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Lip sync issue on iPad, video&audio is not synchronized

Hi,

On our system, we push video(H.264) and audio(AAC-LC) RTP streams to Wowza publishing point, then use iPad to watch the live streaming from Wowza, we get the lip sync issue, audio is ahead of video about 5 seconds in 10 minutes, then if I refresh the player, the issue just gone, and then, video lags again…, this issue only happens on iPad, when we use Android or Silverlight to play the same program, there is no lip sync issue, does anyone know what’s the problem?

thanks,

This is usually an encoder issue. You can use this Property setting to see audio/video alignment in the logs:

How to debug AAC or MP3 timecode issues with cupertino packetization

Salvadore

Can you describe your encoder settings?

FPS?

Keyframe interval(GOP)

Frame size

Bitrate

It could be that your FPS/GOP need to be modified.

Also, take a look at this jitter buffer. it will log RTP packet loss and attempt to limit any packet loss issues:

How to turn on an RTP jitter buffer and packet loss logging (RTP and MPEG-TS)

One other thing to try is How to fix unaligned video and audio with a server-side sort buffer

Salvadore

Thank you Salvadore, I did the debug, and it seems it’s not timecode issue, because tc always equal to 0 or 1, but I still experience lip sync issue on iPad, it happens every time.:confused:

This is usually an encoder issue. You can use this Property setting to see audio/video alignment in the logs:

How to debug AAC or MP3 timecode issues with cupertino packetization

Salvadore