qtdemux: Update duration when we get more information
qtdemux: Update duration when we get more information

When dealing with fragmented files, we will get more accurate duration
information via the mfra and moof atoms.

In order for playback to not stop at the initial duration (from the
moov atom), we need to check and update the various duration variables
when we find more information.

Fixes playback of fragmented files in pull mode

loshca/gst-plugins-good,shelsonjava/gst-plugins-good,ikonst/gst-plugins-good,chamois94/gst-plugins-good,rawoul/gst-plugins-good,StreamUtils/gst-plugins-good,ikonst/gst-plugins-good,veo-labs/gst-plugins-good,BigBrother-International/gst-plugins-good,kittee/gst-plugins-good,BigBrother-International/gst-plugins-good,pexip/gst-plugins-good,sh0/gst-plugins-good,ijsf/OpenWebRTC-gst-plugins-good,sebras/gst-plugins-good,froggatt/gst-plugins-good-m,pexip/gst-plugins-good,StreamUtils/gst-plugins-good,Kurento/gst-plugins-good,sebras/gst-plugins-good,rawoul/gst-plugins-good,froggatt/gst-plugins-good-m,hizukiayaka/gst-plugins-good,froggatt/gst-plugins-good-m,freedesktop-unofficial-mirror/gstreamer__gst-plugins-good,chamois94/gst-plugins-good,vatavuserban/gst-plugins-good,GStreamer/gst-plugins-good,freedesktop-unofficial-mirror/gstreamer__gst-plugins-good,shelsonjava/gst-plugins-good,GStreamer/gst-plugins-good,sebras/gst-plugins-good,Kurento/gst-plugins-good,StreamUtils/gst-plugins-good,vatavuserban/gst-plugins-good,sh0/gst-plugins-good,ijsf/OpenWebRTC-gst-plugins-good,froggatt/gst-plugins-good-m,pexip/gst-plugins-good,Kurento/gst-plugins-good,GrokImageCompression/gst-plugins-good,hizukiayaka/gst-plugins-good,GStreamer/gst-plugins-good,sebras/gst-plugins-good,sh0/gst-plugins-good,pexip/gst-plugins-good,hizukiayaka/gst-plugins-good,Kurento/gst-plugins-good,ijsf/OpenWebRTC-gst-plugins-good,ikonst/gst-plugins-good,freedesktop-unofficial-mirror/gstreamer__gst-plugins-good,kittee/gst-plugins-good,stfl/gst-plugins-good,vatavuserban/gst-plugins-good,sh0/gst-plugins-good,BigBrother-International/gst-plugins-good,kittee/gst-plugins-good,rawoul/gst-plugins-good,veo-labs/gst-plugins-good,veo-labs/gst-plugins-good,GrokImageCompression/gst-plugins-good,stfl/gst-plugins-good,Kurento/gst-plugins-good,GrokImageCompression/gst-plugins-good,shelsonjava/gst-plugins-good,stfl/gst-plugins-good,kittee/gst-plugins-good,ijsf/OpenWebRTC-gst-plugins-good,vatavuserban/gst-plugins-good,loshca/gst-plugins-good,chamois94/gst-plugins-good,pexip/gst-plugins-good,stfl/gst-plugins-good,loshca/gst-plugins-good,chamois94/gst-plugins-good,GrokImageCompression/gst-plugins-good,GStreamer/gst-plugins-good,StreamUtils/gst-plugins-good,shelsonjava/gst-plugins-good,BigBrother-International/gst-plugins-good,freedesktop-unofficial-mirror/gstreamer__gst-plugins-good,hizukiayaka/gst-plugins-good,loshca/gst-plugins-good,ikonst/gst-plugins-good,rawoul/gst-plugins-good,veo-labs/gst-plugins-good