avcodec/dca: add math helpers and fixed point DCT

libavcodec/dcadct.h

+/*
+ * Copyright (C) 2016 foo86
+ *
+ * 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 Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_DCADCT_H
+#define AVCODEC_DCADCT_H
+
+#include "libavutil/common.h"
+
+typedef struct DCADCTContext {
+    void (*imdct_half[2])(int32_t *output, const int32_t *input);
+} DCADCTContext;
+
+av_cold void ff_dcadct_init(DCADCTContext *c);
+
+#endif

libavcodec/dcamath.h

+/*
+ * Copyright (C) 2016 foo86
+ *
+ * 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 Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_DCAMATH_H
+#define AVCODEC_DCAMATH_H
+
+#include "libavutil/common.h"
+#include "libavutil/intmath.h"
+
+static inline int32_t norm__(int64_t a, int bits)
+{
+    if (bits > 0)
+        return (int32_t)((a + (INT64_C(1) << (bits - 1))) >> bits);
+    else
+        return (int32_t)a;
+}
+
+static inline int32_t mul__(int32_t a, int32_t b, int bits)
+{
+    return norm__((int64_t)a * b, bits);
+}
+
+static inline int32_t norm13(int64_t a) { return norm__(a, 13); }
+static inline int32_t norm16(int64_t a) { return norm__(a, 16); }
+static inline int32_t norm20(int64_t a) { return norm__(a, 20); }
+static inline int32_t norm21(int64_t a) { return norm__(a, 21); }
+static inline int32_t norm23(int64_t a) { return norm__(a, 23); }
+
+static inline int32_t mul15(int32_t a, int32_t b) { return mul__(a, b, 15); }
+static inline int32_t mul16(int32_t a, int32_t b) { return mul__(a, b, 16); }
+static inline int32_t mul17(int32_t a, int32_t b) { return mul__(a, b, 17); }
+static inline int32_t mul22(int32_t a, int32_t b) { return mul__(a, b, 22); }
+static inline int32_t mul23(int32_t a, int32_t b) { return mul__(a, b, 23); }
+static inline int32_t mul31(int32_t a, int32_t b) { return mul__(a, b, 31); }
+
+static inline int32_t clip23(int32_t a) { return av_clip_intp2(a, 23); }
+
+#endif