Difference between revisions of "Preparing videos for blog posts"

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(Shortening: fix time again)
(add bottom text script)
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Here's a short cheat sheet of how to get videos ready for blog posts. We convert them to the widely supported {{wikipedia|webm}} ({{wikipedia|mp4}} will for example not work on Fedora out of the box), and create short and smaller video thumbnails. These thumbnails will be embedded into the blog post directly as little animated pictures, just like gifs, but much more size efficient.
 
Here's a short cheat sheet of how to get videos ready for blog posts. We convert them to the widely supported {{wikipedia|webm}} ({{wikipedia|mp4}} will for example not work on Fedora out of the box), and create short and smaller video thumbnails. These thumbnails will be embedded into the blog post directly as little animated pictures, just like gifs, but much more size efficient.
  
==== Converting to webm ====
+
==== Convert to webm ====
 
<syntaxhighlight lang="shell-session">
 
<syntaxhighlight lang="shell-session">
 
$ ffmpeg -i video.mp4 video.webm
 
$ ffmpeg -i video.mp4 video.webm
 
</syntaxhighlight>
 
</syntaxhighlight>
  
==== Shortening ====
+
==== Shorten ====
 
Start at 10 seconds and cut after the next 5 seconds:
 
Start at 10 seconds and cut after the next 5 seconds:
  
Line 13: Line 13:
 
</syntaxhighlight>
 
</syntaxhighlight>
  
==== Scaling down ====
+
==== Scale down ====
 
Resize to 300x533 px:
 
Resize to 300x533 px:
  
 
<syntaxhighlight lang="shell-session">
 
<syntaxhighlight lang="shell-session">
 
$ ffmpeg -y -i video-short.webm -vf scale=300:533 video-thumb.webm
 
$ ffmpeg -y -i video-short.webm -vf scale=300:533 video-thumb.webm
 +
</syntaxhighlight>
 +
 +
==== Add bottom text ====
 +
<syntaxhighlight lang="shell">
 +
#!/bin/sh -e
 +
 +
if [ "$#" -ne 3 ]; then
 +
        echo "usage: $(basename $0) input output text"
 +
        exit 1
 +
fi
 +
 +
set -x
 +
font="/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf"
 +
ffmpeg -i "$1" -vf drawtext="fontfile=$font: \
 +
        text=\'$3\': fontcolor=white: fontsize=24: box=1: boxcolor=black@0.5: \
 +
        boxborderw=5: x=(w-text_w)/2: y=h-text_h-15" -codec:a copy "$2"
 
</syntaxhighlight>
 
</syntaxhighlight>
  

Revision as of 11:09, 16 June 2019

Here's a short cheat sheet of how to get videos ready for blog posts. We convert them to the widely supported webm (mp4 will for example not work on Fedora out of the box), and create short and smaller video thumbnails. These thumbnails will be embedded into the blog post directly as little animated pictures, just like gifs, but much more size efficient.

Convert to webm

$ ffmpeg -i video.mp4 video.webm

Shorten

Start at 10 seconds and cut after the next 5 seconds:

$ ffmpeg -ss 00:10:00 -i video.webm -c copy -t 00:00:05 video-short.webm

Scale down

Resize to 300x533 px:

$ ffmpeg -y -i video-short.webm -vf scale=300:533 video-thumb.webm

Add bottom text

#!/bin/sh -e

if [ "$#" -ne 3 ]; then
        echo "usage: $(basename $0) input output text"
        exit 1
fi

set -x
font="/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf"
ffmpeg -i "$1" -vf drawtext="fontfile=$font: \
        text=\'$3\': fontcolor=white: fontsize=24: box=1: boxcolor=black@0.5: \
        boxborderw=5: x=(w-text_w)/2: y=h-text_h-15" -codec:a copy "$2"

Embedding into a post

<video controls width="300" height="533" class="border" autoplay="autoplay" loop mute>
<source src="/static/video/2019-00/video-thumb.webm" />
<a href="/static/video/2019-00/video.webm">Description of the video here</a>
</video>

Make sure to embed the link to the full video somewhere in the text related to the video:

Some text talking about the video ([full video](/static/video/2019-00/video.webm)).