XPost: alt.comp.os.windows-10, rec.photo.digital   
   From: geoff@nospamgeoffwood.org   
      
   On 6/11/2024 9:23 am, Oliver wrote:   
   > After the sig is a series of video conversion commands I'm using on Windows   
   > 10 to fix videos uploaded to Amazon for product reviews - which are great.   
   >   
   > But today I have a video that is too long as it's a video of how a water   
   > pump will self start when the water level gets high & stop when it's low.   
   >   
   > Meanwhile the pump goes through stages, so I had to video the entire five   
   > minute process - but three or more of the five minutes are just waiting.   
   >   
   > Rather than chop the video (which leads the reader to think it's fudged), I   
   > would just like to speed it up (somehow) during the interim periods.   
   >   
   > How do you normally go about speeding up a section of a five minute MP4?   
   >   
   > I don't even know what the proper term to google for is but I found this:   
   > https://shotstack.io/learn/ffmpeg-speed-up-video-slow-down-videos/   
   >   
   > According to that article, this command will double the video's speed.   
   > ffmpeg -i input.mp4 -filter:v "setpts=0.5*PTS" -an output.mp4   
   > But I need the humming of the motor so I'll remove the audio none option.   
   > ffmpeg -i input.mp4 -filter:v "setpts=0.5*PTS" output.mp4   
   > But you still need to speed up the audio so they add the atempo option.   
   > ffmpeg -i input.mp4 -vf "setpts=0.5*PTS" -af "atempo=2.0" output.mp4   
   >   
   > But how do you speed up just a disjoint section or two of a video clip?   
      
   Don't know about free stuff, but in Vegas Pro you simply apply a   
   velocity envelope and set it or fade it to whatever speed you like .   
      
   --   
   geoff   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)