Body: <p>I met this anon on 4chan who made me notice a color issue in my webms. I generally make webm using ffmpeg and I never noticed a change in colors. He suggested me to change the color matrix into 601 but I have no idea of the criteria he used in the first place.</p>
  
  <p><a href="https://i.sstatic.net/LuERk.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/LuERk.jpg" alt="enter image description here"></a></p>
  
  <p>Why there is this difference in colors from source (mkv) and output (webm)? What's the best way to preserve the color scheme during conversion/compression? This is the typical command I use when I convert from mkv to webm:</p>
  
  <pre><code>ffmpeg -threads 4 -i &lt;input&gt; -c:v libvpx -b:v 1500K -vf scale=-1:360 -an -map 0:v:0 &lt;output&gt;
  </code></pre>
  
  <p>What is wrong? I'm going to post more info about the source in 30 minutes, if you need it.</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-09-01T20:00:21.303Z
Comments.Text: Show the console output of the command,
Comments.UserDisplayName: Gyan
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-09-02T00:19:25.040Z
Comments.Text: here is the relevant part https://pastebin.com/if9eNSkV
Comments.UserDisplayName: 1500822802299
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-09-02T17:39:12.343Z
Comments.Text: Basic filter would be `colormatrix=bt709:bt601` This goes before the scale. But without knowing all source properties and intended target, this is a crude guess.
Comments.UserDisplayName: Gyan
Tags: <ffmpeg>
Title: FFMPEG, colormatrix and WEBM conversion
UserDisplayName: 1500822802299
ThreadText: # FFMPEG, colormatrix and WEBM conversion
  
  (Asked by: username_0 on 2017-09-01)
  
  I met this anon on 4chan who made me notice a color issue in my webms. I generally make webm using ffmpeg and I never noticed a change in colors. He suggested me to change the color matrix into 601 but I have no idea of the criteria he used in the first place.
  
  [![enter image description here](https://i.sstatic.net/LuERk.jpg)](https://i.sstatic.net/LuERk.jpg)
  
  Why there is this difference in colors from source (mkv) and output (webm)? What's the best way to preserve the color scheme during conversion/compression? This is the typical command I use when I convert from mkv to webm:
  
  ```
  ffmpeg -threads 4 -i <input> -c:v libvpx -b:v 1500K -vf scale=-1:360 -an -map 0:v:0 <output>
  
  ```
  
  What is wrong? I'm going to post more info about the source in 30 minutes, if you need it.
  
  **Tags:** ffmpeg
  
  > **Comments:**
  > **username_1**: Show the console output of the command,  
  > **username_0**: here is the relevant part https://pastebin.com/if9eNSkV  
  > **username_1**: Basic filter would be `colormatrix=bt709:bt601` This goes before the scale. But without knowing all source properties and intended target, this is a crude guess.  
  
  ---
  
  ## 0 answers
  
  