/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <string.h>
#include <audio_utils/channels.h>
#include "private/private.h"
/*
* Clamps a 24-bit value from a 32-bit sample
*/
static inline int32_t clamp24(int32_t sample)
{
if ((sample>>23) ^ (sample>>31)) {
sample = 0x007FFFFF ^ (sample>>31);
}
return sample;
}
/*
* Converts a uint8x3_t into an int32_t
*/
inline int32_t uint8x3_to_int32(uint8x3_t val) {
#ifdef HAVE_BIG_ENDIAN
int32_t temp = (val.c[0] << 24 | val.c[1] << 16 | val.c[2] << 8) >> 8;
#else
int32_t temp = (val.c[2] << 24 | val.c[1] << 16 | val.c[0] << 8) >> 8;
#endif
return clamp24(temp);
}
/*
* Converts an int32_t to a uint8x3_t
*/
inline uint8x3_t int32_to_uint8x3(int32_t in) {
uint8x3_t out;
#ifdef HAVE_BIG_ENDIAN
out.c[2] = in;
out.c[1] = in >> 8;
out.c[0] = in >> 16;
#else
out.c[0] = in;
out.c[1] = in >> 8;
out.c[2] = in >> 16;
#endif
return out;
}
/* Channel expands (adds zeroes to audio frame end) from an input buffer to an output buffer.
* See expand_channels() function below for parameter definitions.
*
* Move from back to front so that the conversion can be done in-place
* i.e. in_buff == out_buff
* NOTE: num_in_bytes must be a multiple of in_buff_channels * in_buff_sample_size.
*/
#define EXPAND_CHANNELS(in_buff, in_buff_chans, out_buff, out_buff_chans, num_in_bytes, zero) \
{ \
size_t num_in_samples = num_in_bytes / sizeof(*in_buff); \
size_t num_out_samples = (num_in_samples * out_buff_chans) / in_buff_chans; \
typeof(out_buff) dst_ptr = out_buff + num_out_samples - 1; \
size_t src_index; \
typeof(in_buff) src_ptr = in_buff + num_in_samples - 1; \
size_t num_zero_chans = out_buff_chans - in_buff_chans; \
for (src_index = 0; src_index < num_in_samples; src_index += in_buff_chans) { \
size_t dst_offset; \
for (dst_offset = 0; dst_offset < num_zero_chans; dst_offset++) { \
*dst_ptr-- = zero; \
} \
for (; dst_offset < out_buff_chans; dst_offset++) { \
*dst_ptr-- = *src_ptr--; \
} \
} \
/* return number of *bytes* generated */ \
return num_out_samples * sizeof(*out_buff); \
}
/* Channel expands from a MONO input buffer to a MULTICHANNEL output buffer by duplicating the
* single input channel to the first 2 output channels and 0-filling the remaining.
* See expand_channels() function below for parameter definitions.
*
* in_buff_chans MUST be 1 and out_buff_chans MUST be >= 2
*
* Move from back to front so that the conversion can be done in-place
* i.e. in_buff == out_buff
* NOTE: num_in_bytes must be a multiple of in_buff_channels * in_buff_sample_size.
*/
#define EXPAND_MONO_TO_MULTI(in_buff, in_buff_chans, out_buff, out_buff_chans, num_in_bytes, zero) \
{ \
size_t num_in_samples = num_in_bytes / sizeof(*in_buff); \
size_t num_out_samples = (num_in_samples * out_buff_chans) / in_buff_chans; \
typeof(out_buff) dst_ptr = out_buff + num_out_samples - 1; \
size_t src_index; \
typeof(in_buff) src_ptr = in_buff + num_in_samples - 1; \
size_t num_zero_chans = out_buff_chans - in_buff_chans - 1; \
for (src_index = 0; src_index < num_in_samples; src_index += in_buff_chans) { \
size_t dst_offset; \
for (dst_offset = 0; dst_offset < num_zero_chans; dst_offset++) { \
*dst_ptr-- = zero; \
} \
for (; dst_offset < out_buff_chans; dst_offset++) { \
*dst_ptr-- = *src_ptr; \
} \
src_ptr--; \
} \
/* return number of *bytes* generated */ \
return num_out_samples * sizeof(*out_buff); \
}
/* Channel contracts (removes from audio frame end) from an input buffer to an output buffer.
* See contract_channels() function below for parameter definitions.
*
* Move from front to back so that the conversion can be done in-place
* i.e. in_buff == out_buff
* NOTE: num_in_bytes must be a multiple of in_buff_channels * in_buff_sample_size.
*/
#define CONTRACT_CHANNELS(in_buff, in_buff_chans, out_buff, out_buff_chans, num_in_bytes) \
{ \
size_t num_in_samples = num_in_bytes / sizeof(*in_buff); \
size_t num_out_samples = (num_in_samples * out_buff_chans) / in_buff_chans; \
size_t num_skip_samples = in_buff_chans - out_buff_chans; \
typeof(out_buff) dst_ptr = out_buff; \
typeof(in_buff) src_ptr = in_buff; \
size_t src_index; \
for (src_index = 0; src_index < num_in_samples; src_index += in_buff_chans) { \
size_t dst_offset; \
for (dst_offset = 0; dst_offset < out_buff_chans; dst_offset++) { \
*dst_ptr++ = *src_ptr++; \
} \
src_ptr += num_skip_samples; \
} \
/* return number of *bytes* generated */ \
return num_out_samples * sizeof(*out_buff); \
}
/* Channel contracts from a MULTICHANNEL input buffer to a MONO output buffer by mixing the
* first two input channels into the single output channel (and skipping the rest).
* See contract_channels() function below for parameter definitions.
*
* in_buff_chans MUST be >= 2 and out_buff_chans MUST be 1
*
* Move from front to back so that the conversion can be done in-place
* i.e. in_buff == out_buff
* NOTE: num_in_bytes must be a multiple of in_buff_channels * in_buff_sample_size.
* NOTE: Overload of the summed channels is avoided by averaging the two input channels.
* NOTE: Can not be used for uint8x3_t samples, see CONTRACT_TO_MONO_24() below.
*/
#define CONTRACT_TO_MONO(in_buff, out_buff, num_in_bytes) \
{ \
size_t num_in_samples = num_in_bytes / sizeof(*in_buff); \
size_t num_out_samples = (num_in_samples * out_buff_chans) / in_buff_chans; \
size_t num_skip_samples = in_buff_chans - 2; \
typeof(out_buff) dst_ptr = out_buff; \
typeof(in_buff) src_ptr = in_buff; \
int32_t temp0, temp1; \
size_t src_index; \
for (src_index = 0; src_index < num_in_samples; src_index += in_buff_chans) { \
temp0 = *src_ptr++; \
temp1 = *src_ptr++; \
/* *dst_ptr++ = temp >> 1; */ \
/* This bit of magic adds and normalizes without overflow (or so claims hunga@) */ \
/* Bitwise half adder trick, see http://en.wikipedia.org/wiki/Adder_(electronics) */ \
/* Hacker's delight, p. 19 http://www.hackersdelight.org/basics2.pdf */ \
*dst_ptr++ = (temp0 & temp1) + ((temp0 ^ temp1) >> 1); \
src_ptr += num_skip_samples; \
} \
/* return number of *bytes* generated */ \
return num_out_samples * sizeof(*out_buff); \
}
/* Channel contracts from a MULTICHANNEL uint8x3_t input buffer to a MONO uint8x3_t output buffer
* by mixing the first two input channels into the single output channel (and skipping the rest).
* See contract_channels() function below for parameter definitions.
*
* Move from front to back so that the conversion can be done in-place
* i.e. in_buff == out_buff
* NOTE: num_in_bytes must be a multiple of in_buff_channels * in_buff_sample_size.
* NOTE: Overload of the summed channels is avoided by averaging the two input channels.
* NOTE: Can not be used for normal, scalar samples, see CONTRACT_TO_MONO() above.
*/
#define CONTRACT_TO_MONO_24(in_buff, out_buff, num_in_bytes) \
{ \
size_t num_in_samples = num_in_bytes / sizeof(*in_buff); \
size_t num_out_samples = (num_in_samples * out_buff_chans) / in_buff_chans; \
size_t num_skip_samples = in_buff_chans - 2; \
typeof(out_buff) dst_ptr = out_buff; \
typeof(in_buff) src_ptr = in_buff; \
int32_t temp; \
size_t src_index; \
for (src_index = 0; src_index < num_in_samples; src_index += in_buff_chans) { \
temp = uint8x3_to_int32(*src_ptr++); \
temp += uint8x3_to_int32(*src_ptr++); \
*dst_ptr = int32_to_uint8x3(temp >> 1); \
src_ptr += num_skip_samples; \
} \
/* return number of *bytes* generated */ \
return num_out_samples * sizeof(*out_buff); \
}
/*
* Convert a buffer of N-channel, interleaved samples to M-channel
* (where N > M).
* in_buff points to the buffer of samples
* in_buff_channels Specifies the number of channels in the input buffer.
* out_buff points to the buffer to receive converted samples.
* out_buff_channels Specifies the number of channels in the output buffer.
* sample_size_in_bytes Specifies the number of bytes per sample.
* num_in_bytes size of input buffer in BYTES
* returns
* the number of BYTES of output data.
* NOTE
* channels > M are thrown away.
* The out and sums buffers must either be completely separate (non-overlapping), or
* they must both start at the same address. Partially overlapping buffers are not supported.
*/
static size_t contract_channels(const void* in_buff, size_t in_buff_chans,
void* out_buff, size_t out_buff_chans,
unsigned sample_size_in_bytes, size_t num_in_bytes)
{
switch (sample_size_in_bytes) {
case 1:
if (out_buff_chans == 1) {
/* Special case Multi to Mono */
CONTRACT_TO_MONO((const uint8_t*)in_buff, (uint8_t*)out_buff, num_in_bytes);
// returns in macro
} else {
CONTRACT_CHANNELS((const uint8_t*)in_buff, in_buff_chans,
(uint8_t*)out_buff, out_buff_chans,
num_in_bytes);
// returns in macro
}
case 2:
if (out_buff_chans == 1) {
/* Special case Multi to Mono */
CONTRACT_TO_MONO((const int16_t*)in_buff, (int16_t*)out_buff, num_in_bytes);
// returns in macro
} else {
CONTRACT_CHANNELS((const int16_t*)in_buff, in_buff_chans,
(int16_t*)out_buff, out_buff_chans,
num_in_bytes);
// returns in macro
}
case 3:
if (out_buff_chans == 1) {
/* Special case Multi to Mono */
CONTRACT_TO_MONO_24((const uint8x3_t*)in_buff,
(uint8x3_t*)out_buff, num_in_bytes);
// returns in macro
} else {
CONTRACT_CHANNELS((const uint8x3_t*)in_buff, in_buff_chans,
(uint8x3_t*)out_buff, out_buff_chans,
num_in_bytes);
// returns in macro
}
case 4:
if (out_buff_chans == 1) {
/* Special case Multi to Mono */
CONTRACT_TO_MONO((const int32_t*)in_buff, (int32_t*)out_buff, num_in_bytes);
// returns in macro
} else {
CONTRACT_CHANNELS((const int32_t*)in_buff, in_buff_chans,
(int32_t*)out_buff, out_buff_chans,
num_in_bytes);
// returns in macro
}
default:
return 0;
}
}
/*
* Convert a buffer of N-channel, interleaved samples to M-channel
* (where N < M).
* in_buff points to the buffer of samples
* in_buff_channels Specifies the number of channels in the input buffer.
* out_buff points to the buffer to receive converted samples.
* out_buff_channels Specifies the number of channels in the output buffer.
* sample_size_in_bytes Specifies the number of bytes per sample.
* num_in_bytes size of input buffer in BYTES
* returns
* the number of BYTES of output data.
* NOTE
* channels > N are filled with silence.
* The out and sums buffers must either be completely separate (non-overlapping), or
* they must both start at the same address. Partially overlapping buffers are not supported.
*/
static size_t expand_channels(const void* in_buff, size_t in_buff_chans,
void* out_buff, size_t out_buff_chans,
unsigned sample_size_in_bytes, size_t num_in_bytes)
{
static const uint8x3_t packed24_zero; /* zero 24 bit sample */
switch (sample_size_in_bytes) {
case 1:
if (in_buff_chans == 1) {
/* special case of mono source to multi-channel */
EXPAND_MONO_TO_MULTI((const uint8_t*)in_buff, in_buff_chans,
(uint8_t*)out_buff, out_buff_chans,
num_in_bytes, 0);
// returns in macro
} else {
EXPAND_CHANNELS((const uint8_t*)in_buff, in_buff_chans,
(uint8_t*)out_buff, out_buff_chans,
num_in_bytes, 0);
// returns in macro
}
case 2:
if (in_buff_chans == 1) {
/* special case of mono source to multi-channel */
EXPAND_MONO_TO_MULTI((const int16_t*)in_buff, in_buff_chans,
(int16_t*)out_buff, out_buff_chans,
num_in_bytes, 0);
// returns in macro
} else {
EXPAND_CHANNELS((const int16_t*)in_buff, in_buff_chans,
(int16_t*)out_buff, out_buff_chans,
num_in_bytes, 0);
// returns in macro
}
case 3:
if (in_buff_chans == 1) {
/* special case of mono source to multi-channel */
EXPAND_MONO_TO_MULTI((const uint8x3_t*)in_buff, in_buff_chans,
(uint8x3_t*)out_buff, out_buff_chans,
num_in_bytes, packed24_zero);
// returns in macro
} else {
EXPAND_CHANNELS((const uint8x3_t*)in_buff, in_buff_chans,
(uint8x3_t*)out_buff, out_buff_chans,
num_in_bytes, packed24_zero);
// returns in macro
}
case 4:
if (in_buff_chans == 1) {
/* special case of mono source to multi-channel */
EXPAND_MONO_TO_MULTI((const int32_t*)in_buff, in_buff_chans,
(int32_t*)out_buff, out_buff_chans,
num_in_bytes, 0);
// returns in macro
} else {
EXPAND_CHANNELS((const int32_t*)in_buff, in_buff_chans,
(int32_t*)out_buff, out_buff_chans,
num_in_bytes, 0);
// returns in macro
}
default:
return 0;
}
}
size_t adjust_channels(const void* in_buff, size_t in_buff_chans,
void* out_buff, size_t out_buff_chans,
unsigned sample_size_in_bytes, size_t num_in_bytes)
{
if (out_buff_chans > in_buff_chans) {
return expand_channels(in_buff, in_buff_chans, out_buff, out_buff_chans,
sample_size_in_bytes, num_in_bytes);
} else if (out_buff_chans < in_buff_chans) {
return contract_channels(in_buff, in_buff_chans, out_buff, out_buff_chans,
sample_size_in_bytes, num_in_bytes);
} else if (in_buff != out_buff) {
memcpy(out_buff, in_buff, num_in_bytes);
}
return num_in_bytes;
}