Project # 2006-146 INTEX-B2
INtercontinental Chemical Transport EXperiment, Phase B2
Principal Investigator(s): Bill Brune, et al.
NSF/NCAR C-130Q Hercules (N130AR)
Digital Image and MPEG Movie Information
Digital images were acquired from a forward-facing cockpit camera. The field of view is 67° horizontal by 53° vertical. Raw image resolution is 704 (horizontal) x 480 (vertical) rectangular pixels. Pixel height is 1.1 times the pixel width. When displayed on a computer monitor, a square will appear as a rectangle with an aspect ratio of 1.1.
The images were acquired at 1 frame per second. They are stored as compressed JPEG files, typically 25kB each. The [original] file name is in the form "c130__fwd_yymmdd_hhmmss.jpg" where "c130" is the platform, "fwd" indicates the forward viewing direction, yymmdd is the 2-digit year, month, and day, and hhmmss is the UTC hours, minutes, and seconds. Each image is annotated at the top left with the date and time as reported to the camera by the aircraft ntp server. The images are stored in tar files covering a one-hour period. The tar files are about 100 MB in size. Occasionally the very beginning or end of a flight may be missing. There may be occasional few-second gaps due to network congestion.
The flight movies are made from the one-frame-per-second images, but they play back at 15 frames per second. Therefore, an entire 10-hour flight is viewable as a 40-minute movie. Playback software often has options for varying the playback speed as well as single-frame step capability, forward and backward. The aircraft position, attitude, and a number of state parameters are included as a sidebar in the movie.
To create the MPEG-4 movie files the raw images were scaled to create square pixels appropriate for computer display, and the netCDF data were added to the side to give a standard movie resolution of 720 x 480. These processed-image files were then compiled into a movie using the linux FFMPEG tools. The movie file for a flight is about 250 MB in size. They can be played by a variety of players, but note that Microsoft Windows Media Player does not yet have MPEG-4 compatibility. Players are available at no charge from the websites listed in the table. (Versions released prior to January 2006 have not been tested.)
|mplayer||Linux, Mac, Win||http://www.mplayerhq.hu/homepage/design6/info.html|
|VLC||Linux, Mac, Win||http://www.videolan.org/vlc|
FF01: Missing the last few minutes.
RF01: Movie truncated due to darkness.
RF02: video about 20 seconds behind data at beginning; OK by 18:10. Forest fire at 19:57.
RF03: Missing data from 15:56 to 16:19 (value = -32767). Missing last few minutes of flight (movie ends at 23:49). Multiple fires at 21:10.
RF11: First third of flight is in darkness.