Move audio channel API from libavcodec to libavcore.

Originally committed as revision 25787 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 113 insertions, 0 deletions

diff --git a/libavcore/audioconvert.c b/libavcore/audioconvert.c
new file mode 100644
index 0000000..171d6b1
--- /dev/null
+++ b/libavcore/audioconvert.c
@@ -0,0 +1,113 @@
+/*
+ * Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * audio conversion routines
+ */
+
+#include "libavutil/avstring.h"
+#include "audioconvert.h"
+
+static const char * const channel_names[] = {
+    "FL", "FR", "FC", "LFE", "BL",  "BR",  "FLC", "FRC",
+    "BC", "SL", "SR", "TC",  "TFL", "TFC", "TFR", "TBL",
+    "TBC", "TBR",
+    [29] = "DL",
+    [30] = "DR",
+};
+
+static const char *get_channel_name(int channel_id)
+{
+    if (channel_id < 0 || channel_id >= FF_ARRAY_ELEMS(channel_names))
+        return NULL;
+    return channel_names[channel_id];
+}
+
+static const struct {
+    const char *name;
+    int         nb_channels;
+    int64_t     layout;
+} channel_layout_map[] = {
+    { "mono",        1,  AV_CH_LAYOUT_MONO },
+    { "stereo",      2,  AV_CH_LAYOUT_STEREO },
+    { "4.0",         4,  AV_CH_LAYOUT_4POINT0 },
+    { "quad",        4,  AV_CH_LAYOUT_QUAD },
+    { "5.0",         5,  AV_CH_LAYOUT_5POINT0 },
+    { "5.0",         5,  AV_CH_LAYOUT_5POINT0_BACK },
+    { "5.1",         6,  AV_CH_LAYOUT_5POINT1 },
+    { "5.1",         6,  AV_CH_LAYOUT_5POINT1_BACK },
+    { "5.1+downmix", 8,  AV_CH_LAYOUT_5POINT1|AV_CH_LAYOUT_STEREO_DOWNMIX, },
+    { "7.1",         8,  AV_CH_LAYOUT_7POINT1 },
+    { "7.1(wide)",   8,  AV_CH_LAYOUT_7POINT1_WIDE },
+    { "7.1+downmix", 10, AV_CH_LAYOUT_7POINT1|AV_CH_LAYOUT_STEREO_DOWNMIX, },
+    { 0 }
+};
+
+int64_t av_get_channel_layout(const char *name)
+{
+    int i = 0;
+    do {
+        if (!strcmp(channel_layout_map[i].name, name))
+            return channel_layout_map[i].layout;
+        i++;
+    } while (channel_layout_map[i].name);
+
+    return 0;
+}
+
+void av_get_channel_layout_string(char *buf, int buf_size,
+                                  int nb_channels, int64_t channel_layout)
+{
+    int i;
+
+    for (i = 0; channel_layout_map[i].name; i++)
+        if (nb_channels    == channel_layout_map[i].nb_channels &&
+            channel_layout == channel_layout_map[i].layout) {
+            av_strlcpy(buf, channel_layout_map[i].name, buf_size);
+            return;
+        }
+
+    snprintf(buf, buf_size, "%d channels", nb_channels);
+    if (channel_layout) {
+        int i,ch;
+        av_strlcat(buf, " (", buf_size);
+        for(i=0,ch=0; i<64; i++) {
+            if ((channel_layout & (1L<<i))) {
+                const char *name = get_channel_name(i);
+                if (name) {
+                    if (ch>0) av_strlcat(buf, "|", buf_size);
+                    av_strlcat(buf, name, buf_size);
+                }
+                ch++;
+            }
+        }
+        av_strlcat(buf, ")", buf_size);
+    }
+}
+
+int av_get_channel_layout_nb_channels(int64_t channel_layout)
+{
+    int count;
+    uint64_t x = channel_layout;
+    for (count = 0; x; count++)
+        x &= x-1; // unset lowest set bit
+    return count;
+}