1. AV sync is taken care by StageFright. 2. Qcom does implement audio OMX which uses hardware acceleration. They are not open sourced yet and also it depends on which chipset you are talking about. On snapdragon they all are software decoders, which uses SF software codecs.
3. Android provides the entire framework for playback, these OMX decoders are just to enable hardware acceleration. Remaining parsing, AV sync, time stamp etc., are taken care by the framework. Hope this helps. From: [email protected] [mailto:[email protected]] On Behalf Of ?? Sent: Friday, January 28, 2011 7:16 AM To: Deva R Cc: [email protected] Subject: Re: [android-porting] why samsung and qcom do not implement audio omx section in /hardware thank you Deva, so, in your opinion h/w video omx decoder and s/w audio decoder can work together, since they work in two independent threads, i agree with you. here is place that confuses me: as to the synchronization of a/v, do we need to do something else, or only rely on stagefright to control the a/v pace. 2011/1/28 Deva R <[email protected]<mailto:[email protected]>> > ps: > also, i have review the code of ti in android_root/hardware/ti/omp3, they > do have audio decoders such as aac, mp3, wma etc, > from normal logical, we should implement video and audio omx component > together, so we can play movie in full omx way. video codecs are not listed as mostly they will run in DSP side or a h/w accelerated subsystem, which wont be part of android code. and during av playback, there will 2 handles active (each to decode audio/video bit streams) as long as we have a omx handle to talk to,bridged to hardware/software codec, android can go ahead with playback. ps. complete releases can be found in www.git.omapzoom.org<http://www.git.omapzoom.org> projects > i wonder why they(samsung and qcom) do not implement the audio omx section, > however, they have video omx's implementation. > here is my guess: > 1. they do not implement audio decoder, but only using the audio decoder > originally in Android > 2. they implement their own audio codec as the same way of Android's audio > codec, then substitute them, > 3. they have other implementations of decoding audio that we do not know probably they use s/w codecs only (which comes by default with stagefright/opencore) with current generation mobile processors, decoding aac/mp3 in arm side is feasible and not that of an overhead. also, there may be implementations which are not public, where h/w accelerated audio codecs are integrated. On Thu, Jan 27, 2011 at 10:15 PM, 王川 <[email protected]<mailto:[email protected]>> wrote: > hi group, > i'm working on implementation of vendor omx section in froyo, and make > it run together with stagefright. > i notice that in android_root/hardware/qcom/media folder there are qcom's > implementations. > also i checked out samsung's omx code (from > git://github.com/codeworkx/android_device_samsung_galaxys.git<http://github.com/codeworkx/android_device_samsung_galaxys.git>), > in which > there is also no audio omx component section. > i wonder why they(samsung and qcom) do not implement the audio omx section, > however, they have video omx's implementation. > here is my guess: > 1. they do not implement audio decoder, but only using the audio decoder > originally in Android > 2. they implement their own audio codec as the same way of Android's audio > codec, then substitute them, > 3. they have other implementations of decoding audio that we do not know > can anyone give me some ideas? and what is your strategy of audio decoder, > omx way or using android's internal audio decoder > > ps: > also, i have review the code of ti in android_root/hardware/ti/omp3, they > do have audio decoders such as aac, mp3, wma etc, > from normal logical, we should implement video and audio omx component > together, so we can play movie in full omx way. > my question is: why qcom and samsung do not implement audio omx but only > video omx component? and what audio decoder do they use when playing movie? > > > > -- > unsubscribe: > [email protected]<mailto:android-porting%[email protected]> > website: http://groups.google.com/group/android-porting > -- Regards, Deva www.bittoggler.com<http://www.bittoggler.com> -- unsubscribe: [email protected] website: http://groups.google.com/group/android-porting -- unsubscribe: [email protected] website: http://groups.google.com/group/android-porting
