Axis Q7401 -> Wowza 2 -> JW Player or Flow Player audio/video sync issue

[alexlee3]

I'm having an audio/video synchronization problem.

Audio gradually plays faster than video and the gap gets bigger as time passes.

Here are what I have set up:

1) AXIS Q7401
Video: H.264, 250kbits constant bitrate
Audio: AAC, 16KHz sampling, 64kbits

2) Wowza Media Server
Application Name: live
Stream type: live-lowlatency
Application.xml:
Streams/Properties/Property/sortPackets: true
Streams/Properties/Property/sortBufferSize: 750
Streams/Properties/Property/flushInterval: 30

I used the streammanager to receive stream from AXIS Q7401.
Stream type that I used for pulling from AXIS Q7401 was rtp-record.

3) JW Player 5.5, Flow Player 3.2.7

4) Web Browser - Crome with Flash Player 10.2


First, the audio/video are in sync. But it gets tilted as time passes.

It seems that there is a problem in RTSP->RTMP re-streaming.
The reason why I think that is the problem is that even if I set JWPlayer's bufferlength to 1 sec, the audio/video are out of sync by more than 3 seconds if I play it for 3hours.

Is there any setting that I can try in Wowza Media Server?

Thank you for your help!

[charlie]

In general these issues are on the encoding side. The AAC stream is slightly off and it will drift out of sync over time.

Does this describe your problem:

Connect a player to the stream and stream for 2 hours. The stream slowly drifts out of sync. If I disconnect the player and re-connect then the stream is back in sync but again slowly drifts out of sync.

If you increase the sample frequency of the audio encoding to 48KHz you might have more luck.

Charlie

[alexlee3]

Thank you for your reply Charlie.

You said,

Connect a player to the stream and stream for 2 hours. The stream slowly drifts out of sync. If I disconnect the player and re-connect then the stream is back in sync but again slowly drifts out of sync.

If you increase the sample frequency of the audio encoding to 48KHz you might have more luck.

Charlie

I also tested it, and it is as you said.

However, if I play the RTSP stream from AXIS Q7401 directly through VLC Player 1.1.7, the sync doesn't drift-it stays the same.

Also, AXIS Q7401 doesn't support 48KHz sample rate(16 KHz is the maximum), but it has options to different bitrates.

Do you think adjusting the bitrate can help?

Also, if I use HTTP streaming, would the problem be solved?

[shareimd]

I am having the same issue, we are using the Q7401 and the audio does exactly what you are stating.

Have you had any luck?

[rrlanham]

Have you checked for firmware update?

Richard

[shareimd]

We are using the most current one, I assume you were talking about the Q7401?