[FFmpeg-devel] [PATCH] audioconvert: make av_get_channel_layout accept composite names.

[Nicolas George]

Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
---
 libavutil/audioconvert.c |   47 +++++++++++++++++++++++++++++++++++++--------
 libavutil/audioconvert.h |   12 +++++++++++
 2 files changed, 50 insertions(+), 9 deletions(-)

diff --git a/libavutil/audioconvert.c b/libavutil/audioconvert.c
index f4c74f6..fc03d7d 100644
--- a/libavutil/audioconvert.c
+++ b/libavutil/audioconvert.c
@@ -72,23 +72,52 @@ static const struct {
     { "5.1",         6,  AV_CH_LAYOUT_5POINT1_BACK },
     { "7.1",         8,  AV_CH_LAYOUT_7POINT1 },
     { "7.1(wide)",   8,  AV_CH_LAYOUT_7POINT1_WIDE },
-    { "5.1+downmix", 8,  AV_CH_LAYOUT_5POINT1|AV_CH_LAYOUT_STEREO_DOWNMIX, },
-    { "7.1+downmix", 10, AV_CH_LAYOUT_7POINT1|AV_CH_LAYOUT_STEREO_DOWNMIX, },
+    { "downmix",     2,  AV_CH_LAYOUT_STEREO_DOWNMIX, },
     { 0 }
 };
 
-int64_t av_get_channel_layout(const char *name)
+static int64_t get_channel_layout_single(const char *name, int name_len)
 {
-    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);
+    int i;
+    char *end;
+    int64_t layout;
 
+    for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map) - 1; i++) {
+        if (strlen(channel_layout_map[i].name) == name_len &&
+            !memcmp(channel_layout_map[i].name, name, name_len))
+            return channel_layout_map[i].layout;
+    }
+    for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++)
+        if (channel_names[i] &&
+            strlen(channel_names[i]) == name_len &&
+            !memcmp(channel_names[i], name, name_len))
+            return (int64_t)1 << i;
+    i = strtol(name, &end, 10);
+    if (end - name == name_len ||
+        (end + 1 - name == name_len && *end  == 'c'))
+        return av_get_default_channel_layout(i);
+    layout = strtoll(name, &end, 0);
+    if (end - name == name_len)
+        return layout;
     return 0;
 }
 
+int64_t av_get_channel_layout(const char *name)
+{
+    const char *n, *e;
+    const char *name_end = name + strlen(name);
+    int64_t layout = 0, layout_single;
+
+    for (n = name; n < name_end; n = e + 1) {
+        for (e = n; e < name_end && *e != '+' && *e != '|'; e++);
+        layout_single = get_channel_layout_single(n, e - n);
+        if (!layout_single)
+            return 0;
+        layout |= layout_single;
+    }
+    return layout;
+}
+
 void av_get_channel_layout_string(char *buf, int buf_size,
                                   int nb_channels, int64_t channel_layout)
 {
diff --git a/libavutil/audioconvert.h b/libavutil/audioconvert.h
index 8cef7f6..4e0e98c 100644
--- a/libavutil/audioconvert.h
+++ b/libavutil/audioconvert.h
@@ -75,6 +75,18 @@
 
 /**
  * Return a channel layout id that matches name, 0 if no match.
+ * name can be one or several of the following notations,
+ * separated by '+' or '|':
+ * - the name of an usual channel layout (mono, stereo, 4.0, quad, 5.0,
+ *   5.0(side), 5.1, 5.1(side), 7.1, 7.1(wide), downmix);
+ * - the name of a single channel (FL, FR, FC, LFE, BL, BR, FLC, FRC, BC,
+ *   SL, SR, TC, TFL, TFC, TFR, TBL, TBC, TBR, DL, DR);
+ * - a number of channels, in decimal, optionnally followed by 'c', yielding
+ *   the default channel layout for that number of channels (@see
+ *   av_get_default_channel_layout);
+ * - a channel layout mask, in hexadecimal starting with "0x" (see the
+ *   AV_CH_* macros).
+ + Example: "stereo+FC" = "2+FC" = "2c+1c" = "0x7"
  */
 int64_t av_get_channel_layout(const char *name);
 
-- 
1.7.7.1