@@ -102,6 +102,7 @@ show_help(){

   echo "  --disable-fft            disable FFT code"

   echo "  --disable-golomb         disable Golomb code"

   echo "  --disable-mdct           disable MDCT code"

+  echo "  --disable-rdft           disable RDFT code"

   echo "  --enable-hardcoded-tables use hardcoded tables instead of runtime generation"

   echo "  --enable-memalign-hack   emulate memalign, interferes with memory debuggers"

   echo "  --enable-beos-netserver  enable BeOS netserver"

@@ -781,6 +782,7 @@ CONFIG_LIST="

     nonfree

     postproc

     powerpc_perf

+    rdft

     shared

     small

     static

@@ -29,6 +29,7 @@ OBJS-$(CONFIG_ENCODERS)                += faandct.o jfdctfst.o jfdctint.o

 OBJS-$(CONFIG_FFT)                     += fft.o

 OBJS-$(CONFIG_GOLOMB)                  += golomb.o

 OBJS-$(CONFIG_MDCT)                    += mdct.o

+OBJS-$(CONFIG_RDFT)                    += rdft.o

 OBJS-$(CONFIG_OLDSCALER)               += imgresample.o

 # decoders/encoders

@@ -674,6 +674,8 @@ typedef struct FFTContext {

     void (*imdct_half)(struct MDCTContext *s, FFTSample *output, const FFTSample *input);

 } FFTContext;

+extern FFTSample* ff_cos_tabs[13];

+

 /**

  * Sets up a complex FFT.

  * @param nbits           log2 of the length of the input array

@@ -759,6 +761,35 @@ void ff_imdct_half_sse(MDCTContext *s, FFTSample *output, const FFTSample *input

 void ff_mdct_calc(MDCTContext *s, FFTSample *out, const FFTSample *input);

 void ff_mdct_end(MDCTContext *s);

+/* Real Discrete Fourier Transform */

+

+enum RDFTransformType {

+    RDFT,

+    IRDFT,

+    RIDFT,

+    IRIDFT,

+};

+

+typedef struct {

+    int nbits;

+    int inverse;

+    int sign_convention;

+

+    /* pre/post rotation tables */

+    FFTSample *tcos;

+    FFTSample *tsin;

+    FFTContext fft;

+} RDFTContext;

+

+/**

+ * Sets up a real FFT.

+ * @param nbits           log2 of the length of the input array

+ * @param trans           the type of transform

+ */

+int ff_rdft_init(RDFTContext *s, int nbits, enum RDFTransformType trans);

+void ff_rdft_calc(RDFTContext *s, FFTSample *data);

+void ff_rdft_end(RDFTContext *s);

+

 #define WRAPPER8_16(name8, name16)\

 static int name16(void /*MpegEncContext*/ *s, uint8_t *dst, uint8_t *src, int stride, int h){\

     return name8(s, dst           , src           , stride, h)\

@@ -42,7 +42,7 @@ DECLARE_ALIGNED_16(FFTSample, ff_cos_8192[4096]);

 DECLARE_ALIGNED_16(FFTSample, ff_cos_16384[8192]);

 DECLARE_ALIGNED_16(FFTSample, ff_cos_32768[16384]);

 DECLARE_ALIGNED_16(FFTSample, ff_cos_65536[32768]);

-static FFTSample *ff_cos_tabs[] = {

+FFTSample *ff_cos_tabs[] = {

     ff_cos_16, ff_cos_32, ff_cos_64, ff_cos_128, ff_cos_256, ff_cos_512, ff_cos_1024,

     ff_cos_2048, ff_cos_4096, ff_cos_8192, ff_cos_16384, ff_cos_32768, ff_cos_65536,

 };

new file mode 100644

@@ -0,0 +1,127 @@

+/*

+ * (I)RDFT transforms

+ * Copyright (c) 2009 Alex Converse <alex dot converse at gmail dot com>

+ *

+ * This file is part of FFmpeg.

+ *

+ * FFmpeg is free software; you can redistribute it and/or

+ * modify it under the terms of the GNU Lesser General Public

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

+ * version 2.1 of the License, or (at your option) any later version.

+ *

+ * FFmpeg 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 FFmpeg; if not, write to the Free Software

+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

+ */

+#include <math.h>

+#include "dsputil.h"

+

+/**

+ * @file rdft.c

+ * (Inverse) Real Discrete Fourier Transforms.

+ */

+

+/* sin(2*pi*x/n) for 0<=x<n/4, followed by n/2<=x<3n/4 */

+DECLARE_ALIGNED_16(FFTSample, ff_sin_16[8]);

+DECLARE_ALIGNED_16(FFTSample, ff_sin_32[16]);

+DECLARE_ALIGNED_16(FFTSample, ff_sin_64[32]);

+DECLARE_ALIGNED_16(FFTSample, ff_sin_128[64]);

+DECLARE_ALIGNED_16(FFTSample, ff_sin_256[128]);

+DECLARE_ALIGNED_16(FFTSample, ff_sin_512[256]);

+DECLARE_ALIGNED_16(FFTSample, ff_sin_1024[512]);

+DECLARE_ALIGNED_16(FFTSample, ff_sin_2048[1024]);

+DECLARE_ALIGNED_16(FFTSample, ff_sin_4096[2048]);

+DECLARE_ALIGNED_16(FFTSample, ff_sin_8192[4096]);

+DECLARE_ALIGNED_16(FFTSample, ff_sin_16384[8192]);

+DECLARE_ALIGNED_16(FFTSample, ff_sin_32768[16384]);

+DECLARE_ALIGNED_16(FFTSample, ff_sin_65536[32768]);

+FFTSample *ff_sin_tabs[] = {

+    ff_sin_16, ff_sin_32, ff_sin_64, ff_sin_128, ff_sin_256, ff_sin_512, ff_sin_1024,

+    ff_sin_2048, ff_sin_4096, ff_sin_8192, ff_sin_16384, ff_sin_32768, ff_sin_65536,

+};

+

+av_cold int ff_rdft_init(RDFTContext *s, int nbits, enum RDFTransformType trans)

+{

+    int n = 1 << nbits;

+    int i;

+    const double theta = (trans == RDFT || trans == IRIDFT ? -1 : 1)*2*M_PI/n;

+

+    s->nbits           = nbits;

+    s->inverse         = trans == IRDFT || trans == IRIDFT;

+    s->sign_convention = trans == RIDFT || trans == IRIDFT ? 1 : -1;

+

+    if (nbits < 4 || nbits > 16)

+        return -1;

+

+    if (ff_fft_init(&s->fft, nbits-1, trans == IRDFT || trans == RIDFT) < 0)

+        return -1;

+

+    s->tcos = ff_cos_tabs[nbits-4];

+    s->tsin = ff_sin_tabs[nbits-4]+(trans == RDFT || trans == IRIDFT)*(n>>2);

+    for (i = 0; i < (n>>2); i++) {

+        s->tcos[i] = cos(i*theta);

+        s->tsin[i] = sin(i*theta);

+    }

+    return 0;

+}

+

+/** Map one real FFT into two parallel real even and odd FFTs. Then interleave

+ * the two real FFTs into one complex FFT. Unmangle the results.

+ * ref: http://www.engineeringproductivitytools.com/stuff/T0001/PT10.HTM

+ */

+void ff_rdft_calc_c(RDFTContext* s, FFTSample* data)

+{

+    int i, i1, i2;

+    FFTComplex ev, od;

+    const int n = 1 << s->nbits;

+    const float k1 = 0.5;

+    const float k2 = 0.5 - s->inverse;

+    const FFTSample *tcos = s->tcos;

+    const FFTSample *tsin = s->tsin;

+

+    if (!s->inverse) {

+        ff_fft_permute(&s->fft, (FFTComplex*)data);

+        ff_fft_calc(&s->fft, (FFTComplex*)data);

+    }

+    /* i=0 is a special case because of packing, the DC term is real, so we

+       are going to throw the N/2 term (also real) in with it. */

+    ev.re = data[0];

+    data[0] = ev.re+data[1];

+    data[1] = ev.re-data[1];

+    for (i = 1; i < (n>>2); i++) {

+        i1 = 2*i;

+        i2 = n-i1;

+        /* Separate even and odd FFTs */

+        ev.re =  k1*(data[i1  ]+data[i2  ]);

+        od.im = -k2*(data[i1  ]-data[i2  ]);

+        ev.im =  k1*(data[i1+1]-data[i2+1]);

+        od.re =  k2*(data[i1+1]+data[i2+1]);

+        /* Apply twiddle factors to the odd FFT and add to the even FFT */

+        data[i1  ] =  ev.re + od.re*tcos[i] - od.im*tsin[i];

+        data[i1+1] =  ev.im + od.im*tcos[i] + od.re*tsin[i];

+        data[i2  ] =  ev.re - od.re*tcos[i] + od.im*tsin[i];

+        data[i2+1] = -ev.im + od.im*tcos[i] + od.re*tsin[i];

+    }

+    data[2*i+1]=s->sign_convention*data[2*i+1];

+    if (s->inverse) {

+        data[0] *= k1;

+        data[1] *= k1;

+        ff_fft_permute(&s->fft, (FFTComplex*)data);

+        ff_fft_calc(&s->fft, (FFTComplex*)data);

+    }

+}

+

+void ff_rdft_calc(RDFTContext *s, FFTSample *data)

+{

+    ff_rdft_calc_c(s, data);

+}

+

+av_cold void ff_rdft_end(RDFTContext *s)

+{

+    ff_fft_end(&s->fft);

+}