Hi Eugene, The KSAUDIO_POSITIONEX struct contains a TimerFrequency field, I suspect that you can use that to specify that information to the audio engine. This should allow drivers to derive their timestamp information from an arbitrary source. So if you use KeQPC for timestamps, use KeQPF for TimerFrequency field. Regards, /Rob -----Original Message----- From: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Eugene Muzychenko Sent: den 8 januari 2013 07:38 To: wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] Timestamp source for KSAUDIO_POSITIONEX Hello! MSDN docs say that KSAUDIO_POSITIONEX descriptor used in KSPROPERTY_AUDIO_POSITIONEX property request should be filled with timestamp values but say nothing about timestamp source requirements (for example, counter frequency and/or resolution). KSPROPERTY_AUDIO_POSITIONEX request is issued by Windows audio engine during processing IAudioCaptureClient::GetBuffer and IAudioClock::GetPosition. For these methods, it is explicitly said that QueryPerformanceCounter is used. Does it mean that a developer that uses WASAPI can suppose that all timestamps are generated by QueryPerformanceCounter and each audio filter must use KeQueryPerformanceCounter to fill KSAUDIO_POSITIONEX fields? Regards, Eugene ****************** WDMAUDIODEV addresses: Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx URL to WDMAUDIODEV page: http://www.wdmaudiodev.com/ ****************** WDMAUDIODEV addresses: Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx URL to WDMAUDIODEV page: http://www.wdmaudiodev.com/
