Avidemux Forum

Avidemux => Windows => Topic started by: borkoborko39 on March 22, 2021, 07:36:11 PM

Title: Audio skips after merging
Post by: borkoborko39 on March 22, 2021, 07:36:11 PM
Hi, so with Premiere i cut 30 second video in half and changed places so the video loops seamless and added cross fade in the middle then i rendered in h264 mp4. The video is fine but when i merge with avidemux i hear the audio stops for milisecond right where the appended video starts then continues. How can i fix that audio jump? After merging the video is 60 seconds and the audio jumps right at 30th second then continues with the appended video. Im trying to make 8 hour video on loop so rendering is not an option for me :D
Title: Re: Audio skips after merging
Post by: eumagga0x2a on March 22, 2021, 09:28:42 PM
I suspect that this is related to the presence of B-frames in video stream and the gap between appended videos represents the B-frame delay (i.e. the timestamp of the first frame in video as shown by Avidemux). Please try to export video with the number of B-frames set to zero (I don't know whether Premiere allows to control that).
Title: Re: Audio skips after merging
Post by: borkoborko39 on March 23, 2021, 10:38:53 AM
I tried different settings with premiere and in avidemux timecode now is exactly at 0 but still skips. What video editor or converter i can use to set the correct timing?
Title: Re: Audio skips after merging
Post by: eumagga0x2a on March 23, 2021, 11:58:57 PM
Using the latest git (in this particular case the last release – 2.7.8 – is recent enough), I cannot reproduce a gap at least when the first frame starts at 0 (no B-frames). However, depending on the particular waveform at the cut point, the latter can be audible as a click, see the magnified waveform of the cut point after appending a MOV file with H.264 video and PCM audio to itself:

cut-point-sine-wave.png

For the cut point to be inaudible, the clip needs to start and to end with silence.