Add support for decoding using FFmpeg in the main example

CMakeLists.txt

@@ -78,9 +78,7 @@ option(WHISPER_BUILD_SERVER   "whisper: build server example" ${WHISPER_STANDALO
 option(WHISPER_CURL "whisper: use libcurl to download model from an URL" OFF)
 option(WHISPER_SDL2 "whisper: support for libSDL2" OFF)
 
-if (CMAKE_SYSTEM_NAME MATCHES "Linux")
-    option(WHISPER_FFMPEG "whisper: support building and linking with ffmpeg libs (avcodec, swresample, ...)" OFF)
-endif()
+option(WHISPER_FFMPEG "whisper: support building and linking with ffmpeg libs (avcodec, swresample, ...)" OFF)
 
 option(WHISPER_COREML                "whisper: enable Core ML framework"  OFF)
 option(WHISPER_COREML_ALLOW_FALLBACK "whisper: allow non-CoreML fallback" OFF)

Makefile

@@ -839,6 +839,12 @@ override CXXFLAGS := $(CXXFLAGS) -DWHISPER_USE_CURL
 override LDFLAGS  := $(LDFLAGS) -lcurl
 endif
 
+ifdef WHISPER_FFMPEG
+OBJ_COMMON += examples/ffmpeg-transcode.o
+override CXXFLAGS := $(CXXFLAGS) -DWHISPER_FFMPEG
+override LDFLAGS  := $(LDFLAGS) -lavutil -lavformat -lavcodec -lswscale -lswresample
+endif
+
 #
 # Print build information
 #

README.md

@@ -205,7 +205,15 @@ The command downloads the `base.en` model converted to custom `ggml` format and
 
 For detailed usage instructions, run: `./main -h`
 
-Note that the [main](examples/main) example currently runs only with 16-bit WAV files, so make sure to convert your input before running the tool.
+Note that the [main](examples/main) example currently runs by default with 16-bit WAV files.
+
+Building with `WHISPER_FFMPEG=1` enables ffmpeg support to handle other formats:
+
+```bash
+WHISPER_FFMPEG=1 make main
+```
+
+If you do not want to rebuild it, convert your input before running the tool.
 For example, you can use `ffmpeg` like this:
 
 ```bash