FFMPEG -F Concat Video, Audio Sync Issue

[Shohag_ifas]

i am having issue, to concat video, it looses the audio sync and audio started from previous video.

here is the code i am trying:

1: re-encode file a (1):

ffmpeg.exe -i "f:\1.avi" -af apad -vf scale=1280:720 -crf 15.0 -vcodec libx264 -acodec aac -ar 48000 -b:a 192k -coder 1 -rc_lookahead 60 -threads 0 -shortest -avoid_negative_ts make_zero -fflags +genpts 01.mp4

2: re-encode file b (2):

ffmpeg.exe -i "f:\2.mp4" -af apad -vf scale=1280:720 -crf 15.0 -vcodec libx264 -acodec aac -ar 48000 -b:a 192k -coder 1 -rc_lookahead 60 -threads 0 -shortest -avoid_negative_ts make_zero -fflags +genpts 02.mp4

3: Now contact using following command:

ffmpeg.exe -f concat -safe 0 -i "f:\files.txt" -c copy test.mp4

but audio is not synced with video ;(

i also uploaded both video (and also the output) on dropbox:

Video Sync Issue Source And Result Files

so, any help, how to make audio perfectly sync with video would be great

[poisondeathray]

You need to match the framerate of the 1st file (e.g. add -r 25 as an output option)

ffmpeg.exe -i "f:\1.avi" -r 25 -af apad -vf scale=1280:720 -crf 15.0 -vcodec libx264 -acodec aac -ar 48000 -b:a 192k -coder 1 -rc_lookahead 60 -threads 0 -shortest -avoid_negative_ts make_zero -fflags +genpts 01.mp4

[Shohag_ifas]

You need to match the framerate of the 1st file (e.g. add -r 25 as an output option)

oh! man, i was so dumb, i was concerned about same frame/video size, codec etc, but forgot about the frame rate and passed too many hours to figure out ;(

thanks a lot you have saved my day.

You OWE me 1 ton of thanks..

best regards