[FFmpeg-user] How would your rendering a video to a slower rate (slow mo)

[Pavel Koshevoy]

On 10/30/2012 5:57 AM, Nicolas George wrote:
> Le nonidi 9 brumaire, an CCXXI, Jason Brower a écrit :
>> I am planning to build a backend tool that needs to render a video
>> is slow motion about 1/4 speed or slower and I want to keep the
>> audio and video in as much sync as I can.  It's for a site that will
>> help people read lips.
>> Is there a way to do this in ffmpeg?
> You can look the setpts filter for video and the atempo filter for audio.

... and you'll need to daisy-chain atempo if you want to go below 1/2 
speed (or above 2x speed)

I could work on removing 1/2 speed limit, but I am not yet convinced it 
is really necessary.  At half speed everyone sounds too slow already.

     Pavel.