[OSM-talk] JOSM Audio Mapping - Technical Issues

David Earl david at frankieandshadow.com
Fri Jan 2 12:24:30 GMT 2009

I should also have said that the system *does* also handle multiple 
files already if you modify the GPX file to refer to the relevant audio 
files at the correct time stamps (as described in the help file).

A preprocessor to do this automatically would be very handy for people 
who want to work in this way.


On 02/01/2009 12:17, David Earl wrote:
> JOSM Audio is designed to sync *continuous* audio with the GPX track. 
> This means you don't have to fiddle with the recorder buttons every time 
> you want a voice note, you can just leave it in a pocket; but nor do you 
> have to listen to inordinate amounts of heavy breathing.
> See the JOSM help file at 
> http://josm.openstreetmap.de/wiki/Help/HowTo/AudioMapping for details 
> (or use Help while in JOSM, same thing).
> I too have an Olympus recorder. The clock on mine is about 0.15% out, 
> which means that a continuous sound track can be many tens of metres out 
> after an hour's recording, so make sure you at least check whether you 
> need to calibrate (as described in the help). I guess the time stamps 
> for multiple files will suffer from the same problem too unless the 
> recorder sampling rate and the time stamps run off a different clock.
> Note that in the long play mode the Olympus recorder (well, my model, so 
> I guess all of them) records 4 bit audio, so you'll need to convert it 
> to 8-bit using Audacity or similar before it is usable in JOSM. This is 
> quick and easy for one long file, but a bit tedious if you have to do it 
> for many small files.
> It would be relatively simple to extend the existing functionality to 
> also process a folder full of time-stamped WAV files, one for each GPX 
> waypoint; but really it is much easier just to record one long session - 
> easier to record, easier to preprocess and easier to handle in JOSM.
> Someone mentioned that someone has broken audio in a recent JOSM 
> version. I haven't had a chance to check yet, but I have made no changes 
> to the audio recently.
> On a bike, I suggest using a cheapo PC headset (with a bit of sponge 
> over the mic) rather than the built-in mic as it is completely hands 
> free then.
> David
> On 01/01/2009 16:58, Gregory wrote:
>> I got a new olympus digital voice recorder for Christmas, which means I 
>> have to use http://code.google.com/p/odvr/ to download the recordings to 
>> my linux/ubuntu computer. Unfortunatly when downloading the wav files 
>> the recorded date gets lost, but a table of the times can be displayed 
>> on the command prompt.
>> How does JOSM Audio get the date/time of the wav files?
>> I tried changing the linux files atime and mtime (last accessed/modified 
>> time), but the location marker for the audio does not change. Is it 
>> using the ctime (created time)? I can not change the ctime and it gets 
>> set to the time the files were downloaded off the voice recorder.
>> I have filled an issue with the odvr downloader, but I want to confirm 
>> that it is the ctime that needs to be right for JOSM. I was recording 
>> ~2sec comments as I passed a location, so I have a trip with 60 
>> recordings waiting to be mapped.
>> My final idea is maybe I could make a JOSM plugin (now I've learnt some 
>> Java) that takes a fixed-width txt table of time stamps and names, and 
>> match the times to an open gpx file to create waypoints. This would mean 
>> I have to open audio files outside of josm, but at least I would know 
>> where they were recorded. Such a plugin may help people with other media 
>> problems, ao I wonder has something along those lines already been done?
>> I've been told audio mapping is more amazing than photo mapping, and it 
>> would be ideal cycling in these cold winter months. Sadly it's not going 
>> to well yet, so I hope to get this sorted.
>> Gregory Marler
>> http://www.livingwithdragons.com
>> ------------------------------------------------------------------------
>> _______________________________________________
>> talk mailing list
>> talk at openstreetmap.org
>> http://lists.openstreetmap.org/listinfo/talk
> _______________________________________________
> talk mailing list
> talk at openstreetmap.org
> http://lists.openstreetmap.org/listinfo/talk

More information about the talk mailing list