Answers.Body: <p>Figured it out. The difference in scrubbing performance comes from different <a href="https://en.wikipedia.org/wiki/Group_of_pictures" rel="nofollow noreferrer">GOP</a> in those two videos. The video which played smoothly had GOP=(N, M)=(15, 1).</p>
  <p>So for people who'll encounter this issue in videos produced by their capture software: to fix it set keyframe interval to low value e.g. 30 frames (0.5sec)</p>
  <p>It's also possible to convert existing videos using ffmpeg in order to add more keyframes e.g.</p>
  <pre><code>ffmpeg -i input.mp4 -c:v libx264 -crf 16 -preset faster -g 15 output.mp4
  </code></pre>
  <p>where <code>-g 15</code> sets keyframe every 15 frames</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-11-05T05:41:20.270Z
Answers.LastActivityDate: 2022-11-07T19:26:36.353Z
Answers.LastEditDate: 2022-11-07T19:26:36.353Z
Answers.UserDisplayName: Wilhelm Olejnik
Body: <p>I have two, at first glance very similar <a href="https://mega.nz/folder/Z0VGHbaQ#VqTrfNIkMqYnK2H5vyapnA" rel="nofollow noreferrer">mp4 files</a> (A &amp; B), each of them created by different capture software.</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>File</th>
  <th>Captured using</th>
  <th>codec</th>
  <th>resolution</th>
  <th>fps</th>
  <th>bitrate</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>A.mp4</td>
  <td>Elgato 4K Capture Utility</td>
  <td>h.264</td>
  <td>2560x1440</td>
  <td>60</td>
  <td>106Mb/s</td>
  </tr>
  <tr>
  <td>B.mp4</td>
  <td>Xsplit Broadcaster</td>
  <td>h.264</td>
  <td>2560x1440</td>
  <td>60</td>
  <td>128Mb/s</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>I noticed that scrubbing video A is very smooth while scrubbing video B is extremely choppy.</p>
  <p><a href="https://youtube.com/watch?v=SsMr8u9K4B0" rel="nofollow noreferrer">This video</a> illustrates the difference. Note that althought for demonstration purpose I've used DaVinci Resolve software, the same scrubbing performance is present in other programs e.g. VLC Player.</p>
  <p>I would like to understand what is causing this difference in scrubbing performance. Looking at task manager graphs, it seems like video B is more complex to decode but I have no idea why.</p>
  <p>This is what I got using MediaInfo
  <a href="https://i.sstatic.net/JrMjI.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/JrMjI.jpg" alt="Media info" /></a></p>
  
Tags: <encoding><h.264><performance>
Title: Different decode performance in two similar H.264 videos
UserDisplayName: Wilhelm Olejnik
ThreadText: # Different decode performance in two similar H.264 videos
  
  (Asked by: username_0 on 2022-11-05)
  
  I have two, at first glance very similar [mp4 files](https://mega.nz/folder/Z0VGHbaQ#VqTrfNIkMqYnK2H5vyapnA) (A & B), each of them created by different capture software.
  
  | File | Captured using | codec | resolution | fps | bitrate |
  | --- | --- | --- | --- | --- | --- |
  | A.mp4 | Elgato 4K Capture Utility | h.264 | 2560x1440 | 60 | 106Mb/s |
  | B.mp4 | Xsplit Broadcaster | h.264 | 2560x1440 | 60 | 128Mb/s |
  
  I noticed that scrubbing video A is very smooth while scrubbing video B is extremely choppy.
  
  [This video](https://youtube.com/watch?v=SsMr8u9K4B0) illustrates the difference. Note that althought for demonstration purpose I've used DaVinci Resolve software, the same scrubbing performance is present in other programs e.g. VLC Player.
  
  I would like to understand what is causing this difference in scrubbing performance. Looking at task manager graphs, it seems like video B is more complex to decode but I have no idea why.
  
  This is what I got using MediaInfo
  [![Media info](https://i.sstatic.net/JrMjI.jpg)](https://i.sstatic.net/JrMjI.jpg)
  
  **Tags:** encoding, h.264, performance
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_0 on 2022-11-05. Score: 1
  
  Figured it out. The difference in scrubbing performance comes from different [GOP](https://en.wikipedia.org/wiki/Group_of_pictures) in those two videos. The video which played smoothly had GOP=(N, M)=(15, 1).
  
  So for people who'll encounter this issue in videos produced by their capture software: to fix it set keyframe interval to low value e.g. 30 frames (0.5sec)
  
  It's also possible to convert existing videos using ffmpeg in order to add more keyframes e.g.
  
  ```
  ffmpeg -i input.mp4 -c:v libx264 -crf 16 -preset faster -g 15 output.mp4
  
  ```
  
  where `-g 15` sets keyframe every 15 frames
  
  
  ---
  
  