From a8cc6a74547e6485f3aa9fe597f5d1dc176cca8a Mon Sep 17 00:00:00 2001
From: Thom Johansen <thomj@rockbox.org>
Date: Sun, 29 Jan 2006 02:10:28 +0000
Subject: Initial multi-band EQ support for software codec platforms. Now go
 start making that user interface!

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@8478 a1c6a512-1295-4272-9138-f99709370657
---
 apps/eq.h | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 apps/eq.h

(limited to 'apps/eq.h')

diff --git a/apps/eq.h b/apps/eq.h
new file mode 100644
index 0000000..f761638
--- /dev/null
+++ b/apps/eq.h
@@ -0,0 +1,41 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2006 Thom Johansen
+ *
+ * All files in this archive are subject to the GNU General Public License.
+ * See the file COPYING in the source tree root for full license agreement.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#ifndef _EQ_H
+#define _EQ_H
+
+/* These depend on the fixed point formats used by the different filter types
+   and need to be changed when they change.
+ */
+#define EQ_PEAK_SHIFT 3
+#define EQ_SHELF_SHIFT 7
+
+struct eqfilter {
+    long coefs[5];        /* Order is b0, b1, b2, a1, a2 */
+    long history[2][4];
+};
+
+void eq_pk_coefs(unsigned long cutoff, unsigned long Q, long db, long *c);
+void eq_ls_coefs(unsigned long cutoff, unsigned long Q, long db, long *c);
+void eq_hs_coefs(unsigned long cutoff, unsigned long Q, long db, long *c);
+void eq_filter(long **x, struct eqfilter *f, unsigned num,
+               unsigned samples, unsigned shift);
+
+#endif
+
-- 
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