Answers.Body: <p>Well, discovered this almost by accident - but it turns out, to preserve the alpha gradual  fades, you MUST add Composite and transform: Composition track: automatic; Compositing: Alpha blend, for the duration of the image sequence:</p>
  <p><a href="https://i.sstatic.net/Zvkxx.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Zvkxx.png" alt="kdenlive image sequence video track with Composite" /></a></p>
  <p>... - even if the image sequence is the only track (so compositing then works against the background)!</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2023-04-30T08:27:31.470Z
Answers.LastActivityDate: 2023-04-30T08:27:31.470Z
Answers.UserDisplayName: sdbbs
Body: <p>This is probably the same question as <a href="https://www.reddit.com/r/kdenlive/comments/ik44o2/image_sequences_cutting_and_transparency/" rel="nofollow noreferrer">https://www.reddit.com/r/kdenlive/comments/ik44o2/image_sequences_cutting_and_transparency/</a> ( and probably related to <a href="https://kdenlive.org/en/project/compositing-with-transparency/" rel="nofollow noreferrer">https://kdenlive.org/en/project/compositing-with-transparency/</a> )</p>
  <p>Let's say I have an image sequence, with transparent background, and an element (here a rectangle) with a fill color with fading alpha/transparency; for instance, one generated with <code>imagemagick</code>:</p>
  <pre class="lang-bash prettyprint-override"><code>for ix in `seq 1 9`; do \
    convert -size 640x480 xc:none \
     -strokewidth 0 -fill &quot;rgba( 255, 215, 30, 0.$ix )&quot; \
       -draw &quot;rectangle 30,30 500,250&quot; \
     -strokewidth 2 -stroke blue -fill none \
     -draw &quot;rectangle 0,0 639,479&quot; output$ix.png; \
  done
  </code></pre>
  <p>It is very difficult obtaining a proper .gif animation directly from the above images; so I opened each one in an image viewer, took screenshot of the image viewer, and finally composed the screenshot images with <code>convert -delay 0 -loop 0 Screenshot*.png animation_im.gif</code>, just to show what this image sequence looks like:</p>
  <p><a href="https://i.sstatic.net/pAhp6.gif" rel="nofollow noreferrer"><img src="https://i.sstatic.net/pAhp6.gif" alt="image sequence animated gif via screenshots" /></a></p>
  <p>The animation above shows that there is a &quot;gradual&quot; or &quot;continuous&quot; &quot;fade&quot; of the color via the alpha channel.</p>
  <p>Now, the problem is - typically, if I import this image sequence in <code>kdenlive</code> (<code>kdenlive-23.04.0-x86_64.AppImage</code>), and I render a video - the gradual fade is <em>gone</em>/disappears, and the only thing I get is a sudden/instantaneous appearance of the rectangle; similar to output of <code>convert -delay 0 -loop 0 output*.png animation_im.gif</code> (ran on the original image sequence):</p>
  <p><a href="https://i.sstatic.net/r3odF.gif" rel="nofollow noreferrer"><img src="https://i.sstatic.net/r3odF.gif" alt="animated gif from original image sequence" /></a></p>
  <p>So, my question is: how do I preserve an alpha/transparency gradual/continuous fade in an image sequence, also in the rendered video output of <code>kdenlive</code>?</p>
  
Tags: <kdenlive><alpha>
Title: KDenlive, image sequence, and transparency/alpha/opacity of fades
UserDisplayName: sdbbs
ThreadText: # KDenlive, image sequence, and transparency/alpha/opacity of fades
  
  (Asked by: username_0 on 2023-04-30)
  
  This is probably the same question as <https://www.reddit.com/r/kdenlive/comments/ik44o2/image_sequences_cutting_and_transparency/> ( and probably related to <https://kdenlive.org/en/project/compositing-with-transparency/> )
  
  Let's say I have an image sequence, with transparent background, and an element (here a rectangle) with a fill color with fading alpha/transparency; for instance, one generated with `imagemagick`:
  
  ```bash
  for ix in `seq 1 9`; do \
    convert -size 640x480 xc:none \
     -strokewidth 0 -fill "rgba( 255, 215, 30, 0.$ix )" \
       -draw "rectangle 30,30 500,250" \
     -strokewidth 2 -stroke blue -fill none \
     -draw "rectangle 0,0 639,479" output$ix.png; \
  done
  
  ```
  
  It is very difficult obtaining a proper .gif animation directly from the above images; so I opened each one in an image viewer, took screenshot of the image viewer, and finally composed the screenshot images with `convert -delay 0 -loop 0 Screenshot*.png animation_im.gif`, just to show what this image sequence looks like:
  
  [![image sequence animated gif via screenshots](https://i.sstatic.net/pAhp6.gif)](https://i.sstatic.net/pAhp6.gif)
  
  The animation above shows that there is a "gradual" or "continuous" "fade" of the color via the alpha channel.
  
  Now, the problem is - typically, if I import this image sequence in `kdenlive` (`kdenlive-23.04.0-x86_64.AppImage`), and I render a video - the gradual fade is *gone*/disappears, and the only thing I get is a sudden/instantaneous appearance of the rectangle; similar to output of `convert -delay 0 -loop 0 output*.png animation_im.gif` (ran on the original image sequence):
  
  [![animated gif from original image sequence](https://i.sstatic.net/r3odF.gif)](https://i.sstatic.net/r3odF.gif)
  
  So, my question is: how do I preserve an alpha/transparency gradual/continuous fade in an image sequence, also in the rendered video output of `kdenlive`?
  
  **Tags:** kdenlive, alpha
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_0 on 2023-04-30. Score: 1
  
  Well, discovered this almost by accident - but it turns out, to preserve the alpha gradual fades, you MUST add Composite and transform: Composition track: automatic; Compositing: Alpha blend, for the duration of the image sequence:
  
  [![kdenlive image sequence video track with Composite](https://i.sstatic.net/Zvkxx.png)](https://i.sstatic.net/Zvkxx.png)
  
  ... - even if the image sequence is the only track (so compositing then works against the background)!
  
  
  ---
  
  