rtpdec: Malloc the fmtp value buffer

This allows very large value strings, needed for xiph extradata.

Patch by Josh Allmann, joshua dot allmann at gmail

Originally committed as revision 23859 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/rtpdec.c

@@ -538,8 +538,14 @@ int ff_parse_fmtp(AVStream *stream, PayloadContext *data, const char *p,
                                     char *attr, char *value))
 {
     char attr[256];
-    char value[4096];
+    char *value;
     int res;
+    int value_size = strlen(p) + 1;
+
+    if (!(value = av_malloc(value_size))) {
+        av_log(stream, AV_LOG_ERROR, "Failed to allocate data for FMTP.");
+        return AVERROR(ENOMEM);
+    }
 
     // remove protocol identifier
     while (*p && *p == ' ') p++; // strip spaces
@@ -548,11 +554,14 @@ int ff_parse_fmtp(AVStream *stream, PayloadContext *data, const char *p,
 
     while (ff_rtsp_next_attr_and_value(&p,
                                        attr, sizeof(attr),
-                                       value, sizeof(value))) {
+                                       value, value_size)) {
 
         res = parse_fmtp(stream, data, attr, value);
-        if (res < 0)
+        if (res < 0 && res != AVERROR_PATCHWELCOME) {
+            av_free(value);
             return res;
+        }
     }
+    av_free(value);
     return 0;
 }