1 /* GStreamer

     2  * Copyright (C) <2007> Sebastian Dröge <slomo@circular-chaos.org>

     3  *

     4  * This library is free software; you can redistribute it and/or

     5  * modify it under the terms of the GNU Library General Public

     6  * License as published by the Free Software Foundation; either

     7  * version 2 of the License, or (at your option) any later version.

     8  *

     9  * This library is distributed in the hope that it will be useful,

    10  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    12  * Library General Public License for more details.

    13  *

    14  * You should have received a copy of the GNU Library General Public

    15  * License along with this library; if not, write to the

    16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

    17  * Boston, MA 02111-1307, USA.

    18  */

    19 

    20 /**

    21  * SECTION:gstfft

    22  * @short_description: General FFT functions and declarations

    23  * 

    24  * This library includes general definitions and functions, useful for

    25  * all typed FFT classes.

    26  *

    27  */

    28 

    29 #include <glib.h>

    30 

    31 #include "gstfft.h"

    32 #include "kiss_fft_s16.h"

    33 

    34 /**

    35  * gst_fft_next_fast_length:

    36  * @n: Number for which the next fast length should be returned

    37  *

    38  * Returns the next number to @n that is entirely a product

    39  * of 2, 3 and 5. Using this as the @len parameter for

    40  * the different GstFFT types will provide the best performance.

    41  *

    42  * Returns: the next fast FFT length.

    43  *

    44  */

    45 #ifdef __SYMBIAN32__

    46 EXPORT_C

    47 #endif

    48 

    49 gint

    50 gst_fft_next_fast_length (gint n)

    51 {

    52   gint half = (n + 1) / 2;

    53 

    54   /* It's the same for all data types so call the s16

    55    * version */

    56 

    57   /* The real FFT needs an even length so calculate that */

    58   return 2 * kiss_fft_s16_next_fast_size (half);

    59 }