⚠️ This content has been written a long time ago. As such, it might not reflect my current thoughts anymore. I keep this page online because it might still contain valid information.

Converting my blog posts to audio files

2022-03-22 // I proofread this article and fixed some links. I also recently removed the audio files on this website because I stopped generating audio files a while ago. It was cool and probably useful 10 years ago but I expect screen readers to be a lot more efficient nowadays.

Yesterday, I discovered the say command on my Mac. Its aim is to convert text to audible speech and that works really well. Then, I had the idea of creating audio files from my blog posts because (1) it’s fun and (2) it could possibly improve accessibility on this website.

The say command generates aiff audio files but that isn’t supported by the audio HTM5 tag. I converted the aiff files to mp3 using the well-known ffmpeg tool.

Please welcome Speaker, my fun work from last evening! Speaker aims to convert my blog posts written in markdown to mp3 files. It is a tiny shell script I enjoyed writing.

  ./speaker [-h] [-d <output directory>] <filename>

I used roundup to test it. I love shell scripts but writing them without any tests is a pain, there is often a condition that is not good, a typo, or something else. That often makes me crazy… Well, problem solved with roundup! Here is my test suite output:

$ ./speaker-test.sh
it_shows_help_with_no_argv:                      [PASS]
it_shows_help_with_h_option:                     [PASS]
it_creates_mp3_file:                             [PASS]
it_creates_mp3_file_in_existing_directory:       [PASS]
it_creates_mp3_file_in_new_directory:            [PASS]
Tests:    5 | Passed:   5 | Failed:   0

To sanitize the text to speech, I used some regular expressions. It probably needs some improvements but it works pretty well:

# Sanitize markdown content
content=`echo "$content" | sed -e 's/[\*_]//g'`
content=`echo "$content" | sed -e 's/\[\(.*\)\](\(.*\))/\1/g'`
content=`echo "$content" | sed -e 's/:[p|D]/./g'`

For the other parts, you can take a look at the code :)

Because I wanted to expose these audio files on this website, I tweaked the template to integrate an audio tag. I also used html5media to render this tag in all major browsers (I don’t know if there is a better solution).

<audio src="/mp3/my-blog-title.mp3" controls preload></audio>

Last, to automagically generate audio files, I wrote a pre-commit script to build the audio file when I commit blog posts.

That’s all folks!

Feel free to fork and edit this post if you find a typo, thank you so much! This post is licensed under the Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license.

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