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Filling the Disk Cache
A disk cache will fill automatically as you work within SynthEyes, storing each frame you use.
If you want to fill the cache all at once, perhaps before working on a shot at all, you should open SynthEyes, open the shot, and click Play to play through the entire shot. If you are using only a portion of the shot's entire frame, then only frames within that range will be valid in the cache. If you want the entire shot to be valid in the cache (for example, to work disconnected when you might change the frame range), then you should load the disk cache before changing the beginning and ending frames of the shot.
The Shot/Enable Prefetch and Shot/Read 1f at a time settings may affect how fast frames read, and thus how long it takes to fill the cache. The best settings will depend on your particular machine and the exact details of the source imagery (file type and codec), so you may want to experiment a little. You can monitor the playback frame rate on the SynthEyes status line to help.
When a shot is played, reading and decoding the original imagery and storing it in the disk cache, a large data flow is produced.
If your machine has RAM available, some of the disk cache will be stored temporarily by the operating system in that RAM, which saves time versus writing it to disk immediately. The operating system will move some of the data to the disk as it needs to use that RAM instead.
Once all available RAM has been used, additional frames can be decoded only as fast as they can be stored to disk. For example, with a 30 MB/sec non-SSD disk and 6 MB/frame, frames will be read at about 5 frames/second.
SSD drives are recommended for disk caches because they are much faster than hard drives. An Intel 520 SSD is specified to write at up to 520 MB/sec (6 Gbit/sec SATA), which would permit writes 10x faster, in the 50 frame/sec range. At that speed, the image decode time will dominate the playback rate. (SSDs similarly read much faster than hard drives, which is useful once the shot is in the disk cache.)
When you close SynthEyes, any unsaved data will immediately be queued to be written to disk. That can be tens of GBs depending on size of the file and the amount of RAM on your machine. Since a standard non-SSD disk drive has only a few tens of MBs/sec of write speed, saving the remaining data can take ten minutes or more. Your operating system does that automatically in the background, so that it will have little impact on other things you are doing.
Warning : if your electric power fails or you force your machine to shut off before the BAFF file has been completely written, then any un-saved data will be lost. The BAFF file will be unusable, since it will claim to have many valid frames, but some will not have the complete image stored. Although this is inconvenient, it is easily rectified by clicking Script/Flush Shot's Caches..
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