Added flac and mp3 output format.

README.md

@@ -1,10 +1,13 @@
 # tuxrecord
 
-Record audio to a WAV file on **Linux** using **ALSA** as the recording source.
+Record audio to WAV, FLAC or MP3 files on **Linux** using **ALSA** as the
+recording source.
 
 `tuxrecord` is the Linux port of the former macOS-only **macrecord** tool. The
 Swift/AVFoundation code was rewritten in **C99** and now uses the native ALSA
-capture API (`libasound`); it builds with **GCC**.
+capture API (`libasound`); it builds with **GCC**. WAV output is written
+directly, while FLAC and MP3 are encoded in real time through the system
+`libFLAC` and `libmp3lame` libraries, so no intermediate WAV file is written.
 macrecord was created by my good friend Armin. You can find his code here:
 [https://codeberg.org/armin/macrecord](https://codeberg.org/armin/macrecord)
 
@@ -13,6 +16,11 @@ macrecord was created by my good friend Armin. You can find his code here:
 - GCC and GNU make
 - ALSA development headers (`libasound2-dev` on Debian/Ubuntu,
   `alsa-lib-devel` on Fedora, `alsa-lib` on Arch)
+- FLAC and LAME (MP3) development headers, used for the real-time encoders
+  (`libflac-dev` and `libmp3lame-dev` on Debian/Ubuntu, `flac-devel` and
+  `lame-devel` on Fedora, `flac` and `lame` on Arch). They are only needed to
+  build; at run time the shared `libFLAC` / `libmp3lame` libraries are used.
+- `pkg-config` (used to locate ALSA, FLAC and LAME)
 
 ## Usage
 
@@ -32,6 +40,10 @@ tuxrecord -p myrec
 # Use a specific ALSA capture device
 tuxrecord -D hw:1,0
 
+# Encode to FLAC (lossless) or MP3 (lossy) in real time
+tuxrecord -f flac
+tuxrecord --format mp3
+
 # Record from PipeWire (the PipeWire sound server)
 tuxrecord -D pipewire
 ```
@@ -44,6 +56,7 @@ tuxrecord -D pipewire
 | `-d <secs>`    | Stop automatically after `<secs>` seconds                |
 | `-p <prefix>`  | Filename prefix instead of `tuxrecord`                   |
 | `-D <device>`  | ALSA capture device (default: `default`; `pipewire` on PipeWire systems) |
+| `-f, --format <fmt>` | Output format: `wav`, `flac` or `mp3` (default: `wav`) |
 | `-h, --help`   | Show help                                                |
 
 Run `arecord -l` to list available ALSA capture devices. On systems with
@@ -55,9 +68,27 @@ or `wpctl status` (see "Recording from PipeWire" below).
 - **q** - Stop recording and save the file
 - **Ctrl+C** - Stop recording and save the file
 
-The file is written as `<prefix>__<timestamp>.wav` (default prefix
-`tuxrecord`). The VU meter shows the input level of the left and right channels
-in real time when stderr is a terminal.
+The file is written as `<prefix>__<timestamp>.<ext>` where `<ext>` is `wav`,
+`flac` or `mp3` depending on `-f/--format` (default prefix `tuxrecord`, default
+format `wav`). The VU meter shows the input level of the left and right
+channels in real time when stderr is a terminal.
+
+## Output formats
+
+Audio is captured once and handed to the selected encoder as it arrives, so
+FLAC and MP3 are produced **in real time** — no intermediate WAV file is
+written and no second conversion pass runs afterwards. A small reusable buffer
+converts the captured 16-bit samples to the layout the encoder expects.
+
+- **wav** (default) — uncompressed 16-bit little-endian PCM in a RIFF/WAVE
+  container, written directly by tuxrecord.
+- **flac** — lossless compression via libFLAC (streaming, default
+  compression level 5).
+- **mp3** — lossy compression via LAME at a constant 192 kbit/s, quality 2.
+
+`wav` and `flac` preserve the captured stream exactly; `mp3` is lossy. The
+classic 4 GiB RIFF limit applies to `wav` only (the program stops cleanly
+before exceeding it); `flac` and `mp3` have no such limit.
 
 ## Recording system audio
 
@@ -128,9 +159,9 @@ tuxrecord -D pipewire
 ```
 
 The `.monitor` source carries exactly what the sink is playing, so anything
-your players output ends up in the WAV file. Every capture follows the same
-`<prefix>__<timestamp>.wav` naming and can be stopped with `q` or **Ctrl+C**.
-The default setting can be restored later with
+your players output ends up in the recorded file. Every capture follows the
+same `<prefix>__<timestamp>.<ext>` naming and can be stopped with `q` or
+**Ctrl+C**. The default setting can be restored later with
 `pactl set-default-source <your-input-source>`.
 
 ### Troubleshooting
@@ -150,7 +181,8 @@ The default setting can be restored later with
 ```bash
 make
 # or directly:
-# gcc -std=c99 -O2 -Wall -Wextra tuxrecord.c -o tuxrecord $(pkg-config --libs alsa) -lm
+# gcc -std=c99 -O2 -Wall -Wextra tuxrecord.c -o tuxrecord \
+#   $(pkg-config --cflags --libs alsa flac lame) -lm
 ```
 
 Install (installs to `$(PREFIX)/bin`, default `/usr/local/bin`):