Video Conversion Out of Synch Audio

[the-ether]

Hi guys,

I was trying to downsize a mkv file by re-enconding it using "ffmpeg -i file_video.mkv -c:v libx264 -b:v 1000k -c:a aac -b:a 128k output.mp4" but after running that the audio is out of synch (sometimes just stops for a few frames.). Is there anything I can do to fix the mp4?

Thanks guys.

[ProWo]

You should add the video framerate with -vf fps=24000/1001 (for 23.976, as example).

ffmpeg -i file_video.mkv -vf fps=24000/1001 -c:v libx264 -b:v 1000k -c:a aac -b:a 128k output.mp4