avfilter/af_aphaser: move wave table generation code into separate file

Signed-off-by: Paul B Mahol <onemda@gmail.com>

1 files changed, 84 insertions, 0 deletions

diff --git a/libavfilter/generate_wave_table.c b/libavfilter/generate_wave_table.c
new file mode 100644
index 0000000..bee9c00
--- /dev/null
+++ b/libavfilter/generate_wave_table.c
@@ -0,0 +1,84 @@
+/*
+ * 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
+ */
+
+#include <stdint.h>
+#include "libavutil/avassert.h"
+#include "avfilter.h"
+#include "generate_wave_table.h"
+
+void ff_generate_wave_table(enum WaveType wave_type,
+                            enum AVSampleFormat sample_fmt,
+                            void *table, int table_size,
+                            double min, double max, double phase)
+{
+    uint32_t i, phase_offset = phase / M_PI / 2 * table_size + 0.5;
+
+    for (i = 0; i < table_size; i++) {
+        uint32_t point = (i + phase_offset) % table_size;
+        double d;
+
+        switch (wave_type) {
+        case WAVE_SIN:
+            d = (sin((double)point / table_size * 2 * M_PI) + 1) / 2;
+            break;
+        case WAVE_TRI:
+            d = (double)point * 2 / table_size;
+            switch (4 * point / table_size) {
+            case 0: d = d + 0.5; break;
+            case 1:
+            case 2: d = 1.5 - d; break;
+            case 3: d = d - 1.5; break;
+            }
+            break;
+        default:
+            av_assert0(0);
+        }
+
+        d  = d * (max - min) + min;
+        switch (sample_fmt) {
+        case AV_SAMPLE_FMT_FLT: {
+            float *fp = (float *)table;
+            *fp++ = (float)d;
+            table = fp;
+            continue; }
+        case AV_SAMPLE_FMT_DBL: {
+            double *dp = (double *)table;
+            *dp++ = d;
+            table = dp;
+            continue; }
+        }
+
+        d += d < 0 ? -0.5 : 0.5;
+        switch (sample_fmt) {
+        case AV_SAMPLE_FMT_S16: {
+            int16_t *sp = table;
+            *sp++ = (int16_t)d;
+            table = sp;
+            continue; }
+        case AV_SAMPLE_FMT_S32: {
+            int32_t *ip = table;
+            *ip++ = (int32_t)d;
+            table = ip;
+            continue; }
+        default:
+            av_assert0(0);
+        }
+    }
+}
+
+