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Best Practices for Using STJ Format

Introduction

The Standard Transcription JSON (STJ) format is designed to be flexible and comprehensive. Following best practices ensures consistency, interoperability, and ease of use across different applications and services.

General Guidelines

Consistent Field Usage

  • Mandatory Fields: Always include all mandatory fields as specified in the STJ specification.
  • Optional Fields: Use optional fields where appropriate to enhance the richness of the data.

Data Types and Formats

  • Timestamps: Represent all time fields (start, end) in seconds as floating-point numbers.
  • Language Codes: Use standard ISO 639-1 or ISO 639-3 language codes.
  • Creation Timestamp: Use the ISO 8601 format for the created_at field (e.g., "2023-10-20T12:00:00Z").

Naming Conventions

  • Field Names: Use lowercase letters with underscores (_) for multi-word field names.
  • Identifiers: Use unique strings for id fields in speakers and styles.

Handling Languages

Distinction Between Source and Transcription Languages

  • Source Languages (metadata.source.languages):
  • Represent the languages present in the original media.

  • Useful for understanding the content and planning transcription or translation processes.

  • Transcription Languages (metadata.languages):

  • Represent the languages included in the transcription.
  • May differ from source languages if translations are included.

Per-Segment Language Annotation

  • Specify Language per Segment:
  • Use the language field in each segment to indicate the language of the transcribed text.
  • Crucial for multilingual transcriptions and translations.

Examples

  • Transcription with Translation:
  • Source media contains English and Spanish.
  • Transcription includes translations into French and German.
  • metadata.source.languages: ["en", "es"]
  • metadata.languages: ["fr", "de"]

Transcription Segments

Time Alignment

  • Non-Overlapping Segments: Ensure that segments do not overlap in time.
  • Sequential Order: Segments should be ordered sequentially based on their start times.

Speaker Identification

  • Consistent Speaker IDs: Use consistent speaker_id values throughout the transcript.
  • Unknown Speakers: If the speaker is unknown, omit the speaker_id field or use a placeholder like "speaker_id": "Unknown".

Language Annotation

  • Per-Segment Language: Specify the language field for each segment in multilingual transcripts.
  • Default Language: If the entire transcript is in a single language, specifying language in each segment is optional.

Words Array

  • Detailed Word Data: Include the words array in segments when word-level timing or confidence is needed.
  • Minimal Segments: If word-level details are not required, omit the words array to reduce file size.

Handling word_timing_mode

  • Complete Word Data:
  • When word_timing_mode is "complete", ensure that all words in the text field are represented in the words array.
  • Partial Word Data:
  • When word_timing_mode is "partial", include as many words as have timing data, and ensure they are in the correct order.
  • No Word Data:
  • When there is no word-level timing data, you may omit the words array or set word_timing_mode to "none".

Styling

  • Use of Styles: Define styles in the styles array and reference them in segments using style_id.
  • Default Styles: If no styling is needed, omit the styles section.

Confidence Scores

  • Including Confidence: Provide confidence scores for segments and words when available.
  • Interpreting Confidence: Use the confidence_threshold from metadata to determine if segments need review.

Additional Information

  • Custom Data: Use the additional_info field to include application-specific data.
  • Namespacing: For custom fields, use a prefix (e.g., x_custom_field) to avoid conflicts with future specification updates.

Metadata

Accurate Source Information

  • Source URI: Provide the uri in metadata.source if the source media is accessible.
  • Duration: Ensure duration matches the actual length of the media.

Creation Timestamp

  • ISO 8601 Format: Use the ISO 8601 format for the created_at field (e.g., "2023-10-20T12:00:00Z").

Validation

  • Schema Validation: Validate STJ files against the provided JSON schema to ensure compliance.
  • Automated Testing: Incorporate validation into automated testing workflows.

Interoperability

  • Compatibility: When converting to other formats (e.g., SRT, VTT), ensure that essential information is preserved.
  • Extensions: Avoid breaking changes when extending the format for specific needs.

Performance Considerations

  • File Size: Be mindful of file size, especially when including detailed word-level data.
  • Efficient Parsing: Structure data to facilitate efficient parsing and processing by applications.

Security

  • Data Sanitization: Sanitize any user-generated content to prevent injection attacks.
  • Sensitive Information: Avoid including sensitive personal information in the additional_info or other fields unless necessary and secured.

Conclusion

By adhering to these best practices, you can ensure that your use of the STJ format is consistent, reliable, and compatible with a wide range of tools and applications.