avidec: read some of the Nikon specific tags produced by Nikon cameras

Originally committed as revision 25821 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/avidec.c

@@ -301,6 +301,42 @@ static void avi_metadata_creation_time(AVMetadata **metadata, char *date)
     }
 }
 
+static void avi_read_nikon(AVFormatContext *s, uint64_t end)
+{
+    while (url_ftell(s->pb) < end) {
+        uint32_t tag  = get_le32(s->pb);
+        uint32_t size = get_le32(s->pb);
+        switch (tag) {
+        case MKTAG('n', 'c', 't', 'g'): {  /* Nikon Tags */
+            uint64_t tag_end = url_ftell(s->pb) + size;
+            while (url_ftell(s->pb) < tag_end) {
+                uint16_t tag  = get_le16(s->pb);
+                uint16_t size = get_le16(s->pb);
+                const char *name = NULL;
+                char buffer[64] = {0};
+                size -= get_buffer(s->pb, buffer,
+                                   FFMIN(size, sizeof(buffer)-1));
+                switch (tag) {
+                case 0x03:  name = "maker";  break;
+                case 0x04:  name = "model";  break;
+                case 0x13:  name = "creation_time";
+                    if (buffer[4] == ':' && buffer[7] == ':')
+                        buffer[4] = buffer[7] = '-';
+                    break;
+                }
+                if (name)
+                    av_metadata_set2(&s->metadata, name, buffer, 0);
+                url_fskip(s->pb, size);
+            }
+            break;
+        }
+        default:
+            url_fskip(s->pb, size);
+            break;
+        }
+    }
+}
+
 static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
 {
     AVIContext *avi = s->priv_data;
@@ -354,6 +390,8 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
             }
             else if (tag1 == MKTAG('I', 'N', 'F', 'O'))
                 avi_read_info(s, list_end);
+            else if (tag1 == MKTAG('n', 'c', 'd', 't'))
+                avi_read_nikon(s, list_end);
 
             break;
         case MKTAG('I', 'D', 'I', 'T'): {