cmdutils: add -layouts option.

Extract of the output:

| Individual channels:
| NAME        DESCRIPTION
| FL          front left
| FR          front right
| <snip>
| SDR         surround direct right
|
| Standard channel layouts:
| NAME        DECOMPOSITION
| mono        FC
| stereo      FL+FR
| <snip>
| octagonal   FL+FR+FC+BL+BR+BC+SL+SR
| downmix     DL+DR

1 files changed, 29 insertions, 0 deletions

diff --git a/cmdutils.c b/cmdutils.c
index a5871c3207..619a4a81e5 100644
--- a/cmdutils.c
+++ b/cmdutils.c
@@ -1087,6 +1087,35 @@ int show_pix_fmts(const char *opt, const char *arg)
     return 0;
 }
 
+int show_layouts(const char *opt, const char *arg)
+{
+    int i = 0;
+    uint64_t layout, j;
+    const char *name, *descr;
+
+    printf("Individual channels:\n"
+           "NAME        DESCRIPTION\n");
+    for (i = 0; i < 63; i++) {
+        name = av_get_channel_name((uint64_t)1 << i);
+        if (!name)
+            continue;
+        descr = av_get_channel_description((uint64_t)1 << i);
+        printf("%-12s%s\n", name, descr);
+    }
+    printf("\nStandard channel layouts:\n"
+           "NAME        DECOMPOSITION\n");
+    for (i = 0; !av_get_standard_channel_layout(i, &layout, &name); i++) {
+        if (name) {
+            printf("%-12s", name);
+            for (j = 1; j; j <<= 1)
+                if ((layout & j))
+                    printf("%s%s", (layout & (j - 1)) ? "+" : "", av_get_channel_name(j));
+            printf("\n");
+        }
+    }
+    return 0;
+}
+
 int show_sample_fmts(const char *opt, const char *arg)
 {
     int i;