[FFmpeg-cvslog] ac3enc: use generic fixed-point mdct
Mans Rullgard
git at videolan.org
Mon Apr 4 03:01:16 CEST 2011
ffmpeg | branch: master | Mans Rullgard <mans at mansr.com> | Mon Mar 21 18:07:59 2011 +0000| [79997def65fd2313b48a5f3c3a884c6149ae9b5d] | committer: Mans Rullgard
ac3enc: use generic fixed-point mdct
This makes the AC3 encoder use the shared fixed-point MDCT rather
than its own implementation. The checksum changes are due to
different rounding in the MDCT.
Signed-off-by: Mans Rullgard <mans at mansr.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=79997def65fd2313b48a5f3c3a884c6149ae9b5d
---
libavcodec/ac3enc.c | 26 +++--
libavcodec/ac3enc_fixed.c | 298 +-------------------------------------------
libavcodec/ac3enc_fixed.h | 61 ---------
libavcodec/ac3enc_float.c | 11 --
libavcodec/ac3enc_float.h | 47 -------
tests/ref/acodec/ac3_fixed | 2 +-
tests/ref/lavf/rm | 2 +-
7 files changed, 23 insertions(+), 424 deletions(-)
diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c
index a869d7d..372f019 100644
--- a/libavcodec/ac3enc.c
+++ b/libavcodec/ac3enc.c
@@ -29,6 +29,8 @@
//#define DEBUG
//#define ASSERT_LEVEL 2
+#include <stdint.h>
+
#include "libavutil/audioconvert.h"
#include "libavutil/avassert.h"
#include "libavutil/crc.h"
@@ -39,6 +41,7 @@
#include "ac3dsp.h"
#include "ac3.h"
#include "audioconvert.h"
+#include "fft.h"
#ifndef CONFIG_AC3ENC_FLOAT
@@ -55,16 +58,22 @@
#define AC3_REMATRIXING_NONE 1
#define AC3_REMATRIXING_ALWAYS 3
-/** Scale a float value by 2^bits and convert to an integer. */
-#define SCALE_FLOAT(a, bits) lrintf((a) * (float)(1 << (bits)))
-
-
#if CONFIG_AC3ENC_FLOAT
-#include "ac3enc_float.h"
+#define MAC_COEF(d,a,b) ((d)+=(a)*(b))
+typedef float SampleType;
+typedef float CoefType;
+typedef float CoefSumType;
#else
-#include "ac3enc_fixed.h"
+#define MAC_COEF(d,a,b) MAC64(d,a,b)
+typedef int16_t SampleType;
+typedef int32_t CoefType;
+typedef int64_t CoefSumType;
#endif
+typedef struct AC3MDCTContext {
+ const SampleType *window; ///< MDCT window function
+ FFTContext fft; ///< FFT context for MDCT calculation
+} AC3MDCTContext;
/**
* Encoding Options used by AVOption.
@@ -279,8 +288,6 @@ static av_cold void mdct_end(AC3MDCTContext *mdct);
static av_cold int mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct,
int nbits);
-static void mdct512(AC3MDCTContext *mdct, CoefType *out, SampleType *in);
-
static void apply_window(DSPContext *dsp, SampleType *output, const SampleType *input,
const SampleType *window, unsigned int len);
@@ -386,7 +393,8 @@ static void apply_mdct(AC3EncodeContext *s)
block->coeff_shift[ch] = normalize_samples(s);
- mdct512(&s->mdct, block->mdct_coef[ch], s->windowed_samples);
+ s->mdct.fft.mdct_calcw(&s->mdct.fft, block->mdct_coef[ch],
+ s->windowed_samples);
}
}
}
diff --git a/libavcodec/ac3enc_fixed.c b/libavcodec/ac3enc_fixed.c
index 967c7f0..720d87d 100644
--- a/libavcodec/ac3enc_fixed.c
+++ b/libavcodec/ac3enc_fixed.c
@@ -26,54 +26,17 @@
* fixed-point AC-3 encoder.
*/
+#define CONFIG_FFT_FLOAT 0
#undef CONFIG_AC3ENC_FLOAT
#include "ac3enc.c"
-/** Scale a float value by 2^15, convert to an integer, and clip to range -32767..32767. */
-#define FIX15(a) av_clip(SCALE_FLOAT(a, 15), -32767, 32767)
-
-
/**
* Finalize MDCT and free allocated memory.
*/
static av_cold void mdct_end(AC3MDCTContext *mdct)
{
- mdct->nbits = 0;
- av_freep(&mdct->costab);
- av_freep(&mdct->sintab);
- av_freep(&mdct->xcos1);
- av_freep(&mdct->xsin1);
- av_freep(&mdct->rot_tmp);
- av_freep(&mdct->cplx_tmp);
-}
-
-
-/**
- * Initialize FFT tables.
- * @param ln log2(FFT size)
- */
-static av_cold int fft_init(AVCodecContext *avctx, AC3MDCTContext *mdct, int ln)
-{
- int i, n, n2;
- float alpha;
-
- n = 1 << ln;
- n2 = n >> 1;
-
- FF_ALLOC_OR_GOTO(avctx, mdct->costab, n2 * sizeof(*mdct->costab), fft_alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, mdct->sintab, n2 * sizeof(*mdct->sintab), fft_alloc_fail);
-
- for (i = 0; i < n2; i++) {
- alpha = 2.0 * M_PI * i / n;
- mdct->costab[i] = FIX15(cos(alpha));
- mdct->sintab[i] = FIX15(sin(alpha));
- }
-
- return 0;
-fft_alloc_fail:
- mdct_end(mdct);
- return AVERROR(ENOMEM);
+ ff_fft_end(&mdct->fft);
}
@@ -84,167 +47,9 @@ fft_alloc_fail:
static av_cold int mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct,
int nbits)
{
- int i, n, n4, ret;
-
- n = 1 << nbits;
- n4 = n >> 2;
-
- mdct->nbits = nbits;
-
- ret = fft_init(avctx, mdct, nbits - 2);
- if (ret)
- return ret;
-
+ int ret = ff_mdct_init(&mdct->fft, nbits, 0, 1.0);
mdct->window = ff_ac3_window;
-
- FF_ALLOC_OR_GOTO(avctx, mdct->xcos1, n4 * sizeof(*mdct->xcos1), mdct_alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, mdct->xsin1, n4 * sizeof(*mdct->xsin1), mdct_alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, mdct->rot_tmp, n * sizeof(*mdct->rot_tmp), mdct_alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, mdct->cplx_tmp, n4 * sizeof(*mdct->cplx_tmp), mdct_alloc_fail);
-
- for (i = 0; i < n4; i++) {
- float alpha = 2.0 * M_PI * (i + 1.0 / 8.0) / n;
- mdct->xcos1[i] = FIX15(-cos(alpha));
- mdct->xsin1[i] = FIX15(-sin(alpha));
- }
-
- return 0;
-mdct_alloc_fail:
- mdct_end(mdct);
- return AVERROR(ENOMEM);
-}
-
-
-/** Butterfly op */
-#define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
-{ \
- int ax, ay, bx, by; \
- bx = pre1; \
- by = pim1; \
- ax = qre1; \
- ay = qim1; \
- pre = (bx + ax) >> 1; \
- pim = (by + ay) >> 1; \
- qre = (bx - ax) >> 1; \
- qim = (by - ay) >> 1; \
-}
-
-
-/** Complex multiply */
-#define CMUL(pre, pim, are, aim, bre, bim, rshift) \
-{ \
- pre = (MUL16(are, bre) - MUL16(aim, bim)) >> rshift; \
- pim = (MUL16(are, bim) + MUL16(bre, aim)) >> rshift; \
-}
-
-
-/**
- * Calculate a 2^n point complex FFT on 2^ln points.
- * @param z complex input/output samples
- * @param ln log2(FFT size)
- */
-static void fft(AC3MDCTContext *mdct, IComplex *z, int ln)
-{
- int j, l, np, np2;
- int nblocks, nloops;
- register IComplex *p,*q;
- int tmp_re, tmp_im;
-
- np = 1 << ln;
-
- /* reverse */
- for (j = 0; j < np; j++) {
- int k = av_reverse[j] >> (8 - ln);
- if (k < j)
- FFSWAP(IComplex, z[k], z[j]);
- }
-
- /* pass 0 */
-
- p = &z[0];
- j = np >> 1;
- do {
- BF(p[0].re, p[0].im, p[1].re, p[1].im,
- p[0].re, p[0].im, p[1].re, p[1].im);
- p += 2;
- } while (--j);
-
- /* pass 1 */
-
- p = &z[0];
- j = np >> 2;
- do {
- BF(p[0].re, p[0].im, p[2].re, p[2].im,
- p[0].re, p[0].im, p[2].re, p[2].im);
- BF(p[1].re, p[1].im, p[3].re, p[3].im,
- p[1].re, p[1].im, p[3].im, -p[3].re);
- p+=4;
- } while (--j);
-
- /* pass 2 .. ln-1 */
-
- nblocks = np >> 3;
- nloops = 1 << 2;
- np2 = np >> 1;
- do {
- p = z;
- q = z + nloops;
- for (j = 0; j < nblocks; j++) {
- BF(p->re, p->im, q->re, q->im,
- p->re, p->im, q->re, q->im);
- p++;
- q++;
- for(l = nblocks; l < np2; l += nblocks) {
- CMUL(tmp_re, tmp_im, mdct->costab[l], -mdct->sintab[l], q->re, q->im, 15);
- BF(p->re, p->im, q->re, q->im,
- p->re, p->im, tmp_re, tmp_im);
- p++;
- q++;
- }
- p += nloops;
- q += nloops;
- }
- nblocks = nblocks >> 1;
- nloops = nloops << 1;
- } while (nblocks);
-}
-
-
-/**
- * Calculate a 512-point MDCT
- * @param out 256 output frequency coefficients
- * @param in 512 windowed input audio samples
- */
-static void mdct512(AC3MDCTContext *mdct, int32_t *out, int16_t *in)
-{
- int i, re, im, n, n2, n4;
- int16_t *rot = mdct->rot_tmp;
- IComplex *x = mdct->cplx_tmp;
-
- n = 1 << mdct->nbits;
- n2 = n >> 1;
- n4 = n >> 2;
-
- /* shift to simplify computations */
- for (i = 0; i <n4; i++)
- rot[i] = -in[i + 3*n4];
- memcpy(&rot[n4], &in[0], 3*n4*sizeof(*in));
-
- /* pre rotation */
- for (i = 0; i < n4; i++) {
- re = ((int)rot[ 2*i] - (int)rot[ n-1-2*i]) >> 1;
- im = -((int)rot[n2+2*i] - (int)rot[n2-1-2*i]) >> 1;
- CMUL(x[i].re, x[i].im, re, im, -mdct->xcos1[i], mdct->xsin1[i], 15);
- }
-
- fft(mdct, x, mdct->nbits - 2);
-
- /* post rotation */
- for (i = 0; i < n4; i++) {
- re = x[i].re;
- im = x[i].im;
- CMUL(out[n2-1-2*i], out[2*i], re, im, mdct->xsin1[i], mdct->xcos1[i], 0);
- }
+ return ret;
}
@@ -304,101 +109,6 @@ static void scale_coefficients(AC3EncodeContext *s)
}
-#ifdef TEST
-/*************************************************************************/
-/* TEST */
-
-#include "libavutil/lfg.h"
-
-#define MDCT_NBITS 9
-#define MDCT_SAMPLES (1 << MDCT_NBITS)
-#define FN (MDCT_SAMPLES/4)
-
-
-static void fft_test(AC3MDCTContext *mdct, AVLFG *lfg)
-{
- IComplex in[FN], in1[FN];
- int k, n, i;
- float sum_re, sum_im, a;
-
- for (i = 0; i < FN; i++) {
- in[i].re = av_lfg_get(lfg) % 65535 - 32767;
- in[i].im = av_lfg_get(lfg) % 65535 - 32767;
- in1[i] = in[i];
- }
- fft(mdct, in, 7);
-
- /* do it by hand */
- for (k = 0; k < FN; k++) {
- sum_re = 0;
- sum_im = 0;
- for (n = 0; n < FN; n++) {
- a = -2 * M_PI * (n * k) / FN;
- sum_re += in1[n].re * cos(a) - in1[n].im * sin(a);
- sum_im += in1[n].re * sin(a) + in1[n].im * cos(a);
- }
- av_log(NULL, AV_LOG_DEBUG, "%3d: %6d,%6d %6.0f,%6.0f\n",
- k, in[k].re, in[k].im, sum_re / FN, sum_im / FN);
- }
-}
-
-
-static void mdct_test(AC3MDCTContext *mdct, AVLFG *lfg)
-{
- int16_t input[MDCT_SAMPLES];
- int32_t output[AC3_MAX_COEFS];
- float input1[MDCT_SAMPLES];
- float output1[AC3_MAX_COEFS];
- float s, a, err, e, emax;
- int i, k, n;
-
- for (i = 0; i < MDCT_SAMPLES; i++) {
- input[i] = (av_lfg_get(lfg) % 65535 - 32767) * 9 / 10;
- input1[i] = input[i];
- }
-
- mdct512(mdct, output, input);
-
- /* do it by hand */
- for (k = 0; k < AC3_MAX_COEFS; k++) {
- s = 0;
- for (n = 0; n < MDCT_SAMPLES; n++) {
- a = (2*M_PI*(2*n+1+MDCT_SAMPLES/2)*(2*k+1) / (4 * MDCT_SAMPLES));
- s += input1[n] * cos(a);
- }
- output1[k] = -2 * s / MDCT_SAMPLES;
- }
-
- err = 0;
- emax = 0;
- for (i = 0; i < AC3_MAX_COEFS; i++) {
- av_log(NULL, AV_LOG_DEBUG, "%3d: %7d %7.0f\n", i, output[i], output1[i]);
- e = output[i] - output1[i];
- if (e > emax)
- emax = e;
- err += e * e;
- }
- av_log(NULL, AV_LOG_DEBUG, "err2=%f emax=%f\n", err / AC3_MAX_COEFS, emax);
-}
-
-
-int main(void)
-{
- AVLFG lfg;
- AC3MDCTContext mdct;
-
- mdct.avctx = NULL;
- av_log_set_level(AV_LOG_DEBUG);
- mdct_init(&mdct, 9);
-
- fft_test(&mdct, &lfg);
- mdct_test(&mdct, &lfg);
-
- return 0;
-}
-#endif /* TEST */
-
-
AVCodec ff_ac3_fixed_encoder = {
"ac3_fixed",
AVMEDIA_TYPE_AUDIO,
diff --git a/libavcodec/ac3enc_fixed.h b/libavcodec/ac3enc_fixed.h
deleted file mode 100644
index 0c9e6a1..0000000
--- a/libavcodec/ac3enc_fixed.h
+++ /dev/null
@@ -1,61 +0,0 @@
-/*
- * The simplest AC-3 encoder
- * Copyright (c) 2000 Fabrice Bellard
- * Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles at gmail.com>
- * Copyright (c) 2006-2010 Prakash Punnoor <prakash at punnoor.de>
- *
- * This file is part of Libav.
- *
- * Libav 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.
- *
- * Libav 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 Libav; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-/**
- * @file
- * fixed-point AC-3 encoder header.
- */
-
-#ifndef AVCODEC_AC3ENC_FIXED_H
-#define AVCODEC_AC3ENC_FIXED_H
-
-#include <stdint.h>
-
-
-typedef int16_t SampleType;
-typedef int32_t CoefType;
-typedef int64_t CoefSumType;
-
-#define MAC_COEF(d,a,b) MAC64(d,a,b)
-
-
-/**
- * Compex number.
- * Used in fixed-point MDCT calculation.
- */
-typedef struct IComplex {
- int16_t re,im;
-} IComplex;
-
-typedef struct AC3MDCTContext {
- const int16_t *window; ///< MDCT window function
- int nbits; ///< log2(transform size)
- int16_t *costab; ///< FFT cos table
- int16_t *sintab; ///< FFT sin table
- int16_t *xcos1; ///< MDCT cos table
- int16_t *xsin1; ///< MDCT sin table
- int16_t *rot_tmp; ///< temp buffer for pre-rotated samples
- IComplex *cplx_tmp; ///< temp buffer for complex pre-rotated samples
-} AC3MDCTContext;
-
-#endif /* AVCODEC_AC3ENC_FIXED_H */
diff --git a/libavcodec/ac3enc_float.c b/libavcodec/ac3enc_float.c
index 19afd27..d2435de 100644
--- a/libavcodec/ac3enc_float.c
+++ b/libavcodec/ac3enc_float.c
@@ -69,17 +69,6 @@ static av_cold int mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct,
/**
- * Calculate a 512-point MDCT
- * @param out 256 output frequency coefficients
- * @param in 512 windowed input audio samples
- */
-static void mdct512(AC3MDCTContext *mdct, float *out, float *in)
-{
- mdct->fft.mdct_calc(&mdct->fft, out, in);
-}
-
-
-/**
* Apply KBD window to input samples prior to MDCT.
*/
static void apply_window(DSPContext *dsp, float *output, const float *input,
diff --git a/libavcodec/ac3enc_float.h b/libavcodec/ac3enc_float.h
deleted file mode 100644
index ecdc421..0000000
--- a/libavcodec/ac3enc_float.h
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * The simplest AC-3 encoder
- * Copyright (c) 2000 Fabrice Bellard
- * Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles at gmail.com>
- * Copyright (c) 2006-2010 Prakash Punnoor <prakash at punnoor.de>
- *
- * This file is part of Libav.
- *
- * Libav 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.
- *
- * Libav 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 Libav; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-/**
- * @file
- * floating-point AC-3 encoder header.
- */
-
-#ifndef AVCODEC_AC3ENC_FLOAT_H
-#define AVCODEC_AC3ENC_FLOAT_H
-
-#include "fft.h"
-
-
-typedef float SampleType;
-typedef float CoefType;
-typedef float CoefSumType;
-
-#define MAC_COEF(d,a,b) ((d)+=(a)*(b))
-
-
-typedef struct AC3MDCTContext {
- const float *window; ///< MDCT window function
- FFTContext fft; ///< FFT context for MDCT calculation
-} AC3MDCTContext;
-
-#endif /* AVCODEC_AC3ENC_FLOAT_H */
diff --git a/tests/ref/acodec/ac3_fixed b/tests/ref/acodec/ac3_fixed
index d4ade32..ce1a8ec 100644
--- a/tests/ref/acodec/ac3_fixed
+++ b/tests/ref/acodec/ac3_fixed
@@ -1,2 +1,2 @@
-346073c97eada69330f61e103a170ca1 *./tests/data/acodec/ac3.rm
+408f47ee5a60866fc751f7bc2314cbd6 *./tests/data/acodec/ac3.rm
98751 ./tests/data/acodec/ac3.rm
diff --git a/tests/ref/lavf/rm b/tests/ref/lavf/rm
index bb0b1db..fbf3e0f 100644
--- a/tests/ref/lavf/rm
+++ b/tests/ref/lavf/rm
@@ -1,2 +1,2 @@
-7b7ede9548a09346675edad36acfbf19 *./tests/data/lavf/lavf.rm
+da74fe749c2eb21bbead7de81d2f3078 *./tests/data/lavf/lavf.rm
346706 ./tests/data/lavf/lavf.rm
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