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Allow mono downsampling mode

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Allows for reduced resource usage when I2S is used as an input to a mono
AEC.
This commit is contained in:
Sam Chesney
2016-12-07 10:11:47 +00:00
parent bcc9c23a71
commit 3fe1a6e8cc
1 changed files with 14 additions and 4 deletions
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18
module_usb_audio/audio_io/audio_io.xc
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@@ -37,6 +37,16 @@
#define I2S_DOWNSAMPLE_FACTOR (1)
#endif
#ifndef I2S_DOWNSAMPLE_MONO
#define I2S_DOWNSAMPLE_MONO (0)
#endif
#if (I2S_DOWNSAMPLE_MONO == 1)
#define I2S_DOWNSAMPLE_CHANS (I2S_CHANS_DAC/2)
#else
#define I2S_DOWNSAMPLE_CHANS I2S_CHANS_DAC
#endif
#if (I2S_DOWNSAMPLE_FACTOR != 1) && (I2S_DOWNSAMPLE_FACTOR != 3)
#error "Unsupported I2S downsampling configuration"
#endif
@@ -62,9 +72,9 @@ static union ds3Data
{
long long doubleWordAlignmentEnsured;
/* [Number of I2S channels][Number of samples/phases][Taps per phase] */
int32_t delayLine[I2S_CHANS_DAC][I2S_DOWNSAMPLE_FACTOR][24];
int32_t delayLine[I2S_DOWNSAMPLE_CHANS][I2S_DOWNSAMPLE_FACTOR][24];
} ds3Data;
static int64_t ds3Sum[I2S_CHANS_DAC];
static int64_t ds3Sum[I2S_DOWNSAMPLE_CHANS];
#endif
#if (DSD_CHANS_DAC != 0)
@@ -778,7 +788,7 @@ unsigned static deliver(chanend c_out, chanend ?c_spd_out,
asm volatile("in %0, res[%1]" : "=r"(sample) : "r"(p_i2s_adc[index++]));
samplesIn[buffIndex][((frameCount-1)&(I2S_CHANS_PER_FRAME-1))+i] = bitrev(sample); // channels 1, 3, 5.. on each line.
#if (I2S_DOWNSAMPLE_FACTOR > 1)
#if ((I2S_DOWNSAMPLE_FACTOR > 1) && !I2S_DOWNSAMPLE_MONO)
if ((I2S_DOWNSAMPLE_FACTOR - 1) == downsamplingCounter)
{
samplesIn[buffIndex][((frameCount-1)&(I2S_CHANS_PER_FRAME-1))+i] =
@@ -797,7 +807,7 @@ unsigned static deliver(chanend c_out, chanend ?c_spd_out,
src_ds3_voice_coefs[downsamplingCounter],
samplesIn[readBuffNo][((frameCount-1)&(I2S_CHANS_PER_FRAME-1))+i]);
}
#endif // (I2S_DOWNSAMPLE_FACTOR > 1)
#endif // ((I2S_DOWNSAMPLE_FACTOR > 1) && !I2S_DOWNSAMPLE_MONO)
}
#endif