[gegl] ff-save: only rescale audio packet timestamp when we actually have one

[Øyvind Kolås <ok src gnome org>]

commit a7fc6b4b3fa9d190c6b0f1223f0792e4452bbd25
Author: Øyvind Kolås <pippin gimp org>
Date:   Fri Jun 30 20:55:39 2017 +0200

    ff-save: only rescale audio packet timestamp when we actually have one

 operations/external/ff-save.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/operations/external/ff-save.c b/operations/external/ff-save.c
index e506217..f50c182 100644
--- a/operations/external/ff-save.c
+++ b/operations/external/ff-save.c
@@ -510,13 +510,13 @@ write_audio_frame (GeglProperties *o, AVFormatContext * oc, AVStream * st)
     av_frame_make_writable (frame);
     ret = avcodec_encode_audio2 (c, &pkt, frame, &got_packet);
 
-    av_packet_rescale_ts (&pkt, st->codec->time_base, st->time_base);
     if (ret < 0) {
       fprintf (stderr, "Error encoding audio frame: %s\n", av_err2str (ret));
     }
 
     if (got_packet)
     {
+      av_packet_rescale_ts (&pkt, st->codec->time_base, st->time_base);
       pkt.stream_index = st->index;
       av_interleaved_write_frame (oc, &pkt);
       av_packet_unref (&pkt);