alsaloop: Fix the silence generation in xrun_sync

The silence frames generation in xrun_sync() seems to be currently
a bit off as snd_pcm_format_set_silence() uses a wrong buffer address
and size for zero-ing out the data. Consequently instead of clearing
out the last frame(s), snd_pcm_format_set_silence() ends up silencing
samples somewhere else in the buffer. This is partilarly more obvious
for higher frame sizes (e.g. more than 2 channels).

This patch fixes this issue by correcting the parameters passed to
snd_pcm_format_set_silence().

BugLink: https://github.com/alsa-project/alsa-utils/pull/58
Signed-off-by: Dragos Tarcatu <dragos_tarcatu@mentor.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

diff --git a/alsaloop/pcmjob.c b/alsaloop/pcmjob.c
index 1b7925a205bed5afea365adb3cd4db7c574fa4fb..6a9aff4dd49a6248f99648be589ae6913df52b01 100644 (file)
--- a/alsaloop/pcmjob.c
+++ b/alsaloop/pcmjob.c
@@ -969,13 +969,14 @@ static int xrun_sync(struct loopback *loop)
                                        "sync: playback silence added %li samples\n", (long)diff);
                        play->buf_pos -= diff;
                        play->buf_pos %= play->buf_size;
-                       if ((err = snd_pcm_format_set_silence(play->format, play->buf + play->buf_pos * play->channels, diff)) < 0)
+                       err =  snd_pcm_format_set_silence(play->format, play->buf + play->buf_pos * play->frame_size,
+                                                         diff * play->channels);
+                       if (err < 0)
                                return err;
                        play->buf_count += diff;
                }
                if ((err = snd_pcm_prepare(play->handle)) < 0) {
                        logit(LOG_CRIT, "%s prepare failed: %s\n", play->id, snd_strerror(err));
-
                        return err;
                }
                delay1 = writeit(play);
@@ -1001,7 +1002,9 @@ static int xrun_sync(struct loopback *loop)
                                        "sync: playback short, silence filling %li / buf_count=%li\n", (long)delay1, play->buf_count);
                        if (delay1 > diff)
                                delay1 = diff;
-                       if ((err = snd_pcm_format_set_silence(play->format, play->buf + play->buf_pos * play->channels, delay1)) < 0)
+                       err = snd_pcm_format_set_silence(play->format, play->buf + play->buf_pos * play->frame_size,
+                                                        delay1 * play->channels);
+                       if (err < 0)
                                return err;
                        play->buf_pos += delay1;
                        play->buf_pos %= play->buf_size;