Class OpusMultistream


  • public class OpusMultistream
    extends java.lang.Object
    Opus Multistream API

    The multistream API allows individual Opus streams to be combined into a single packet, enabling support for up to 255 channels. Unlike an elementary Opus stream, the encoder and decoder must negotiate the channel configuration before the decoder can successfully interpret the data in the packets produced by the encoder. Some basic information, such as packet duration, can be computed without any special negotiation.

    The format for multistream Opus packets is defined in RFC 7845 and is based on the self-delimited Opus framing described in Appendix B of RFC 6716. Normal Opus packets are just a degenerate case of multistream Opus packets, and can be encoded or decoded with the multistream API by setting streams to 1 when initializing the encoder or decoder.

    Multistream Opus streams can contain up to 255 elementary Opus streams. These may be either "uncoupled" or "coupled", indicating that the decoder is configured to decode them to either 1 or 2 channels, respectively. The streams are ordered so that all coupled streams appear at the beginning.

    A mapping table defines which decoded channel i should be used for each input/output (I/O) channel j. This table is typically provided as an unsigned char array. Let i = mapping[j] be the index for I/O channel j. If i < 2*coupled_streams, then I/O channel j is encoded as the left channel of stream (i/2) if i is even, or as the right channel of stream (i/2) if i is odd. Otherwise, I/O channel j is encoded as mono in stream (i - coupled_streams), unless it has the special value 255, in which case it is omitted from the encoding entirely (the decoder will reproduce it as silence). Each value i must either be the special value 255 or be less than streams + coupled_streams.

    The output channels specified by the encoder should use the Vorbis channel ordering. A decoder may wish to apply an additional permutation to the mapping the encoder used to achieve a different output channel order (e.g. for outputing in WAV order).

    Each multistream packet contains an Opus packet for each stream, and all of the Opus packets in a single multistream packet must have the same duration. Therefore the duration of a multistream packet can be extracted from the TOC sequence of the first stream, which is located at the beginning of the packet, just like an elementary Opus stream:

    
     int nb_samples, nb_frames;
     nb_frames = opus_packet_get_nb_frames(data, len);
     if (nb_frames < 1)
         return nb_frames;
     nb_samples = opus_packet_get_samples_per_frame(data, 48000) * nb_frames;

    The general encoding and decoding process proceeds exactly the same as in the normal encoder and decoder APIs. See their documentation for an overview of how to use the corresponding multistream functions.

    • Method Detail

      • opus_multistream_encoder_get_size

        public static int opus_multistream_encoder_get_size​(int streams,
                                                            int coupled_streams)
        Gets the size of an OpusMSEncoder structure.
        Parameters:
        streams - the total number of streams to encode from the input. This must be no more than 255.
        coupled_streams - number of coupled (2 channel) streams to encode. This must be no larger than the total number of streams. Additionally, The total number of encoded channels (streams + coupled_streams) must be no more than 255.
        Returns:
        the size in bytes on success, or a negative error code on error
      • opus_multistream_surround_encoder_get_size

        public static int opus_multistream_surround_encoder_get_size​(int channels,
                                                                     int mapping_family)
      • nopus_multistream_encoder_create

        public static long nopus_multistream_encoder_create​(int Fs,
                                                            int channels,
                                                            int streams,
                                                            int coupled_streams,
                                                            long mapping,
                                                            int application,
                                                            long error)
        Unsafe version of: multistream_encoder_create
        Parameters:
        channels - number of channels in the input signal. This must be at most 255. It may be greater than the number of coded channels (streams + coupled_streams).
      • opus_multistream_encoder_create

        public static long opus_multistream_encoder_create​(int Fs,
                                                           int streams,
                                                           int coupled_streams,
                                                           java.nio.ByteBuffer mapping,
                                                           int application,
                                                           @Nullable
                                                           java.nio.IntBuffer error)
        Allocates and initializes a multistream encoder state.

        Call multistream_encoder_destroy to release this object when finished.

        Parameters:
        Fs - sampling rate of the input signal (in Hz). One of:
        800012000160002400048000
        streams - the total number of streams to encode from the input. This must be no more than the number of channels.
        coupled_streams - number of coupled (2 channel) streams to encode. This must be no larger than the total number of streams. Additionally, The total number of encoded channels (streams + coupled_streams) must be no more than the number of input channels.
        mapping - Mapping from encoded channels to input channels. As an extra constraint, the multistream encoder does not allow encoding coupled streams for which one channel is unused since this is never a good idea.
        application - the target encoder application
        error - returns OK on success, or a negative error code on failure
      • nopus_multistream_surround_encoder_create

        public static long nopus_multistream_surround_encoder_create​(int Fs,
                                                                     int channels,
                                                                     int mapping_family,
                                                                     long streams,
                                                                     long coupled_streams,
                                                                     long mapping,
                                                                     int application,
                                                                     long error)
      • opus_multistream_surround_encoder_create

        public static long opus_multistream_surround_encoder_create​(int Fs,
                                                                    int mapping_family,
                                                                    java.nio.IntBuffer streams,
                                                                    java.nio.IntBuffer coupled_streams,
                                                                    java.nio.ByteBuffer mapping,
                                                                    int application,
                                                                    @Nullable
                                                                    java.nio.IntBuffer error)
      • nopus_multistream_encoder_init

        public static int nopus_multistream_encoder_init​(long st,
                                                         int Fs,
                                                         int channels,
                                                         int streams,
                                                         int coupled_streams,
                                                         long mapping,
                                                         int application)
        Unsafe version of: multistream_encoder_init
        Parameters:
        channels - number of channels in the input signal. This must be at most 255. It may be greater than the number of coded channels (streams + coupled_streams).
      • opus_multistream_encoder_init

        public static int opus_multistream_encoder_init​(long st,
                                                        int Fs,
                                                        int streams,
                                                        int coupled_streams,
                                                        java.nio.ByteBuffer mapping,
                                                        int application)
        Initialize a previously allocated multistream encoder state.

        The memory pointed to by st must be at least the size returned by multistream_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 - multistream encoder state to initialize
        Fs - sampling rate of input signal (Hz). One of:
        800012000160002400048000
        streams - the total number of streams to encode from the input. This must be no more than the number of channels.
        coupled_streams - number of coupled (2 channel) streams to encode. This must be no larger than the total number of streams. Additionally, The total number of encoded channels (streams + coupled_streams) must be no more than the number of input channels.
        mapping - mapping from encoded channels to input channels. As an extra constraint, the multistream encoder does not allow encoding coupled streams for which one channel is unused since this is never a good idea.
        application - the target encoder application
        Returns:
        OK on success, or a negative error code on failure
      • nopus_multistream_surround_encoder_init

        public static int nopus_multistream_surround_encoder_init​(long st,
                                                                  int Fs,
                                                                  int channels,
                                                                  long streams,
                                                                  long coupled_streams,
                                                                  long mapping,
                                                                  int application)
      • opus_multistream_surround_encoder_init

        public static int opus_multistream_surround_encoder_init​(long st,
                                                                 int Fs,
                                                                 java.nio.IntBuffer streams,
                                                                 java.nio.IntBuffer coupled_streams,
                                                                 java.nio.ByteBuffer mapping,
                                                                 int application)
      • nopus_multistream_encode

        public static int nopus_multistream_encode​(long st,
                                                   long pcm,
                                                   int frame_size,
                                                   long data,
                                                   int max_data_bytes)
        Unsafe version of: multistream_encode
        Parameters:
        max_data_bytes - size of the allocated memory for the output payload. This may be used to impose an upper limit on the instant bitrate, but should not be used as the only bitrate control. Use SET_BITRATE_REQUEST to control the bitrate.
      • opus_multistream_encode

        public static int opus_multistream_encode​(long st,
                                                  java.nio.ShortBuffer pcm,
                                                  int frame_size,
                                                  java.nio.ByteBuffer data)
        Encodes a multistream Opus frame.
        Parameters:
        st - multistream encoder state
        pcm - the input signal as interleaved samples. This must contain frame_size*channels samples.
        frame_size - number of samples per channel in the input signal. This must be an Opus frame size for the encoder's sampling rate. For example, at 48 kHz the permitted values are 120, 240, 480, 960, 1920, and 2880. Passing in a duration of less than 10 ms (480 samples at 48 kHz) will prevent the encoder from using the LPC or hybrid modes.
        data - output payload. This must contain storage for at max_data_bytes.
        Returns:
        the length of the encoded packet (in bytes) on success or a negative error code on failure
      • nopus_multistream_encode_float

        public static int nopus_multistream_encode_float​(long st,
                                                         long pcm,
                                                         int frame_size,
                                                         long data,
                                                         int max_data_bytes)
        Unsafe version of: multistream_encode_float
        Parameters:
        max_data_bytes - size of the allocated memory for the output payload. This may be used to impose an upper limit on the instant bitrate, but should not be used as the only bitrate control. Use SET_BITRATE_REQUEST to control the bitrate.
      • opus_multistream_encode_float

        public static int opus_multistream_encode_float​(long st,
                                                        java.nio.FloatBuffer pcm,
                                                        int frame_size,
                                                        java.nio.ByteBuffer data)
        Encodes a multistream Opus frame from floating point input.
        Parameters:
        st - multistream encoder state
        pcm - the input signal as interleaved samples 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. This must contain frame_size*channels samples.
        frame_size - number of samples per channel in the input signal. This must be an Opus frame size for the encoder's sampling rate. For example, at 48 kHz the permitted values are 120, 240, 480, 960, 1920, and 2880. Passing in a duration of less than 10 ms (480 samples at 48 kHz) will prevent the encoder from using the LPC or hybrid modes.
        data - output payload. This must contain storage for at max_data_bytes.
        Returns:
        the length of the encoded packet (in bytes) on success or a negative error code on failure
      • opus_multistream_encoder_destroy

        public static void opus_multistream_encoder_destroy​(long st)
        Frees an OpusMSEncoder allocated by multistream_encoder_create.
        Parameters:
        st - multistream encoder state to be freed
      • opus_multistream_decoder_get_size

        public static int opus_multistream_decoder_get_size​(int streams,
                                                            int coupled_streams)
        Gets the size of an OpusMSDecoder structure.
        Parameters:
        streams - the total number of streams coded in the input. This must be no more than 255.
        coupled_streams - number streams to decode as coupled (2 channel) streams. This must be no larger than the total number of streams. Additionally, The total number of coded channels (streams + coupled_streams) must be no more than 255.
        Returns:
        the size in bytes on success, or a negative error code on failure
      • nopus_multistream_decoder_create

        public static long nopus_multistream_decoder_create​(int Fs,
                                                            int channels,
                                                            int streams,
                                                            int coupled_streams,
                                                            long mapping,
                                                            long error)
        Unsafe version of: multistream_decoder_create
        Parameters:
        channels - number of channels to decode. One of:
        12
      • opus_multistream_decoder_create

        public static long opus_multistream_decoder_create​(int Fs,
                                                           int streams,
                                                           int coupled_streams,
                                                           java.nio.ByteBuffer mapping,
                                                           @Nullable
                                                           java.nio.IntBuffer error)
        Allocates and initializes a multistream decoder state.

        Call multistream_decoder_destroy to release this object when finished.

        Parameters:
        Fs - sampling rate of input signal (Hz). One of:
        800012000160002400048000
        streams - the total number of streams coded in the input. This must be no more than 255.
        coupled_streams - number streams to decode as coupled (2 channel) streams. This must be no larger than the total number of streams. Additionally, The total number of coded channels (streams + coupled_streams) must be no more than 255.
        mapping - mapping from coded channels to output channels
        error - returns OK on success, or a negative error code on failure
      • nopus_multistream_decoder_init

        public static int nopus_multistream_decoder_init​(long st,
                                                         int Fs,
                                                         int channels,
                                                         int streams,
                                                         int coupled_streams,
                                                         long mapping)
        Unsafe version of: multistream_decoder_init
        Parameters:
        channels - number of channels to decode. One of:
        12
      • opus_multistream_decoder_init

        public static int opus_multistream_decoder_init​(long st,
                                                        int Fs,
                                                        int streams,
                                                        int coupled_streams,
                                                        java.nio.ByteBuffer mapping)
        Intialize a previously allocated decoder state object.

        The memory pointed to by st must be at least the size returned by multistream_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 - multistream decoder state to initialize
        Fs - sampling rate of input signal (Hz). One of:
        800012000160002400048000
        streams - the total number of streams coded in the input. This must be no more than 255.
        coupled_streams - number streams to decode as coupled (2 channel) streams. This must be no larger than the total number of streams. Additionally, The total number of coded channels (streams + coupled_streams) must be no more than 255.
        mapping - mapping from coded channels to output channels
        Returns:
        OK on success, or a negative error code on failure
      • nopus_multistream_decode

        public static int nopus_multistream_decode​(long st,
                                                   long data,
                                                   int len,
                                                   long pcm,
                                                   int frame_size,
                                                   int decode_fec)
        Unsafe version of: multistream_decode
        Parameters:
        len - number of bytes in payload
      • opus_multistream_decode

        public static int opus_multistream_decode​(long st,
                                                  @Nullable
                                                  java.nio.ByteBuffer data,
                                                  java.nio.ShortBuffer pcm,
                                                  int frame_size,
                                                  int decode_fec)
        Decode a multistream Opus packet.
        Parameters:
        st - multistream decoder
        data - input payload (Use a NULL pointer to indicate packet loss)
        pcm - output signal, with interleaved samples. This must contain room for frame_size*channels samples.
        frame_size - number of samples per channel of available space in pcm.

        If this is less than the maximum packet duration (120ms; 5760 for 48kHz), this function will not be capable of decoding some packets. In the case of PLC (data==NULL) or FEC (decode_fec=1), then frame_size needs to be exactly the duration of audio that is missing, otherwise the decoder will not be in the optimal state to decode the next incoming packet. For the PLC and FEC cases, frame_size must be a multiple of 2.5 ms.

        decode_fec - flag (0 or 1) to request that any in-band forward error correction data be decoded. If no such data is available, the frame is decoded as if it were lost.
        Returns:
        number of decoded samples on success or a negative error code on failure
      • nopus_multistream_decode_float

        public static int nopus_multistream_decode_float​(long st,
                                                         long data,
                                                         int len,
                                                         long pcm,
                                                         int frame_size,
                                                         int decode_fec)
        Unsafe version of: multistream_decode_float
        Parameters:
        len - number of bytes in payload
      • opus_multistream_decode_float

        public static int opus_multistream_decode_float​(long st,
                                                        @Nullable
                                                        java.nio.ByteBuffer data,
                                                        java.nio.FloatBuffer pcm,
                                                        int frame_size,
                                                        int decode_fec)
        Decode a multistream Opus packet with floating point output.
        Parameters:
        st - multistream decoder
        data - input payload. Use a NULL pointer to indicate packet loss
        pcm - output signal, with interleaved samples. (This must contain room for frame_size*channels samples.)
        frame_size - number of samples per channel of available space in pcm.

        If this is less than the maximum packet duration (120ms; 5760 for 48kHz), this function will not be capable of decoding some packets. In the case of PLC (data==NULL) or FEC (decode_fec=1), then frame_size needs to be exactly the duration of audio that is missing, otherwise the decoder will not be in the optimal state to decode the next incoming packet. For the PLC and FEC cases, frame_size must be a multiple of 2.5 ms.

        decode_fec - flag (0 or 1) to request that any in-band forward error correction data be decoded. If no such data is available, the frame is decoded as if it were lost.
        Returns:
        number of decoded samples on success or a negative error code on failure
      • opus_multistream_decoder_destroy

        public static void opus_multistream_decoder_destroy​(long st)
        Frees an OpusMSDecoder allocated by multistream_decoder_create.
        Parameters:
        st - multistream decoder state to be freed
      • opus_multistream_encoder_ctl

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

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