X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=compress.c;h=a6c3d32a18990719f454c971a1ead2de46659e0e;hp=337230106c2aa559d57961daeeea6659fce58cc1;hb=74097b7a166823e4eeadfb8b180abdc294cdb633;hpb=471684761a2039bbc89aa1e3c33c62de6bef86cf

diff --git a/compress.c b/compress.c
index 33723010..a6c3d32a 100644
--- a/compress.c
+++ b/compress.c
@@ -1,13 +1,13 @@
 /*
- * Copyright (C) 2005-2007 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005-2008 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
 
-/** \file compress.c paraslash's dynamic audio range compressor */
+/** \file compress.c Paraslash's dynamic audio range compressor. */
 
 /*
- * Used ideas of AudioCompress, (C) 2002-2004  M. Hari Nezumi <magenta@trikuare.cx>
+ * Uses ideas of AudioCompress, (C) 2002-2004  M. Hari Nezumi <magenta@trikuare.cx>
  */
 
 #include "para.h"
@@ -17,22 +17,20 @@
 #include "filter.h"
 #include "string.h"
 
-/** the size of the output data buffer */
+/** The size of the output data buffer. */
 #define COMPRESS_CHUNK_SIZE 40960
 
-/** data specific to the compress filter */
+/** Data specific to the compress filter. */
 struct private_compress_data {
-	/** the current multiplier */
+	/** The current multiplier. */
 	unsigned current_gain;
-	/** points to the configuration data for this instance of the compress filter */
+	/** Points to the configuration data for this instance of the compress filter. */
 	struct compress_filter_args_info *conf;
-	/** minimal admissible gain */
-	unsigned min_gain;
-	/** maximal admissible gain */
+	/** Maximal admissible gain. */
 	unsigned max_gain;
-	/** number of samples already seen */
+	/** Number of samples already seen. */
 	unsigned num_samples;
-	/** absolute value of the maximal sample in the current block */
+	/** Absolute value of the maximal sample in the current block. */
 	unsigned peak;
 };
 
@@ -51,43 +49,29 @@ static ssize_t compress(char *inbuf, size_t inbuf_len, struct filter_node *fn)
 		/* be careful in that heat, my dear */
 		int sample = *ip++, adjusted_sample;
 
-		if (sample > 0) {
-			adjusted_sample = (sample * pcd->current_gain)
-				>> gain_shift;
-			if (unlikely(adjusted_sample > 32767)) {
-				adjusted_sample = 32767;
-				pcd->current_gain = (3 * pcd->current_gain +
-					(1 << pcd->conf->inertia_arg)) / 4;
-				pcd->peak = 0;
-			} else
-				if (adjusted_sample > pcd->peak)
-					pcd->peak = adjusted_sample;
-		} else {
-			adjusted_sample = -((-sample * pcd->current_gain)
-				>> gain_shift);
-			if (unlikely(adjusted_sample < -32768)) {
-				adjusted_sample = -32768;
-				pcd->current_gain = (3 * pcd->current_gain +
-					(1 << pcd->conf->inertia_arg)) / 4;
-				pcd->peak = 0;
-			} else
-				if (-adjusted_sample > pcd->peak)
-					pcd->peak = -adjusted_sample;
-		}
-		*op++ = adjusted_sample;
+		adjusted_sample = (PARA_ABS(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);
+			adjusted_sample = 32767;
+			pcd->current_gain = (3 * pcd->current_gain +
+				(1 << pcd->conf->inertia_arg)) / 4;
+			pcd->peak = 0;
+		} else
+			pcd->peak = PARA_MAX(pcd->peak, adjusted_sample);
+		*op++ = sample >= 0? adjusted_sample : -adjusted_sample;
 		if (likely(++pcd->num_samples & mask))
 			continue;
+//		PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain,
+//			pcd->peak);
 		if (pcd->peak < pcd->conf->target_level_arg) {
 			if (pcd->current_gain < pcd->max_gain)
 				pcd->current_gain++;
-		} else {
-			if (pcd->current_gain > pcd->min_gain + 1)
-				pcd->current_gain -= 2;
-		}
-//		PARA_DEBUG_LOG("gain: %lu, peak: %d\n", pcd->current_gain,
-//			pcd->peak);
+		} else
+			pcd->current_gain = PARA_MAX(pcd->current_gain - 2,
+				1 << pcd->conf->inertia_arg);
 		pcd->peak = 0;
-//		PARA_INFO_LOG("sample: %lu\n", ABS(sample));
 	}
 	fn->loaded += length;
 	return length;
@@ -117,14 +101,13 @@ static void open_compress(struct filter_node *fn)
 	fn->bufsize = COMPRESS_CHUNK_SIZE;
 	fn->buf = para_malloc(fn->bufsize);
 	pcd->current_gain = 1 << pcd->conf->inertia_arg;
-	pcd->min_gain = 1 << (pcd->conf->inertia_arg - pcd->conf->aggressiveness_arg);
 	pcd->max_gain = 1 << (pcd->conf->inertia_arg + pcd->conf->aggressiveness_arg);
 }
 
 /**
- * the init function of the compress filter
+ * The init function of the compress filter.
  *
- * \param f pointer to the struct to initialize
+ * \param f Pointer to the struct to initialize.
  */
 void compress_init(struct filter *f)
 {