Monorepo for Aesthetic.Computer
aesthetic.computer
native: bigger SOF buffer (20ms/80ms) + louder keepalive dither (±32)
Log analysis from obsidian-nebula-moss showed two remaining issues:
- XRUN + short write 96/480 frames — 10ms buffer too tight
- sdmode still cycling — ±1 dither @ S32_LE <<8 = -108 dBFS,
below the SOF silence detector threshold
Fixes:
- SOF period/buffer bumped from 10ms/40ms to 20ms/80ms. Reduces
XRUNs at high gain where short writes create audible glitches.
- Keepalive dither bumped from ±1 to ±32 int16 (~-72 dBFS at
S32_LE). Still inaudible but enough RMS to hold the DSP
pipeline active so the amp doesn't cycle on/off mid-playback.
Should fix the "fuzzy" sound quality user reported.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
+20
-11
+20
-11
fedac/native/src/audio.c
+20
-11
fedac/native/src/audio.c
···
1505
1505
buffer[i * 2] = (int16_t)(mix_l * 32000);
1506
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buffer[i * 2 + 1] = (int16_t)(mix_r * 32000);
1507
1507
1508
-
/* DAPM keepalive: inject ±1 LSB when the buffer would
1509
-
* otherwise be all zeros. At S32_LE (after <<16) this
1510
-
* becomes ±65536 ≈ -90 dBFS — utterly inaudible.
1511
-
* Previous ±160 was audible as 24kHz fizz through the
1512
-
* amp. ±1 is enough to prevent the SOF DSP silence
1513
-
* detector from powering down the SSP1 BE DAI. */
1508
+
/* DAPM keepalive: inject dither when buffer would otherwise
1509
+
* be all zeros. At S32_LE with <<8 shift, int16 dither X
1510
+
* becomes X<<8 int32 = roughly X/128 % of full scale. The
1511
+
* SOF DSP silence detector cuts around -80 dBFS, so we
1512
+
* need the dither amplitude in int32 to land around
1513
+
* -70 dBFS to reliably hold the amp alive. ±32 int16
1514
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* → ±8192 int32 ≈ -72 dBFS — still inaudible but enough
1515
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* RMS to keep the pipeline active. (±1 was -108 dBFS,
1516
+
* below the silence threshold, which is why the amp
1517
+
* kept cycling on/off producing "fuzzy" audio.) */
1514
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if (buffer[i * 2] == 0 && buffer[i * 2 + 1] == 0) {
1515
-
buffer[i * 2] = (i & 1) ? 1 : -1;
1516
-
buffer[i * 2 + 1] = (i & 1) ? -1 : 1;
1519
+
int16_t d = (i & 1) ? 32 : -32;
1520
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buffer[i * 2] = d;
1521
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buffer[i * 2 + 1] = -d;
1517
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}
1518
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1524
// HDMI audio: 1-pole low-pass filter + downsample
···
2059
2064
snd_pcm_uframes_t period;
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snd_pcm_uframes_t buffer_size;
2061
2066
if (sof_active) {
2062
-
period = rate / 100; // 10ms (480 frames at 48kHz)
2063
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buffer_size = period * 4; // 40ms total — SOF DAPM-friendly
2064
-
fprintf(stderr, "[audio] SOF platform detected — period=%lu buffer=%lu (10ms/40ms)\n",
2067
+
period = rate / 50; // 20ms (960 frames at 48kHz)
2068
+
buffer_size = period * 4; // 80ms total — larger buffer
2069
+
// reduces XRUN-induced "fuzzy"
2070
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// audio at high software gain.
2071
+
// Previous 10ms/40ms produced
2072
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// 96/480-frame short writes.
2073
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fprintf(stderr, "[audio] SOF platform detected — period=%lu buffer=%lu (20ms/80ms)\n",
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(unsigned long)period, (unsigned long)buffer_size);
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} else {
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period = rate / 1000; // 1ms on HDA-direct paths