rtmpproto: Support alternative slist parameter in rtmp URLs

Support the URL scheme where the playpath is in an RTMP URL is
passed as the slist argument and the app is given infront of the
query part of the URL:

rtmp://host[:port]/[app]?slist=[playpath]

(other arguments in the query part are stripped as they are not used)
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/rtmpproto.c

@@ -2382,7 +2382,7 @@ static int rtmp_open(URLContext *s, const char *uri, int flags)
 {
     RTMPContext *rt = s->priv_data;
     char proto[8], hostname[256], path[1024], auth[100], *fname;
-    char *old_app;
+    char *old_app, *qmark, fname_buffer[1024];
     uint8_t buf[2048];
     int port;
     AVDictionary *opts = NULL;
@@ -2480,7 +2480,19 @@ reconnect:
     }
 
     //extract "app" part from path
-    if (!strncmp(path, "/ondemand/", 10)) {
+    qmark = strchr(path, '?');
+    if (qmark && strstr(qmark, "slist=")) {
+        char* amp;
+        // After slist we have the playpath, before the params, the app
+        av_strlcpy(rt->app, path + 1, qmark - path);
+        fname = strstr(path, "slist=") + 6;
+        // Strip any further query parameters from fname
+        amp = strchr(fname, '&');
+        if (amp) {
+            av_strlcpy(fname_buffer, fname, amp - fname + 1);
+            fname = fname_buffer;
+        }
+    } else if (!strncmp(path, "/ondemand/", 10)) {
         fname = path + 10;
         memcpy(rt->app, "ondemand", 9);
     } else {