On Mon, Dec 09, 2024 at 12:45:22AM -0500, George Koehler wrote:
> I had some trouble playing unsigned 8-bit (u8) audio.  I heard noise
> at the end of the audio.  sndiod(8) was reading u8 from the socket and
> filled the last round with bytes of 0.  These 0s are not silent in u8.
> 
> I am now running this diff, which fills the last round with bytes of
> 0x80 if the samples aren't signed.  My diff is wrong for other
> unsigned formats but seems to work for u8.
> 
> Reproduce using audio/sox to write a .wav with u8 (-e unsigned) or
> s16 (-e signed) and play it.  I wrote a u8.  There was noise,
> 
> $ sox sample.wav -e un un.wav trim 0 1 vol 0.5
> $ play un.wav
> 
> I converted my u8 to s16.  The noise went away,
> 
> $ sox un.wav -e si si.wav
> $ play si.wav
> 

thank you for the fix and the test case. To make it work for any
unsigned encoding we could use enc_sil_do() instead of memset().

diff --git a/sndiod/sock.c b/sndiod/sock.c
index af0cb72..443052d 100644
--- a/sndiod/sock.c
+++ b/sndiod/sock.c
@@ -986,6 +986,7 @@ sock_execmsg(struct sock *f)
 	struct ctl *c;
 	struct slot *s = f->slot;
 	struct amsg *m = &f->rmsg;
+	struct conv conv;
 	unsigned char *data;
 	unsigned int size, ctl;
 	int cmd;
@@ -1182,7 +1183,8 @@ sock_execmsg(struct sock *f)
 					panic();
 				}
 #endif
-				memset(data, 0, f->ralign);
+				enc_init(&conv, &s->par, s->mix.nch);
+				enc_sil_do(&conv, data, f->ralign / s->mix.bpf);
 				abuf_wcommit(&s->mix.buf, f->ralign);
 				f->ralign = s->round * s->mix.bpf;
 			}