Initial version 0.0.0 of libopenaptx library based on ffmpeg 4.0

Besides dynamic shared library there are also two utilities openaptxenc
and openaptxdec for encoding and decoding aptX and aptX HD streams.

Makefile

@@ -0,0 +1,43 @@
+MAJOR := 0
+MINOR := 0
+PATCH := 0
+
+PREFIX := /usr/local
+BINDIR := bin
+LIBDIR := lib
+INCDIR := include
+
+LIBNAME := libopenaptx.so
+SONAME := $(LIBNAME).$(MAJOR)
+FILENAME := $(SONAME).$(MINOR).$(PATCH)
+
+UTILITIES := openaptxenc openaptxdec
+
+HEADERS := openaptx.h
+
+BUILD := $(FILENAME) $(SONAME) $(LIBNAME) $(UTILITIES)
+
+all: $(BUILD)
+
+install: $(BUILD)
+	mkdir -p $(DESTDIR)/$(PREFIX)/$(LIBDIR)
+	cp -a $(FILENAME) $(SONAME) $(LIBNAME) $(DESTDIR)/$(PREFIX)/$(LIBDIR)
+	mkdir -p $(DESTDIR)/$(PREFIX)/$(BINDIR)
+	cp -a $(UTILITIES) $(DESTDIR)/$(PREFIX)/$(BINDIR)
+	mkdir -p $(DESTDIR)/$(PREFIX)/$(INCDIR)
+	cp -a $(HEADERS) $(DESTDIR)/$(PREFIX)/$(INCDIR)
+
+$(FILENAME): openaptx.c $(HEADERS)
+	$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) -I. -shared -fPIC -Wl,-soname,$(SONAME) -o $@ $<
+
+$(SONAME): $(FILENAME)
+	ln -sf $< $@
+
+$(LIBNAME): $(SONAME)
+	ln -sf $< $@
+
+%: %.c $(LIBNAME) $(HEADERS)
+	$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) -I. -o $@ $< $(LIBNAME)
+
+clean:
+	$(RM) $(BUILD)

README

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+This is Open Source implementation of Audio Processing Technology codec (aptX)
+derived from ffmpeg 4.0 project and licensed under LGPLv2.1+. This codec is
+mainly used in Bluetooth A2DP profile.
+
+It provides dynamic linked shared library libopenaptx.so and simple command line
+utilities openaptxenc and openaptxdec for encoding and decoding operations.
+There is support for aptX and aptX HD codec variants. Both variants operates on
+a raw 24 bit signed stereo audio samples. aptX provides fixed compress ratio 6:1
+and aptX HD fixed compress ratio 4:1.
+
+For building and installing into system simply run: make install. For building
+without installing run: LD_RUN_PATH='$ORIGIN' make
+
+Usage of command line utilities together with sox for resampling or playing:
+
+To convert Wave audio file sample.wav into aptX audio file sample.aptx run:
+
+$ sox sample.wav -t raw -r 44.1k -s -3 -c 2 - | openaptxenc > sample.aptx
+
+To convert aptX audio file sample.aptx into Wave audio file sample.wav run:
+
+$ openaptxdec < sample.aptx | sox -t raw -r 44.1k -s -3 -c 2 - sample.wav
+
+To convert MP3 audio file sample.mp3 into aptX HD audio file sample.aptxhd run:
+
+$ sox sample.mp3 -t raw -r 44.1k -s -3 -c 2 - | openaptxenc --hd > sample.aptxhd
+
+To play aptX HD audio file sample.aptxhd run:
+
+$ openaptxdec --hd < sample.aptxhd | play -t raw -r 44.1k -s -3 -c 2 -