Updated README

Added mention of optional mpg123 decoder library.

3 files changed, 10 insertions, 7 deletions

diff --git a/README.md b/README.md
index 89cd8e55..95767aee 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,7 @@ Like Gemini, Lagrange has been designed with minimalism in mind. It depends on a
 * Sidebar for page outline, managing bookmarks and identities, and viewing history
 * Multiple tabs
 * Identity management — create and use TLS client certificates
+* Audio playback: MP3, Ogg Vorbis, WAV
 * And more! Open `about:help` in the app, or see [help.gmi](https://git.skyjake.fi/skyjake/lagrange/raw/branch/release/res/about/help.gmi)
 
 ## Downloads
@@ -25,11 +26,12 @@ Prebuilt binaries for Windows and macOS can be found in [Releases][rel].
 This is how to build Lagrange in a Unix-like environment. The required tools are a C11 compiler (e.g., Clang or GCC), CMake and `pkg-config`.
 
 1. Download and extract a source tarball from [Releases][rel]. Alternatively, you may also clone the repository and its submodules: `git clone --recursive --branch release https://git.skyjake.fi/skyjake/lagrange`
-2. Check that you have the dependencies installed: CMake, SDL 2, OpenSSL 1.1.1, libpcre, zlib, libunistring. For example, on macOS this would do the trick (using Homebrew): ```brew install cmake sdl2 openssl@1.1 pcre libunistring``` Or on Ubuntu: ```sudo apt install cmake libsdl2-dev libssl-dev libpcre3-dev zlib1g-dev libunistring-dev```
-3. Create a build directory.
-4. In your empty build directory, run CMake: ```cmake {path_of_lagrange_sources} -DCMAKE_BUILD_TYPE=Release```
-5. Build it: ```cmake --build .```
-6. Now you can run `lagrange`, `lagrange.exe`, or `Lagrange.app`.
+2. Check that you have the required dependencies installed: CMake, SDL 2, OpenSSL 1.1.1, libpcre, zlib, libunistring. For example, on macOS this would do the trick (using Homebrew): ```brew install cmake sdl2 openssl@1.1 pcre libunistring``` Or on Ubuntu: ```sudo apt install cmake libsdl2-dev libssl-dev libpcre3-dev zlib1g-dev libunistring-dev```
+3. Optionally, install the mpg123 decoder library for MPEG audio support. For example, the macOS Homebrew package is `mpg123` and on Ubuntu it is `libmpg123-dev`.
+4. Create a build directory.
+5. In your empty build directory, run CMake: ```cmake {path_of_lagrange_sources} -DCMAKE_BUILD_TYPE=Release```
+6. Build it: ```cmake --build .```
+7. Now you can run `lagrange`, `lagrange.exe`, or `Lagrange.app`.
 
 ### Installing to a directory
 
diff --git a/res/about/help.gmi b/res/about/help.gmi
index 668f0381..80eb62ab 100644
--- a/res/about/help.gmi
+++ b/res/about/help.gmi
@@ -28,6 +28,7 @@ Like Gemini, Lagrange has been designed with minimalism in mind. It depends on a
 * Select and copy text with the mouse
 * Find text on the page
 * Open image links inline on the same page
+* Audio playback: MP3, Ogg Vorbis, WAV
 * Open links via keyboard shortcuts
 * Instant back/forward navigation
 * Smooth scrolling
@@ -118,7 +119,7 @@ The sidebar can be toggled via menus or by pressing ${SHIFT+}${CTRL+}L. It has f
 * Bookmarks: List of bookmarks that you've created. These appear first in search results for quick and easy access.
 * History: Chronological list of visited URLs. This is not a full history of all the URLs you've accessed over time — only unique URLs are shown at the latest access time.
 * Identities: TLS client certificates.
-* Outline: List of the headings in the currently open tab. Useful when reading longer documents. 
+* Outline: List of the headings in the currently open tab. Useful when reading longer documents.
 
 ${CTRL+}1 through ${CTRL+}4 switch between the sidebar tabs, or hide the sidebar if the current tab's key is pressed.
 
diff --git a/res/about/license.gmi b/res/about/license.gmi
index ac4310c7..ef92d647 100644
--- a/res/about/license.gmi
+++ b/res/about/license.gmi
@@ -31,7 +31,7 @@ SDL 2.0 and newer are available under the zlib license:
 
 ## mpg123
 
-mpg123 is a fast console MPEG audio player and decoder library. It is licensed under LGPL 2.1.
+mpg123 is a fast console MPEG audio player and decoder library. It is licensed under LGPL 2.1. Lagrange uses the libmpg123 decoder library when playing back MPEG audio.
 => https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html GNU LGPL version 2.1
 => https://mpg123.org/ mpg123