Speech to Text Workflow Operation

ID: speechtotext

Description

The speech to text operation can be used to generate subtitles for Videos or Audio files. Currently, there are two STT engines available, Whisper and Vosk. The subtitles file format ist WebVTT.

Parameter Table

configuration keys	required	Example	description
source-flavor	yes	source/presenter	The source media package to use
target-flavor	yes	archive	Flavor of the produced subtitle file. The subflavor supports the language-code placeholder #{lang}
target-element	no	attachment	Define where to append the subtitles file. Possibilities are: as a 'track' or as an 'attachment'. The default is "attachment".
language-code	no	de	The language of the video or audio source (default is "eng"). Vosk only: It has to match the name of the language model directory. See 'vosk-cli'.
language-fallback	yes*	en	The fallback value if the dublin core/media package language field is not present.
target-tags	no	delivery/captions	Tags for the subtitle file (Whisper only: If no language-code,the tag lang:{code} will be auto generated)
translate	no	true	Transcription is translated into English, valid values true or false (Whisper Only)

*Vosk Only, default value can be modified on Vosk config file.

Requirements

In order for it to work, you have to install the vosk-cli or whisper package

Operation Examples

If you want to display the subtitles in the Paella player, the WebVTT files have to be published and the target SubFlavor has to be configured like this: vtt+LANG, where LANG is the language option, that will be displayed in the Paella player. Please note the description above for the language-code field.

Paella Player also can detect the tag lang:{code} to show the language in the subtitle menu.

<operation
    id="speechtotext"
    description="Generates subtitles for video and audio files">
  <configurations>
    <configuration key="source-flavor">*/source</configuration>
    <configuration key="target-flavor">captions/vtt+en</configuration>
    <configuration key="target-element">attachment</configuration>
    <configuration key="target-tags">archive,subtitle,engage-download</configuration>
    <configuration key="language-code">eng</configuration>
  </configurations>
</operation>

<operation
    id="speechtotext"
    description="Generates subtitles for video and audio files, derive language-code from metadata">
    <configurations>
      <configuration key="source-flavor">*/source</configuration>
      <configuration key="target-flavor">captions/vtt+#{lang}</configuration>
      <configuration key="target-element">attachment</configuration>
      <configuration key="target-tags">archive,subtitle,engage-download</configuration>
    </configurations>
</operation>

Language code

The accepted language code are the two letter codes defined in ISO 639-1. A reference list can be found here:

List of ISO 639-1 codes