GeoVid Android App
This page describes technical details of our GeoVid georeferenced video application running on Android-based mobile phones.
OBJECTIVES
The purpose of this Android application is to provide easy video recording annotated with location meta-data and to allow uploading of this information to our georeferenced video search services.
NOTE: By its very nature this Android app will collect location, direction, date and time information and submit it to our server. We do not collect any personally identifiable information. If you have privacy concerns about the collection of such information, please do not use this app!
FEATURES
- Record geo-referenced videos with DVD-quality (640 x 480, 3 Mbps) video resolution.
- Display the GPS trajectory of a recorded video with color-coded GPS accuracy info.
- Upload recorded videos to our search server (http://geovid.org), where users can submit geo-referenced queries (such as range, directional and surround queries) and display videos via newly designed web interface.
- Segment a DASH-compliant video during video uploading, which makes the video quickly visible to the public, typically less than 10 seconds soon after the user requests a video uploading. More detailed technology behind this is covered in our recent ACM MMsys 2012 publication.
- Automated upload failure recovery.
VERSION HISTORY
- v1.5.1
The latest version contains many bug fixes, background uploading, notifications, etc. Records all sensor values (accelerometer, magnetic field, computed compass, light level, GPS signals, and WiFi fingerprints).
INSTALLATION
USERS GUIDE
When you start the application for the first time, you may see a black screen after the installation since there have been no videos recorded. To use our application, please click the "MENU" key on your phone to launch the main menu.
MAIN MENU OPTIONS
- RECORDING
After pressing the "Record" option, the app enters the recording-ready state (left), which displays verbose sensor information (GPS locations, accuracy, magnetic compass information, and ambient light level). You can click on the screen to disable the verbose text output (center). You can also see a GPS signal indicator in the screen's bottom-left corner. We recommend not to start recording a video until a GPS signal is received. Otherwise, your video would have no location information associated with it. When clicking the "Record" button in the bottom-right corner, the app immediately begins to record video as shown in the right figure. To stop recording, you may press either the "BACK" key on your phone or the "Stop" button in the bottom-right corner of the recording screen, which brings you to show a Context Menu that will be explained later on this page.
Initial camera preview screen
Toggle screen without verbose info
Recording screen
- STOP UPLOAD
The application supports video uploading in the background. Even if you close the application, your uploading requests will be continuously processed until all the requests are completed. Usually you may see their progress status in the notification bar on your phone (as depicted in the following figure). However, sometimes the upload status bar may appear frozen for a lengthy amount of time, due to unexpected connection errors. To solve this issue temporarily, you may select "STOP UPLOAD" in the main menu. You may also use this option to manually cancel all uploading requests.
Once uploading is completed (or has failed due to connection errors) you will be notified via the progress status view in the notification bar.
- CHANGE SERVER URL
To use a different server (this is not currently supported) you can change the upload URL with this option. Once modified, all subsequent uploading will be posted to the url you newly specified.
CONTEXT MENU OPTIONS OF A VIDEO
You will see this option dialog after stopping video recording or selecting a video from the thumbnail view.
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In the context menu, the following options are provided:
- REPLAY
You can replay the video by selecting the "Preview" option.
- DISPLAY VIDEO TRAJECTORY
Choose 'View Trajectory' to see the path you have travelled during the recording of the video. In Google Maps, red lines imply that GPS signals you received are accurate enough to pin-point your current location (2-6 meters under good conditions); purple lines indicate that the signals were corrupted because of mapping to a previously-known WiFi (or GPS) location when GPS signals were temporarily unavailable, which in fact is quite normal and will be eliminated automatically after the post-processing at a server. So you don't have to worry about such outliers. During the preparation of the map route, your dialog may seem frozen for a while, if there are many GPS points to be handled.
- UPLOADING
Choose this option to upload a chosen video. The upload operation will run in the background so you may start many upload requests at the same time. If the file was uploaded previously (we examine the upload status of a given video, comparing the file length of the video and its meta-data), your upload request will be automatically cancelled without incurring any further data transfer.
- EXPORT SENSOR DATA (to KML)
This functionality is designed to view the video trajectory in Google Earth. Unfortunately, the exported KML files are not visible in the Android application. You may manually copy the KML file to your PC to view it. We hope this functionality will be integrated with Google Earth if Google provides such an Android application in the future.
- DELETE
Once you have chosen this option, your recorded video will be removed from your application permanently. If you have uploaded the video, you can view it via our search services.
FUTURE PLANS
Currently, we do not implement any authentication mechanism as to whether contents are uploaded by a valid user. For user identification, we plan to use the "OpenID" approach, using a social media account such as Twitter or Facebook. For full user privacy protection, we will use "OAuth", where our application does not store any privacy-sensitive information such as a user's password.
We are also working on support for a real-time, low-bandwidth uploading service, where a user can upload meta-data instantly during video recording while submitting the actual video content later.
SUPPLEMENTARY MATERIALS
We may provide some of the format specifications and APIs at a later point in time, if there is community interest for this.
CREDITS
The GeoVid Android app is maintained by Dr. Beomjoo Seo. If you have questions, feedback, or suggestions, please drop me an email (see the Contact Us page).