Analog Video Recording in Windows
Current generation windows PCs can easily record (capture) analog video. Although many video capture setups record the video with MP4 or similar codecs, these codecs are lossy (lower quality). To preserve as much signal as possible when recording occultation data, we use lossless codecs. For this reason, we do not recommend the software shipped with most video capture hardware. This guide explains the hardware configuration, software configuration, and steps for recording high quality analog video with a PC.
Any recent generation Windows PC should be able to record high quality video without dropping frames. Windows 7, 8, or 10 is best but Windows XP systems also work. The PC must have a USB port available for the video capture device and it should have roughly 10GB of free space on the hard drive. Laptop or desktop is fine. Obviously, laptops and tablets are more portable and therefore a better option than a desktop if you will be observing (and recording) away from home (or observatory). The most portable option is a “compute stick” (e.g. the Kangaroo Mobile Desktop and the Intel Compute Stick). The Kangaroo Mobile Desktop is the most convenient since it has a built in battery. Compute sticks are very small but do not have a built-in monitor or keyboard. See the section below on Advanced Topics for more information on using a compute stick for recording.
Analog Video Capture Hardware
We currently recommend the StarTech SVID2USB23 analog video capture device. The older SVID2USB2 is also a good option but tends to be more expensive. Much of this guide will refer to the SVID2USB2 but they are interchangeable. These devices are generally available on Amazon for less than $50. NOTE: You will still need an IOTA-VTI or similar video time inserter to provide accurate time stamps for your video recording BEFORE it is recorded with a PC.
We recommend the Lagarith video codec (losssless compression). The resulting AVI files will be about 4GB for a 10 min recording.
Video Capture Software
For Windows 7, 8, and 10 we can recommend three options for video capture software: “IOTA_VideoCapture”, “OccuRec”, and LiMovie. Both the IOTA_VideoCapture program and LiMovie generate an AVI file which can be viewed with a wide variety of software programs. OccuRec generates an AAV file which can be viewed and analyzed by the program “Tangra”.
For Windows XP we recommend “VirtualDub”. note: VirtualDub does not work on many Windows 8 or Windows 10 systems. VirtualDub generates an AVI file.
- Install the Lagarith video codec
- You will find the Lagarith installer via the Lagarith website (use the installer version rather than the manual install version).
- Install the SVID2USB2 drivers : instructions
- General PC configuration for video recording : notes
- Installing the video capture software (choose one)
Practice and Prepare – before recording an important occultation event, do a test run with your setup to eliminate problems beforehand. Lunar occultations are a good test for recording occultations. Total lunar occultations occur on most nights of an early moon and do not require travel (you can observe from home). Asteroid occultations are usually more challenging and much less frequent for any given location.
Here are a few suggestions:
Before leaving home for a remote observation:
- Verify that the system time on your recording computer is accurate
- Verify that you have enough free space on your hard drive for your expected recording duration
- Optional – setup/schedule the event timer for recording
- Put the computer in Airplane mode
- Shut down all programs other than your application for capturing video
- Shut down your recording computer – avoid any data loss due to improper power down.
- Transfer video file to main computer for analyzing the data. If you recorded onto a tablet or stick computer, it is generally much easier to copy the video file from the recording computer a USB stick , then transfer from the USB stick to the main computer.
View / Analyze Captured Video Files
If you recorded your video with a small computer, transfer it to a “main computer” (larger screen, faster processor) to analyze the video.
- If you recorded with the Lagarith codec (IOTA_VideoCapture or VirtualDub), you must also install the Lagarith codec on the computer used to analyze your video.
- If you recorded your video with OccuRec, you must use the free program Tangra to analyze the Video.
- Using Compute Sticks for highly portable setups (tbd)
2016 Jul 20 (Steve Preston) Initial version