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Squeezelite-esp32

What is this

Squeezelite-esp32 is an audio software suite made to run on espressif's ESP32 wifi (b/g/n) and bluetooth chipset. It offers the following capabilities

Depending on the hardware connected to the ESP32, you can send audio to a local DAC, to SPDIF or to a Bluetooth speaker. The bare minimum required hardware is a WROVER module with 4MB of Flash and 4MB of PSRAM (https://www.espressif.com/en/products/modules/esp32). With that module standalone, just apply power and you can stream to a Bluetooth speaker. You can also send audio to most I2S DAC as well as to SPDIF receivers using just a cable or an optical transducer (you'll need one resistor...)

But squeezelite-esp32 is highly extensible and you can add

Other features include

Supported Hardware

Any esp32-based hardware with at least 4MB of flash and 4MB of PSRAM will be capable of running squeezelite-esp32 and there are various boards that include such chip. A few are mentionned below, but any should work.

Raw WROVER module

Per above description, a WROVER module is enough to run Squeezelite-esp32, but that requires a bit of tinkering to extend it to have analogue audio or hardware buttons (e.g.)

Please note that when sending to a Bluetooth speaker, then resampling must be enabled (using -R) option if you want to send audio with rate other than 44.1kHz. Similarly, when using SPDIF, only 44.1kHz and 48kHz are supported so you might have to enable resampling as well. If you connect a DAC, choice will depends on its capabilities. See below for more details.

Most DAC will work out-of-the-box with simply an I2S connection, but some require specific commands to be sent using I2C. See DAC option below to understand how to send these dedicated commands. There is build-in support for TAS575x, TAS5780, TAS5713 and AC101 DAC.

SqueezeAMP

This is the main hardware companion of Squeezelite-esp32 and has been developped together. Details on capabilities can be found here and here.

if you want to rebuild, use the squeezelite-esp32-SqueezeAmp-sdkconfig.defaults configuration file.

NB: You can use the pre-build binaries SqueezeAMP4MBFlash which has all the hardware I/O set properly. You can also use the generic binary I2S4MBFlash in which case the NVS parameters shall be set to get the exact same behavior

ESP32-A1S

Works with ESP32-A1S module that includes audio codec and headset output. You still need to use a demo board like this or an external amplifier if you want direct speaker connection.

The board showed above has the following IO set

So a possible config would be

[{"gpio":5,"normal":{"pressed":"ACTRLS_TOGGLE"}},{"gpio":18,"pull":true,"shifter_gpio":5,"normal":{"pressed":"ACTRLS_VOLUP"}, "shifted":{"pressed":"ACTRLS_NEXT"}}, {"gpio":23,"pull":true,"shifter_gpio":5,"normal":{"pressed":"ACTRLS_VOLDOWN"},"shifted":{"pressed":"ACTRLS_PREV"}}]

T-WATCH2020 by LilyGo

This is a fun smartwatch based on ESP32. It has a 240x240 ST7789 screen and onboard audio. Not very useful to listen to anything but it works. This is an example of a device that requires an I2C set of commands for its dac (see below). There is a build-option if you decide to rebuild everything by yourself, otherwise the I2S default option works with the following parameters

ESP32-WROVER + I2S DAC

Squeezelite-esp32 requires esp32 chipset and 4MB PSRAM. ESP32-WROVER meets these requirements. To get an audio output an I2S DAC can be used. Cheap PCM5102 I2S DACs work others may also work. PCM5012 DACs can be hooked up via:

I2S - WROVER
VCC - 3.3V
3.3V - 3.3V
GND - GND
FLT - GND
DMP - GND
SCL - GND
BCK - (BCK - see below)
DIN - (DO - see below)
LCK - (WS - see below) FMT - GND
XMT - 3.3V

Use the squeezelite-esp32-I2S-4MFlash-sdkconfig.defaults configuration file.

SqueezeAmpToo !

And the super cool project https://github.com/rochuck/squeeze-amp-too

Configuration

To access NVS, in the webUI, go to credits and select "shows nvs editor". Go into the NVS editor tab to change NFS parameters. In syntax description below <> means a value while [] describe optional parameters.

I2C

The NVS parameter "i2c_config" set the i2c's gpio used for generic purpose (e.g. display). Leave it blank to disable I2C usage. Note that on SqueezeAMP, port must be 1. Default speed is 400000 but some display can do up to 800000 or more. Syntax is

sda=<gpio>,scl=<gpio>[,port=0|1][,speed=<speed>]

SPI

The NVS parameter "spi_config" set the spi's gpio used for generic purpose (e.g. display). Leave it blank to disable SPI usage. The DC parameter is needed for displays. Syntax is

data=<gpio>,clk=<gpio>[,dc=<gpio>][,host=1|2]

DAC/I2S

The NVS parameter "dac_config" set the gpio used for i2s communication with your DAC. You can define the defaults at compile time but nvs parameter takes precedence except for SqueezeAMP and A1S where these are forced at runtime. If your DAC also requires i2c, then you must go the re-compile route. Syntax is

bck=<gpio>,ws=<gpio>,do=<gpio>[,mute=<gpio>[:0|1][,model=TAS57xx|TAS5713|AC101|I2S][,sda=<gpio>,scl=gpio[,i2c=<addr>]]

if "model" is not set or is not recognized, then default "I2S" is used. I2C parameters are optional an only needed if your dac requires an I2C control (See 'dac_controlset' below). Note that "i2c" parameters are decimal, hex notation is not allowed.

The parameter "dac_controlset" allows definition of simple commands to be sent over i2c for init, power on and off using a JSON syntax:

{ init: [ {"reg":<register>,"val":<value>,"mode":<nothing>|"or"|"and"}, ... {{"reg":<register>,"val":<value>,"mode":<nothing>|"or"|"and"} ],
  poweron: [ {"reg":<register>,"val":<value>,"mode":<nothing>|"or"|"and"}, ... {{"reg":<register>,"val":<value>,"mode":<nothing>|"or"|"and"} ],
  poweroff: [ {"reg":<register>,"val":<value>,"mode":<nothing>|"or"|"and"}, ... {{"reg":<register>,"val":<value>,"mode":<nothing>|"or"|"and"} ] }

This is standard JSON notation, so if you are not familiar with it, Google is your best friend. Be aware that the '...' means you can have as many entries as you want, it's not part of the syntax. Every section is optional, but it does not make sense to set i2c in the 'dac_config' parameter and not setting anything here. The parameter 'mode' allows to or the register with the value or to and it. Don't set 'mode' if you simply want to write. Note that all values must be decimal. You can use a validator like this to verify your syntax

NB: For well-known configuration, this is ignored

SPDIF

The NVS parameter "spdif_config" sets the i2s's gpio needed for SPDIF.

SPDIF is made available by re-using i2s interface in a non-standard way, so although only one pin (DO) is needed, the controller must be fully initialized, so the bit clock (bck) and word clock (ws) must be set as well. As i2s and SPDIF are mutually exclusive, you can reuse the same IO if your hardware allows so.

You can define the defaults at compile time but nvs parameter takes precedence except for SqueezeAMP where these are forced at runtime.

Leave it blank to disable SPDIF usage, you can also define them at compile time using "make menuconfig". Syntax is

bck=<gpio>,ws=<gpio>,do=<gpio>

NB: For well-known configuration, this is ignored

Display

The NVS parameter "display_config" sets the parameters for an optional display. Syntax is

I2C,width=<pixels>,height=<pixels>[address=<i2c_address>][,reset=<gpio>][,HFlip][,VFlip][driver=SSD1306|SSD1326[:1|4]|SSD1327|SH1106]
SPI,width=<pixels>,height=<pixels>,cs=<gpio>[,back=<gpio>][,reset=<gpio>][,speed=<speed>][,HFlip][,VFlip][driver=SSD1306|SSD1322|SSD1326[:1|4]|SSD1327|SH1106|SSD1675|ST7735|ST7789[,rotate]]

To use the display on LMS, add repository https://raw.githubusercontent.com/sle118/squeezelite-esp32/master/plugin/repo.xml. You will then be able to tweak how the vu-meter and spectrum analyzer are displayed, as well as size of artwork. You can also install the excellent plugin "Music Information Screen" which is super useful to tweak the layout.

The NVS parameter "metadata_config" sets how metadata is displayed for AirPlay and Bluetooth. Syntax is

[format=<display_content>][,speed=<speed>][,pause=<pause>]

Infrared

You can use any IR receiver compatible with NEC protocol (38KHz). Vcc, GND and output are the only pins that need to be connected, no pullup, no filtering capacitor, it's a straight connection.

The IR codes are send "as is" to LMS, so only a Logitech SB remote from Boom, Classic or Touch will work. I think the file Slim_Devices_Remote.ir in the "server" directory of LMS can be modified to adapt to other codes, but I've not tried that.

In AirPlay and Bluetooth mode, only these native remotes are supported, I've not added the option to make your own mapping

See "set GPIO" below to set the GPIO associated to infrared receiver (option "ir").

Set GPIO

The parameter "set_GPIO" is used to assign GPIO to various functions.

GPIO can be set to GND provide or Vcc at boot. This is convenient to power devices that consume less than 40mA from the side connector. Be careful because there is no conflict checks being made wrt which GPIO you're changing, so you might damage your board or create a conflict here.

The <amp> parameter can use used to assign a GPIO that will be set to active level (default 1) when playback starts. It will be reset when squeezelite becomes idle. The idle timeout is set on the squeezelite command line through -C <timeout>

If you have an audio jack that supports insertion (use :0 or :1 to set the level when inserted), you can specify which GPIO it's connected to. Using the parameter jack_mutes_amp allows to mute the amp when headset (e.g.) is inserted.

You can set the Green and Red status led as well with their respective active state (:0 or :1)

The <ir> parameter set the GPIO associated to an IR receiver. No need to add pullup or capacitor

Syntax is:

<gpio>=Vcc|GND|amp[:1|0]|ir|jack[:0|1]|green[:0|1]|red[:0|1]|spkfault[:0|1][,<repeated sequence for next GPIO>]

You can define the defaults for jack, spkfault leds at compile time but nvs parameter takes precedence except for well-known configurations where these are forced at runtime.

LED

See §set_GPIO for how to set the green and red LEDs. In addition, their brightness can be controlled using the "led_brigthness" parameter. The syntax is

[green=0..100][,red=0..100]

NB: For well-known configuration, this is ignored

Rotary Encoder

One rotary encoder is supported, quadrature shift with press. Such encoders usually have 2 pins for encoders (A and B), and common C that must be set to ground and an optional SW pin for press. A, B and SW must be pulled up, so automatic pull-up is provided by ESP32, but you can add your own resistors. A bit of filtering on A and B (~470nF) helps for debouncing which is not made by software.

Encoder is normally hard-coded to respectively knob left, right and push on LMS and to volume down/up/play toggle on BT and AirPlay. Using the option 'volume' makes it hard-coded to volume down/up/play toggle all the time (even in LMS). The option 'longpress' allows an alternate mode when SW is long-pressed. In that mode, left is previous, right is next and press is toggle. Every long press on SW alternates between modes (the main mode actual behavior depends on 'volume').

There is also the possibility to use 'knobonly' option (exclusive with 'volume' and 'longpress'). This mode attempts to offer a single knob full navigation which is a bit contorded due to LMS UI's principles. Left, Right and Press obey to LMS's navigation rules and especially Press always goes to lower submenu item, even when navigating in the Music Library. That causes a challenge as there is no 'Play', 'Back' or 'Pause' button. Workaround are as of below:

The speed of double click (or left-right) can be set using the optional parameter of 'knobonly'. This is not a perfect solution, and other ideas are welcome. Be aware that the longer you set double click speed, the less responsive the interface will be. The reason is that I need to wait for that delay before deciding if it's a single or double click. It can also make menu navigation "hesitations" being easoly interpreted as 'Pause'

Use parameter rotary_config with the following syntax:

A=<gpio>,B=<gpio>[,SW=gpio>[[,knobonly[=<ms>]|[,volume][,longpress]]

HW note: all gpio used for rotary have internal pull-up so normally there is no need to provide Vcc to the encoder. Nevertheless if the encoder board you're using also has its own pull-up that are stronger than ESP32's ones (which is likely the case), then there will be crosstalk between gpio, so you must bring Vcc. Look at your board schematic and you'll understand that these board pull-up create a "winning" pull-down when any other pin is grounded.

See also the "IMPORTANT NOTE" on the "Buttons" section and remember that when 'lms_ctrls_raw' (see below) is activated, none of these knobonly,volume,longpress options apply, raw button codes (not actions) are simply sent to LMS

Buttons

Buttons are described using a JSON string with the following syntax

[
{"gpio":<num>,		
 "type":"BUTTON_LOW | BUTTON_HIGH",	
 "pull":[true|false],
 "long_press":<ms>, 
 "debounce":<ms>,
 "shifter_gpio":<-1|num>,
 "normal": {"pressed":"<action>","released":"<action>"},
 "longpress": { <same> },
 "shifted": { <same> },
 "longshifted": { <same> },
 },
 { ... },
 { ... },
]

Where (all parameters are optionals except gpio)

Where <action> is either the name of another configuration to load (remap) or one amongst

ACTRLS_NONE, ACTRLS_VOLUP, ACTRLS_VOLDOWN, ACTRLS_TOGGLE, ACTRLS_PLAY, 
ACTRLS_PAUSE, ACTRLS_STOP, ACTRLS_REW, ACTRLS_FWD, ACTRLS_PREV, ACTRLS_NEXT, 
BCTRLS_UP, BCTRLS_DOWN, BCTRLS_LEFT, BCTRLS_RIGHT,
KNOB_LEFT, KNOB_RIGHT, KNOB_PUSH

One you've created such a string, use it to fill a new NVS parameter with any name below 16(?) characters. You can have as many of these configs as you can. Then set the config parameter "actrls_config" with the name of your default config

For example a config named "buttons" :

[{"gpio":4,"type":"BUTTON_LOW","pull":true,"long_press":1000,"normal":{"pressed":"ACTRLS_VOLDOWN"},"longpress":{"pressed":"buttons_remap"}},
 {"gpio":5,"type":"BUTTON_LOW","pull":true,"shifter_gpio":4,"normal":{"pressed":"ACTRLS_VOLUP"}, "shifted":{"pressed":"ACTRLS_TOGGLE"}}]

Defines two buttons

While the config named "buttons_remap"

[{"gpio":4,"type":"BUTTON_LOW","pull":true,"long_press":1000,"normal":{"pressed":"BCTRLS_DOWN"},"longpress":{"pressed":"buttons"}},
 {"gpio":5,"type":"BUTTON_LOW","pull":true,"shifter_gpio":4,"normal":{"pressed":"BCTRLS_UP"}}]

Defines two buttons

Below is a difficult but functional 2-buttons interface for your decoding pleasure

buttons

[{"gpio":4,"type":"BUTTON_LOW","pull":true,"long_press":1000,
 "normal":{"pressed":"ACTRLS_VOLDOWN"},
 "longpress":{"pressed":"buttons_remap"}},
 {"gpio":5,"type":"BUTTON_LOW","pull":true,"long_press":1000,"shifter_gpio":4,
 "normal":{"pressed":"ACTRLS_VOLUP"}, 
 "shifted":{"pressed":"ACTRLS_TOGGLE"}, 
 "longpress":{"pressed":"ACTRLS_NEXT"}}
]

buttons_remap

[{"gpio":4,"type":"BUTTON_LOW","pull":true,"long_press":1000,
 "normal":{"pressed":"BCTRLS_DOWN"},
 "longpress":{"pressed":"buttons"}},
 {"gpio":5,"type":"BUTTON_LOW","pull":true,"long_press":1000,"shifter_gpio":4,
 "normal":{"pressed":"BCTRLS_UP"},
 "shifted":{"pressed":"BCTRLS_PUSH"},
 "longpress":{"pressed":"ACTRLS_PLAY"},
 "longshifted":{"pressed":"BCTRLS_LEFT"}}
]

<strong>IMPORTANT NOTE</strong>: LMS also supports the possibility to send 'raw' button codes. It's a bit complicated, so bear with me. Buttons can either be processed by SqueezeESP32 and mapped to a "function" like play/pause or they can be just sent to LMS as plain (raw) code and the full logic of press/release/longpress is handled by LMS, you don't have any control on that.

The benefit of the "raw" mode is that you can build a player which is as close as possible to a Boom (e.g.) but you can't use the remapping function nor longress or shift logics to do your own mapping when you have a limited set of buttons. In 'raw' mode, all you really need to define is the mapping between the gpio and the button. As far as LMS is concerned, any other option in these JSON payloads does not matter. Now, when you use BT or AirPlay, the full JSON construct described above fully applies, so the shift, longpress, remapping options still work.

There is no good or bad option, it's your choice. Use the NVS parameter "lms_ctrls_raw" to change that option

Battery / ADC

The NVS parameter "bat_config" sets the ADC1 channel used to measure battery/DC voltage. Scale is a float ratio applied to every sample of the 12 bits ADC. A measure is taken every 10s and an average is made every 5 minutes (not a sliding window). Syntax is

channel=0..7,scale=<scale>,cells=<2|3>

NB: Set parameter to empty to disable battery reading. For well-known configuration, this is ignored (except for SqueezeAMP where number of cells is required)

Configuration

Setup WiFi

Setup squeezelite command line (optional)

At this point, the device should have disabled its built-in access point and should be connected to a known WiFi network.

Monitor

In addition of the esp-idf serial link monitor option, you can also enable a telnet server (see NVS parameters) where you'll have access to a ton of logs of what's happening inside the WROVER.

Update Squeezelite

Recovery

Additional configuration notes (from the Web UI)

The squeezelite options are very similar to the regular Linux ones. Differences are :

- the output is -o ["BT -n '<sinkname>' "] | [I2S]
- if you've compiled with RESAMPLE option, normal soxr options are available using -R [-u <options>]. Note that anything above LQ or MQ will overload the CPU
- if you've used RESAMPLE16, <options> are (b|l|m)[:i], with b = basic linear interpolation, l = 13 taps, m = 21 taps, i = interpolate filter coefficients

For example, so use a BT speaker named MySpeaker, accept audio up to 192kHz and resample everything to 44100 and use 16 bits resample with medium quality, the command line is:

squeezelite -o "BT -n 'BT <sinkname>'" -b 500:2000 -R -u m -Z 192000 -r "44100-44100"

See squeezlite command line, but keys options are

- Z <rate> : tell LMS what is the max sample rate supported before LMS resamples
- R (see above)
- r "<minrate>-<maxrate>"
- C <sec> : set timeout to switch off amp gpio
- W : activate WAV and AIFF header parsing

Building everything yourself

Setting up ESP-IDF

Docker

You can use docker to build squeezelite-esp32 (optional) First you need to build the Docker container:

docker build -t esp-idf .

Then you need to run the container:

docker run -i -t -v `pwd`:/workspace/squeezelite-esp32 esp-idf

The above command will mount this repo into the docker container and start a bash terminal for you to then follow the below build steps

Manual Install of ESP-IDF

<strong>Currently the master branch of this project requires this IDF with gcc 5.2 (toolschain dated 20181001) If you want to use a more recent version of gcc and IDF (4.0 stable), move to cmake-master branch</strong>

You can install IDF manually on Linux or Windows (using the Subsystem for Linux) following the instructions at: https://www.instructables.com/id/ESP32-Development-on-Windows-Subsystem-for-Linux/ And then copying the i2s.c patch file from this repo over to the esp-idf folder You also need to use esp-dsp recent version or at least make sure you have this patch https://github.com/espressif/esp-dsp/pull/12/commits/8b082c1071497d49346ee6ed55351470c1cb4264. As of this writing (08.2020), espressif has patched esp-dsp so this is no more needed

Building Squeezelite-esp32

Don't forget the to choose one of the config files in build_scripts/ and rename it sdkconfig.defaults or sdkconfig as many important WiFi/BT options are set there. The codecs libraries will not be rebuilt by these scripts (it's a tedious process - see below)

Using make (deprecated)

MOST IMPORTANT: create the right default config file

# Build recovery.bin, bootloader.bin, ota_data_initial.bin, partitions.bin  
# force appropriate rebuild by touching all the files which may have a RECOVERY_APPLICATION specific source compile logic
	find . \( -name "*.cpp" -o -name "*.c" -o -name "*.h" \) -type f -print0 | xargs -0 grep -l "RECOVERY_APPLICATION" | xargs touch
	export PROJECT_NAME="recovery" 
	make -j4 all EXTRA_CPPFLAGS='-DRECOVERY_APPLICATION=1'
make flash
#
# Build squeezelite.bin
# Now force a rebuild by touching all the files which may have a RECOVERY_APPLICATION specific source compile logic
find . \( -name "*.cpp" -o -name "*.c" -o -name "*.h" \) -type f -print0 | xargs -0 grep -l "RECOVERY_APPLICATION" | xargs touch
export PROJECT_NAME="squeezelite" 
make -j4 app EXTRA_CPPFLAGS='-DRECOVERY_APPLICATION=0'
python ${IDF_PATH}/components/esptool_py/esptool/esptool.py --chip esp32 --port ${ESPPORT} --baud ${ESPBAUD} --before default_reset --after hard_reset write_flash -z --flash_mode dio --flash_freq 80m --flash_size detect 0x150000 ./build/squeezelite.bin  
# monitor serial output
make monitor

You can also manually download the recovery & initial boot

python ${IDF_PATH}/components/esptool_py/esptool/esptool.py --chip esp32 --port ${ESPPORT} --baud ${ESPBAUD} --before default_reset --after hard_reset write_flash -z --flash_mode dio --flash_freq 80m --flash_size detect 0xd000 ./build/ota_data_initial.bin 0x1000 ./build/bootloader/bootloader.bin 0x10000 ./build/recovery.bin 0x8000 ./build/partitions.bin

Using cmake

Create you config using 'idf.py menuconfig' then build binaries using 'idf.py all'. It will build the recovery and the application (squeezelite) itself. See the recommended command to upload everything. Otherwise, if you just want to download squeezelite, do

python.exe <idf_path>\components\esptool_py\esptool\esptool.py -p COM<n> -b 921600 --before default_reset --after hard_reset write_flash --flash_mode dio --flash_size detect --flash_freq 80m 0x150000 build\squeezelite.bin

Use 'idf monitor' to monitor the application (see esp-idf documentation)

Additional misc notes to do you build (kitchen sink)

codecs