[FFmpeg-user] framerate conversion with sync audio

[Steve Boyer]

On Tue, Oct 11, 2016 at 5:00 PM, Steve Boyer <steveboyer85 at gmail.com> wrote:
>
>
> Have you tried experimenting with the audio filter "atempo"? I'm guessing
> here, but try:
>
> ffmpeg -i ...<your options here> -af atempo=0.96 <outfile>
>
> (24/25 = 0.96)
>
> Wow, I messed that one up completely. Incorporating Carl's suggestion as
well of -vf setpts, the filter chain should look something like:

ffmpeg -i <inputfile> -vf setpts=PTS*0.8 -af=atune=25/24 <codec options>
<output file>
or if -r works for you:
ffmpeg -r 25 -i <inputfile> -af=atune=25/24 <codec options> <output file>

Just a heads-up: on a test clip, looks like using -ss and -r before -i
causes frame-sync issues, so if you were wanting to skip forward into your
test clip, make sure to use -ss after -i <inputfile>.


> ~Steve
>
>