Answers.Body: <p>Depends on <strong>how much time stretch is key</strong> to synchronize the shot. </p>
  
  <ol>
  <li><p>In order to increase the speed of the whole layer use the <strong>Time Stretch</strong> feature (<em>Right Click the Layer > Time > Time Stretch</em>) <em>Note: values below 100 increase the speed. Values above 110 often results in bad quality. To solve this, see motion calculation (3.)</em>   </p></li>
  <li><p>To vary the speed of a layer, it's ok in most cases to use the standard <strong>Time Remapping</strong> feature (<em>Right Click the Layer > Time > Enable Time Remapping</em>) This makes it possible to keyframe the time/speed of your layer.</p></li>
  <li><p>In some situations, especially for generating slow motion shots you need to <strong>calculate the motion in between the frames</strong> with <a href="http://en.wikipedia.org/wiki/Optical_flow" rel="nofollow noreferrer">optical flow</a> technology like <a href="http://www.revisionfx.com/products/twixtor/" rel="nofollow noreferrer">twixtor</a>. You can also play with <a href="https://github.com/slowmoVideo/slowmoVideo/" rel="nofollow noreferrer"><strong>SlomoVideo</strong></a> as an open source alternative. For further information, see this article: <a href="http://www.fxguide.com/featured/art_of_optical_flow/" rel="nofollow noreferrer">http://www.fxguide.com/featured/art_of_optical_flow/</a></p></li>
  </ol>
  
  <hr>
  
  <p>For <strong>audio preview workflow</strong>, see: <a href="https://video.stackexchange.com/questions/15319/how-can-i-preview-with-audio-in-after-effects-and-be-able-to-pause-resume-the/15321#15321">How can I preview with audio in After Effects and be able to pause / resume the preview?</a></p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-06-19T07:51:22.280Z
Answers.LastActivityDate: 2015-06-19T09:50:09.283Z
Answers.LastEditDate: 2017-04-13T12:46:08.110Z
Answers.UserDisplayName: p2or
Body: <ul>
  <li><p>There's a video of a man, drawing something.</p></li>
  <li><p>There's a violin symphony music.</p></li>
  </ul>
  
  <p>I want to sync the video, I mean the movements of hand with the symphony.</p>
  
  <p>For example, I want the hand to move fast, when the music rate is fast, etc.</p>
  
  <p>What I have to look for to achieve this?</p>
  
Tags: <after-effects><sync><motion><music>
Title: How to sync motion and music in After Effects
UserDisplayName: Farzad
ThreadText: # How to sync motion and music in After Effects
  
  (Asked by: username_0 on 2015-06-19)
  
  * There's a video of a man, drawing something.
  * There's a violin symphony music.
  
  I want to sync the video, I mean the movements of hand with the symphony.
  
  For example, I want the hand to move fast, when the music rate is fast, etc.
  
  What I have to look for to achieve this?
  
  **Tags:** after-effects, sync, motion, music
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2015-06-19. Score: 2 | Accepted answer
  
  Depends on **how much time stretch is key** to synchronize the shot.
  
  1. In order to increase the speed of the whole layer use the **Time Stretch** feature (*Right Click the Layer > Time > Time Stretch*) *Note: values below 100 increase the speed. Values above 110 often results in bad quality. To solve this, see motion calculation (3.)*
  2. To vary the speed of a layer, it's ok in most cases to use the standard **Time Remapping** feature (*Right Click the Layer > Time > Enable Time Remapping*) This makes it possible to keyframe the time/speed of your layer.
  3. In some situations, especially for generating slow motion shots you need to **calculate the motion in between the frames** with [optical flow](http://en.wikipedia.org/wiki/Optical_flow) technology like [twixtor](http://www.revisionfx.com/products/twixtor/). You can also play with [**SlomoVideo**](https://github.com/slowmoVideo/slowmoVideo/) as an open source alternative. For further information, see this article: <http://www.fxguide.com/featured/art_of_optical_flow/>
  
  ---
  
  For **audio preview workflow**, see: [How can I preview with audio in After Effects and be able to pause / resume the preview?](https://video.stackexchange.com/questions/15319/how-can-i-preview-with-audio-in-after-effects-and-be-able-to-pause-resume-the/15321#15321)
  
  
  ---
  
  