This seems like a reasonable goal if you've got the right hardware, Right?
aplay -L you'll want to see that you have a iec958 (optical out) device.
iec958:CARD=PCH,DEV=0 HDA Intel PCH, ALC892 Digital IEC958 (S/PDIF) Digital Audio Output
Check to see what format and bitrate is actually being used by the device:
~ cat /proc/asound/card0/pcm1p/sub0/hw_params
access: MMAP_INTERLEAVED format: S16_LE subformat: STD channels: 2 rate: 48000 (48000/1) period_size: 44100 buffer_size: 88200
This seems like an interesting tool to dump optical output information, even if it doesn't appear to do much in consumer mode.
The original quake soundrack was recorded to the cd with pre-emphasis applied to the tracks. This means that the higher frequencies would be boosted prior to writing the tracks, resulting in a better signal to noise ratio. If you use a dedicaated cd device or direct line, the emphasis bit will be detected, boost removed, and you hear what you expect. Unfortuantely, if you read the tracks as data for copying to flac, the boost will persist and you'll have a heavy high frequency version of the soundtrack. This is well handled with SoX but it took me an embarrasingly long amount of time actually learn emphasis existed in spite of decades of listening to this cd.
quake soundtrack solutions - source of the enlightenment.