#338 Add support for alsa equalizer plugin (#339)

Author: GioF71

doc/equalizer.md

@@ -0,0 +1,64 @@
+# Equalizer support
+
+## References
+
+Look at [this](https://forums.lyrion.org/forum/user-forums/general-discussion/1758009-sqeezebox-docker-configuration) thread for some context.  
+
+## Example configuration
+
+### Custom asound.conf file
+
+Create a file (it's not required it to be at /etc/asound.conf), similar to the following:
+
+```text
+ctl.equal {
+    type equal;
+}
+ 
+pcm.plugequal {
+    type equal;
+    slave.pcm "plughw:DAC";
+}
+ 
+pcm.equal {
+    type plug;
+    slave.pcm plugequal;
+}
+```
+
+Replace the line that says `slave.pcm "plughw:DAC"` with your dac information. You might need to set something like `slave.pcm "plughw:0"`, `slave.pcm "plughw:1,0"`. YMMV.  
+Save the file as (e.g.) eq-asound.conf in the same directory where you are going to save your docker-compose.yaml file.
+
+### Compose file
+
+A simple compose file should look like the following:
+
+```text
+services:
+  squeezelite:
+    image: giof71/squeezelite:latest-alsa
+    devices:
+      - /dev/snd:/dev/snd
+    environment:
+      - USER_MODE=yes
+      - PUID=1000
+      - PGID=1000
+      - AUDIO_GID=29
+      - SQUEEZELITE_AUDIO_DEVICE=equal
+      - SQUEEZELITE_NAME=Aune X1S
+      - SQUEEZELITE_MODEL_NAME=Aune X1S Manjaro i5
+      - SQUEEZELITE_SERVER_PORT=${SQUEEZELITE_SERVER_PORT:-}
+    volumes:
+      - ./eq-asound.conf:/etc/asound.conf:ro
+    restart: unless-stopped
+```
+
+I am using the typical values for PUID, PGID and AUDIO_GID. Again, this depends on your setup. Retrieve the id of the audio group using:
+
+```text
+getent group audio
+```
+
+Run the container as usual. In order to use the equalizer, run the following:
+
+`docker-compose exec -u 1000 squeezelite alsamixer -D equal`

doc/release.md

@@ -10,6 +10,7 @@ Older build might be dropped in order to save space on docker-hub and incur in l
 
 Date|Type|Description
 :---|:---|:---
+2025-06-28|Improvement|Add support for alsa equalizer plugin (see [#338](https://github.com/GioF71/squeezelite-docker/issues/338))
 2025-06-26|Update|Sourceforge binaries version bump (see [#336](https://github.com/GioF71/squeezelite-docker/issues/336))
 2025-04-07|Update|Sourceforge binaries version bump (see [#334](https://github.com/GioF71/squeezelite-docker/issues/334))
 2025-03-16|Update|Sourceforge binaries version bump (see [#332](https://github.com/GioF71/squeezelite-docker/issues/332))

install/install-dep.sh

@@ -30,7 +30,7 @@ if [[ "${BUILD_MODE}" == "sf" ]]; then
     apt-get update
     if [[ -z "${BINARY_MODE}" ]] || [[ "${BINARY_MODE}" == "full" ]] || [[ "${BINARY_MODE}" == "alsa" ]]; then
         echo "Installing support for Alsa ..."
-        apt-get install --no-install-recommends -y libasound2
+        apt-get install --no-install-recommends -y libasound2 libasound2-plugin-equal alsa-utils
         echo "Support for Alsa installed."
     fi
     if [[ -z "${BINARY_MODE}" ]] || [[ "${BINARY_MODE}" == "full" ]] || [[ "${BINARY_MODE}" == "pulse" ]]; then
@@ -60,8 +60,11 @@ elif [[ "${BUILD_MODE}" == "std" ]]; then
         apt-get update
         apt-get install -y bluetooth bluez-alsa-utils alsa-utils
         echo "Finished installing packages for bluetooth ..."
-    else
-        echo "No additional packages to install."
+    elif [[ "${BINARY_MODE}" == "full" ]] || [[ "${BINARY_MODE}" == "alsa" ]]; then
+        echo "Installing packages for alsa mode ..."
+        apt-get update
+        apt-get install -y libasound2-plugin-equal alsa-utils
+        echo "Finished installing packages for alsa mode ..."
     fi
 elif [[ "${BUILD_MODE}" == "r2" ]]; then
     echo "Preparing for Squeezelite R2 (compiling)"
@@ -70,6 +73,8 @@ elif [[ "${BUILD_MODE}" == "r2" ]]; then
         git \
         build-essential \
         libasound2 \
+        libasound2-plugin-equal \
+        alsa-utils \
         libasound2-dev \
         libflac-dev \
         libmad0-dev \