pcm: hw: add drain_silence configuration keyword

  # Add silence in drain (-1 = auto /default/, 0 = off, > 0 milliseconds)
  [drain_silence INT]

Signed-off-by: Jaroslav Kysela <perex@perex.cz>

diff --git a/src/pcm/pcm_hw.c b/src/pcm/pcm_hw.c
index d6bc7ee05c30cf46be4d7a642bf625e85dae080e..6d7b2d48df98eb6403792d9ccf0d1074f74f8cda 100644 (file)
--- a/src/pcm/pcm_hw.c
+++ b/src/pcm/pcm_hw.c
@@ -111,6 +111,7 @@ typedef struct {
                int max;
        } rates;
        int channels;
+       int drain_silence;
        /* for chmap */
        unsigned int chmap_caps;
        snd_pcm_chmap_query_t **chmap_override;
@@ -738,8 +739,16 @@ static int snd_pcm_hw_drain(snd_pcm_t *pcm)
 
        if (pcm->stream != SND_PCM_STREAM_PLAYBACK)
                goto __skip_silence;
-       /* compute end silence size, align to period size + extra time */
+       if (hw->drain_silence == 0)
+               goto __skip_silence;
        snd_pcm_sw_params_current_no_lock(pcm, &sw_params);
+       if (hw->drain_silence > 0) {
+               silence_size = (pcm->rate * hw->drain_silence) / 1000;
+               if (silence_size > pcm->buffer_size)
+                       silence_size = pcm->buffer_size;
+               goto __manual_silence;
+       }
+       /* compute end silence size, align to period size + extra time */
        if ((pcm->boundary % pcm->period_size) == 0) {
                silence_size = pcm->period_size - (*pcm->appl.ptr % pcm->period_size);
                if (silence_size == pcm->period_size)
@@ -752,6 +761,7 @@ static int snd_pcm_hw_drain(snd_pcm_t *pcm)
                silence_size = pcm->period_size;
        }
        silence_size += pcm->rate / 10; /* 1/10th of second */
+__manual_silence:
        if (sw_params.silence_size < silence_size) {
                /* fill the silence soon as possible (in the bellow ioctl
                 * or the next period wake up)
@@ -1818,6 +1828,7 @@ pcm.name {
        [rate INT]              # Restrict only to the given rate
          or [rate [INT INT]]   # Restrict only to the given rate range (min max)
        [chmap MAP]             # Override channel maps; MAP is a string array
+       [drain_silence INT]     # Add silence in drain (-1 = auto /default/, 0 = off, > 0 milliseconds)
 }
 \endcode
 
@@ -1850,7 +1861,7 @@ int _snd_pcm_hw_open(snd_pcm_t **pcmp, const char *name,
        long card = -1, device = 0, subdevice = -1;
        const char *str;
        int err, sync_ptr_ioctl = 0;
-       int min_rate = 0, max_rate = 0, channels = 0;
+       int min_rate = 0, max_rate = 0, channels = 0, drain_silence = -1;
        snd_pcm_format_t format = SND_PCM_FORMAT_UNKNOWN;
        snd_config_t *n;
        int nonblock = 1; /* non-block per default */
@@ -1991,6 +2002,16 @@ int _snd_pcm_hw_open(snd_pcm_t **pcmp, const char *name,
                        }
                        continue;
                }
+               if (strcmp(id, "drain_silence") == 0) {
+                       long val;
+                       err = snd_config_get_integer(n, &val);
+                       if (err < 0) {
+                               SNDERR("Invalid type for %s", id);
+                               goto fail;
+                       }
+                       drain_silence = val;
+                       continue;
+               }
                SNDERR("Unknown field %s", id);
                err = -EINVAL;
                goto fail;
@@ -2033,6 +2054,7 @@ int _snd_pcm_hw_open(snd_pcm_t **pcmp, const char *name,
        }
        if (chmap)
                hw->chmap_override = chmap;
+       hw->drain_silence = drain_silence;
 
        return 0;