From 2821524107efec826c1584226f263127c22b2572 Mon Sep 17 00:00:00 2001
|
From: Nyx Zheng <zyh@rock-chips.com>
|
Date: Mon, 16 Jul 2018 17:33:30 +0800
|
Subject: [PATCH] add gain for audio input
|
|
Signed-off-by: Nyx Zheng <zyh@rock-chips.com>
|
---
|
src/pcm/pcm.c | 18 ++++++++++++++++++
|
1 file changed, 18 insertions(+)
|
|
diff --git a/src/pcm/pcm.c b/src/pcm/pcm.c
|
index 9c90afb..281fbe3 100644
|
--- a/src/pcm/pcm.c
|
+++ b/src/pcm/pcm.c
|
@@ -825,6 +825,23 @@ void DCBDoing(void* pIn, int length, int channels)
|
}
|
}
|
#endif
|
+void add_gain(void* pIn, int length, int channels)
|
+{
|
+ int i = 0;
|
+ int16_t * pInBuf = (int16_t *)pIn;
|
+ char *alsa_gain_level = getenv("ALSA_LIB_ADD_GAIN");
|
+ if(alsa_gain_level) {
|
+ int level = atoi(alsa_gain_level);
|
+ //printf("gain level:%d\n",level);
|
+ for(i = 0; i < length; i ++ ) {
|
+ int curChannel = i % channels;
|
+ if(curChannel < channels - 2 ) {//audio loopback no need to add gain
|
+ (*pInBuf) <<= level;
|
+ }
|
+ pInBuf++;
|
+ }
|
+ }
|
+}
|
/* check whether the PCM is in the unexpected state */
|
static int bad_pcm_state(snd_pcm_t *pcm, unsigned int supported_states)
|
{
|
@@ -1675,6 +1692,7 @@ snd_pcm_sframes_t snd_pcm_readi(snd_pcm_t *pcm, void *buffer, snd_pcm_uframes_t
|
#ifdef DCB_FILTER_16BIT
|
DCBDoing((void*)buffer, tmp * pcm->frame_bits / 8 / sizeof(int16_t), pcm->channels);
|
#endif
|
+ add_gain((void*)buffer, tmp * pcm->frame_bits / 8 / sizeof(int16_t), pcm->channels);
|
return tmp;
|
}
|
|
--
|
2.7.4
|
