Just to add to that, Is the AndroidAudioStream MIO implementation meant for writing directly to H/W ?
On Mar 11, 3:49 pm, mahamannu <[email protected]> wrote: > Thanks Dave > > I want to avoid mixing Music Stream [ from Pvplayer ] with other > Streams and re-direct the music stream to a different Audio H/W > Interface. Is it possible to send MIO buffers directly to H/W ? > Firstly what are the penalties for bypassing audio Flinger. As I > understand it is provifing Stream/Track based routing and Volume > control. MediaPlayerInterface.h recommends to implement > MediaplayerHWInterface to write directly to the HW. Are there changes > required in MediaPlayerService.cpp for this. I noticed that currently > it tries to get a Player Handle and since currently PvPlayer is of > type MediaPlayerInterface, it's audiosink object ends up forming > "tracks" to write to AudioFlinger. > Also, since AudioFlinger has the interface to AudioHardwareInterface ; > does another call to OpenOutputStream need to be made elsewhere if MIO > is to write buffers directly to H/W ? > > The other design that I can think of is to have a second AudioFlinger > object instantiated by AudioSystem which will only get Music Tracks > and write to its dedicated H/W. What issues do you see with this > design ? Does the AudioFlinger need to be made multi-threaded and > thread-safe fo this ? > > thanks, M > > On Mar 5, 9:55 pm, Dave Sparks <[email protected]> wrote: > > > > > AudioFlinger mixes into a small buffer which determines the latency > > (along with the underlying hardware latency). The source buffers can > > be any size. The mix buffer size has to be larger than the scheduler > > interval (typically 20ms) or audio will stutter under load. That means > > best case latency is around 40ms for a ping-pong buffer audio driver. > > > On Mar 5, 2:45 pm,mahamannu<[email protected]> wrote: > > > > Hi, > > > > I'd like to know if the Audio Flinger uses the same mixer buffer for > > > combining Audio streams from Media Service playback [ Potentially > > > large buffer] , System sound [ ringtone , DTMF etc ] , Gaming Audio > > > [ Low latency ; small buffer ; ] at a given time. Usually Gaming Audio > > > might also use Media Service playback ; so essentially there may be 2 > > > or more PV playback inputs to Audio Flinger. The concern is that > > > although the MIO Audio component supports Flush [ in case of a seek/FF/ > > > Rewind on a stream] ; the next flush will be done at the DSP/H/W > > > level; which will not be able to distinguish between type of data if > > > it is mixed. It would be nice to not mix a Large Media Service output > > > buffer for optimization purposes with System sound ; as a flush at the > > > h/w will cause no system sound to be played or if the mixing is done > > > in serial fashion ; the time senstive System sound will play after a > > > large playback buffer has finished playing. > > > > Manu- Hide quoted text - > > > - Show quoted text -- Hide quoted text - > > - Show quoted text - --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "android-framework" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-framework?hl=en -~----------~----~----~----~------~----~------~--~---
