/* ** Copyright (C) 2001-2013 Erik de Castro Lopo ** ** 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 #include /* Include this header file to use functions from libsndfile. */ #include /* 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 struct 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" ; /* The SF_INFO struct must be initialized before using it. */ memset (&sfinfo, 0, sizeof (sfinfo)) ; /* 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 */