From 4524d2408d085cca4af1a783f52174128e45b16c Mon Sep 17 00:00:00 2001
From: Andre Noll <maan@systemlinux.org>
Date: Sun, 6 Jul 2008 20:26:12 +0200
Subject: [PATCH] compress.c: Activate pre-amplification.

Use the amplification value announced by para_server to
pre-amplify the stream.
---
 compress.c | 14 +++++++++++---
 filter.c   |  2 ++
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/compress.c b/compress.c
index a6c3d32a..dd77de81 100644
--- a/compress.c
+++ b/compress.c
@@ -16,10 +16,13 @@
 #include "sched.h"
 #include "filter.h"
 #include "string.h"
+#include "audiod.h"
 
 /** The size of the output data buffer. */
 #define COMPRESS_CHUNK_SIZE 40960
 
+extern char *stat_item_values[NUM_STAT_ITEMS];
+
 /** Data specific to the compress filter. */
 struct private_compress_data {
 	/** The current multiplier. */
@@ -32,6 +35,8 @@ struct private_compress_data {
 	unsigned num_samples;
 	/** Absolute value of the maximal sample in the current block. */
 	unsigned peak;
+	/** Amplification factor. */
+	unsigned amp;
 };
 
 static ssize_t compress(char *inbuf, size_t inbuf_len, struct filter_node *fn)
@@ -47,10 +52,9 @@ static ssize_t compress(char *inbuf, size_t inbuf_len, struct filter_node *fn)
 		return 0;
 	for (i = 0; i < length / 2; i++) {
 		/* be careful in that heat, my dear */
-		int sample = *ip++, adjusted_sample;
+		int sample = *ip++, adjusted_sample = (PARA_ABS(sample) * (64 + pcd->amp)) >> 6;
 
-		adjusted_sample = (PARA_ABS(sample) * pcd->current_gain)
-			>> gain_shift;
+		adjusted_sample = (adjusted_sample * pcd->current_gain) >> gain_shift;
 		if (unlikely(adjusted_sample > 32767)) { /* clip */
 			PARA_NOTICE_LOG("clip: sample: %d, adjusted sample: %d\n",
 				sample, adjusted_sample);
@@ -102,6 +106,10 @@ static void open_compress(struct filter_node *fn)
 	fn->buf = para_malloc(fn->bufsize);
 	pcd->current_gain = 1 << pcd->conf->inertia_arg;
 	pcd->max_gain = 1 << (pcd->conf->inertia_arg + pcd->conf->aggressiveness_arg);
+	if (stat_item_values[SI_AMPLIFICATION])
+		sscanf(stat_item_values[SI_AMPLIFICATION], "%u", &pcd->amp);
+	PARA_NOTICE_LOG("amplification: %u (scaling factor: %1.2f)\n", pcd->amp,
+		pcd->amp / 64.0 + 1.0);
 }
 
 /**
diff --git a/filter.c b/filter.c
index 939f9b56..bab827d3 100644
--- a/filter.c
+++ b/filter.c
@@ -17,6 +17,8 @@
 #include "stdout.h"
 #include "error.h"
 
+char *stat_item_values[NUM_STAT_ITEMS] = {NULL};
+
 /** Initialize the array of errors for para_filter. */
 INIT_FILTER_ERRLISTS;
 
-- 
2.39.5