fixed wrong track dur estimation in fragmented files
fixed wrong track dur estimation in fragmented files

gpac/gpac,gpac/gpac,rbouqueau/gpac,gpac/gpac,rbouqueau/gpac,rbouqueau/gpac,rbouqueau/gpac,rbouqueau/gpac,gpac/gpac,rbouqueau/gpac,gpac/gpac,gpac/gpac,gpac/gpac,rbouqueau/gpac,gpac/gpac,rbouqueau/gpac