From: Andre Noll <maan@tuebingen.mpg.de>
Date: Sat, 1 Sep 2018 19:07:54 +0000 (+0200)
Subject: compress: Overhaul the meaning of --aggressiveness.
X-Git-Tag: v0.6.3~42^2
X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=commitdiff_plain;h=99f21f0b6ecf29f949cdbce285e241a2e3ef3093;hp=e0441a354b25f6fdd97480fe4e1f4f942347611f

compress: Overhaul the meaning of --aggressiveness.

Large values for the argument to --aggressiveless are next to useless
because they correspond to gain factors which are much too large. The
default value of four is already too large as it allows for a 16-fold
volume amplification.

This patch changes the meaning of the argument to be a multiplication
rather than a shift. Admissible values are restricted to the range
0..10, which allows for fine-grained control over the maximal gain
factor.

The maximal gain factor is four, so the inertia argument must not
exceed 14 to guarantee that no integer overflow can happen.
---

diff --git a/compress_filter.c b/compress_filter.c
index 0c76fd78..15bed6df 100644
--- a/compress_filter.c
+++ b/compress_filter.c
@@ -123,7 +123,7 @@ static void compress_open(struct filter_node *fn)
 	fn->private_data = pcd;
 	fn->min_iqs = 2; /* 16 bit audio */
 	pcd->current_gain = 1U << inertia;
-	pcd->max_gain = 1U << (inertia + aggressiveness);
+	pcd->max_gain = (1U << inertia) * (1.0 + 3.0 * aggressiveness / 10.0);
 }
 
 static void *compress_setup(const struct lls_parse_result *lpr)
@@ -136,20 +136,15 @@ static void *compress_setup(const struct lls_parse_result *lpr)
 		exit(EXIT_FAILURE);
 	}
 	val = U32_OPTVAL(AGGRESSIVENESS, lpr);
-	if (val == 0 || val > 15) {
+	if (val > 10) {
 		PARA_EMERG_LOG("aggressiveness (%u) out of range\n", val);
 		exit(EXIT_FAILURE);
 	}
 	val = U32_OPTVAL(INERTIA, lpr);
-	if (val == 0 || val > 15) {
+	if (val == 0 || val > 14) {
 		PARA_EMERG_LOG("inertia (%u) out of range\n", val);
 		exit(EXIT_FAILURE);
 	}
-	val = U32_OPTVAL(AGGRESSIVENESS, lpr) + U32_OPTVAL(INERTIA, lpr);
-	if (val > 16) {
-		PARA_EMERG_LOG("inertia + aggressiveness (%u) > 16\n", val);
-		exit(EXIT_FAILURE);
-	}
 	val = U32_OPTVAL(TARGET_LEVEL, lpr);
 	if (val > 32767) {
 		PARA_EMERG_LOG("target-level (%u) out of range\n", val);
diff --git a/m4/lls/filter_cmd.suite.m4 b/m4/lls/filter_cmd.suite.m4
index dece6e6e..c026a628 100644
--- a/m4/lls/filter_cmd.suite.m4
+++ b/m4/lls/filter_cmd.suite.m4
@@ -35,25 +35,25 @@ caption = filters
 		[/help]
 	[option aggressiveness]
 		short_opt = a
-		summary = controls the maximum amount to amplify by (1-15)
+		summary = controls the maximum amount to amplify by (0-10)
 		typestr = bits
 		arg_info = required_arg
 		arg_type = uint32
 		default_val = 4
 		[help]
-			This caps the maximal gain factor to 2**bits. The sum of the arguments
-			to --aggressiveness and --inertia (see below) must not exceed 16.
+			This controls the maximal gain factor. Zero means to not amplify
+			at all while the value 10 corresponds to maximal gain factor which
+			results in a 4-fold increase in volume.
 		[/help]
 	[option inertia]
 		short_opt = i
-		summary = how much inertia ramping has (1-15)
+		summary = how much inertia ramping has (1-14)
 		typestr = bits
 		arg_info = required_arg
 		arg_type = uint32
 		default_val = 6
 		[help]
-			Larger values cause smaller volume adjustments. See --aggressiveness
-			above.
+			Larger values cause smaller volume adjustments.
 		[/help]
 	[option target-level]
 		short_opt = t