three values is
260	as follows:
261	
262		0 - mono, default 0xffff (no attenuation)
263		1 - left, default 0xffff (no attenuation)
264		2 - right, default 0xffff (no attenuation)
265	
266	name='EMU10K1 PCM Send Routing',index 0-31
267	
268	This control specifies the destination - FX-bus accumulators. There are
269	twelve values with this mapping:
270	
271		 0 -  mono, A destination (FX-bus 0-15), default 0
272		 1 -  mono, B destination (FX-bus 0-15), default 1
273		 2 -  mono, C destination (FX-bus 0-15), default 2
274		 3 -  mono, D destination (FX-bus 0-15), default 3
275		 4 -  left, A destination (FX-bus 0-15), default 0
276		 5 -  left, B destination (FX-bus 0-15), default 1
277		 6 -  left, C destination (FX-bus 0-15), default 2
278		 7 -  left, D destination (FX-bus 0-15), default 3
279		 8 - right, A destination (FX-bus 0-15), default 0
280		 9 - right, B destination (FX-bus 0-15), default 1
281		10 - right, C destination (FX-bus 0-15), default 2
282		11 - right, D destination (FX-bus 0-15), default 3
283	
284	Don't forget that it's illegal to assign a channel to the same FX-bus accumulator 
285	more than once (it means 0=0 && 1=0 is an invalid combination).
286	 
287	name='EMU10K1 PCM Send Volume',index 0-31
288	
289	It specifies the attenuation (amount) for given destination in range 0-255.
290	The channel mapping is following:
291	
292		 0 -  mono, A destination attn, default 255 (no attenuation)
293		 1 -  mono, B destination attn, default 255 (no attenuation)
294		 2 -  mono, C destination attn, default 0 (mute)
295		 3 -  mono, D destination attn, default 0 (mute)
296		 4 -  left, A destination attn, default 255 (no attenuation)
297		 5 -  left, B destination attn, default 0 (mute)
298		 6 -  left, C destination attn, default 0 (mute)
299		 7 -  left, D destination attn, default 0 (mute)
300		 8 - right, A destination attn, default 0 (mute)
301		 9 - right, B destination attn, default 255 (no attenuation)
302		10 - right, C destination attn, default 0 (mute)
303		11 - right, D destination attn, default 0 (mute)
304	
305	
306	
307	4) MANUALS/PATENTS:
308	-------------------
309	
310	ftp://opensource.creative.com/pub/doc
311	-------------------------------------
312	
313	        Files:
314	        LM4545.pdf      AC97 Codec
315	
316	        m2049.pdf       The EMU10K1 Digital Audio Processor
317	
318	        hog63.ps        FX8010 - A DSP Chip Architecture for Audio Effects
319	
320	
321	WIPO Patents
322	------------
323	        Patent numbers:
324	        WO 9901813 (A1) Audio Effects Processor with multiple asynchronous (Jan. 14, 1999)
325	                        streams
326	
327	        WO 9901814 (A1) Processor with Instruction Set for Audio Effects (Jan. 14, 1999)
328	
329	        WO 9901953 (A1) Audio Effects Processor having Decoupled Instruction
330	                        Execution and Audio Data Sequencing (Jan. 14, 1999)
331	
332	
333	US Patents (http://www.uspto.gov/)
334	----------------------------------
335	
336	        US 5925841      Digital Sampling Instrument employing cache memory (Jul. 20, 1999)
337	
338	        US 5928342      Audio Effects Processor integrated on a single chip (Jul. 27, 1999)
339	                        with a multiport memory onto which multiple asynchronous
340	                        digital sound samples can be concurrently loaded
341	
342	        US 5930158      Processor with Instruction Set for Audio Effects (Jul. 27, 1999)
343	
344	        US 6032235      Memory initialization circuit (Tram) (Feb. 29, 2000)
345	
346	        US 6138207      Interpolation looping of audio samples in cache connected to    (Oct. 24, 2000)
347	                        system bus with prioritization and modification of bus transfers
348	                        in accordance with loop ends and minimum block sizes
349	
350	        US 6151670      Method for conserving memory storage using a (Nov. 21, 2000)
351	                        pool of  short term memory registers
352	
353	        US 6195715      Interrupt control for multiple programs communicating with      (Feb. 27, 2001)
354	                        a common interrupt by associating programs to GP registers,
355	                        defining interrupt register, polling GP registers, and invoking
356	                        callback routine associated with defined interrupt register
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