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authorCharis Kouzinopoulos <kouzinopoulos@gmail.com>2006-04-18 09:42:29 -0400
committerJaroslav Kysela <perex@suse.cz>2006-04-27 15:10:19 -0400
commit5732e7a2cece461252bfcf2653bb09ab88ba36c5 (patch)
tree7fcdda160e4affe37c56880635f5b288bd0faf18
parentc128b82cf4095bb64aec435cf58d67fb78272f2f (diff)
[ALSA] Fix typos and add information about Jack support to Audiophile-Usb.txt
Signed-off-by: Charis Kouzinopoulos <kouzinopoulos@gmail.com> Signed-off-by: Thibault Le Meur <Thibault.LeMeur@supelec.fr> Signed-off-by: Takashi Iwai <tiwai@suse.de>
-rw-r--r--Documentation/sound/alsa/Audiophile-Usb.txt81
1 files changed, 54 insertions, 27 deletions
diff --git a/Documentation/sound/alsa/Audiophile-Usb.txt b/Documentation/sound/alsa/Audiophile-Usb.txt
index 4692c8e77dc1..b535c2a198f8 100644
--- a/Documentation/sound/alsa/Audiophile-Usb.txt
+++ b/Documentation/sound/alsa/Audiophile-Usb.txt
@@ -1,4 +1,4 @@
1 Guide to using M-Audio Audiophile USB with ALSA and Jack v1.2 1 Guide to using M-Audio Audiophile USB with ALSA and Jack v1.3
2 ======================================================== 2 ========================================================
3 3
4 Thibault Le Meur <Thibault.LeMeur@supelec.fr> 4 Thibault Le Meur <Thibault.LeMeur@supelec.fr>
@@ -22,16 +22,16 @@ The device has 4 audio interfaces, and 2 MIDI ports:
22 * Midi In (Mi) 22 * Midi In (Mi)
23 * Midi Out (Mo) 23 * Midi Out (Mo)
24 24
25The internal DAC/ADC has the following caracteristics: 25The internal DAC/ADC has the following characteristics:
26* sample depth of 16 or 24 bits 26* sample depth of 16 or 24 bits
27* sample rate from 8kHz to 96kHz 27* sample rate from 8kHz to 96kHz
28* Two ports can't use different sample depths at the same time.Moreover, the 28* Two ports can't use different sample depths at the same time. Moreover, the
29Audiophile USB documentation gives the following Warning: "Please exit any 29Audiophile USB documentation gives the following Warning: "Please exit any
30audio application running before switching between bit depths" 30audio application running before switching between bit depths"
31 31
32Due to the USB 1.1 bandwidth limitation, a limited number of interfaces can be 32Due to the USB 1.1 bandwidth limitation, a limited number of interfaces can be
33activated at the same time depending on the audio mode selected: 33activated at the same time depending on the audio mode selected:
34 * 16-bit/48kHz ==> 4 channels in/ 4 channels out 34 * 16-bit/48kHz ==> 4 channels in/4 channels out
35 - Ai+Ao+Di+Do 35 - Ai+Ao+Di+Do
36 * 24-bit/48kHz ==> 4 channels in/2 channels out, 36 * 24-bit/48kHz ==> 4 channels in/2 channels out,
37 or 2 channels in/4 channels out 37 or 2 channels in/4 channels out
@@ -41,8 +41,8 @@ activated at the same time depending on the audio mode selected:
41 41
42Important facts about the Digital interface: 42Important facts about the Digital interface:
43-------------------------------------------- 43--------------------------------------------
44 * The Do port additionnaly supports surround-encoded AC-3 and DTS passthrough, 44 * The Do port additionally supports surround-encoded AC-3 and DTS passthrough,
45though I haven't tested it under linux 45though I haven't tested it under Linux
46 - Note that in this setup only the Do interface can be enabled 46 - Note that in this setup only the Do interface can be enabled
47 * Apart from recording an audio digital stream, enabling the Di port is a way 47 * Apart from recording an audio digital stream, enabling the Di port is a way
48to synchronize the device to an external sample clock 48to synchronize the device to an external sample clock
@@ -60,24 +60,23 @@ synchronization error (for instance sound played at an odd sample rate)
60The Audiophile USB MIDI ports will be automatically supported once the 60The Audiophile USB MIDI ports will be automatically supported once the
61following modules have been loaded: 61following modules have been loaded:
62 * snd-usb-audio 62 * snd-usb-audio
63 * snd-seq
64 * snd-seq-midi 63 * snd-seq-midi
65 64
66No additionnal setting is required. 65No additional setting is required.
67 66
682.2 - Audio ports 672.2 - Audio ports
69----------------- 68-----------------
70 69
71Audio functions of the Audiophile USB device are handled by the snd-usb-audio 70Audio functions of the Audiophile USB device are handled by the snd-usb-audio
72module. This module can work in a default mode (without any device-specific 71module. This module can work in a default mode (without any device-specific
73parameter), or in an advanced mode with the device-specific parameter called 72parameter), or in an "advanced" mode with the device-specific parameter called
74"device_setup". 73"device_setup".
75 74
762.2.1 - Default Alsa driver mode 752.2.1 - Default Alsa driver mode
77 76
78The default behaviour of the snd-usb-audio driver is to parse the device 77The default behavior of the snd-usb-audio driver is to parse the device
79capabilities at startup and enable all functions inside the device (including 78capabilities at startup and enable all functions inside the device (including
80all ports at any sample rates and any sample depths supported). This approach 79all ports at any supported sample rates and sample depths). This approach
81has the advantage to let the driver easily switch from sample rates/depths 80has the advantage to let the driver easily switch from sample rates/depths
82automatically according to the need of the application claiming the device. 81automatically according to the need of the application claiming the device.
83 82
@@ -114,9 +113,9 @@ gain).
114For people having this problem, the snd-usb-audio module has a new module 113For people having this problem, the snd-usb-audio module has a new module
115parameter called "device_setup". 114parameter called "device_setup".
116 115
1172.2.2.1 - Initializing the working mode of the Audiohile USB 1162.2.2.1 - Initializing the working mode of the Audiophile USB
118 117
119As far as the Audiohile USB device is concerned, this value let the user 118As far as the Audiophile USB device is concerned, this value let the user
120specify: 119specify:
121 * the sample depth 120 * the sample depth
122 * the sample rate 121 * the sample rate
@@ -174,20 +173,20 @@ The parameter can be given:
174 173
175IMPORTANT NOTE WHEN SWITCHING CONFIGURATION: 174IMPORTANT NOTE WHEN SWITCHING CONFIGURATION:
176------------------------------------------- 175-------------------------------------------
177 * You may need to _first_ intialize the module with the correct device_setup 176 * You may need to _first_ initialize the module with the correct device_setup
178 parameter and _only_after_ turn on the Audiophile USB device 177 parameter and _only_after_ turn on the Audiophile USB device
179 * This is especially true when switching the sample depth: 178 * This is especially true when switching the sample depth:
180 - first trun off the device 179 - first turn off the device
181 - de-register the snd-usb-audio module 180 - de-register the snd-usb-audio module (modprobe -r)
182 - change the device_setup parameter (by either manually reprobing the module 181 - change the device_setup parameter by changing the device_setup
183 or changing modprobe.conf) 182 option in /etc/modprobe.conf
184 - turn on the device 183 - turn on the device
185 184
1862.2.2.3 - Audiophile USB's device_setup structure 1852.2.2.3 - Audiophile USB's device_setup structure
187 186
188If you want to understand the device_setup magic numbers for the Audiophile 187If you want to understand the device_setup magic numbers for the Audiophile
189USB, you need some very basic understanding of binary computation. However, 188USB, you need some very basic understanding of binary computation. However,
190this is not required to use the parameter and you may skip thi section. 189this is not required to use the parameter and you may skip this section.
191 190
192The device_setup is one byte long and its structure is the following: 191The device_setup is one byte long and its structure is the following:
193 192
@@ -231,11 +230,11 @@ Caution:
231 230
2322.2.3 - USB implementation details for this device 2312.2.3 - USB implementation details for this device
233 232
234You may safely skip this section if you're not interrested in driver 233You may safely skip this section if you're not interested in driver
235development. 234development.
236 235
237This section describes some internals aspect of the device and summarize the 236This section describes some internal aspects of the device and summarize the
238data I got by usb-snooping the windows and linux drivers. 237data I got by usb-snooping the windows and Linux drivers.
239 238
240The M-Audio Audiophile USB has 7 USB Interfaces: 239The M-Audio Audiophile USB has 7 USB Interfaces:
241a "USB interface": 240a "USB interface":
@@ -277,9 +276,9 @@ Here is a short description of the AltSettings capabilities:
277 - 16-bit depth, 8-48kHz sample mode 276 - 16-bit depth, 8-48kHz sample mode
278 - Synch playback (Do), audio format type III IEC1937_AC-3 277 - Synch playback (Do), audio format type III IEC1937_AC-3
279 278
280In order to ensure a correct intialization of the device, the driver 279In order to ensure a correct initialization of the device, the driver
281_must_know_ how the device will be used: 280_must_know_ how the device will be used:
282 * if DTS is choosen, only Interface 2 with AltSet nb.6 must be 281 * if DTS is chosen, only Interface 2 with AltSet nb.6 must be
283 registered 282 registered
284 * if 96KHz only AltSets nb.1 of each interface must be selected 283 * if 96KHz only AltSets nb.1 of each interface must be selected
285 * if samples are using 24bits/48KHz then AltSet 2 must me used if 284 * if samples are using 24bits/48KHz then AltSet 2 must me used if
@@ -290,7 +289,7 @@ _must_know_ how the device will be used:
290 is not connected 289 is not connected
291 290
292When device_setup is given as a parameter to the snd-usb-audio module, the 291When device_setup is given as a parameter to the snd-usb-audio module, the
293parse_audio_enpoint function uses a quirk called 292parse_audio_endpoints function uses a quirk called
294"audiophile_skip_setting_quirk" in order to prevent AltSettings not 293"audiophile_skip_setting_quirk" in order to prevent AltSettings not
295corresponding to device_setup from being registered in the driver. 294corresponding to device_setup from being registered in the driver.
296 295
@@ -317,9 +316,8 @@ However you may see the following warning message:
317using the "default" ALSA device. This is less efficient than it could be. 316using the "default" ALSA device. This is less efficient than it could be.
318Consider using a hardware device instead rather than using the plug layer." 317Consider using a hardware device instead rather than using the plug layer."
319 318
320
3213.2 - Patching alsa to use direct pcm device 3193.2 - Patching alsa to use direct pcm device
322------------------------------------------- 320--------------------------------------------
323A patch for Jack by Andreas Steinmetz adds support for Big Endian devices. 321A patch for Jack by Andreas Steinmetz adds support for Big Endian devices.
324However it has not been included in the CVS tree. 322However it has not been included in the CVS tree.
325 323
@@ -331,3 +329,32 @@ After having applied the patch you can run jackd with the following command
331line: 329line:
332 % jackd -R -dalsa -Phw:1,0 -r48000 -p128 -n2 -D -Chw:1,1 330 % jackd -R -dalsa -Phw:1,0 -r48000 -p128 -n2 -D -Chw:1,1
333 331
3323.2 - Getting 2 input and/or output interfaces in Jack
333------------------------------------------------------
334
335As you can see, starting the Jack server this way will only enable 1 stereo
336input (Di or Ai) and 1 stereo output (Ao or Do).
337
338This is due to the following restrictions:
339* Jack can only open one capture device and one playback device at a time
340* The Audiophile USB is seen as 2 (or three) Alsa devices: hw:1,0, hw:1,1
341 (and optionally hw:1,2)
342If you want to get Ai+Di and/or Ao+Do support with Jack, you would need to
343combine the Alsa devices into one logical "complex" device.
344
345If you want to give it a try, I recommend reading the information from
346this page: http://www.sound-man.co.uk/linuxaudio/ice1712multi.html
347It is related to another device (ice1712) but can be adapted to suit
348the Audiophile USB.
349
350Enabling multiple Audiophile USB interfaces for Jackd will certainly require:
351* patching Jack with the previously mentioned "Big Endian" patch
352* patching Jackd with the MMAP_COMPLEX patch (see the ice1712 page)
353* patching the alsa-lib/src/pcm/pcm_multi.c file (see the ice1712 page)
354* define a multi device (combination of hw:1,0 and hw:1,1) in your .asoundrc
355 file
356* start jackd with this device
357
358I had no success in testing this for now, but this may be due to my OS
359configuration. If you have any success with this kind of setup, please
360drop me an email.