user39711: I have two, at first glance very similar mp4 files (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 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


user39711: Figured it out. The difference in scrubbing performance comes from different GOP 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

39711: <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.stack.imgur.com/JrMjI.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/JrMjI.jpg" alt="Media info" /></a></p>
 39711: <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>
