A. HOW TO DOWNLOAD THE DATA
============================ 
1, There are two script prepared for you, "download.sh" and "download.bat"
2, create a folder for the data you are downloading, for example, "dataset".
3, If you are linux and mac user, do it as following command,
cd dataset
./download.sh
4, If you are windows user, please download wget(http://gnuwin32.sourceforge.net/packages/wget.htm) first.Then copy the executable file its depending file of wget to "dataset", copy "download.bat" to "dataset",run download.bat.


B. DESCRIPTION OF THE METADATA FILE (.xml)
==============================================
Each video clip has associated XML file which contains the properties of the video and text file
containing the raw sensor trace of the file.

XML file description is given below. Fields marked optional may or may not exist:

(a) name: File name of the video

(b) deviceId: Identifies of the mobile phone

(c) start: Start time of the video clip in milliseconds from epoch

(d) end: End time of the video clip in milliseconds from epoch

(e) datemodified: Modification timestamp of the video file (in milliseconds from epoch). This field is set to zero if video is not modified after creation.

(f) resolution: Frame resolution of the video in pixels

(g) framerate: Frame rate of the video in frames per second

(h) filesize: Size of the file in bytes

(i) segmentsize(Optional): Unit is in milliseconds. Segment size is the period of aggregation of the orientation sensor data during the recording phase of the video. 
As the video is recorded, sensor data is produced along with it. We average the orientation sensor data over this period and create a field called "segment" in the XML. 
This average value is used to reduce  the upload of all raw orientation sensor data to the server. 

(j) Orientation: Compass sensor readings
    1. Direction: Average Direction towards which the camera faces for the duration of the clip
    2. Inclination: Average Forward/Backward inclination of the phone for the duration of the clip
    3. Roll: Average Sideward orientation of the phone for the duration of the clip
    
(k) Location(Optional): GPS sensor readings
    1. Latitude: Weighted average of latitude for the duration of the clip. Weights are accuracy values from GPS sensor
    2. Longitude: Weighted average of longitude for the duration of the clip. Weights are accuracy values from GPS sensor
    3. Accuracy: Average accuracy of GPS sensor readings for the duration of the clip
    4. Sample mean Latitude: Unweighted average of latitude for the duration of the clip
    5. Sample mean Longitude: Unweighted average of longitude for the duration of the clip
    6. Sample Standard Deviation Latitude: Unweighted standard deviation of latitude for the duration of the clip
    7. Sample Standard Deviation Longitude: Unweighted standard deviation of longitude for the duration of the clip
    If the GPS readings are not available, then this field is marked with message "No location readings available"

(l) Segment(Optional): As already mentioned, the recording interval of the video is divided into segments. For instance, if the segmentsize is 5secs and the video recording is for 20sec,
[0,5) is segment 0, [5,10) is segment 1, [10,15) is segment 2, [15,20) is segment 3. The orientation sensor data produced during each segment is averaged and the average values
are mentioned in the corresponding "segment" field in the XML. The attributes of the "segment" are given below:
1. index: auto-generated sequential id for each segment
2. Orientation field (direction, inclination, roll) already described above.
3. numreadings: Number of readings produced during that segment.
If this field does not exist, the data could be regenerated using the raw sensor trace (.txt) file.


C. DESCRIPTION OF THE SENSOR TRACE FILE (.txt)
==========================================
Sensor Trace Description:

1. (Field 1) Timestamp of the sensor reading (in milliseconds from epoch)

2. (Field 2,3,4) orientation sensor data. 
(a) Direction of phone in radians
(b) Inclination of phone in radians
(c) Roll of phone in radians

3. (Field 5,6,7) phone acceleration(movement) sensor data. 
(a) Acceleration in x direction
(b) Acceleration in y direction
(c) Acceleration in z direction

For more information, refer to:
http://developer.android.com/reference/android/hardware/SensorManager.html


D. EVENT, START TIME, END TIME
==========================================
NAF_160312, 2012-03-16 20:00:00, 2012-03-16 21:00:00
NAF_230312, 2012-03-23 20:30:00, 2012-03-23 21:20:00
SAF_290512, 2012-05-29 18:00:00, 2012-05-29 20:30:00
RAF_100812, 2012-08-10 10:00:00, 2012-08-10 13:00:00
GT_090912, 2012-09-09 20:30:00, 2012-09-09 21:30:00
NS_271212, 2012-12-27 20:00:00, 2012-12-27 20:30:00
