Changes between Initial Version and Version 1 of ventana/audio

Timestamp:

10/22/2017 05:28:45 AM (8 years ago)

Author:

trac

Comment:

--

ventana/audio

@@ +1 @@
+[[PageOutline]]
+
+= Ventana Audio =
+The Advanced Linux Sound Architecture (ALSA) system is the current audio driver subsystem in Linux.
+
+The hardware that is used:
+ * [http://cache.freescale.com/files/analog/doc/data_sheet/SGTL5000.pdf?pspll=1 Freescale SGTL5000] with line level input and output (standard board configuration) or (custom board configuration)
+ headphone level output (custom board configuration) - 45mW max into 16ohme@3.3V load, and mic input
+ * tda1997x (HDMI Audio in)(i.MX6)
+ * imxhdmisoc (HDMI Audio out)(i.MX6)
+
+For information regarding Audio / Video breakout adapters for Ventana see:
+ * [wiki:ventana/breakoutadapters Audio / Video breakout Adapters]
+
+Note that by default, Ventana family boards that have analog audio have a default strapping of [http://en.wikipedia.org/wiki/Line_level line level] audio (both input and output). However, there is an option to load Headphone level output/Mic level input on request. Please contact sales@gateworks.com if you would like a special built with these loadings.
+
+
+== Devices ==
+The following commands are useful when dealing with multiple audio devices (These commands are done on a GW5400 which has multiple sources of audio in/out - different boards will have different devices at varied locations):
+ * see a list of all audio cards:
+{{{
+$ cat /proc/asound/cards
+ 0 [sgtl5000audio  ]: sgtl5000-audio - sgtl5000-audio
+                      sgtl5000-audio
+ 1 [tda1997xaudio  ]: tda1997x-audio - tda1997x-audio
+                      tda1997x-audio
+ 2 [imxhdmisoc     ]: imx-hdmi-soc - imx-hdmi-soc
+                      imx-hdmi-soc
+}}}
+  * There are 3 audio cards in the system:
+   * 0: sgtl5000audio (Analog Audio in/out)
+   * 1: tda1997xaudio (HDMI Audio in)
+   * 2: imxhdmisoc (HDMI Audio out)
+    * Note that this is only available for playback if the framebuffer is not blanked
+ * see a list of all playback devices:
+{{{
+$ aplay -l
+**** List of PLAYBACK Hardware Devices ****
+card 0: sgtl5000audio [sgtl5000-audio], device 0: HiFi sgtl5000-0 []
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+card 2: imxhdmisoc [imx-hdmi-soc], device 0: IMX HDMI TX mxc-hdmi-soc-0 []
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+}}}
+  * the above shows 2 playback capable devices:
+   * card 0: the sgtl5000audio device which has one subdevice (0) - this can be represented as 'hw:0,0'
+   * card 2: the imxhdmisoc device which has one subdevice (0) - this can be represented as 'hw:2,0'
+   * Note that card 1 is not listed as it is an HDMI Audio input only and not capable of playback
+ * see a list of all playback device 'names'
+{{{
+$ aplay -L
+null
+    Discard all samples (playback) or generate zero samples (capture)
+sysdefault:CARD=sgtl5000audio
+    sgtl5000-audio, 
+    Default Audio Device
+sysdefault:CARD=imxhdmisoc
+    imx-hdmi-soc, 
+    Default Audio Device
+}}}
+  * the above shows 3 playback devices shown by name (Note that this is the name what can be used with 'aplay -D <devicename>' to specify playback device):
+   * null - a null device
+   * sysdefault:CARD=sgtl5000audio - Analog audio out
+   * sysdefault:CARD=imxhdmisoc - HDMI audio out
+ * see a list of all capture devices:
+{{{
+root@ventana:~# arecord -l
+**** List of CAPTURE Hardware Devices ****
+card 0: sgtl5000audio [sgtl5000-audio], device 0: HiFi sgtl5000-0 []
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+card 1: tda1997xaudio [tda1997x-audio], device 0: IMX HDMI RX tda1997x-0 []
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+}}}
+  * the above shows 2 capture capable devices:
+   * card 0: the sgtl5000audio device which has one subdevice (0) - this can be represented as 'hw:0,0'
+   * card 1: the tda1997xaudio device which has one subdevice (0) - this can be represented as 'hw:1,0'
+   * Note that card 2 is not listed as it is an HDMI Audio output only and not capable of capture
+ * see a list of all record device 'names':
+{{{
+$ arecord -L
+null
+    Discard all samples (playback) or generate zero samples (capture)
+sysdefault:CARD=sgtl5000audio
+    sgtl5000-audio, 
+    Default Audio Device
+sysdefault:CARD=tda1997xaudio
+    tda1997x-audio, 
+    Default Audio Device
+}}}
+  * the above shows 3 capture devices shown by name (Note that this is the name what can be used with 'arecord -D <devicename>' to specify capture device):
+   * 'null' - a null device
+   * 'sysdefault:CARD=sgtl5000audio' - Analog audio in
+   * 'sysdefault:CARD=tda1997xaudio' - HDMI audio in
+ * display audio controls:
+{{{
+amixer
+}}}
+  * you can use the '-c <cardno>' parameter to amixer to specify a specific card (card number for /proc/asound/cards such as 'amixer -c 0' for the first card)
+  * see 'amixer -h' for details on setting/getting various controls
+
+
+[=#amixer]
+== Mixer (mux/gain/volume) ==
+The ALSA mixer controls the muxing of inputs to outputs, capture gains, and volume levels.  The settings vary per card.
+
+You can use the amixer command to get/set/list available controls per card:
+ * list controls for card0:
+{{{
+amixer -c0
+}}}
+
+
+[=#amixer-sgtl5000]
+=== sgtl5000 (analog audio) ===
+Note that by default, Ventana family boards that have analog audio have a default strapping of [http://en.wikipedia.org/wiki/Line_level line level] audio (both input and output).
+
+However, there is an option to load Headphone level output and/or Mic level input on request. Please contact sales@gateworks.com if you would like a special built with these loadings.
+
+
+[=#amixer-sgtl5000-lineout]
+==== Line Level Audio Output ====
+common amixer settings for line level audio:
+{{{
+# set output level to max
+amixer -c 0 -q sset "PCM" 100%
+# set capture mux
+amixer -c 0 -q sset "Capture Mux" LINE_IN
+amixer -c 0 -q sset "Line In Function" on
+# set capture gain
+amixer -c 0 -q sset "Capture" 8
+}}}
+
+
+[=#amixer-sgtl5000-hpout]
+==== Headphone Level Audio Output ====
+If you've ordered a board with HP level audio the following specifications apply:
+ * sgtl5000 can drive 45mW max into a 16ohm load at 3.3V (53mA)
+
+common amixer settings for headphone level audio:
+{{{
+# Set zero cross detect gain
+amixer -c 0 sset Headphone Playback ZC 60%
+}}}
+
+In addition, you will also have to make a change to your device tree file in the kernel. Below is a sample patch of what you will have to do (filename depends on product you've ordered)
+{{{
+#!diff
+diff --git a/arch/arm/boot/dts/imx6qdl-gw52xx.dtsi b/arch/arm/boot/dts/imx6qdl-gw52xx.dtsi
+index ed71beb..1c0b229 100644
+--- a/arch/arm/boot/dts/imx6qdl-gw52xx.dtsi
++++ b/arch/arm/boot/dts/imx6qdl-gw52xx.dtsi
+@@ -109,7 +109,7 @@
+                audio-codec = <&codec>;
+                audio-routing =
+                        "LINE_IN", "Line In Jack",
+-                       "Line Out Jack", "LINE_OUT";
++                       "Headphone Jack", "HP_OUT";
+                mux-int-port = <1>;
+                mux-ext-port = <4>;
+        };
+}}}
+
+The defaults for the analog audio (which are found by running 'amixer' with no args) are:
+ * Output Level (PCM) (0 - 192)
+  * Front Left: Playback 192 [100%]
+  * Front Right: Playback 192 [100%]
+ * Capture Mux (MIC_IN or LINE_IN)
+  * MIC_IN
+ * Capture Gain (0-15):
+  * Front Left: Capture 5 [33%]
+  * Front Right: Capture 6 [40%]
+
+
+
+[=#amixer-hdmi-out]
+=== HDMI (digital audio) ===
+
+The '''imxhdmisoc''' audio (output only) device can be used to send digital audio to a connected (and unblanked) HDMI monitor that has speakers.
+
+The '''tda1997xaudio''' audio (input only) device (on GW5400 models) can be used to capture digital audio from a connected (and unblanked) HDMI source that streams audio. Note that HDMI audio supports multiple sample-rates and the sample-rate available to capture depends on the incoming source stream. The source stream's audio sample rate can be found via sysfs /sys/bus/i2c/drivers/tda1997x/2-0048/audmode
+
+
+[=#alsa-utils]
+== ALSA utility (alsa-utils package) examples (arecord/aplay) ==
+The alsa-utils package contains the arecord, aplay, amixer applications
+
+aplay:
+ * playback pre-recorded sound to analog audio device (GW54xx/GW53xx/GW52xx)
+{{{
+aplay -D sysdefault:CARD=sgtl5000audio /usr/share/sounds/alsa/Front_Center.wav
+}}}
+ * playback pre-recorded sound to HDMI audio output device
+{{{
+aplay -D sysdefault:CARD=imxhdmisoc /usr/share/sounds/alsa/Front_Center.wav
+}}}
+
+arecord:
+ * record 10 seconds of CD quality audio (16bit, 44.1KHz, stereo) from analog audio device to /tmp/foo.wav
+{{{
+arecord -D sysdefault:CARD=sgtl5000audio -f cd -d 10 -t wav /tmp/foo.wav
+}}}
+  * make sure you have specified the capture gain and input device (see above)
+
+
+== Codecs ==
+For Codec support (Encoder / Decoder) details please see:
+ * [wiki:ventana/codec Ventana Codecs]
+
+
+
+[=#gstreamer]
+== Gstreamer examples ==
+For GStreamer information and examples please see:
+ * [wiki:Yocto/gstreamer/audio GStreamer Audio Wiki Page]