forked from FFmpeg/FFmpeg
Add support for fixed-point MDCT sizes other than 512.
Originally committed as revision 26046 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles
parent
234b70d346
commit
86c9673bab
1 changed files with 64 additions and 36 deletions
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@ -37,9 +37,6 @@
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#include "audioconvert.h"
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#define MDCT_NBITS 9
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#define MDCT_SAMPLES (1 << MDCT_NBITS)
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/** Maximum number of exponent groups. +1 for separate DC exponent. */
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#define AC3_MAX_EXP_GROUPS 85
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@ -60,6 +57,11 @@ typedef struct IComplex {
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typedef struct AC3MDCTContext {
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AVCodecContext *avctx; ///< parent context for av_log()
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int nbits; ///< log2(transform size)
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int16_t *costab; ///< FFT cos table
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int16_t *sintab; ///< FFT sin table
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int16_t *xcos1; ///< MDCT cos table
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int16_t *xsin1; ///< MDCT sin table
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int16_t *rot_tmp; ///< temp buffer for pre-rotated samples
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IComplex *cplx_tmp; ///< temp buffer for complex pre-rotated samples
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} AC3MDCTContext;
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@ -145,12 +147,6 @@ typedef struct AC3EncodeContext {
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} AC3EncodeContext;
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/** MDCT and FFT tables */
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static int16_t costab[64];
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static int16_t sintab[64];
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static int16_t xcos1[128];
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static int16_t xsin1[128];
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/**
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* LUT for number of exponent groups.
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* exponent_group_tab[exponent strategy-1][number of coefficients]
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@ -209,6 +205,11 @@ static void deinterleave_input_samples(AC3EncodeContext *s,
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*/
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static av_cold void mdct_end(AC3MDCTContext *mdct)
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{
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mdct->nbits = 0;
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av_freep(&mdct->costab);
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av_freep(&mdct->sintab);
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av_freep(&mdct->xcos1);
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av_freep(&mdct->xsin1);
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av_freep(&mdct->rot_tmp);
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av_freep(&mdct->cplx_tmp);
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}
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@ -219,7 +220,7 @@ static av_cold void mdct_end(AC3MDCTContext *mdct)
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* Initialize FFT tables.
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* @param ln log2(FFT size)
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*/
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static av_cold void fft_init(int ln)
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static av_cold int fft_init(AC3MDCTContext *mdct, int ln)
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{
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int i, n, n2;
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float alpha;
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@ -227,11 +228,21 @@ static av_cold void fft_init(int ln)
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n = 1 << ln;
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n2 = n >> 1;
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FF_ALLOC_OR_GOTO(mdct->avctx, mdct->costab, n2 * sizeof(*mdct->costab),
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fft_alloc_fail);
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FF_ALLOC_OR_GOTO(mdct->avctx, mdct->sintab, n2 * sizeof(*mdct->sintab),
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fft_alloc_fail);
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for (i = 0; i < n2; i++) {
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alpha = 2.0 * M_PI * i / n;
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costab[i] = FIX15(cos(alpha));
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sintab[i] = FIX15(sin(alpha));
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mdct->costab[i] = FIX15(cos(alpha));
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mdct->sintab[i] = FIX15(sin(alpha));
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}
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return 0;
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fft_alloc_fail:
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mdct_end(mdct);
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return AVERROR(ENOMEM);
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}
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@ -241,13 +252,21 @@ static av_cold void fft_init(int ln)
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*/
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static av_cold int mdct_init(AC3MDCTContext *mdct, int nbits)
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{
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int i, n, n4;
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int i, n, n4, ret;
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n = 1 << nbits;
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n4 = n >> 2;
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fft_init(nbits - 2);
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mdct->nbits = nbits;
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ret = fft_init(mdct, nbits - 2);
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if (ret)
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return ret;
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FF_ALLOC_OR_GOTO(mdct->avctx, mdct->xcos1, n4 * sizeof(*mdct->xcos1),
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mdct_alloc_fail);
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FF_ALLOC_OR_GOTO(mdct->avctx, mdct->xsin1 , n4 * sizeof(*mdct->xsin1),
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mdct_alloc_fail);
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FF_ALLOC_OR_GOTO(mdct->avctx, mdct->rot_tmp, n * sizeof(*mdct->rot_tmp),
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mdct_alloc_fail);
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FF_ALLOC_OR_GOTO(mdct->avctx, mdct->cplx_tmp, n4 * sizeof(*mdct->cplx_tmp),
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@ -255,12 +274,13 @@ static av_cold int mdct_init(AC3MDCTContext *mdct, int nbits)
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for (i = 0; i < n4; i++) {
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float alpha = 2.0 * M_PI * (i + 1.0 / 8.0) / n;
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xcos1[i] = FIX15(-cos(alpha));
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xsin1[i] = FIX15(-sin(alpha));
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mdct->xcos1[i] = FIX15(-cos(alpha));
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mdct->xsin1[i] = FIX15(-sin(alpha));
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}
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return 0;
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mdct_alloc_fail:
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mdct_end(mdct);
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return AVERROR(ENOMEM);
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}
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@ -293,7 +313,7 @@ mdct_alloc_fail:
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* @param z complex input/output samples
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* @param ln log2(FFT size)
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*/
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static void fft(IComplex *z, int ln)
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static void fft(AC3MDCTContext *mdct, IComplex *z, int ln)
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{
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int j, l, np, np2;
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int nblocks, nloops;
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@ -345,7 +365,7 @@ static void fft(IComplex *z, int ln)
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p++;
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q++;
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for(l = nblocks; l < np2; l += nblocks) {
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CMUL(tmp_re, tmp_im, costab[l], -sintab[l], q->re, q->im);
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CMUL(tmp_re, tmp_im, mdct->costab[l], -mdct->sintab[l], q->re, q->im);
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BF(p->re, p->im, q->re, q->im,
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p->re, p->im, tmp_re, tmp_im);
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p++;
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@ -367,29 +387,33 @@ static void fft(IComplex *z, int ln)
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*/
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static void mdct512(AC3MDCTContext *mdct, int32_t *out, int16_t *in)
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{
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int i, re, im;
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int i, re, im, n, n2, n4;
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int16_t *rot = mdct->rot_tmp;
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IComplex *x = mdct->cplx_tmp;
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n = 1 << mdct->nbits;
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n2 = n >> 1;
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n4 = n >> 2;
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/* shift to simplify computations */
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for (i = 0; i < MDCT_SAMPLES/4; i++)
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rot[i] = -in[i + 3*MDCT_SAMPLES/4];
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memcpy(&rot[MDCT_SAMPLES/4], &in[0], 3*MDCT_SAMPLES/4*sizeof(*in));
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for (i = 0; i <n4; i++)
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rot[i] = -in[i + 3*n4];
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memcpy(&rot[n4], &in[0], 3*n4*sizeof(*in));
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/* pre rotation */
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for (i = 0; i < MDCT_SAMPLES/4; i++) {
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re = ((int)rot[ 2*i] - (int)rot[MDCT_SAMPLES -1-2*i]) >> 1;
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im = -((int)rot[MDCT_SAMPLES/2+2*i] - (int)rot[MDCT_SAMPLES/2-1-2*i]) >> 1;
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CMUL(x[i].re, x[i].im, re, im, -xcos1[i], xsin1[i]);
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for (i = 0; i < n4; i++) {
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re = ((int)rot[ 2*i] - (int)rot[ n-1-2*i]) >> 1;
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im = -((int)rot[n2+2*i] - (int)rot[n2-1-2*i]) >> 1;
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CMUL(x[i].re, x[i].im, re, im, -mdct->xcos1[i], mdct->xsin1[i]);
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}
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fft(x, MDCT_NBITS - 2);
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fft(mdct, x, mdct->nbits - 2);
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/* post rotation */
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for (i = 0; i < MDCT_SAMPLES/4; i++) {
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for (i = 0; i < n4; i++) {
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re = x[i].re;
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im = x[i].im;
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CMUL(out[MDCT_SAMPLES/2-1-2*i], out[2*i], re, im, xsin1[i], xcos1[i]);
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CMUL(out[n2-1-2*i], out[2*i], re, im, mdct->xsin1[i], mdct->xcos1[i]);
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}
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}
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@ -1824,10 +1848,12 @@ init_fail:
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#include "libavutil/lfg.h"
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#define MDCT_NBITS 9
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#define MDCT_SAMPLES (1 << MDCT_NBITS)
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#define FN (MDCT_SAMPLES/4)
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static void fft_test(AVLFG *lfg)
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static void fft_test(AC3MDCTContext *mdct, AVLFG *lfg)
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{
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IComplex in[FN], in1[FN];
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int k, n, i;
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@ -1838,7 +1864,7 @@ static void fft_test(AVLFG *lfg)
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in[i].im = av_lfg_get(lfg) % 65535 - 32767;
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in1[i] = in[i];
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}
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fft(in, 7);
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fft(mdct, in, 7);
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/* do it by hand */
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for (k = 0; k < FN; k++) {
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@ -1855,7 +1881,7 @@ static void fft_test(AVLFG *lfg)
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}
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static void mdct_test(AVLFG *lfg)
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static void mdct_test(AC3MDCTContext *mdct, AVLFG *lfg)
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{
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int16_t input[MDCT_SAMPLES];
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int32_t output[AC3_MAX_COEFS];
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@ -1869,7 +1895,7 @@ static void mdct_test(AVLFG *lfg)
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input1[i] = input[i];
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}
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mdct512(output, input);
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mdct512(mdct, output, input);
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/* do it by hand */
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for (k = 0; k < AC3_MAX_COEFS; k++) {
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@ -1897,12 +1923,14 @@ static void mdct_test(AVLFG *lfg)
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int main(void)
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{
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AVLFG lfg;
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AC3MDCTContext mdct;
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mdct.avctx = NULL;
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av_log_set_level(AV_LOG_DEBUG);
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mdct_init(9);
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mdct_init(&mdct, 9);
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fft_test(&lfg);
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mdct_test(&lfg);
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fft_test(&mdct, &lfg);
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mdct_test(&mdct, &lfg);
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return 0;
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}
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