Class OpusCustom


  • public class OpusCustom
    extends java.lang.Object
    Opus Custom is an optional part of the Opus specification and reference implementation which uses a distinct API from the regular API and supports frame sizes that are not normally supported. Use of Opus Custom is discouraged for all but very special applications for which a frame size different from 2.5, 5, 10, or 20 ms is needed (for either complexity or latency reasons) and where interoperability is less important.

    In addition to the interoperability limitations the use of Opus custom disables a substantial chunk of the codec and generally lowers the quality available at a given bitrate. Normally when an application needs a different frame size from the codec it should buffer to match the sizes but this adds a small amount of delay which may be important in some very low latency applications. Some transports (especially constant rate RF transports) may also work best with frames of particular durations.

    Libopus only supports custom modes if they are enabled at compile time.

    The Opus Custom API is similar to the regular API but the custom_encoder_create and custom_decoder_create calls take an additional mode parameter which is a structure produced by a call to custom_mode_create. Both the encoder and decoder must create a mode using the same sample rate (fs) and frame size (frame size) so these parameters must either be signaled out of band or fixed in a particular implementation.

    Similar to regular Opus the custom modes support on the fly frame size switching, but the sizes available depend on the particular frame size in use. For some initial frame sizes on a single on the fly size is available.

    • Method Detail

      • nopus_custom_mode_create

        public static long nopus_custom_mode_create​(int Fs,
                                                    int frame_size,
                                                    long error)
        Unsafe version of: custom_mode_create
      • opus_custom_mode_create

        public static long opus_custom_mode_create​(int Fs,
                                                   int frame_size,
                                                   @Nullable
                                                   java.nio.IntBuffer error)
        Creates a new mode struct. This will be passed to an encoder or decoder. The mode MUST NOT BE DESTROYED until the encoders and decoders that use it are destroyed as well.
        Parameters:
        Fs - sampling rate (8000 to 96000 Hz)
        frame_size - number of samples (per channel) to encode in each packet (64 - 1024, prime factorization must contain zero or more 2s, 3s, or 5s and no other primes
        error - returned error code (if NULL, no error will be returned)
      • opus_custom_mode_destroy

        public static void opus_custom_mode_destroy​(long mode)
        Destroys a mode struct. Only call this after all encoders and decoders using this mode are destroyed as well.
        Parameters:
        mode - mode to be freed
      • opus_custom_encoder_get_size

        public static int opus_custom_encoder_get_size​(long mode,
                                                       int channels)
        Gets the size of an OpusCustomEncoder structure.
        Parameters:
        mode - mode configuration
        channels - number of channels
        Returns:
        size
      • opus_custom_encoder_init

        public static int opus_custom_encoder_init​(long st,
                                                   long mode,
                                                   int channels)
        Initializes a previously allocated encoder state.

        The memory pointed to by st must be the size returned by custom_encoder_get_size. This is intended for applications which use their own allocator instead of malloc.

        To reset a previously initialized state use the RESET_STATE CTL.

        Parameters:
        st - encoder state
        mode - contains all the information about the characteristics of the stream (must be the same characteristics as used for the decoder)
        channels - number of channels
        Returns:
        OK Success or a negative error code
      • nopus_custom_encoder_create

        public static long nopus_custom_encoder_create​(long mode,
                                                       int channels,
                                                       long error)
        Unsafe version of: custom_encoder_create
      • opus_custom_encoder_create

        public static long opus_custom_encoder_create​(long mode,
                                                      int channels,
                                                      @Nullable
                                                      java.nio.IntBuffer error)
        Creates a new encoder state.

        Each stream needs its own encoder state (can't be shared across simultaneous streams).

        Parameters:
        mode - contains all the information about the characteristics of the stream (must be the same characteristics as used for the decoder)
        channels - number of channels
        error - returns an error code
        Returns:
        newly created encoder state
      • opus_custom_encoder_destroy

        public static void opus_custom_encoder_destroy​(long st)
        Destroys a an encoder state.
        Parameters:
        st - state to be freed
      • nopus_custom_encode_float

        public static int nopus_custom_encode_float​(long st,
                                                    long pcm,
                                                    int frame_size,
                                                    long compressed,
                                                    int maxCompressedBytes)
        Unsafe version of: custom_encode_float
        Parameters:
        maxCompressedBytes - maximum number of bytes to use for compressing the frame (can change from one frame to another)
      • opus_custom_encode_float

        public static int opus_custom_encode_float​(long st,
                                                   java.nio.FloatBuffer pcm,
                                                   int frame_size,
                                                   java.nio.ByteBuffer compressed)
        Encodes a frame of audio.
        Parameters:
        st - encoder state
        pcm - PCM audio in float format, with a normal range of +/-1.0. Samples with a range beyond +/-1.0 are supported but will be clipped by decoders using the integer API and should only be used if it is known that the far end supports extended dynamic range. There must be exactly frame_size samples per channel.
        frame_size - number of samples per frame of input signal
        compressed - the compressed data is written here. This may not alias pcm and must be at least maxCompressedBytes long.
        Returns:
        the number of bytes written to compress on success, or a negative error code
      • nopus_custom_encode

        public static int nopus_custom_encode​(long st,
                                              long pcm,
                                              int frame_size,
                                              long compressed,
                                              int maxCompressedBytes)
        Unsafe version of: custom_encode
        Parameters:
        maxCompressedBytes - maximum number of bytes to use for compressing the frame (can change from one frame to another)
      • opus_custom_encode

        public static int opus_custom_encode​(long st,
                                             java.nio.ShortBuffer pcm,
                                             int frame_size,
                                             java.nio.ByteBuffer compressed)
        Encodes a frame of audio.
        Parameters:
        st - encoder state
        pcm - PCM audio in signed 16-bit format (native endian). (There must be exactly frame_size samples per channel.)
        frame_size - number of samples per frame of input signal
        compressed - the compressed data is written here. This may not alias pcm and must be at least maxCompressedBytes long.
        Returns:
        the number of bytes written to compress on success, or a negative error code
      • opus_custom_decoder_get_size

        public static int opus_custom_decoder_get_size​(long mode,
                                                       int channels)
        Gets the size of an OpusCustomDecoder structure.
        Parameters:
        mode - mode configuration
        channels - number of channels
        Returns:
        size
      • opus_custom_decoder_init

        public static int opus_custom_decoder_init​(long st,
                                                   long mode,
                                                   int channels)
        Initializes a previously allocated decoder state.

        The memory pointed to by st must be the size returned by custom_decoder_get_size. This is intended for applications which use their own allocator instead of malloc.

        To reset a previously initialized state use the RESET_STATE CTL.

        Parameters:
        st - decoder state
        mode - contains all the information about the characteristics of the stream (must be the same characteristics as used for the encoder)
        channels - number of channels
        Returns:
        OK Success or a negative error code
      • nopus_custom_decoder_create

        public static long nopus_custom_decoder_create​(long mode,
                                                       int channels,
                                                       long error)
        Unsafe version of: custom_decoder_create
      • opus_custom_decoder_create

        public static long opus_custom_decoder_create​(long mode,
                                                      int channels,
                                                      @Nullable
                                                      java.nio.IntBuffer error)
        Creates a new decoder state.

        Each stream needs its own decoder state (can't be shared across simultaneous streams).

        Parameters:
        mode - contains all the information about the characteristics of the stream (must be the same characteristics as used for the encoder)
        channels - number of channels
        error - returns an error code
        Returns:
        newly created decoder state
      • opus_custom_decoder_destroy

        public static void opus_custom_decoder_destroy​(long st)
        Destroys a an decoder state.
        Parameters:
        st - state to be freed
      • nopus_custom_decode_float

        public static int nopus_custom_decode_float​(long st,
                                                    long data,
                                                    int len,
                                                    long pcm,
                                                    int frame_size)
        Unsafe version of: custom_decode_float
        Parameters:
        len - number of bytes in payload
      • opus_custom_decode_float

        public static int opus_custom_decode_float​(long st,
                                                   @Nullable
                                                   java.nio.ByteBuffer data,
                                                   java.nio.FloatBuffer pcm,
                                                   int frame_size)
        Decode an opus custom frame with floating point output.
        Parameters:
        st - decoder state
        data - input payload. Use a NULL pointer to indicate packet loss.
        pcm - output signal (interleaved if 2 channels) (length is frame_size*channels*sizeof(float)
        frame_size - number of samples per channel of available space in pcm
        Returns:
        number of decoded samples, or a negative error code
      • nopus_custom_decode

        public static int nopus_custom_decode​(long st,
                                              long data,
                                              int len,
                                              long pcm,
                                              int frame_size)
        Unsafe version of: custom_decode
        Parameters:
        len - number of bytes in payload
      • opus_custom_decode

        public static int opus_custom_decode​(long st,
                                             @Nullable
                                             java.nio.ByteBuffer data,
                                             java.nio.ShortBuffer pcm,
                                             int frame_size)
        Decode an opus custom frame.
        Parameters:
        st - decoder state
        data - input payload. Use a NULL pointer to indicate packet loss.
        pcm - output signal (interleaved if 2 channels) (length is frame_size*channels*sizeof(opus_int16)
        frame_size - number of samples per channel of available space in pcm
        Returns:
        number of decoded samples, or a negative error code
      • opus_custom_encoder_ctl

        public static int opus_custom_encoder_ctl​(long st,
                                                  int request)
        
        public static int opus_custom_encoder_ctl​(long st,
                                                  Opus.CTLRequest request)
        
        Performs a CTL function on an Opus custom encoder.
        Parameters:
        st - encoder state
        request - CTL request
      • opus_custom_decoder_ctl

        public static int opus_custom_decoder_ctl​(long st,
                                                  int request)
        
        public static int opus_custom_decoder_ctl​(long st,
                                                  Opus.CTLRequest request)
        
        Performs a CTL function on an Opus custom decoder.
        Parameters:
        st - decoder state
        request - CTL request