avfilter/internal: add fixme to ff_norm_qscale() to document obvious scaling issue

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavfilter/internal.h

@@ -377,6 +377,8 @@ void ff_filter_graph_remove_filter(AVFilterGraph *graph, AVFilterContext *filter
 
 /**
  * Normalize the qscale factor
+ * FIXME the H264 qscale is a log based scale, mpeg1/2 is not, the code below
+ *       cannot be optimal
  */
 static inline int ff_norm_qscale(int qscale, int type)
 {