diff --git a/v4l2/grabvidseq.c b/v4l2/grabvidseq.c
index 5c3f9d2..b120711 100644
--- a/v4l2/grabvidseq.c
+++ b/v4l2/grabvidseq.c
@@ -240,7 +240,7 @@ else	{
 	}
 
 fimg_clear(&cumul);
-cumul.fval = 255.0;
+cumul.fval = 255.0;		/* must be read from camera XXX */
 cumul.count = 0;
 
 to_save = &cumul;
@@ -347,6 +347,8 @@ if (verbosity) fprintf(stderr, "saving cumul to '%s'\n", outfile);
 maxvalue = cumul.fval * cumul.count;
 if (verbosity) {
 	fprintf(stderr, "theorical maxvalue = %g\n", maxvalue);
+	fprintf(stderr, "computed max value = %g\n",
+					fimg_get_maxvalue(&cumul));
 	}
 switch (contrast) {
 	case CONTRAST_NONE: