diff --git a/ffmpeg.c b/ffmpeg.c
index 90f05ce12f..880e45214c 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -2205,7 +2205,10 @@ static int transcode_init(OutputFile *output_files, int nb_output_files,
                     codec->time_base.num *= icodec->ticks_per_frame;
                     codec->time_base.den *= 2;
                 }
-            } else if(!(oc->oformat->flags & AVFMT_VARIABLE_FPS)) {
+            } else if(!(oc->oformat->flags & AVFMT_VARIABLE_FPS)
+                      && strcmp(oc->oformat->name, "mov") && strcmp(oc->oformat->name, "mp4") && strcmp(oc->oformat->name, "3gp")
+                      && strcmp(oc->oformat->name, "3g2") && strcmp(oc->oformat->name, "psp") && strcmp(oc->oformat->name, "ipod")
+            ) {
                 if(   copy_tb<0 && av_q2d(icodec->time_base)*icodec->ticks_per_frame > av_q2d(ist->st->time_base)
                                 && av_q2d(ist->st->time_base) < 1.0/500
                    || copy_tb==0){