int16_t WebRtcOpus_Decode(OpusDecInst* inst, int16_t* encoded,
int16_t encoded_bytes, int16_t* decoded,
int16_t* audio_type) {
/* Enough for 120 ms (the largest Opus packet size) of mono audio at 48 kHz
* and resampler overlap. This will need to be enlarged for stereo decoding.
*/
int16_t buffer16[kWebRtcOpusMaxFrameSize];
int32_t buffer32[kWebRtcOpusMaxFrameSize + 7];
int decoded_samples;
int blocks;
int16_t output_samples;
int i;
/* If mono case, just do a regular call to the decoder.
* If stereo, call to WebRtcOpus_Decode() gives left channel as output, and
* calls to WebRtcOpus_Decode_slave() give right channel as output.
* This is to make stereo work with the current setup of NetEQ, which
* requires two calls to the decoder to produce stereo. */
/* Decode to a temporary buffer. */
decoded_samples = DecodeNative(inst->decoder_left, encoded, encoded_bytes,
buffer16, audio_type);
if (decoded_samples < 0) {
return -1;
}
if (inst->channels == 2) {
/* The parameter |decoded_samples| holds the number of samples pairs, in
* case of stereo. Number of samples in |buffer16| equals |decoded_samples|
* times 2. */
for (i = 0; i < decoded_samples; i++) {
/* Take every second sample, starting at the first sample. This gives
* the left channel. */
buffer16[i] = buffer16[i * 2];
}
}
/* Resample from 48 kHz to 32 kHz. */
for (i = 0; i < 7; i++) {
buffer32[i] = inst->state_48_32_left[i];
inst->state_48_32_left[i] = buffer16[decoded_samples - 7 + i];
}
for (i = 0; i < decoded_samples; i++) {
buffer32[7 + i] = buffer16[i];
}
/* Resampling 3 samples to 2. Function divides the input in |blocks| number
* of 3-sample groups, and output is |blocks| number of 2-sample groups.
* When this is removed, the compensation in WebRtcOpus_DurationEst should be
* removed too. */
blocks = decoded_samples / 3;
WebRtcSpl_Resample48khzTo32khz(buffer32, buffer32, blocks);
output_samples = (int16_t) (blocks * 2);
WebRtcSpl_VectorBitShiftW32ToW16(decoded, output_samples, buffer32, 15);
return output_samples;
}
int16_t WebRtcOpus_DecodeSlave(OpusDecInst* inst, int16_t* encoded,
int16_t encoded_bytes, int16_t* decoded,
int16_t* audio_type) {
/* Enough for 120 ms (the largest Opus packet size) of mono audio at 48 kHz
* and resampler overlap. This will need to be enlarged for stereo decoding.
*/
int16_t buffer16[kWebRtcOpusMaxFrameSize];
int32_t buffer32[kWebRtcOpusMaxFrameSize + 7];
int decoded_samples;
int blocks;
int16_t output_samples;
int i;
/* Decode to a temporary buffer. */
decoded_samples = DecodeNative(inst->decoder_right, encoded, encoded_bytes,
buffer16, audio_type);
if (decoded_samples < 0) {
return -1;
}
if (inst->channels == 2) {
/* The parameter |decoded_samples| holds the number of samples pairs, in
* case of stereo. Number of samples in |buffer16| equals |decoded_samples|
* times 2. */
for (i = 0; i < decoded_samples; i++) {
/* Take every second sample, starting at the second sample. This gives
* the right channel. */
buffer16[i] = buffer16[i * 2 + 1];
}
} else {
/* Decode slave should never be called for mono packets. */
return -1;
}
/* Resample from 48 kHz to 32 kHz. */
for (i = 0; i < 7; i++) {
buffer32[i] = inst->state_48_32_right[i];
inst->state_48_32_right[i] = buffer16[decoded_samples - 7 + i];
}
for (i = 0; i < decoded_samples; i++) {
buffer32[7 + i] = buffer16[i];
}
/* Resampling 3 samples to 2. Function divides the input in |blocks| number
* of 3-sample groups, and output is |blocks| number of 2-sample groups. */
blocks = decoded_samples / 3;
WebRtcSpl_Resample48khzTo32khz(buffer32, buffer32, blocks);
output_samples = (int16_t) (blocks * 2);
WebRtcSpl_VectorBitShiftW32ToW16(decoded, output_samples, buffer32, 15);
return output_samples;
}
int16_t WebRtcOpus_Decode(OpusDecInst* inst, int16_t* encoded,
int16_t encoded_bytes, int16_t* decoded,
int16_t* audio_type) {
/* Enough for 120 ms (the largest Opus packet size) of mono audio at 48 kHz
* and resampler overlap. This will need to be enlarged for stereo decoding.
*/
int16_t buffer16[kWebRtcOpusMaxFrameSize];
int32_t buffer32[kWebRtcOpusMaxFrameSize + 7];
int decoded_samples;
int blocks;
int16_t output_samples;
int i;
/* Decode to a temporary buffer. */
decoded_samples = DecodeNative(inst, encoded, encoded_bytes, buffer16,
audio_type);
if (decoded_samples < 0) {
return -1;
}
/* Resample from 48 kHz to 32 kHz. */
for (i = 0; i < 7; i++) {
buffer32[i] = inst->state_48_32[i];
inst->state_48_32[i] = buffer16[decoded_samples -7 + i];
}
for (i = 0; i < decoded_samples; i++) {
buffer32[7 + i] = buffer16[i];
}
/* Resampling 3 samples to 2. Function divides the input in |blocks| number
* of 3-sample groups, and output is |blocks| number of 2-sample groups. */
blocks = decoded_samples / 3;
WebRtcSpl_Resample48khzTo32khz(buffer32, buffer32, blocks);
output_samples = (int16_t) (blocks * 2);
WebRtcSpl_VectorBitShiftW32ToW16(decoded, output_samples, buffer32, 15);
return output_samples;
}
