[FFmpeg-cvslog] r21338 - in trunk: configure libavcodec/Makefile libavcodec/dct.c libavcodec/dsputil.h libavcodec/fft-test.c
vitor
subversion
Wed Jan 20 01:39:47 CET 2010
Author: vitor
Date: Wed Jan 20 01:39:47 2010
New Revision: 21338
Log:
Floating point discrete cosine transform
Added:
trunk/libavcodec/dct.c
Modified:
trunk/configure
trunk/libavcodec/Makefile
trunk/libavcodec/dsputil.h
trunk/libavcodec/fft-test.c
Modified: trunk/configure
==============================================================================
--- trunk/configure Wed Jan 20 01:34:10 2010 (r21337)
+++ trunk/configure Wed Jan 20 01:39:47 2010 (r21338)
@@ -99,6 +99,7 @@ Configuration options:
--disable-fastdiv disable table-based division
--enable-small optimize for size instead of speed
--disable-aandct disable AAN DCT code
+ --disable-dct disable DCT code
--disable-fft disable FFT code
--disable-golomb disable Golomb code
--disable-lpc disable LPC code
@@ -862,6 +863,7 @@ CONFIG_LIST="
avisynth
beos_netserver
bzlib
+ dct
doc
fastdiv
ffmpeg
Modified: trunk/libavcodec/Makefile
==============================================================================
--- trunk/libavcodec/Makefile Wed Jan 20 01:34:10 2010 (r21337)
+++ trunk/libavcodec/Makefile Wed Jan 20 01:39:47 2010 (r21338)
@@ -27,6 +27,7 @@ OBJS = allcodecs.o
# parts needed for many different codecs
OBJS-$(CONFIG_AANDCT) += aandcttab.o
OBJS-$(CONFIG_ENCODERS) += faandct.o jfdctfst.o jfdctint.o
+OBJS-$(CONFIG_DCT) += dct.o
FFT-OBJS-$(CONFIG_HARDCODED_TABLES) += cos_tables.o
OBJS-$(CONFIG_FFT) += fft.o $(FFT-OBJS-yes)
OBJS-$(CONFIG_GOLOMB) += golomb.o
Added: trunk/libavcodec/dct.c
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ trunk/libavcodec/dct.c Wed Jan 20 01:39:47 2010 (r21338)
@@ -0,0 +1,139 @@
+/*
+ * (I)DCT Transforms
+ * Copyright (c) 2009 Peter Ross <pross at xvid.org>
+ * Copyright (c) 2010 Alex Converse <alex.converse at gmail.com>
+ * Copyright (c) 2010 Vitor Sessak
+ *
+ * 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 St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file libavcodec/dct.c
+ * (Inverse) Discrete Cosine Transforms. These are also known as the
+ * type II and type III DCTs respectively.
+ */
+
+#include <math.h>
+#include "dsputil.h"
+
+av_cold int ff_dct_init(DCTContext *s, int nbits, int inverse)
+{
+ int n = 1 << nbits;
+ int i;
+
+ s->nbits = nbits;
+ s->inverse = inverse;
+
+ ff_init_ff_cos_tabs(nbits+2);
+
+ s->costab = ff_cos_tabs[nbits+2];
+
+ s->csc2 = av_malloc(n/2 * sizeof(FFTSample));
+
+ if (ff_rdft_init(&s->rdft, nbits, inverse) < 0) {
+ av_free(s->csc2);
+ return -1;
+ }
+
+ for (i = 0; i < n/2; i++)
+ s->csc2[i] = 0.5 / sin((M_PI / (2*n) * (2*i + 1)));
+
+ return 0;
+}
+
+/* sin((M_PI * x / (2*n)) */
+#define SIN(s,n,x) (s->costab[(n) - (x)])
+
+/* cos((M_PI * x / (2*n)) */
+#define COS(s,n,x) (s->costab[x])
+
+static void ff_dct_calc_c(DCTContext *ctx, FFTSample *data)
+{
+ int n = 1 << ctx->nbits;
+ int i;
+
+ if (ctx->inverse) {
+ float next = data[n - 1];
+ float inv_n = 1.0f / n;
+
+ for (i = n - 2; i >= 2; i -= 2) {
+ float val1 = data[i ];
+ float val2 = data[i - 1] - data[i + 1];
+ float c = COS(ctx, n, i);
+ float s = SIN(ctx, n, i);
+
+ data[i ] = c * val1 + s * val2;
+ data[i + 1] = s * val1 - c * val2;
+ }
+
+ data[1] = 2 * next;
+
+ ff_rdft_calc(&ctx->rdft, data);
+
+ for (i = 0; i < n / 2; i++) {
+ float tmp1 = data[i ] * inv_n;
+ float tmp2 = data[n - i - 1] * inv_n;
+ float csc = ctx->csc2[i] * (tmp1 - tmp2);
+
+ tmp1 += tmp2;
+ data[i ] = tmp1 + csc;
+ data[n - i - 1] = tmp1 - csc;
+ }
+ } else {
+ float next;
+ for (i=0; i < n/2; i++) {
+ float tmp1 = data[i ];
+ float tmp2 = data[n - i - 1];
+ float s = SIN(ctx, n, 2*i + 1);
+
+ s *= tmp1 - tmp2;
+ tmp1 = (tmp1 + tmp2) * 0.5f;
+
+ data[i ] = tmp1 + s;
+ data[n-i-1] = tmp1 - s;
+ }
+
+ ff_rdft_calc(&ctx->rdft, data);
+
+ next = data[1] * 0.5;
+ data[1] *= -1;
+
+ for (i = n - 2; i >= 0; i -= 2) {
+ float inr = data[i ];
+ float ini = data[i + 1];
+ float c = COS(ctx, n, i);
+ float s = SIN(ctx, n, i);
+
+ data[i ] = c * inr + s * ini;
+
+ data[i+1] = next;
+
+ next += s * inr - c * ini;
+ }
+ }
+}
+
+void ff_dct_calc(DCTContext *s, FFTSample *data)
+{
+ ff_dct_calc_c(s, data);
+}
+
+av_cold void ff_dct_end(DCTContext *s)
+{
+ ff_rdft_end(&s->rdft);
+ av_free(s->csc2);
+}
Modified: trunk/libavcodec/dsputil.h
==============================================================================
--- trunk/libavcodec/dsputil.h Wed Jan 20 01:34:10 2010 (r21337)
+++ trunk/libavcodec/dsputil.h Wed Jan 20 01:39:47 2010 (r21338)
@@ -899,6 +899,26 @@ int ff_rdft_init(RDFTContext *s, int nbi
void ff_rdft_calc(RDFTContext *s, FFTSample *data);
void ff_rdft_end(RDFTContext *s);
+/* Discrete Cosine Transform */
+
+typedef struct {
+ int nbits;
+ int inverse;
+ FFTSample *data;
+ RDFTContext rdft;
+ const float *costab;
+ FFTSample *csc2;
+} DCTContext;
+
+/**
+ * Sets up (Inverse)DCT.
+ * @param nbits log2 of the length of the input array
+ * @param inverse >0 forward transform, <0 inverse transform
+ */
+int ff_dct_init(DCTContext *s, int nbits, int inverse);
+void ff_dct_calc(DCTContext *s, FFTSample *data);
+void ff_dct_end (DCTContext *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)\
Modified: trunk/libavcodec/fft-test.c
==============================================================================
--- trunk/libavcodec/fft-test.c Wed Jan 20 01:34:10 2010 (r21337)
+++ trunk/libavcodec/fft-test.c Wed Jan 20 01:39:47 2010 (r21338)
@@ -128,6 +128,39 @@ static void mdct_ref(float *output, floa
}
}
+static void idct_ref(float *output, float *input, int nbits)
+{
+ int n = 1<<nbits;
+ int k, i;
+ double a, s;
+
+ /* do it by hand */
+ for (i = 0; i < n; i++) {
+ s = 0.5 * input[0];
+ for (k = 1; k < n; k++) {
+ a = M_PI*k*(i+0.5) / n;
+ s += input[k] * cos(a);
+ }
+ output[i] = 2 * s / n;
+ }
+}
+static void dct_ref(float *output, float *input, int nbits)
+{
+ int n = 1<<nbits;
+ int k, i;
+ double a, s;
+
+ /* do it by hand */
+ for (k = 0; k < n; k++) {
+ s = 0;
+ for (i = 0; i < n; i++) {
+ a = M_PI*k*(i+0.5) / n;
+ s += input[i] * cos(a);
+ }
+ output[k] = s;
+ }
+}
+
static float frandom(AVLFG *prng)
{
@@ -166,6 +199,7 @@ static void help(void)
"-h print this help\n"
"-s speed test\n"
"-m (I)MDCT test\n"
+ "-d (I)DCT test\n"
"-i inverse transform test\n"
"-n b set the transform size to 2^b\n"
"-f x set scale factor for output data of (I)MDCT to x\n"
@@ -177,6 +211,7 @@ enum tf_transform {
TRANSFORM_FFT,
TRANSFORM_MDCT,
TRANSFORM_RDFT,
+ TRANSFORM_DCT,
};
int main(int argc, char **argv)
@@ -190,6 +225,7 @@ int main(int argc, char **argv)
FFTContext s1, *s = &s1;
FFTContext m1, *m = &m1;
RDFTContext r1, *r = &r1;
+ DCTContext d1, *d = &d1;
int fft_nbits, fft_size, fft_size_2;
double scale = 1.0;
AVLFG prng;
@@ -197,7 +233,7 @@ int main(int argc, char **argv)
fft_nbits = 9;
for(;;) {
- c = getopt(argc, argv, "hsimrn:f:");
+ c = getopt(argc, argv, "hsimrdn:f:");
if (c == -1)
break;
switch(c) {
@@ -216,6 +252,9 @@ int main(int argc, char **argv)
case 'r':
transform = TRANSFORM_RDFT;
break;
+ case 'd':
+ transform = TRANSFORM_DCT;
+ break;
case 'n':
fft_nbits = atoi(optarg);
break;
@@ -257,6 +296,13 @@ int main(int argc, char **argv)
ff_rdft_init(r, fft_nbits, do_inverse ? IRDFT : RDFT);
fft_ref_init(fft_nbits, do_inverse);
break;
+ case TRANSFORM_DCT:
+ if (do_inverse)
+ av_log(NULL, AV_LOG_INFO,"IDCT");
+ else
+ av_log(NULL, AV_LOG_INFO,"DCT");
+ ff_dct_init(d, fft_nbits, do_inverse);
+ break;
}
av_log(NULL, AV_LOG_INFO," %d test\n", fft_size);
@@ -321,6 +367,17 @@ int main(int argc, char **argv)
tab_ref[0].im = tab_ref[fft_size_2].re;
check_diff((float *)tab_ref, (float *)tab2, fft_size, 1.0);
}
+ break;
+ case TRANSFORM_DCT:
+ memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
+ ff_dct_calc(d, tab);
+ if (do_inverse) {
+ idct_ref(tab_ref, tab1, fft_nbits);
+ } else {
+ dct_ref(tab_ref, tab1, fft_nbits);
+ }
+ check_diff((float *)tab_ref, (float *)tab, fft_size, 1.0);
+ break;
}
/* do a speed test */
@@ -351,6 +408,10 @@ int main(int argc, char **argv)
memcpy(tab2, tab1, fft_size * sizeof(FFTSample));
ff_rdft_calc(r, tab2);
break;
+ case TRANSFORM_DCT:
+ memcpy(tab2, tab1, fft_size * sizeof(FFTSample));
+ ff_dct_calc(d, tab2);
+ break;
}
}
duration = gettime() - time_start;
@@ -374,6 +435,9 @@ int main(int argc, char **argv)
case TRANSFORM_RDFT:
ff_rdft_end(r);
break;
+ case TRANSFORM_DCT:
+ ff_dct_end(d);
+ break;
}
return 0;
}
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