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Bug 617223 - [tags] Add tags for direction of capture and movement
[tags] Add tags for direction of capture and movement
Status: RESOLVED FIXED
Product: GStreamer
Classification: Platform
Component: gstreamer (core)
git master
Other All
: Normal enhancement
: 0.10.30
Assigned To: GStreamer Maintainers
GStreamer Maintainers
Depends on:
Blocks:
 
 
Reported: 2010-04-29 22:22 UTC by Thiago Sousa Santos
Modified: 2010-05-03 17:02 UTC
See Also:
GNOME target: ---
GNOME version: ---


Attachments
tags: Adds geo location direction tags (4.28 KB, patch)
2010-04-30 00:59 UTC, Thiago Sousa Santos
committed Details | Review

Description Thiago Sousa Santos 2010-04-29 22:22:50 UTC
We could add tags for tagging direction of movement and capture (0 to 360 degrees).

I propose:

GST_TAG_GEO_LOCATION_CAPTURE_DIRECTION (double from 0 to 360 degrees, 0 is geographic north, clockwise)
GST_TAG_GEO_LOCATION_MOVEMENT_DIRECTION (same).

Meanwhile, we could also have
GST_TAG_GEO_LOCATION_MOVEMENT_SPEED (in m/s or km/h?)

I don't care about this one, but as we add the movement direction we might also add the speed, right?

I'll prepare a patch.

FYI, those are used in exif (which xmp uses)
Comment 1 Tim-Philipp Müller 2010-04-29 22:52:40 UTC
> GST_TAG_GEO_LOCATION_CAPTURE_DIRECTION (double from 0 to 360 degrees, 0 is
> geographic north, clockwise)

This is the direction into which the camera is pointed?


> GST_TAG_GEO_LOCATION_MOVEMENT_DIRECTION (same).

Makes sense, but in what scenario is this interesting in a multimedia context? When snapshotting/filming out of a train window or something? Or just for completeness sake?

> Meanwhile, we could also have
> GST_TAG_GEO_LOCATION_MOVEMENT_SPEED (in m/s or km/h?)
> 
> I don't care about this one, but as we add the movement direction we might also
> add the speed, right?

Agreed. I'd go for m/s, it seems more 'neutral' and natural.

The DOP might also be of interest, as an indication how precise the lat/long/elev values are, but maybe that value is too GPS-specific?
Comment 2 Thiago Sousa Santos 2010-04-29 23:26:42 UTC
(In reply to comment #1)
> > GST_TAG_GEO_LOCATION_CAPTURE_DIRECTION (double from 0 to 360 degrees, 0 is
> > geographic north, clockwise)
> 
> This is the direction into which the camera is pointed?

Exactly

> 
> 
> > GST_TAG_GEO_LOCATION_MOVEMENT_DIRECTION (same).
> 
> Makes sense, but in what scenario is this interesting in a multimedia context?
> When snapshotting/filming out of a train window or something? Or just for
> completeness sake?

Yes, I guess that's the scenario. I looked up those while browsing exif/xmp spec and thought we should get all those in one go.

> 
> > Meanwhile, we could also have
> > GST_TAG_GEO_LOCATION_MOVEMENT_SPEED (in m/s or km/h?)
> > 
> > I don't care about this one, but as we add the movement direction we might also
> > add the speed, right?
> 
> Agreed. I'd go for m/s, it seems more 'neutral' and natural.

This completes the movement direction. And I agree m/s is better.

> 
> The DOP might also be of interest, as an indication how precise the
> lat/long/elev values are, but maybe that value is too GPS-specific?

Exif represents it as a Rational (fraction), wikipedia tells us that it mathematically defined [1], so it should be possible to have it. I'll do some further reading.

http://en.wikipedia.org/wiki/Dilution_of_precision_(GPS)#Computation_of_DOP_Values
Comment 3 Thiago Sousa Santos 2010-04-30 00:49:15 UTC
A brief non-technical info about DOP if someone is interested in it: http://www.poly-electronic.ch/dok-gps/gps_eometry.htm
Comment 4 Thiago Sousa Santos 2010-04-30 00:59:25 UTC
Created attachment 159953 [details] [review]
tags: Adds geo location direction tags

Adds 3 new geo location tags involving direction and
movement of capture. Those are:

API: GST_TAG_GEO_LOCATION_CAPTURE_DIRECTION
API: GST_TAG_GEO_LOCATION_MOVEMENT_DIRECTION
API: GST_TAG_GEO_LOCATION_MOVEMENT_SPEED

Fixes #617223
Comment 5 Tim-Philipp Müller 2010-04-30 07:48:23 UTC
Comment on attachment 159953 [details] [review]
tags: Adds geo location direction tags

>+  gst_tag_register (GST_TAG_GEO_LOCATION_CAPTURE_DIRECTION, GST_TAG_FLAG_META,
>+      G_TYPE_DOUBLE, _("geo location capture direction"),
>+      _("indicates the direction the device is pointing to when capturing a "
>+          " a media. It is represented as degrees in floating point "

One " a" too many :)
Comment 6 Thiago Sousa Santos 2010-05-03 17:01:45 UTC
Fixed.

Module: gstreamer
Branch: master
Commit: d020295ae0ed79fe7db3628a5e0ee2158274cfa5
URL:    http://cgit.freedesktop.org/gstreamer/gstreamer/commit/?id=d020295ae0ed79fe7db3628a5e0ee2158274cfa5

Author: Thiago Santos <thiago.sousa.santos@collabora.co.uk>
Date:   Thu Apr 29 21:57:15 2010 -0300

tags: Adds geo location direction tags

Adds 3 new geo location tags involving direction and
movement of capture. Those are:

API: GST_TAG_GEO_LOCATION_CAPTURE_DIRECTION
API: GST_TAG_GEO_LOCATION_MOVEMENT_DIRECTION
API: GST_TAG_GEO_LOCATION_MOVEMENT_SPEED

Fixes #617223