AY Crudentials: 2 Bit Samples
Posted: Sun Jan 22, 2006 11:47 am
2 Bit Samples refer to the source rather than the output.
2Bit samples have the clear advantage of being very memory efficient, since 4 sample values can be stored in every byte.
However, 2 bit samples suffer from low resolution having only 4 possible values.
The classic Rambo and Madonna samples used 2 Bit to great effect.
a 2 Bit sample is either stored in a byte as 0123 or 3210 format whereby the lower 2 bits of the byte store the first value, the next 2 bits hold the second and so forth.
Once the 2 bit entity has been extracted, it is then transformed into a 4 bit value (either through shifting (0,1,2,3 to 0,4,8,12) or used to index a table that holds better values) and finally sent to the AY Volume register.
2Bit samples have the clear advantage of being very memory efficient, since 4 sample values can be stored in every byte.
However, 2 bit samples suffer from low resolution having only 4 possible values.
The classic Rambo and Madonna samples used 2 Bit to great effect.
a 2 Bit sample is either stored in a byte as 0123 or 3210 format whereby the lower 2 bits of the byte store the first value, the next 2 bits hold the second and so forth.
Once the 2 bit entity has been extracted, it is then transformed into a 4 bit value (either through shifting (0,1,2,3 to 0,4,8,12) or used to index a table that holds better values) and finally sent to the AY Volume register.