Note that using the copy codec for audio didn't make a difference.

( -strict -2: as you can see, I'm using the stock release built on a Mac, which seems to scream about AAC a lot. Note that I am purposely setting it to one GOP per slice, on the theory that a GOP size smaller than a segment size might be causing the problem. It always seems that the audio is cutting before the video, and always for the same amount, regardless of the GOP size (being careful of course to make the GOP size a whole fraction of the overall slice size).Īs per Mulvya's request, here are the steps I am performing: UPDATE: I am starting to wonder if it has something to do with some kind of presentation time stamp not being updated correctly, either on the cut or the reassemble side.

Using MP4Box to create a set of small N-secondĬoncat codec from each asset (v1,slice 1 v2,slice 1 v1,slice2.)īecause I am very careful to precondition all the sources to be 'in sync', I would expect that concatenating these files should not cause any audio presentation issues, and should look just like a DASH asset (the actual purpose of this test).

Transcoding all sources into the same bitrate, frame rate, GOP size,.

This seems curious that loss of sync should happen, as I am doing the following: Is it expected that one can concatenate independent MP4-boxed streams?

I am doing some tests with the FFMPEG concat filter (DASH experiments), and am seeing that I start losing lipsync after a few concatenations.

Ffmpeg filter complex concat file