[OSM-talk] Continuous audio in JOSM on tracks without waypoints

[David Earl]

To augment continuous audio synchronized with waypoints that I mailed 
about earlier this week, I have now also added the facility to work with 
continuous audio recordings on tracks where you don't have or don't want 
to use explicit GPS waypoints. This will be in tomorrow's JOSM build.

After loading your GPX track, right click on the GPX layer and choose 
the new "Make Sampled Audio Layer" option. This will ask for your WAV 
file; then it will create a new layer combining the audio track with the 
GPX trackpoints to produce a set of audio markers laid out along the 
track. These will be at least 15 seconds and 75 metres apart, or 
whatever values you choose for these in Advanced Preferences settings 
for "marker.audiosampleminsecs" and "marker.audiosampleminmetres" 
respectively)(*).

You're then in a similar position to applying audio to explicit 
waypoints as per my previous changes: you can synchronise to a marker 
near the beginning of the track, play by reference to the visual 
position on the map, jump forward and back in the commentary, pause and 
resume and so on.

The sampled markers are named according to the time offset from the 
beginning of the sound track (e.g. "1:37", "1:09:07"). To facilitate 
this, I've reversed the default for whether to show text for button 
markers (audio, image and web), but you can turn these off as before, 
transiently from the right button layer menu, or permanently by setting 
marker.buttonlabels to false in Advanced Preferences.

David


(*) the defaults are chosen so that they are about the same for a 
cyclist travelling at 5 metres per second (about 11mph or 18km/h), so 
you get a useful but not overwhelming number of samples, but if you stop 
or slow down, you don't suddenly get a concentration of points close 
together. Of course if you stop and then record intermittently, you'll 
still find it hard to locate the bit of commentary you want - the whole 
idea is it is related to landmark junctions or loops you make in the 
road or whatever. If you're in a car you might want to set the sample 
time a bit shorter, say 7.5 in an urban environment, though the distance 
would probably be the same unless you actually want a higher or lower 
density, and maybe 60 to 90 seconds apart if walking at a typical 1 m/s.