I had some problems adding AC3 support to a WDM/KS driver. I folowed the non-PCM document written by Microsoft but only a waveout device would pass KSDATAFORMAT_SUBTYPE_DOLBY_AC3_SPDIF to the driver. An AC3 decoder graph constructed with a waveout device would play such a stream without an hiccup. The only problem is that Microsoft is fading the classic wave API away in favor of DirectSound. I don't understand why as I don't see a single advantage in using DS. Anyway, DirectSound seems to pass non-PCM streams to the driver only if there's a topology port. I don't grasp the link between AC3 and topology but there has to be a topo connection or you don't get non-audio data. Well, it works now but the performance is extremely bad. The directsound renderer inserts breaks and silence whenever there's some activity on the system, impossible to play a video with AC3, sync is completely lost within seconds. Anyone seen similar behavior and more important, a solution maybe? Thanks, Dirk ****************** 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/