Fixed-point FFT and MDCT

1 files changed, 67 insertions, 0 deletions

diff --git a/libavcodec/fft-internal.h b/libavcodec/fft-internal.h
new file mode 100644
index 0000000000..1f240dbd18
--- /dev/null
+++ b/libavcodec/fft-internal.h
@@ -0,0 +1,67 @@
+/*
+ * 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
+ */
+
+#ifndef AVCODEC_FFT_INTERNAL_H
+#define AVCODEC_FFT_INTERNAL_H
+
+#if CONFIG_FFT_FLOAT
+
+#define FIX15(v) (v)
+#define sqrthalf (float)M_SQRT1_2
+
+#define BF(x, y, a, b) do {                     \
+        x = a - b;                              \
+        y = a + b;                              \
+    } while (0)
+
+#define CMUL(dre, dim, are, aim, bre, bim) do { \
+        (dre) = (are) * (bre) - (aim) * (bim);  \
+        (dim) = (are) * (bim) + (aim) * (bre);  \
+    } while (0)
+
+#else
+
+#include "libavutil/intmath.h"
+#include "mathops.h"
+
+#define SCALE_FLOAT(a, bits) lrint((a) * (double)(1 << (bits)))
+#define FIX15(a) av_clip(SCALE_FLOAT(a, 15), -32767, 32767)
+
+#define sqrthalf ((int16_t)((1<<15)*M_SQRT1_2))
+
+#define BF(x, y, a, b) do {                     \
+        x = (a - b) >> 1;                       \
+        y = (a + b) >> 1;                       \
+    } while (0)
+
+#define CMUL(dre, dim, are, aim, bre, bim) do {                 \
+        (dre) = (MUL16(are, bre) - MUL16(aim, bim)) >> 15;      \
+        (dim) = (MUL16(are, bim) + MUL16(aim, bre)) >> 15;      \
+    } while (0)
+
+#endif /* CONFIG_FFT_FLOAT */
+
+#define ff_imdct_calc_c FFT_NAME(ff_imdct_calc_c)
+#define ff_imdct_half_c FFT_NAME(ff_imdct_half_c)
+#define ff_mdct_calc_c  FFT_NAME(ff_mdct_calc_c)
+
+void ff_imdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input);
+void ff_imdct_half_c(FFTContext *s, FFTSample *output, const FFTSample *input);
+void ff_mdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input);
+
+#endif /* AVCODEC_FFT_INTERNAL_H */