[WIP] Add read speed option - #60
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Bloomca
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Bloomca
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I think this API looks good! I left a few comments for the implementation, also there a few typos in the comments but we can fix it later.
I think we should an example of "slow_read_track" which would read the first track from the default drive at 10x.
@strict-flower One question I am curious about and forgot to ask in the issue. If custom multiplier does persist (we'll need to test it), do you think we should set speed back to optimal in the drive destructor?
| /// By MMC-3 specification, It can be set to the optimal speed of the drive when it executes SET CD SPEED command with read speed (KB/s) = 0xFFFF. | ||
| /// On the Linux, the read speed will selected by the CDROM_SELECT_SPEED ioctl with speed = 0. It'll set the speed automatically and highest speed that supported by the drive. | ||
| Optimal, | ||
| /// Use the custom speed with specified multiplier. |
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We should add some inline documentation that it is 176KB/s * multiplier. Also maybe give an example that 10x is usually slow enough.
| #include <IOKit/storage/IOCDMediaBSDClient.h> | ||
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| Boolean request_cd_read_speed(int fd, uint16_t target_speed_kbs) { | ||
| int ret = ioctl(fd, DKIOCCDSETSPEED, target_speed_kbs); |
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I think we need to pass a pointer there (I remember it from your example in the issue and here it dereferences
| let target_speed_kbs = if multiplier == 0 { | ||
| 0xffff | ||
| } else { | ||
| multiplier * 176400 / 1000 |
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This can overflow. With u16, it is not that hard to do, however, generally seems that audio CD can max out at ~52.
So maybe we can clamp the multiplier to 100x?
| multiplier * 176400 / 1000 | ||
| }; | ||
| if target_speed_kbs > u16::MAX.into() { | ||
| // TODO: Implement error handle (CdReaderError?) |
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Similar to before, I think it might be easier to clamp the multiplier and this way we will never overflow
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Under development
Description
Background discussion is #59
Adds an option to request to set the read speed of the tracks.