diff options
Diffstat (limited to 'libavcodec/mpegaudio_tablegen.h')
| -rw-r--r-- | libavcodec/mpegaudio_tablegen.h | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/libavcodec/mpegaudio_tablegen.h b/libavcodec/mpegaudio_tablegen.h index a222f2c423..6c15d3cb03 100644 --- a/libavcodec/mpegaudio_tablegen.h +++ b/libavcodec/mpegaudio_tablegen.h @@ -3,20 +3,20 @@ * * Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de> * - * This file is part of Libav. + * This file is part of FFmpeg. * - * Libav is free software; you can redistribute it and/or + * 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. * - * Libav is distributed in the hope that it will be useful, + * 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 Libav; if not, write to the Free Software + * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ @@ -39,6 +39,7 @@ static float exp_table_float[512]; static float expval_table_float[512][16]; #define FRAC_BITS 23 +#define IMDCT_SCALAR 1.759 static void mpegaudio_tableinit(void) { @@ -47,7 +48,7 @@ static void mpegaudio_tableinit(void) double value = i / 4; double f, fm; int e, m; - f = value * cbrtf(value) * pow(2, (i & 3) * 0.25); + f = value / IMDCT_SCALAR * cbrtf(value) * pow(2, (i & 3) * 0.25); fm = frexp(f, &e); m = (uint32_t)(fm * (1LL << 31) + 0.5); e += FRAC_BITS - 31 + 5 - 100; @@ -58,7 +59,7 @@ static void mpegaudio_tableinit(void) } for (exponent = 0; exponent < 512; exponent++) { for (value = 0; value < 16; value++) { - double f = (double)value * cbrtf(value) * pow(2, (exponent - 400) * 0.25 + FRAC_BITS + 5); + double f = (double)value * cbrtf(value) * pow(2, (exponent - 400) * 0.25 + FRAC_BITS + 5) / IMDCT_SCALAR; expval_table_fixed[exponent][value] = llrint(f); expval_table_float[exponent][value] = f; } |