watch.c, ladspa_dsp.c: Turn off auto dither.

Call effects_chain_set_dither_params() to disable any dither effects
which have 'bits' set to 'auto'.

Author: bmc0

README.md

@@ -351,8 +351,8 @@ Example:
 	not given, it is set to the same value as `bits` (rounded to the nearest
 	integer).
 
-	**Note:** Currently, `auto` will not work correctly with `ladspa_dsp` or if
-	loaded via `watch`. A default value of 16 is used in those cases.
+	**Note:** Currently, setting `bits` to `auto` disables dither if the effect
+	is loaded via `watch` or used in `ladspa_dsp`.
 
 	[1] S. P. Lipshitz, J. Vanderkooy, and R. A. Wannamaker,
 	"Minimally Audible Noise Shaping," J. AES, vol. 39, no. 11,

dsp.1

@@ -380,8 +380,8 @@ bit depth regardless of the output sample format. \fIbits\fR may be any number.
 not given, it is set to the same value as \fIbits\fR (rounded to the nearest
 integer).
 .sp 0.5
-Note: Currently, \fIauto\fR will not work correctly with \fBladspa_dsp\fR or if
-loaded via \fBwatch\fR. A default value of 16 is used in those cases.
+Note: Currently, setting \fIbits\fR to \fIauto\fR disables dither if the effect
+is loaded via \fBwatch\fR or used in \fBladspa_dsp\fR.
 .sp 0.5
 .RS
 .IP [1] 4

ladspa_dsp.c

@@ -252,6 +252,7 @@ static LADSPA_Handle instantiate_dsp(const LADSPA_Descriptor *desc, unsigned lon
 		LOG_S(LL_ERROR, "error: sample rate mismatch");
 		goto fail;
 	}
+	effects_chain_set_dither_params(&d->chain, 0, 0);  /* disable auto dither */
 	return d;
 
 	fail:

watch.c

@@ -99,6 +99,7 @@ static void watch_reload(struct watch_node *node)
 			}
 			else {
 				destroy_effects_chain(&node->new_chain);
+				effects_chain_set_dither_params(&new_chain, 0, 0);  /* disable auto dither */
 				node->new_chain = new_chain;
 				node->update_chain = 1;
 				pthread_mutex_unlock(&node->lock);