Hi Tobias, It is the device that will tell you via its pins what the acceptable formats are. If the format on the pin tells you that the device accepts 24bit data, but does not use the WAVEFORMATEXTENSIBLE format then you should probably assume that the data has to be packed 24bit. If the pin exposes an extensible format then the format will tell you what the valid bit count is and the package size. The USBAudio.sys driver will not do any data format conversion. The data sent to the driver is expected to match the size of the data it reports that it is capable of. Once a format is selected, that is the format that will be passed to the device. If you are going through kmixer, then it is the intersection with KMixer that will decide the final format of the data, but it will always be one of those the device listed it is capable of. DJ This posting is provided "AS IS" with no warranties, and confers no rights -----Original Message----- From: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of wdm Sent: Tuesday, September 28, 2004 6:53 AM To: 'wdmaudiodev@xxxxxxxxxxxxx' Subject: [wdmaudiodev] 24bit WDM streaming Hi everyone, so far I have only streamed 16bit stuff over WDM-KS and I now want to also support 24bit. If I have a KS-WDM- device which tells me that it supports 24bit (only and not 32bit), can I still stream 32bit values to the driver, or do I need to pack stuff into 24bit units? I would think, that if I use WAVEFORMATEXTENSIBLE and set wValidBitsPerSample to 24, I should be able to still stream 32bits to the device - or have I got it wrong there? Also - what about USB 1.1 devices? would the USBAUDIO.SYS shrink the data to 24bit before transmission before it is sent over the interface (this would obviously save precious bandwitdth) Tobias -- TE-SYSTEMS GmbH - competence in e-communications. Max-von-Laue-Weg 19 - 38448 Wolfsburg - Germany TEL: +49 (0)5361 895-0 - FAX: +49 (0)5361 895-999 PGP-KEY: DB519487D8B620F8141551F31E68A993167535D4 ****************** 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.de/ ****************** 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.de/