回复： Sync of audio in android

[jojo <rjiejie@xxxxxxxxx>]

Hi Marc-André & iordanov

The gstreamer backend should be improved, with the end goal to drop the pulse backend. But changing latency dynamically with GStreamer seems to be tricky. Help welcome!

It's really problem as Marc said about for latency of gstaudio, it's pretty in some pure audio case like music, of cause it has terrible performance problems with video streaming, i suggest that

you can change this option (enable audio) dynamically in the spice session and disable the audio output in my choice by default.

 

Thanks,

- Jojo

在 2013年9月21日星期六，上午12:10，i iordanov 写道：

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@xxxxxxxxx> 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

--

The conscious mind has only one thread of execution.

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