pub enum ReadSpeed {
Unchanged,
Optimal,
CustomMultiplier(u8),
}Expand description
A platform-independent read-speed request for an optical drive.
The requested speed is a preference, not a guarantee. Under MMC, a drive may select the requested rate or a higher supported rate; the OS and drive firmware may further adjust or reject the request.
A successful speed change may remain active for subsequent reads. This crate does not restore the previous setting, although the OS, firmware, or other software may change it later.
Variants§
Unchanged
Do not issue a speed-change request.
This is the default in ReadOptions. The drive
retains whatever speed was previously selected by the OS, firmware, or
another application.
Optimal
Ask the platform and drive to select an automatic or optimal read speed.
On macOS and Windows, this uses the 0xFFFF drive-selected/maximum-speed
sentinel associated with SET CD SPEED (0xBB). On Linux,
CDROM_SELECT_SPEED is called with a speed of zero to request automatic
selection.
CustomMultiplier(u8)
Request a multiple of the nominal CD-DA 1× rate.
One unit represents 176.4 kB/s, so CustomMultiplier(1) requests 1× and
CustomMultiplier(10) requests 10×. macOS and Windows convert the
multiplier to kB/s, while Linux passes it as a speed multiplier.
CustomMultiplier(0) is equivalent to Optimal.