Codec.FFmpeg.Decode

Video decoding API. Includes FFI declarations for the underlying FFmpeg functions, wrappers for these functions that wrap error condition checking, and high level Haskellized interfaces.

FFI Declarations

avformat_open_input :: Ptr AVFormatContext -> CString -> Ptr () -> Ptr AVDictionary -> IO CInt

avformat_find_stream_info :: AVFormatContext -> Ptr () -> IO CInt

av_find_best_stream :: AVFormatContext -> AVMediaType -> CInt -> CInt -> Ptr AVCodec -> CInt -> IO CInt

avcodec_find_decoder :: AVCodecID -> IO AVCodec

avcodec_find_decoder_by_name :: CString -> IO AVCodec

avcodec_get_frame_defaults :: AVFrame -> IO ()

avpicture_get_size :: AVPixelFormat -> CInt -> CInt -> IO CInt

av_malloc :: CSize -> IO (Ptr ())

av_read_frame :: AVFormatContext -> AVPacket -> IO CInt

decode_video :: AVCodecContext -> AVFrame -> Ptr CInt -> AVPacket -> IO CInt

close_input :: Ptr AVFormatContext -> IO ()

av_dict_set :: Ptr AVDictionary -> CString -> CString -> CInt -> IO CInt

dictSet :: Ptr AVDictionary -> String -> String -> IO ()

FFmpeg Decoding Interface

openCamera :: (MonadIO m, MonadError String m) => String -> m AVFormatContext

Open the first video input device enumerated by FFMPEG.

openInput :: (MonadIO m, MonadError String m) => InputSource -> m AVFormatContext

openFile :: (MonadIO m, MonadError String m) => String -> m AVFormatContext

Open an input media file.

frameAsPicture :: AVFrame -> AVPicture

AVFrame is a superset of AVPicture, so we can upcast an AVFrame to an AVPicture.

findDecoder :: (MonadIO m, MonadError String m) => String -> m AVCodec

Find a codec given by name.

checkStreams :: (MonadIO m, MonadError String m) => AVFormatContext -> m ()

Read packets of a media file to get stream information. This is useful for file formats with no headers such as MPEG.

findVideoStream :: (MonadIO m, MonadError String m) => AVFormatContext -> m (CInt, AVCodecContext, AVCodec, AVStream)

Searches for a video stream in an AVFormatContext. If one is found, returns the index of the stream in the container, and its associated AVCodecContext and AVCodec.

getDecoder :: (MonadIO m, MonadError String m) => AVCodecContext -> m AVCodec

Find a registered decoder with a codec ID matching that found in the given AVCodecContext.

openCodec :: (MonadIO m, MonadError String m) => AVCodecContext -> AVCodec -> m AVDictionary

Initialize the given AVCodecContext to use the given AVCodec. **NOTE**: This function is not thread safe!

read_frame_check :: AVFormatContext -> AVPacket -> IO ()

Return the next frame of a stream.

frameReader :: (MonadIO m, MonadError String m) => AVPixelFormat -> InputSource -> m (IO (Maybe AVFrame), IO ())

Read frames of the given AVPixelFormat from a video stream.

frameReaderT :: (Functor m, MonadIO m, MonadError String m) => InputSource -> m (MaybeT IO AVFrame, IO ())

Read RGB frames with the result in the MaybeT transformer.

frameReaderT = fmap (first MaybeT) . frameReader

frameReaderTime :: (MonadIO m, MonadError String m) => AVPixelFormat -> InputSource -> m (IO (Maybe (AVFrame, Double)), IO ())

Read time stamped frames of the given AVPixelFormat from a video stream. Time is given in seconds from the start of the stream.

frameReaderTimeT :: (Functor m, MonadIO m, MonadError String m) => InputSource -> m (MaybeT IO (AVFrame, Double), IO ())

Read time stamped RGB frames with the result in the MaybeT transformer.

frameReaderT = fmap (first MaybeT) . frameReader

prepareReader :: (MonadIO m, MonadError String m) => AVFormatContext -> CInt -> AVPixelFormat -> AVCodecContext -> m (IO (Maybe AVFrame), IO ())

Construct an action that gets the next available frame, and an action to release all resources associated with this video stream.