Use-a-Thon: Waveform thumbnails for audio files

[kayakr]

As a designer I want to see distinct thumbnails for each audio file so I can distinguish repository items at a glance (not so easy if they all have a default thumbnail, see screenshot).

This can be achieved by:

• changing Homarus config to allow PNG thumbnails (see Allow Homarus to generate PNG audio thumbnails Crayfish#78).
• adding an action that uses Homarus to generate a PNG thumbnail from an audio file.

Notes:

• Uses the FFmpeg showwavespic filter, see https://ffmpeg.org/ffmpeg-filters.html#toc-showwavespic and https://trac.ffmpeg.org/wiki/Waveform
• the specific arguments are -filter_complex "aformat=channel_layouts=mono,compand,showwavespic=s=320x120:colors=#ffffff,negate" -frames:v 1.
• to manually try this from a file in the Islandora 8 VM, after creating a Repository Item with model=Audio, and adding an Audio media file sudo ffmpeg -i http://localhost:8000/_flysystem/fedora/2019-10/demo-audio.mp3 -filter_complex "aformat=channel_layouts=mono,compand,showwavespic=s=320x120:colors=#ffffff,negate" -frames:v 1 /var/www/html/drupal/web/sites/default/files/output.png

Add this action (e.g. via Configuration > Development > Configuration synchronization > Import > Single item, Configuration type = Action:

langcode: en
status: true
dependencies:
  module:
    - islandora_image
id: audio_generate_a_thumbnail_from_an_original_file
label: 'Audio - Generate a thumbnail from an original file'
type: node
plugin: generate_image_derivative
configuration:
  queue: islandora-connector-homarus
  event: 'Generate Derivative'
  source_term_uri: 'http://pcdm.org/use#OriginalFile'
  derivative_term_uri: 'http://pcdm.org/use#ThumbnailImage'
  mimetype: image/png
  args: '-filter_complex "aformat=channel_layouts=mono,compand,showwavespic=s=320x120:colors=#ffffff,negate" -frames:v 1'
  destination_media_type: image
  scheme: public
  path: '[date:custom:Y]-[date:custom:m]/[node:nid]-[term:name].png'

[kayakr]

Work in progress action for generating an animated gif thumbnail for a video file such as the What Changes You instance at https://thisvancouver.vpl.ca/

Works on command line:
sudo ffmpeg -i http://localhost:8000/_flysystem/fedora/2019-10/small.mp4 -ss 3 -t 2 -f gif -loop 0 /var/www/html/drupal/web/sites/default/files/output2.gif
but when run via Homarus the resulting gif doesn't animate...

langcode: en
status: true
dependencies:
  module:
    - islandora_image
id: video_generate_animated_thumbnail_from_an_original_file
label: 'Video - Generate animated thumbnail from an original file'
type: node
plugin: generate_image_derivative
configuration:
  queue: islandora-connector-homarus
  event: 'Generate Derivative'
  source_term_uri: 'http://pcdm.org/use#OriginalFile'
  derivative_term_uri: 'http://pcdm.org/use#ThumbnailImage'
  mimetype: image/gif
  args: '-ss 3 -t 2 -f gif -loop 0'
  destination_media_type: image
  scheme: public
  path: '[date:custom:Y]-[date:custom:m]/[node:nid]-[term:name].gif'

Ideally needs a per-item start time, and duration, so that the most representative moment from the video can be represented in the thumbnail.

[Natkeeran]

@dannylamb

This is a nice feature. It seemed to works (I got a black TN with a waveform). Should we included it in the islandora-playbook build?