Stéphane Letz kirjoitti: > Le 20 déc. 08 à 23:47, Hannu Savolainen a écrit : > > >> Stéphane Letz wrote: >> >>> Hi, >>> >>> Does OSS allows to use several cards synchronized using Worldclock? >>> Is yes does each card still appears as a separated device? or as a >>> unique "aggregated" device that would be possibly easier to handle? >>> >>> >> OSS doesn't care if different cards are syncronized to the same >> clock or >> not. If they are synchronized then the application can use device >> files >> that belong to different cards just like multiple "subdevices" of the >> same card. >> > > Do you mean having the application opening the different device files > and doing the standard Read/Write loop for all device files in a > same thread? Like: > > Loop: > > Read device file 1; > Read device file 2; > ..... > Read device file n; > > Do some processing; > > Write device file 1; > Write device file 2; > ..... > Write device file n; > > End loop; > > (assuming all devices are opened with the same sample rate, buffer > size parameters..) > This is what I mean. > How can we be sure that all devices get initialized and started the > same way? Would the first "Read device file 1" be the "blocking" one? > > Normally first read is blocking one because recording is not started before the application calls read for the first time. However it's possible to start all the devices at the same time by using the SNDCTL_DSP_SYNCGROUP ans SNDCTL_DSP_SYNCSTART calls.
It may be difficult to ensure that all the devices have the same buffer/fragment size if they belong to sound cards of different types. However this is not a problem if all devices are similar (same manufacturer/model). >> At this moment there is no aggregated device that works in this way. >> However my ultimate goal is to "virtualize everything" so that >> multiple >> cards can be used as a single huge mixing console where inputs from >> multiple cards and applications can be mixed or routed freely to any >> other sound cards or applications. Using two 64 channel cards as a >> single 128 channel "virtual" one was not part of my plan but it can be >> easily added. The current vmix code has much of the lowest level >> functionality required for this but at this moment I don't know how to >> step ahead. >> >> > > Do yo mean this is an ultimate goal, but without any clear roadmap? I > yes, it the previously described solution a reasonable way to do in > the meantime? > > There is just very thin roadmap. The vmix subsystem can do this task after relatively simple restructuring. The other part of the plan is an user land tool that can be used to configure the system (the mixing/routing matrix). At this moment I don't have any specific plans for this tool. The timeframe for this might be OSS v4.3 (2010?). Best regards, Hannu _______________________________________________ oss-devel mailing list oss-devel@mailman.opensound.com http://mailman.opensound.com/mailman/listinfo/oss-devel
