diff options
Diffstat (limited to '')
| -rw-r--r-- | src/pcm_utils.c | 52 |
1 files changed, 32 insertions, 20 deletions
diff --git a/src/pcm_utils.c b/src/pcm_utils.c index f128c3123..9dfcbd1e6 100644 --- a/src/pcm_utils.c +++ b/src/pcm_utils.c @@ -362,6 +362,29 @@ static size_t pcm_convertSampleRate(int8_t channels, uint32_t inSampleRate, } #endif /* !HAVE_LIBSAMPLERATE */ +static void +pcm_convert_channels_1_to_2(int16_t *dest, const int16_t *src, + unsigned num_frames) +{ + while (num_frames-- > 0) { + int16_t value = *src++; + + *dest++ = value; + *dest++ = value; + } +} + +static void +pcm_convert_channels_2_to_1(int16_t *dest, const int16_t *src, + unsigned num_frames) +{ + while (num_frames-- > 0) { + int32_t a = *src++, b = *src++; + + *dest++ = (a + b) / 2; + } +} + static const int16_t * pcm_convertChannels(int8_t channels, const int16_t *inBuffer, size_t inSize, size_t *outSize) @@ -369,9 +392,6 @@ pcm_convertChannels(int8_t channels, const int16_t *inBuffer, static int16_t *buf; static size_t len; int16_t *outBuffer = NULL; - const int16_t *in; - int16_t *out; - int inSamples, i; switch (channels) { /* convert from 1 -> 2 channels */ @@ -381,17 +401,13 @@ pcm_convertChannels(int8_t channels, const int16_t *inBuffer, len = *outSize; buf = xrealloc(buf, len); } - outBuffer = buf; - - inSamples = inSize >> 1; - in = (const int16_t *)inBuffer; - out = (int16_t *)outBuffer; - for (i = 0; i < inSamples; i++) { - *out++ = *in; - *out++ = *in++; - } + outBuffer = buf; + pcm_convert_channels_1_to_2((int16_t *)buf, + (const int16_t *)inBuffer, + inSize >> 1); break; + /* convert from 2 -> 1 channels */ case 2: *outSize = inSize >> 1; @@ -401,15 +417,11 @@ pcm_convertChannels(int8_t channels, const int16_t *inBuffer, } outBuffer = buf; - inSamples = inSize >> 2; - in = (const int16_t *)inBuffer; - out = (int16_t *)outBuffer; - for (i = 0; i < inSamples; i++) { - *out = (*in++) / 2; - *out++ += (*in++) / 2; - } - + pcm_convert_channels_2_to_1((int16_t *)buf, + (const int16_t *)inBuffer, + inSize >> 2); break; + default: ERROR("only 1 or 2 channels are supported for conversion!\n"); } |