FFmpeg API Call Analyzer

Clang LibTooling tool that finds all FFmpeg API calls in C/C++ source files. Reports which client functions call which FFmpeg APIs, grouped by source file.

Building

Requires CMake 3.14+, LLVM/Clang 16+ dev libraries, and a C++17 compiler.

cmake -B build -G Ninja
cmake --build build
# or ninja -C build

Usage

With a compilation database (recommended)

# Generate the target project compile_commands.json
cmake -B build -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
# or: meson setup build
# or: bear -- make

# Analyze all files in the compilation database
./build/ffmpeg-api-analyzer -p /path/to/build

# Or specify individual files
./build/ffmpeg-api-analyzer -p /path/to/build src/demuxer.c src/decoder.c

With explicit flags

./build/ffmpeg-api-analyzer file.c -- -I/path/to/ffmpeg/include

Bundled examples

Stub FFmpeg headers are included so you can test without installing FFmpeg:

./build/ffmpeg-api-analyzer examples/example.c -- -I examples/include
./build/ffmpeg-api-analyzer examples/example.cpp -- -I examples/include

Output format

JSON array with one object mapping source files to their client functions and the FFmpeg APIs each one calls:

[
  {
    "src/demuxer.c": {
      "open_input": ["avformat_open_input", "avformat_find_stream_info"],
      "close_input": ["avformat_close_input"]
    }
  }
]

Example output

Running on examples/example.c:

[
  {
    "examples/example.c": {
      "decode_video": [
        "avformat_open_input",
        "avformat_find_stream_info",
        "avcodec_open2",
        "avcodec_send_packet",
        "av_frame_free",
        "av_packet_free",
        "avcodec_free_context",
        "avformat_close_input",
        "avcodec_find_decoder",
        "avcodec_alloc_context3",
        "av_frame_alloc",
        "av_packet_alloc"
      ],
      "encode_audio": [
        "avcodec_open2",
        "avcodec_free_context",
        "avcodec_find_encoder",
        "avcodec_alloc_context3"
      ],
      "scale_frame": [
        "sws_freeContext",
        "sws_getContext"
      ]
    }
  }
]

Running on mpv

git clone https://github.com/mpv-player/mpv.git
cd mpv
# Generate the compilation database
meson setup build
./ffmpeg-api-analyzer -p build

Results: 68 source files, 277 calling functions, 242 unique FFmpeg APIs detected.

Sample output:

[
  {
    "audio/aframe.c": {
      "free_frame": ["av_frame_free"],
      "mp_aframe_config_copy": ["av_channel_layout_copy"],
      "mp_aframe_copy_attributes": ["av_frame_copy_props"],
      "mp_aframe_create": ["av_frame_alloc"],
      "mp_aframe_from_avframe": ["av_frame_ref"],
      "mp_aframe_new_ref": ["av_frame_ref"],
      "mp_aframe_pool_allocate": ["av_buffer_pool_uninit", "av_freep", "av_buffer_pool_get"],
      "mp_aframe_pool_destructor": ["av_buffer_pool_uninit"],
      "mp_aframe_reset": ["av_frame_unref"],
      "mp_aframe_skip_samples": ["av_frame_make_writable"],
      "mp_aframe_to_avframe": ["av_frame_clone"]
    },
    "audio/chmap.c": {
      "mp_chmap_diffn": ["av_popcount64_c"]
    },
    "audio/chmap_avchannel.c": {
      "mp_chmap_to_av_layout": ["av_channel_layout_from_mask"]
    }
  }
]