audio / video sync issue in playback

[adam_k]

for every recording i've made, when i play back the archive there is noticable lack of sync between the audio and the person's mouth.   the video seems to lag behind by almost a second.  the good news at least is that the delta is constant.

has anyone else experienced this?  it's happening in any scendario i try, even if i'm just recording myself. 

is the LCCS dev team aware of this?  since audio and video streams are recorded separately, is there any way for me to programatically 'nudge' the streams into sync?

it's currently a show stopper, it looks really bad when the sync is so obviously absent.

[DrAlexGor]

Are you getting this behavior in the sample app that's provided by LCCS SDK ?

Could you test that out and let us know what you get ? You'll have to add an AudioPublisher + Subscriber to the "Recording" sample app but other that it should work ( from what I remember ).

[adam_k]

finally getting back to this..

i did as you suggested and recorded a video of myself using the recording and playback examples provided with the SDK (the 2.2 newest version btw).

the de-syncing of audio and video is definitely there.  it seems especially bad for longer recordings.  however, an interesting thing i discovered in playback:

- sometimes, if i drag the playhead somewhere in the recording, pause, and then hit play, video and audio fall into sync. 

- if i start playback from the beginning of the recording, audio/video is always out of sync.

i understand that the video and audio streams are recorded separately and thus played back separately.  my guess is that when those streams are retrieved and playback begins, one starts before/after the other because they're not retrieved at exactly the same time.  it seems some extra work is required to ensure that their playback commences at exactly the same timestamp within each stream.

i can provide my recordings as an example if required.

this is a total showstopper for me.  it renders the entire recording service useless if the playback can't have sync between audio and video.  i would be happy to help with testing this more.  can someone from the LCCS team comment on this issue?

thanks

adam

[adam_k]

can someone respond to this from adobe? it's completely holding me up with putting my application into production. 

[adam_k]

please, please, can someone from adobe address this? or at least tell me it's not possible?  give me a hint?

i've tried play() on all streams (then called pause() immediately), waiting for all audio/video streams to have full buffers, then resume() on all streams, but no love.

isn't there some way to ensure that playback of all audio/video streams commences simultaneously?

[Former Community Member]

As far as I can tell this can't be easily fixed. It's at artifact of the way the video was recorded.

Since the webcam and audio publishers are separate, they end up in separate streams. Because of this fact, the streams can't be synchronized either live or during playback. From what I've looked at, it seems that the only fix is to make a combined audio/video publisher that would be the union of the webcam/audio publishers. I've started doing this with good results so far, but it's a long way from being completed.