Changes between Version 3 and Version 4 of Help/Preferences/Audio

Timestamp:

2008-03-06T14:28:24+01:00 (17 years ago)

Author:

David Earl <david@…>

Comment:

--

Help/Preferences/Audio

@@ -11 +11 @@
 == Display live audio trace ==
 
-Checking the box will cause an orange "play head" arrow to follow the track while playing back audio, showing where you were at the time you recorded what you are hearing (assuming the sound has been synchronized to the track).
+Checking the box will cause an orange "play head" arrow to follow the track while playing back audio, showing where you were at the time you recorded what you are hearing (assuming the sound has been synchronized to the track). You can drag this play head around to jump to commentary from elsewhere on the track.
 
 == Label audio markers ==
@@ -17 +17 @@
 Markers usually have an associated name or number. A plain marker, such as one made from a GPS waypoint, would show an X with the name alongside. Audio markers - that is, those which have sound associated with them, display a clickable icon to play the sound. This check box controls whether the name is also displayed.
 
-== Create markers from named trackpoints ==
+== Create non-audio markers when reading GPX ==
 
-When you [wiki:Help/Action/Open open a GPX file] any waypoints that were marked are opened in a separate marker layer. However, some GPS devices don't create waypoints, but instead just name poibnts which are part of the ordinary track. With this option checked, such points are automatically treated as if they were waypoints, that is added to a separate marker layer.
+If there are waypoints in the GPX file, a marker layer is usually
+created for explicit display of those waypoints (using a 'x'). If you
+are going to use audio markers in their own layer as well, you probably
+won't want these plain markers as well. This option allows you to
+turn off making the plain marker layer as a side effect of reading a
+GPX file.
 
-If you don't want this to happen always, you can do it on demand for particular GPX layers using the [wiki:Help/Action/MarkersFromNamedPoints Markers From Named Points] action on the conext menu for a GPX layer.
+== When importing audio, make markers from... ==
 
-== Min audio marker sample rate (seconds) ==
+Audio markers help you associate and synchronize between points in the
+audio commentary and positions on the GPS track. This section
+determines what combination of the contents of the GPX data and the
+audio are used to create these markers.
 
-If you have not collected explicit waypoints, you can create artifical audio markers along the GPS track using the [wiki:Help/Action/MakeSampledAudioLayer Make Sampled Audio Layer] action on the conext menu for a GPX layer, which allow you to play the sound recorded at that point of your journey.
+===== Explicit waypoints with valid timestamps =====
 
-This option controls the minimum time interval between such markers. (They must also be a minimum distance apart - see below - to avoid lots being created when you slowed down or stopped during your journey). The default is 15 seconds, which is reasonable for a cyclist doing 5m/s (about 11mph or 18km/h). In a car you'd want less time - say 7 seconds in an urban environment. On foot you'd want more - say 75 seconds.
+With this on any waypoints in the GPX layer are used to make a
+corresponding marker. However, if a waypoint does not have a
+timestamp (the GPS stored the time it was made, as for a track point) it will not be included. Nor will waypoints timed before the first track point be included.
 
-== Min audio marker sample rate (metres) ==
+===== Explicit waypoints with time estimated from track position =====
 
-Controls the minimum distance apart for sampled audio markers, as above. The default is 75m. You would only want to change this if you wanted more or less density of markers.
+Those waypoints which could not be imported using valid time stamps
+can alternatively be included by estimating their time from their
+nearest point on the track. You can treat all waypoints this way by
+also turning off the first option, or only those with inadequate
+timestamps by having both options turned on. However, if your GPS
+allows you to create waypoints away from the track, those which are
+more than about 25m from the track will be excluded: the closest part
+of the track is not clear and the time would probably not be credible.
 
-You will need one or two markers at specific locations to synchronize your soiund terack with. Don't increase the density to do this: use [wiki:Help/Action/MakeAudioMarkerAtPlayHead Make Audio Marker At Play Head] on the context menu for the audio marker layer once you have created it by sampling.
+===== Named trackpoints =====
+
+Some GPS devices don't create waypoints, but instead just name selected points
+which are part of the ordinary track. With this option checked, such
+points are imported as markers as if they were waypoints.
+
+===== Start of track =====
+
+You always need at least one audio marker, and if none of the above
+methods yield any, one called 'start' will always be created at the
+beginning of the track. With this option, you can also add a 'start'
+marker in addition to any others.
 
 == Forward/back time (seconds) ==