Some Video Editing software, such as Sony Vegas and Adobe Aftereffects have problems syncing Audio/Video if the Audio sample rate isn’t 48kHz. The following command re-encodes all Audio channels in the input file to AAC and sets their sample-rate to 48kHz:
# Re-Encode and Re-Sample Audio ffmpeg -i <file> -map 0 -c:v copy -c:a aac -ar 48000 <out>.mp4
Note: Changing the sample-rate requires re-encoding of audio streams, otherwise, the
-ar option is ignored!