comparison src/libsndfile-1.0.25/examples/sfprocess.c @ 0:c7265573341e

Import initial set of sources

+/*
+** Copyright (C) 2001-2011 Erik de Castro Lopo <[e-mail]>
+**
+** All rights reserved.
+**
+** Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**
+**     * Redistributions of source code must retain the above copyright
+**       notice, this list of conditions and the following disclaimer.
+**     * Redistributions in binary form must reproduce the above copyright
+**       notice, this list of conditions and the following disclaimer in
+**       the documentation and/or other materials provided with the
+**       distribution.
+**     * Neither the author nor the names of any contributors may be used
+**       to endorse or promote products derived from this software without
+**       specific prior written permission.
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+** TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+** PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+** CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+** EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+** PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+** OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+** WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+** OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+** ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include	<stdio.h>
+
+/* Include this header file to use functions from libsndfile. */
+#include	<sndfile.h>
+
+/*    This will be the length of the buffer used to hold.frames while
+**    we process them.
+*/
+#define		BUFFER_LEN	1024
+
+/* libsndfile can handle more than 6 channels but we'll restrict it to 6. */
+#define		MAX_CHANNELS	6
+
+/* Function prototype. */
+static void process_data (double *data, int count, int channels) ;
+
+
+int
+main (void)
+{   /* This is a buffer of double precision floating point values
+    ** which will hold our data while we process it.
+    */
+    static double data [BUFFER_LEN] ;
+
+    /* A SNDFILE is very much like a FILE in the Standard C library. The
+    ** sf_open function return an SNDFILE* pointer when they sucessfully
+	** open the specified file.
+    */
+    SNDFILE      *infile, *outfile ;
+
+    /* A pointer to an SF_INFO stutct is passed to sf_open.
+    ** On read, the library fills this struct with information about the file.
+    ** On write, the struct must be filled in before calling sf_open.
+    */
+    SF_INFO		sfinfo ;
+    int			readcount ;
+    const char	*infilename = "input.wav" ;
+    const char	*outfilename = "output.wav" ;
+
+    /* Here's where we open the input file. We pass sf_open the file name and
+    ** a pointer to an SF_INFO struct.
+    ** On successful open, sf_open returns a SNDFILE* pointer which is used
+    ** for all subsequent operations on that file.
+    ** If an error occurs during sf_open, the function returns a NULL pointer.
+	**
+	** If you are trying to open a raw headerless file you will need to set the
+	** format and channels fields of sfinfo before calling sf_open(). For
+	** instance to open a raw 16 bit stereo PCM file you would need the following
+	** two lines:
+	**
+	**		sfinfo.format   = SF_FORMAT_RAW | SF_FORMAT_PCM_16 ;
+	**		sfinfo.channels = 2 ;
+    */
+    if (! (infile = sf_open (infilename, SFM_READ, &sfinfo)))
+    {   /* Open failed so print an error message. */
+        printf ("Not able to open input file %s.\n", infilename) ;
+        /* Print the error message from libsndfile. */
+        puts (sf_strerror (NULL)) ;
+        return  1 ;
+        } ;
+
+    if (sfinfo.channels > MAX_CHANNELS)
+    {   printf ("Not able to process more than %d channels\n", MAX_CHANNELS) ;
+        return  1 ;
+        } ;
+    /* Open the output file. */
+    if (! (outfile = sf_open (outfilename, SFM_WRITE, &sfinfo)))
+    {   printf ("Not able to open output file %s.\n", outfilename) ;
+        puts (sf_strerror (NULL)) ;
+        return  1 ;
+        } ;
+
+    /* While there are.frames in the input file, read them, process
+    ** them and write them to the output file.
+    */
+    while ((readcount = sf_read_double (infile, data, BUFFER_LEN)))
+    {   process_data (data, readcount, sfinfo.channels) ;
+        sf_write_double (outfile, data, readcount) ;
+        } ;
+
+    /* Close input and output files. */
+    sf_close (infile) ;
+    sf_close (outfile) ;
+
+    return 0 ;
+} /* main */
+
+static void
+process_data (double *data, int count, int channels)
+{	double channel_gain [MAX_CHANNELS] = { 0.5, 0.8, 0.1, 0.4, 0.4, 0.9 } ;
+    int k, chan ;
+
+    /* Process the data here.
+    ** If the soundfile contains more then 1 channel you need to take care of
+    ** the data interleaving youself.
+    ** Current we just apply a channel dependant gain.
+    */
+
+    for (chan = 0 ; chan < channels ; chan ++)
+        for (k = chan ; k < count ; k+= channels)
+            data [k] *= channel_gain [chan] ;
+
+    return ;
+} /* process_data */
+