electronicarts: don't set codec timebase

Demuxers are not supposed to set it.
Set stream timebase and framerates instead (this is a cfr container with
no timestamps).

libavformat/electronicarts.c

@@ -417,9 +417,11 @@ static int ea_read_header(AVFormatContext *s)
         st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
         st->codec->codec_id = ea->video_codec;
         st->codec->codec_tag = 0;  /* no fourcc */
-        st->codec->time_base = ea->time_base;
         st->codec->width = ea->width;
         st->codec->height = ea->height;
+        avpriv_set_pts_info(st, 33, ea->time_base.num, ea->time_base.den);
+        st->r_frame_rate = st->avg_frame_rate = (AVRational){ea->time_base.den,
+                                                             ea->time_base.num};
     }
 
     if (ea->audio_codec) {