// Encode encodes an Opus frame.
//
// pcm: the 16-bit PCM input signal (interleaved if 2 channels). Whose length is
// frameSize*channels.
//
// frameSize: the 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 48kHz
// 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: the slice to store the output payload in, containing len(data) bytes
// of space. The length of the slice 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 to control the bitrate.
//
// returns: a slice of the data slice representing the encoded packet, OR nil
// and an error.
func (e *Encoder) Encode(pcm []int16, frameSize int, data []byte) ([]byte, error) {
n := C.opus_encode(
e.cptr(),
(*C.opus_int16)(unsafe.Pointer(&pcm[0])),
C.int(frameSize),
(*C.uchar)(unsafe.Pointer(&data[0])),
C.opus_int32(len(data)),
)
if n > 0 {
return data[:n], nil
}
return nil, opusError(C.int(-n))
}
func (e *Encoder) Encode(pcm []int16, frameSize, maxDataBytes int) ([]byte, error) {
pcmPtr := (*C.opus_int16)(unsafe.Pointer(&pcm[0]))
data := make([]byte, maxDataBytes)
dataPtr := (*C.uchar)(unsafe.Pointer(&data[0]))
encodedC := C.opus_encode(e.cEncoder, pcmPtr, C.int(frameSize), dataPtr, C.opus_int32(len(data)))
encoded := int(encodedC)
if encoded < 0 {
return nil, getErr(C.int(encodedC))
}
return data[0:encoded], nil
}
// Encode raw PCM data and store the result in the supplied buffer. On success,
// returns the number of bytes used up by the encoded data.
func (enc *Encoder) Encode(pcm []int16, data []byte) (int, error) {
if enc.p == nil {
return 0, errEncUninitialized
}
if len(pcm) == 0 {
return 0, fmt.Errorf("opus: no data supplied")
}
if len(data) == 0 {
return 0, fmt.Errorf("opus: no target buffer")
}
n := int(C.opus_encode(
enc.p,
(*C.opus_int16)(&pcm[0]),
C.int(len(pcm)),
(*C.uchar)(&data[0]),
C.opus_int32(cap(data))))
if n < 0 {
return 0, opuserr(n)
}
return n, nil
}