As I know this is quite true in case of audio that cames from/goes to the kmixer. I do not remember exactly, but for copying 10 ms of data several copy calls can happen, not ? In case of DirectKS the amount of data copied depends on the application. Markus. ________________________________ De : wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] De la part de Neetu Sand Envoyé : mardi 10 août 2010 13:55 À : wdmaudiodev@xxxxxxxxxxxxx Objet : [wdmaudiodev] Is ByteCount fixed in CopyTo/From to 10 ms? Hi, Based on my knowledge I know that in CopyTo/From routines of a wavecyclic audio driver receive 10 ms worth of data. Is it true for all sample rate/channel/bit depth combination or does it vary based on some other factor? cheers, Neetu.