--- a/modules/libpr0n/encoders/jpeg/nsJPEGEncoder.cpp
+++ b/modules/libpr0n/encoders/jpeg/nsJPEGEncoder.cpp
@@ -114,17 +114,17 @@ NS_IMETHODIMP nsJPEGEncoder::InitFromDat
     // have options string
     const nsString qualityPrefix(NS_LITERAL_STRING("quality="));
     if (aOutputOptions.Length() > qualityPrefix.Length()  &&
         StringBeginsWith(aOutputOptions, qualityPrefix)) {
       // have quality string
       nsCString value = NS_ConvertUTF16toUTF8(Substring(aOutputOptions,
                                                         qualityPrefix.Length()));
       int newquality = -1;
-      if (PR_sscanf(PromiseFlatCString(value).get(), "%d", &newquality) == 1) {
+      if (PR_sscanf(value.get(), "%d", &newquality) == 1) {
         if (newquality >= 0 && newquality <= 100) {
           quality = newquality;
         } else {
           NS_WARNING("Quality value out of range, should be 0-100, using default");
         }
       } else {
         NS_WARNING("Quality value invalid, should be integer 0-100, using default");
       }