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Audio sync slips when transcoding to AAC

Started by kevmeister, March 28, 2012, 02:11:02 AM

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kevmeister

I'm running 2.6 7787. I am working on TS files from an AVERMedia HD DVR unit at 1080p. I am only clipping the unwanted portions at the beginning and end of the video and transcoding the audio to AAC (FAAC), saving as an MP4 -V2). When I do this, the audio sync of the audio starts in sync with hte video, but gradually slips out of sync. After a couple of minutes, it is very noticeably off.

I am working around this by using a commercial package from AVS, but it has a really crappy editor (no stepping) and won't copy the video. It insists on transcoding it, even if it's H.264 to H.264, so I have and extra lossy operation.

Any ideas or is this a known problem?

mean

Please provide a sample
Does it happen if you use something else than aac, e.g. ac3 for example ?

karl-otto

I made the same experience having input stream .ts (MPEG-TS):

  Video Decoder: Lavcodec
  Video Output: Mpeg4 AVC (x264)
  Audio Output: AAC (lav)
  Output Format: MP4v2 Muxer

and it was not reproduceable with

  Audio Output: AC3 (lav)

karl-otto

Used Avidemux version:
avidemux_r7848_win64.7z 06-Apr-2012 07:05   12M

Jan Gruuthuse

You need to provide sample! No sample no cure. How to provide sample, read this: Cut TS sample. Upload that sample and provide the link to it.