diff spandsp-0.0.6pre17/src/spandsp/private/ima_adpcm.h @ 4:26cd8f1ef0b1

import spandsp-0.0.6pre17
author Peter Meerwald <pmeerw@cosy.sbg.ac.at>
date Fri, 25 Jun 2010 15:50:58 +0200
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.6pre17/src/spandsp/private/ima_adpcm.h	Fri Jun 25 15:50:58 2010 +0200
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+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * private/ima_adpcm.c - Conversion routines between linear 16 bit PCM data
+ *		                 and IMA/DVI/Intel ADPCM format.
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2004 Steve Underwood
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Based on a bit from here, a bit from there, eye of toad,
+ * ear of bat, etc - plus, of course, my own 2 cents.
+ *
+ * $Id: ima_adpcm.h,v 1.1 2008/11/30 10:17:31 steveu Exp $
+ */
+
+#if !defined(_SPANDSP_PRIVATE_IMA_ADPCM_H_)
+#define _SPANDSP_PRIVATE_IMA_ADPCM_H_
+
+/*!
+    IMA (DVI/Intel) ADPCM conversion state descriptor. This defines the state of
+    a single working instance of the IMA ADPCM converter. This is used for
+    either linear to ADPCM or ADPCM to linear conversion.
+*/
+struct ima_adpcm_state_s
+{
+    int variant;
+    /*! \brief The size of a chunk, in samples. */
+    int chunk_size;
+    /*! \brief The last state of the ADPCM algorithm. */
+    int last;
+    /*! \brief Current index into the step size table. */
+    int step_index;
+    /*! \brief The current IMA code byte in progress. */
+    uint16_t ima_byte;
+    int bits;
+};
+
+#endif
+/*- End of file ------------------------------------------------------------*/

Repositories maintained by Peter Meerwald, pmeerw@pmeerw.net.