Videos recorded by OpenStage can be quite large. Depending on the framerate and number of cameras, they can be 10GB or more despite using a form of lossless compression by default. For users who need to archive videos from their vision processor, using the video compression tool to decrease the overall size may be an option. Doing so will require the following steps:
- Download a video from your vision processor.
- Compress the video using the video compression tool at the command line.
- Storing externally or re-uploading the video to your vision processor.
- Optionally deleting the source video.
N.B. The video compression tool uses a high quality form of compression, but it is still lossy. There is no guarantee that compressed videos will track identically in the future.
Download a video from your vision processor
There are two ways to download a video from your vision processor. The first and easiest way is to use Backstage. This can be easily accomplished by right clicking on a video and selecting the "Download" option. While easy, this can be cumbersome to do for each video after a longer capture session.
For downloading videos in bulk, OpenStage vision processors support FTP access. A graphical tool is recommended for users such as:
- WinSCP - https://winscp.net/eng/download.php
- FileZilla - https://filezilla-project.org/
Once installed, simply point your FTP client at the vision processor's IP address. You do not need a user name or password. Once logged in, there will be a "video" folder. Navigate into that folder. Each sub-folder there corresponds to a recorded video on the OpenStage vision processor that you can download. Graphical FTP tools will allow you to multi-select and download in bulk.
Using the Video Compression Tool
The video compression tool ships with the OpenStage Client package and can be found in the "bin" subfolder of your installation. For example, if you installed to the default location with OpenStage 2.5, you would find the tool at the following path:
C:\Program Files\Organic Motion\OpenStage Client 220.127.116.1183\bin\video_compress.exe
Executing the command:
video_compress.exe -video_storage "C:/Share/" -src_video_prefix "Jump" -dst_video_prefix "Jump_Compressed" -quality 1 -compression_type "VP8"
Loads the video at C:/Share/Jump/ and compresses it for tracking. The resulting output is written to C:/Share/Jump_Compressed/
There are a number of options that can be set for the video compression tool. However, it is strongly recommended that you use the options above and only change the storage locations. These settings give excellent results and balance
Compression takes some time particularly for longer videos with more cameras and motion, but it can be quite worthwhile. Consider these statistics from a sample run at OrganicMotion.
- 5,710 frames. ~48 seconds at 120 frames per second.
- 23 cameras.
- Original video size was 25.1GB.
- Compression took 7minutes and 10s.
- Compressed video size was 391MB.
- Compression ratio of about 64:1.
To archive or store the compressed video, you should copy the entire folder for the video. In the above case, we specified a video root of C:/Share/ and wrote a compressed video to the subfolder, Jump_Compressed, as was specified by the -dst_video_prefix argument. Therefore, we would copy the entire Jump_Compressed folder to our storage location. This storage location might be an external USB hard drive or a network attached storage device as suits your use case.
If you do not copy all the files, the video will not be usable. There will be 1 OMV file per camera, 1 OMVMASTER file, and 1 scene.xml file for each video that you archive.
If you have stored compressed or uncompressed video in a second location, you can delete it from your vision processor by right clicking the video and selecting "Delete" to free up space. You may need to refresh the file view in Backstage using the Refresh button afterward to get a correctly updated value for available disk space on the vision processor.