Treat values as fixed point when converting to bit rates during quantization

[nfrechette]

When we try bit rates, we decay our values by simulating quantization to the desired number of bits. Perhaps instead we could quantize once to the highest bit rate, and shift the least significant bits off.

Can we treat the values as fixed point since the range is fixed?

If we can, can we leverage this somehow during decompression or by streaming those truncated bits?