Hello Sagi,
Thank you for contacting National Instruments. It is possible to save frames directly to disk during acquisition. However, you might not be able to save them fast enough. Accessing and creating a new file each time a frame is acquired is rather slow compared to storing all of the frames to a single file (avi.) due to the overhead required to command a hard drive to create a new file. As a result, you will be limited on the rate through which you can write frames to individual files in a real-time environment. This maximum rate is determined my many factors such as processor speed, hard drive bandwidth, platter speeds, operating system, code complexity, and memory speeds. Saving files to the hard drive at 500 files per second might be a bit much.
I can say that if you consider using AVI, you will experience better performance in file I/O mainly because only one file will be opened during the entire acquisition. Once you finish acquiring the frames, you can index through them in LabVIEW with the IMAQ AVI Read Frame VI.
Is it necessary to save the frames to disk in real-time? Have you considered the use of a ring acquisition? A ring acquisition would use the much faster memory on your computer to hold the acquired frames until the hard drive has a chance to write them to disk. Depending on how long you are planning to acquire images, this might be the best way to accomplish your objective. Check out the LL Ring shipping example for more information on the use of a ring acquisition.
Regards,
Mike T
National Instruments
