问题：

[多选] Which two statements are true about the digital audio in a VoIP network？ （）

A .  Standard encoding techniques create an uncompressed digital data rate of 4000 bps.
B .  Standard encoding techniques create an uncompressed digital data rate of 8000 bps.
C .  Standard encoding techniques create an uncompressed digital data rate of 64，000 bps.
D .  Voice quality is not a concern if compression is not used.
E .  Two methods of quantization are linear and logarithmic.
F .  Two methods of compression are u-law and a-law.