Refactor: Modular architecture with pluggable balancers and config support

.gitignore

@@ -1,2 +1,13 @@
+# Compiled binary
 belacoder
-belacoder.o
+
+# Test binaries
+tests/test_balancer
+tests/test_integration
+
+# Object files
+*.o
+
+# Editor files
+*.swp
+*~

Makefile

@@ -1,15 +1,66 @@
 VERSION=$(shell git rev-parse --short HEAD)
-CFLAGS=`pkg-config gstreamer-1.0 gstreamer-app-1.0 srt --cflags` -O2 -Wall -DVERSION=\"$(VERSION)\"
+CFLAGS=`pkg-config gstreamer-1.0 gstreamer-app-1.0 srt --cflags` -O2 -Wall -DVERSION=\"$(VERSION)\" \
+	-I$(SRCDIR) -I$(SRCDIR)/core -I$(SRCDIR)/io -I$(SRCDIR)/net -I$(SRCDIR)/gst
 LDFLAGS=`pkg-config gstreamer-1.0 gstreamer-app-1.0 srt --libs` -ldl
 
+# Test configuration
+TEST_CFLAGS=`pkg-config cmocka --cflags` $(CFLAGS) -g
+TEST_LDFLAGS=`pkg-config cmocka --libs` $(LDFLAGS)
+
+# Source directory
+SRCDIR = src
+TESTDIR = tests
+
+# Object files
+OBJS = $(SRCDIR)/belacoder.o \
+       $(SRCDIR)/io/cli_options.o \
+       $(SRCDIR)/io/pipeline_loader.o \
+       $(SRCDIR)/net/srt_client.o \
+       $(SRCDIR)/gst/encoder_control.o \
+       $(SRCDIR)/gst/overlay_ui.o \
+       $(SRCDIR)/core/balancer_runner.o \
+       $(SRCDIR)/core/bitrate_control.o \
+       $(SRCDIR)/core/config.o \
+       $(SRCDIR)/core/balancer_adaptive.o \
+       $(SRCDIR)/core/balancer_fixed.o \
+       $(SRCDIR)/core/balancer_aimd.o \
+       $(SRCDIR)/core/balancer_registry.o \
+       camlink_workaround/camlink.o
+
+# Test object files (exclude main)
+TEST_OBJS = $(filter-out $(SRCDIR)/belacoder.o, $(OBJS))
+
 all: submodule belacoder
 
 submodule:
 	git submodule init
 	git submodule update
 
-belacoder: belacoder.o camlink_workaround/camlink.o
+belacoder: $(OBJS)
 	$(CC) $(CFLAGS) $^ -o $@ $(LDFLAGS)
 
+# Compile source files (matches subdirectories too)
+$(SRCDIR)/%.o: $(SRCDIR)/%.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+# Test targets
+test: submodule test_balancer test_integration
+
+test_balancer: $(TESTDIR)/test_balancer.o $(TEST_OBJS)
+	$(CC) $(TEST_CFLAGS) $^ -o $(TESTDIR)/$@ $(TEST_LDFLAGS)
+	./$(TESTDIR)/$@
+
+test_integration: $(TESTDIR)/test_integration.o $(TEST_OBJS)
+	$(CC) $(TEST_CFLAGS) $^ -o $(TESTDIR)/$@ $(TEST_LDFLAGS)
+	./$(TESTDIR)/$@
+
+$(TESTDIR)/%.o: $(TESTDIR)/%.c
+	$(CC) $(TEST_CFLAGS) -c $< -o $@
+
 clean:
-	rm -f belacoder *.o camlink_workaround/*.o
+	rm -f belacoder \
+		$(SRCDIR)/*.o $(SRCDIR)/core/*.o $(SRCDIR)/io/*.o $(SRCDIR)/net/*.o $(SRCDIR)/gst/*.o \
+		$(TESTDIR)/*.o $(TESTDIR)/test_balancer $(TESTDIR)/test_integration camlink_workaround/*.o
+
+.PHONY: all submodule clean test test_balancer test_integration
+

README.md

@@ -138,6 +138,26 @@ The Makefile uses `pkg-config` to locate GStreamer and libsrt. Ensure both are i
 pkg-config --modversion gstreamer-1.0 gstreamer-app-1.0 srt
 ```
 
+### Testing
+
+belacoder includes integration tests that verify module behavior without requiring actual hardware:
+
+```bash
+# Install cmocka (test framework)
+sudo apt-get install libcmocka-dev
+
+# Run all tests
+make test
+```
+
+Tests verify:
+- Balancer algorithm behavior (adaptive, fixed, AIMD)
+- Config loading and reload
+- Bitrate bounds enforcement
+- Network condition responses
+
+See [docs/architecture.md](docs/architecture.md) for details on the modular architecture and testing approach.
+
 
 Usage
 -----
@@ -147,31 +167,54 @@ Syntax: belacoder PIPELINE_FILE ADDR PORT [options]
 
 Options:
   -v                  Print the version and exit
+  -c <config file>    Configuration file (INI format, recommended)
   -d <delay>          Audio-video delay in milliseconds
   -s <streamid>       SRT stream ID
   -l <latency>        SRT latency in milliseconds (default: 2000)
   -r                  Reduced SRT packet size (6 TS packets instead of 7)
-  -b <bitrate file>   Bitrate settings file, see below
+  -b <bitrate file>   Bitrate settings file (legacy, use -c instead)
+  -a <algorithm>      Bitrate balancer algorithm (overrides config)
 
-Bitrate settings file syntax:
-MIN BITRATE (bps)
-MAX BITRATE (bps)
----
-Example for 500 Kbps – 6000 Kbps:
+Config file example (belacoder.conf):
+[general]
+min_bitrate = 500    # Kbps
+max_bitrate = 6000   # Kbps (6 Mbps)
+balancer = adaptive  # Algorithm: adaptive, fixed, aimd
 
-    printf "500000\n6000000" > bitrate_file
+[srt]
+latency = 2000       # ms
+
+[adaptive]
+incr_step = 30       # Bitrate increase step (Kbps)
+decr_step = 100      # Bitrate decrease step (Kbps)
+incr_interval = 500  # Min interval between increases (ms)
+decr_interval = 200  # Min interval between decreases (ms)
 
 ---
-Send SIGHUP to reload the bitrate settings while running.
+Send SIGHUP to reload configuration while running:
+    kill -HUP $(pidof belacoder)
 ```
 
 Where:
 
 * `PIPELINE_FILE` is a text file containing the GStreamer pipeline to use. See the `pipeline` directory for ready-made pipelines.
-* `ADDR` is the hostname or IP address of the SRT listener to stream to (only applicable when the GStreamer sink is `appsink name=appsink`).
-* `PORT` is the port of the SRT listener to stream to (only applicable when the GStreamer sink is `appsink name=appsink`).
-* `-d <delay>` is the optional delay in milliseconds to add to the audio stream relative to the video (when using the GStreamer pipelines supplied with belacoder).
-* `-b <bitrate file>` is an optional argument for setting the minimum and maximum **video** bitrate (when using the GStreamer pipelines supplied with belacoder). These settings are reloaded from the file and applied when a SIGHUP signal is received.
+* `ADDR` is the hostname or IP address of the SRT listener to stream to.
+* `PORT` is the port of the SRT listener to stream to.
+* `-c <config file>` is the recommended way to configure bitrate bounds and algorithm settings. See `belacoder.conf.example` for a full example.
+* `-d <delay>` is the optional delay in milliseconds to add to the audio stream relative to the video.
+* `-b <bitrate file>` is the legacy way to set bitrate bounds (use `-c` instead for new deployments).
+
+### Balancer Algorithms
+
+belacoder supports multiple bitrate control algorithms:
+
+| Algorithm | Description | Best For |
+|-----------|-------------|----------|
+| **adaptive** (default) | RTT and buffer-based control with graduated response | Most use cases, variable networks |
+| **fixed** | Constant bitrate, no adaptation | Stable networks, testing |
+| **aimd** | TCP-style Additive Increase Multiplicative Decrease | Fair bandwidth sharing |
+
+Select via config file or override with `-a <algorithm>`.
 
 
 GStreamer Pipelines