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authorDana Conrad <dconrad@fastmail.com>2021-08-09 19:22:52 -0500
committerSolomon Peachy <pizza@shaftnet.org>2021-08-12 10:07:49 +0000
commit6de6e1459de28bef919b869ee757474c615cb787 (patch)
treeecf10a64809863d1cc3626a3b92dec856b937c4e /firmware/target
parent235e41578be60135c8ad682e05440a5b9142ce69 (diff)
downloadrockbox-6de6e1459de28bef919b869ee757474c615cb787.tar.gz
rockbox-6de6e1459de28bef919b869ee757474c615cb787.zip
Eros Q Hosted: Apply DC Bias to PCM Data
Similar to the native port, the hosted port benefits from adding a -1 dc bias to the PCM data. This prevents almost all clicking artifacts. Change-Id: Ic6378716774b6d88df23c476e2ef54d49f33dc72
Diffstat (limited to 'firmware/target')
-rw-r--r--firmware/target/hosted/pcm-alsa.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/firmware/target/hosted/pcm-alsa.c b/firmware/target/hosted/pcm-alsa.c
index 13ebbbcbeb..68002d8158 100644
--- a/firmware/target/hosted/pcm-alsa.c
+++ b/firmware/target/hosted/pcm-alsa.c
@@ -68,6 +68,11 @@
#warning "MIX_FRAME_SAMPLES <1024 may cause dropouts!"
#endif
+/* PCM_DC_OFFSET_VALUE is a workaround for eros q hardware quirk */
+#if !defined(PCM_DC_OFFSET_VALUE)
+# define PCM_DC_OFFSET_VALUE 0
+#endif
+
static const snd_pcm_access_t access_ = SND_PCM_ACCESS_RW_INTERLEAVED; /* access mode */
#if defined(HAVE_ALSA_32BIT)
static const snd_pcm_format_t format = SND_PCM_FORMAT_S32_LE; /* sample format */
@@ -359,8 +364,8 @@ static bool copy_frames(bool first)
sample_t *sample_ptr = &frames[2*(period_size-frames_left)];
for (int i = 0; i < nframes; i++)
{
- *sample_ptr++ = *pcm_ptr++ * dig_vol_mult_l;
- *sample_ptr++ = *pcm_ptr++ * dig_vol_mult_r;
+ *sample_ptr++ = (*pcm_ptr++ * dig_vol_mult_l) + PCM_DC_OFFSET_VALUE;
+ *sample_ptr++ = (*pcm_ptr++ * dig_vol_mult_r) + PCM_DC_OFFSET_VALUE;
}
}
else