quvi: coerce libquvi 0.4 support into allowing format switching

libquvi 0.4 doesn't allow us listing the formats supported by a
streaming site without doing additional network accesses, so switching
formats was not supported with it. (It's different with libquvi 0.9.)

But the most important case is switching between SD and HD. Usually,
--quvi-format=default will get SD, while --quvi-format=best gives HD.
Use this, and pretend that an URL supported by libquvi 0.4 supports both
of these. "cycle quvi-format" will switch between these. If the user
specifies something else via --quvi-format, this is included in the list
of switchable formats additionally to "default" and "best".

1 files changed, 1 insertions, 1 deletions

diff --git a/mpvcore/resolve.h b/mpvcore/resolve.h
index 91684df250..7a60b29114 100644
--- a/mpvcore/resolve.h
+++ b/mpvcore/resolve.h
@@ -38,7 +38,7 @@ struct mp_resolve_result {
 };
 
 struct mp_resolve_src {
-    char *url;
+    char *url;       // can be NULL; otherwise it's the exact video URL
     char *encid;     // indicates quality level, contents are libquvi specific
 };