[Spice-devel] 回复： Sync of audio in android

[i iordanov]

Hi Jojo and SPICE developers,

First of all, Jojo, thank you for your contribution to aSPICE. I am
currently working on integrating your audio code into the main trunk.

I have also noticed that audio and video get out of sync. The issue
seems to be more severe when the bandwidth of the connection is lower.
At home, my phone achieves about ~21Mbit/s with my current router, and
at work it achieves ~38Mbit/s. At 21Mbits/s, the issue is quite
severe, but at 38Mbit/s it is a lot less noticeable. My hypothesis is
that the sync issue occurs in part due to bandwidth limitations.
Perhaps with a 802.11N device that is connected at 150Mbit/s or more,
the issue will not be nearly as noticeable. A typical test of mine
consists of playing a video through youtube, keeping the video size
default. Can somebody comment on the bandwidth requirements of such a
scenario and whether my observations are in line with expectations?

Regardless of what is exacerbating the out of sync issue, in the
future we should be making use of timestamps in order to ensure that
audio and video are synced even in scenarios with limited bandwidth.
This would require dropping either audio packets or video frames, and
we can have an option that controls which one is prioritized. Can
somebody comment on that?

I am thinking that performance will be impacted by audio for the
majority of users at the moment, and there should be an option to turn
it on or off. I have not made up my mind what the default should be,
though, what do you guys think?

Thanks!
iordan

On Sun, Sep 8, 2013 at 11:45 AM, jojo <rjiejie at gmail.com> wrote:
> Hi,
> Is someone maintaining the playback channel of gstaudio  ?
>
> it looks like behind pulseaudio  with some feature :(
>
> Thanks,
>
> - Jojo
>
> 在 2013年9月6日星期五，上午11:00，jojo 写道：
>
> Hi,
> I use "gstaudio" to enable the audio output in android platform,
>
> but there is the sync issue with this approach, it looks like the pulse
> audio is
>
> the better choice.
>
> I research some pulse audio porting in android, some ugly problem looks like
> bellow which i think about :
>
> * much more device(driver) maybe can not used by PA, they implement with HAL
> layer with AudioFlinger
>
> * can not use PA as the regular NDK app in NDK, this will be done by OEM in
> their device
>
> am i right ?
>
> Thanks,
>
> - Jojo
>
>



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