LiveCaptioner Specification

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LiveCaptioner

Every Word, Within Reach.

Overview

LiveCaptioner is an accessible, modular live captioning and multilingual communication platform designed to make spoken communication more accessible, understandable, and inclusive. It provides real-time speech transcription, synchronized captions, live translation, two-way conversation, speaker identification, and intelligent accessibility features.

LiveCaptioner supports individuals, organizations, educational environments, businesses, public spaces, and communication platforms. It is designed to work across live conversations, meetings, presentations, media, and other audio-enabled experiences.

The platform combines real-time captioning with intelligent language assistance, customizable accessibility controls, transcript management, and optional integrations. Its modular architecture allows core captioning capabilities to operate independently while optional plugins extend functionality through external services and specialized integrations.

Design Principles

Accessibility First: Make spoken communication accessible to people with different hearing, language, communication, and cognitive needs.
Real-Time Communication: Deliver responsive transcription, translation, and caption synchronization.
Modular Architecture: Organize essential functionality into independent core modules with optional plugin extensions.
Multilingual Inclusion: Support communication across languages through transcription, translation, and live interpretation.
User Control: Allow users to manage caption settings, language preferences, privacy, retention, and sharing permissions.
Human-in-the-Loop: Preserve human oversight for corrections, translations, AI-assisted changes, and consequential communication decisions.
Privacy and Security: Provide clear controls over audio processing, transcripts, personal information, and external integrations.
Local-First Operation: Support local processing and offline functionality where available.
Interoperability: Support established caption formats, accessibility standards, and integration interfaces.
Extensibility: Allow optional plugins to introduce additional providers, integrations, and specialized capabilities without requiring changes to the core platform.

Core Modules

Live Speech Capture

Capture live speech from supported microphones, audio devices, and system audio sources.
Support multiple audio input sources and configurable input selection.
Allow users to select, switch, and manage audio sources during a session.
Support continuous audio capture for live conversations and presentations.
Provide audio input monitoring and capture status indicators.
Detect changes in audio input availability and report connection problems.
Support configurable audio capture settings.
Allow authorized applications and sessions to provide audio input.
Maintain capture continuity when supported input sources change.
Provide clear indicators showing which audio sources are active.

Intelligent Audio Processing

Process incoming audio to improve speech recognition accuracy.
Apply noise reduction and background noise suppression.
Support automatic volume normalization and audio level adjustment.
Detect speech activity and distinguish speech from silence.
Identify overlapping speech where supported.
Improve audio clarity in environments with background conversations.
Support configurable audio processing profiles.
Adapt processing to different acoustic environments.
Preserve original audio characteristics where necessary for accurate transcription.
Provide processing status and quality indicators.

Real-Time Speech Recognition

Convert live speech into readable text with minimal latency.
Support continuous transcription during active sessions.
Provide configurable recognition language and regional language variants.
Support automatic language detection where available.
Display partial and finalized transcription results.
Correctly handle punctuation, capitalization, and sentence boundaries.
Support specialized vocabulary and contextual terminology.
Allow recognition providers to be selected through supported integrations.
Maintain transcription continuity during temporary service interruptions where possible.
Preserve original transcription independently from AI-enhanced text.
Provide confidence indicators where supported.
Allow users to review and correct recognition errors.

Live Caption Display

Display captions as speech is recognized.
Provide configurable caption positioning and presentation.
Support adjustable font size, typeface, spacing, and line length.
Offer customizable foreground and background colors.
Support high-contrast caption presentation.
Provide adjustable transparency and background opacity.
Allow users to configure the number of visible caption lines.
Support automatic scrolling and manual caption navigation.
Provide caption display modes for individual users and shared environments.
Support fullscreen and compact caption presentation.
Allow users to pause, resume, and clear visible captions.
Maintain readable caption layouts across supported screen sizes.

Caption Timing and Synchronization

Synchronize captions with their corresponding speech.
Maintain accurate timing for live transcription.
Support timestamped caption segments.
Manage caption delays and configurable synchronization settings.
Handle partial captions and finalized caption segments.
Support synchronized captions across connected devices where authorized.
Preserve timing information during transcript export.
Provide mechanisms for correcting caption timing.
Support synchronization with compatible video and media sources.
Maintain caption sequence and continuity during active sessions.

Multilingual Caption Translation

Translate recognized speech into selected target languages.
Support multiple target languages where provider capabilities permit.
Display original-language captions alongside translated captions.
Allow users to switch target languages during a session.
Support configurable translation preferences.
Preserve original transcription separately from translated text.
Maintain caption timing and segment relationships during translation.
Provide language identification and translation status indicators.
Support specialized terminology and approved glossaries.
Allow users to review and correct translated captions.
Provide translation quality indicators where available.
Handle unavailable languages and translation provider failures gracefully.

Two-Way Conversation Mode

Support conversations between participants speaking different languages.
Capture and transcribe speech from both sides of a conversation.
Translate recognized speech into the other participant’s selected language.
Display original and translated captions together.
Allow participants to select their preferred languages independently.
Support alternating and continuous conversation modes.
Provide optional translated speech output.
Identify conversation participants where supported.
Maintain separate transcript segments for each participant.
Support accessible conversation layouts for individual and shared displays.
Allow participants to review and correct conversation transcripts.

Live Interpretation

Provide real-time interpretation between supported languages.
Translate spoken communication while preserving the original message.
Support one-way and two-way interpretation.
Allow users to select interpretation languages.
Provide optional speech output for translated content.
Support configurable interpretation presentation.
Preserve original speech recognition results.
Identify interpretation delays and processing status.
Allow human review and correction of interpreted content.
Support human interpreter integrations through optional plugins.

Speaker Identification and Diarization

Distinguish between different speakers within supported audio sources.
Associate recognized speech with speaker labels.
Maintain speaker consistency throughout a session where possible.
Support configurable speaker names and labels.
Allow users to manually correct speaker assignments.
Identify changes in speakers during conversations.
Support overlapping speech where provider capabilities permit.
Maintain speaker attribution in transcripts and exports.
Provide privacy controls for speaker identification.
Avoid treating speaker identification as verified personal identity.

Punctuation and Caption Formatting

Automatically format recognized speech into readable captions.
Apply punctuation and capitalization.
Identify sentence and paragraph boundaries.
Support configurable caption segmentation.
Provide options for concise and verbatim caption presentation.
Preserve meaningful pauses and speech structure where appropriate.
Support formatting rules for different languages.
Apply consistent formatting across original and translated captions.
Allow users to customize formatting preferences.
Preserve original transcription when formatting or AI-assisted enhancement is applied.

Audio Events and Non-Speech Information

Identify relevant non-speech audio events where supported.
Recognize sounds such as laughter, applause, music, alarms, and environmental noise.
Provide descriptive labels for relevant audio events.
Distinguish audio events from spoken dialogue.
Allow users to configure which events appear in captions.
Support contextual descriptions of important sounds.
Include event timestamps in session transcripts.
Provide optional sound descriptions for accessibility.
Avoid presenting uncertain audio classifications as confirmed facts.

Intelligent Caption Assistance

Provide AI-assisted caption correction and readability improvements.
Identify possible transcription errors.
Suggest punctuation and formatting corrections.
Provide contextual assistance for unclear or incomplete phrases.
Support terminology recognition and contextual vocabulary.
Offer optional caption summarization.
Support clarification of unfamiliar terms and phrases.
Allow users to compare original and AI-enhanced text.
Require user authorization before replacing or modifying finalized transcript content.
Preserve the original transcription and maintain a distinction between recognized speech and AI-generated assistance.
Provide transparency when content has been translated, summarized, corrected, or otherwise enhanced.

Caption Accessibility Intelligence

Adapt caption presentation to user-selected accessibility preferences.
Support readability improvements based on configured accessibility needs.
Provide high-contrast and simplified display options.
Offer configurable caption density and presentation speed.
Support visual indicators for speaker changes and non-speech events.
Provide optional descriptions of relevant audio information.
Support accessible navigation and interaction.
Allow accessibility preferences to be applied consistently across sessions.
Provide guidance for improving caption readability.
Avoid making assumptions about individual accessibility requirements.

Personal Accessibility Profiles

Allow users to create and manage personal captioning profiles.
Store preferred languages and translation settings.
Save caption appearance and display preferences.
Maintain individual accessibility configurations.
Support profiles for different environments and communication situations.
Allow users to switch profiles during a session.
Support authorized profile synchronization across devices.
Provide controls for profile data retention and deletion.
Allow users to configure default captioning and interpretation behavior.

Caption Editing and Correction

Allow users to edit recognized captions and transcript segments.
Correct transcription, punctuation, formatting, and speaker assignments.
Review and correct translated captions.
Preserve original recognized text for comparison.
Track user corrections and applicable revision history.
Support manual approval of AI-assisted suggestions.
Allow authorized collaborators to review and suggest corrections.
Maintain timestamps and speaker associations during editing.
Provide controls for accepting or rejecting proposed changes.
Distinguish original speech recognition from subsequent edits.

Session Management

Create, start, pause, resume, and end captioning sessions.
Provide session identifiers and configurable session names.
Maintain session language and accessibility settings.
Support different session types and captioning configurations.
Display active session status.
Manage session participants and authorized access.
Preserve session continuity during supported interruptions.
Allow users to configure session retention.
Provide controls for saving and deleting session information.
Support individual and shared captioning sessions.

Advanced Session Connectivity

Support authorized connections between multiple devices.
Synchronize captions and session information across connected devices.
Allow participants to join and leave supported sessions.
Provide session access controls and authorization.
Support shared caption displays.
Maintain consistent language and accessibility preferences across connected devices.
Provide connection and synchronization status indicators.
Handle temporary disconnections and reconnections.
Prevent unauthorized access to private sessions.
Maintain session continuity when supported devices reconnect.

Transcript History and Search

Maintain configurable transcript history.
Organize transcripts by date, session, language, and other available metadata.
Allow users to search transcript content.
Support searching by speaker, keyword, and timestamp.
Provide access to previous session transcripts where authorized.
Allow users to review and edit saved transcripts.
Support configurable transcript retention.
Provide controls for deleting individual transcripts or session histories.
Maintain original and revised transcript versions where enabled.
Respect user privacy and retention preferences.

Advanced Caption Navigation

Navigate between caption segments.
Jump to specific timestamps and speakers.
Search and locate relevant transcript passages.
Support keyboard-accessible navigation.
Provide navigation controls for long transcripts.
Highlight the currently active caption segment.
Support synchronized navigation with compatible media.
Allow users to revisit important conversation sections.
Preserve navigation context when switching between transcript views.

Transcript Export and Sharing

Export transcripts in supported text and caption formats.
Preserve timestamps and speaker attribution where available.
Support original and translated transcript exports.
Allow users to select which transcript information is included.
Provide configurable sharing permissions.
Support authorized transcript sharing.
Allow users to export selected session segments.
Maintain attribution and source information where applicable.
Provide privacy controls before sharing or exporting.
Support accessible transcript presentation formats.

Caption Standards and Interoperability

Support established caption and subtitle formats where applicable.
Preserve timestamps, speaker labels, and caption segmentation.
Support interoperability with compatible media and communication platforms.
Provide consistent handling of multilingual captions.
Maintain formatting and synchronization information during conversion.
Support import and export of compatible caption files.
Validate caption data against supported format requirements.
Provide extensible interfaces for additional standards.
Maintain accessibility considerations across supported formats.

Mobile Captioning

Provide live captioning experiences on supported mobile devices.
Support device microphones and available audio input sources.
Offer configurable mobile caption layouts.
Support portrait and landscape presentation.
Provide adjustable text size and contrast.
Support mobile accessibility settings.
Allow users to manage language and translation preferences.
Support session synchronization where authorized.
Provide mobile-friendly transcript navigation and editing.
Maintain privacy and permission controls for mobile audio capture.

Accessibility and Inclusive Design

Support accessible interfaces and interaction patterns.
Provide keyboard navigation and assistive technology compatibility.
Support screen readers where applicable.
Offer high-contrast and customizable visual presentation.
Provide readable typography and adjustable text sizing.
Support reduced visual complexity and simplified layouts.
Make important status information available through accessible indicators.
Provide accessible controls for session management and caption navigation.
Support multilingual interface presentation where available.
Design interactions to accommodate different communication preferences and accessibility requirements.

Caption Developer API

Provide documented interfaces for interacting with core captioning functionality.
Allow authorized applications to access supported transcription and caption services.
Support integration with compatible audio sources and caption displays.
Provide access to session and transcript information according to permissions.
Support timestamped caption data and speaker attribution.
Provide interfaces for translation and interpretation services.
Support event notifications for caption and session changes.
Provide authentication and authorization controls.
Document available capabilities, permissions, and integration requirements.
Support extensibility without compromising core platform functionality.

Caption Quality and Benchmarking

Evaluate transcription accuracy where reference data is available.
Measure caption latency and synchronization performance.
Assess translation quality where suitable evaluation methods exist.
Monitor recognition confidence and processing status where supported.
Identify recurring transcription and formatting problems.
Provide configurable quality metrics.
Support comparisons between compatible recognition and translation providers.
Evaluate caption readability and segmentation.
Provide tools for reviewing caption quality over time.
Respect privacy and consent requirements when collecting evaluation data.

Session Intelligence and Transcript Management

Organize session information and associated transcript data.
Identify key topics and important transcript segments through optional AI assistance.
Support configurable transcript summaries.
Allow users to identify and bookmark important passages.
Provide contextual search and transcript organization.
Maintain relationships between original, translated, and edited content.
Preserve speaker attribution and timestamps.
Allow users to control which intelligent features are enabled.
Clearly distinguish generated summaries and interpretations from original speech.

Notifications and Status Monitoring

Provide notifications for session events and important changes.
Display audio capture and transcription status.
Report language recognition and translation availability.
Identify connectivity and synchronization problems.
Notify users of provider interruptions and recovery.
Provide configurable notification preferences.
Support accessible status announcements.
Avoid unnecessary or disruptive notifications.
Allow users to manage notification behavior during sessions.

Privacy, Security, and User Control

Provide transparent controls for audio capture and processing.
Require appropriate permissions before accessing microphones and other audio sources.
Protect session data and transcripts from unauthorized access.
Support configurable data retention and deletion.
Provide controls for transcript sharing and external integrations.
Allow users to manage connected services and permissions.
Clearly disclose when external providers process audio or transcript information.
Support secure session access and authorized device connections.
Preserve user control over AI-assisted processing and transcript modifications.
Provide privacy controls for speaker identification and profile information.
Avoid retaining audio or transcript data beyond configured retention requirements.
Make privacy and processing settings understandable and accessible.

Local-First and Offline Operation

Support local audio processing and speech recognition where available.
Provide offline captioning capabilities through compatible local services.
Allow users to manage local transcript storage.
Support local processing without requiring external service connections where possible.
Identify features that require internet access or external providers.
Maintain clear status indicators for online and offline functionality.
Support synchronization when connectivity becomes available, subject to user authorization.
Preserve local data and session continuity during temporary connectivity interruptions.
Allow users to choose between supported local and external processing options.

Translation Quality and Review

Provide tools for reviewing translated captions.
Allow users to correct terminology and translation errors.
Support approved glossaries and specialized vocabulary.
Preserve the original-language transcript.
Identify uncertain or incomplete translations where supported.
Allow comparison between original and translated segments.
Support human review and approval.
Maintain translation revision history where enabled.
Provide configurable translation quality indicators.
Distinguish machine-generated translations from human-reviewed content.

Administration and Configuration

Provide configurable platform and session settings.
Manage available recognition and translation providers.
Configure accessibility defaults and supported languages.
Manage optional integrations and plugin permissions.
Support administrative access controls where applicable.
Provide configuration for data retention and privacy policies.
Monitor platform availability and service status.
Allow administrators to manage shared environments.
Provide clear documentation for available settings and permissions.
Maintain user control over personal accessibility preferences.

Optional Plugin Modules

Optional plugins extend LiveCaptioner without making external integrations mandatory for core captioning functionality. Each plugin can be independently enabled, configured, and managed according to its documented permissions and dependencies.

Speech Recognition Providers

Integrate additional speech-to-text providers.
Support provider-specific recognition models and language capabilities.
Allow authorized provider selection and configuration.
Support provider comparison and quality evaluation.
Provide graceful handling of provider failures.

Translation and LLM Providers

Integrate external translation services and language models.
Support additional translation languages and specialized models.
Provide AI-assisted caption correction and summarization.
Support configurable provider selection.
Preserve original transcripts and user review controls.

Video Conferencing Integrations

Connect with supported video conferencing platforms.
Capture authorized meeting audio.
Provide live captions within compatible meeting environments.
Synchronize captions with meeting sessions.
Support participant and speaker information where available.

Browser Integration

Provide captioning for supported browser-based audio and video.
Capture authorized browser audio sources.
Display captions alongside compatible web content.
Support browser-based meetings and presentations.
Provide configurable browser permissions.

Desktop Accessibility Integration

Integrate with supported desktop accessibility services.
Provide system-wide captioning where supported.
Support accessible notifications and caption presentation.
Integrate with compatible assistive technologies.
Allow configurable desktop caption displays.

Live Streaming Integration

Provide captions for supported live streams.
Support caption broadcasting and streaming workflows.
Synchronize captions with live media.
Support multilingual caption streams.
Integrate with compatible streaming platforms.

Media Player Integration

Provide captions for supported audio and video players.
Synchronize captions with media playback.
Support external caption files.
Allow users to select caption languages.
Provide compatible transcript navigation.

Text-to-Speech Integration

Convert translated or recognized text into speech.
Support configurable voices and languages.
Allow users to select speech output preferences.
Provide optional spoken interpretation.
Support accessible audio playback controls.

OCR and Visual Text Recognition

Recognize text displayed within supported visual sources.
Extract relevant text from presentations and shared screens.
Support captioning workflows that combine spoken and visual information.
Distinguish recognized visual text from spoken transcription.
Provide source and confidence indicators where available.

Caption Styling and Presentation

Provide additional caption themes and layouts.
Support advanced typography and visual customization.
Offer specialized presentation modes.
Support branded and public display configurations.
Allow users to save and share presentation profiles.

Specialized Vocabulary and Glossaries

Support industry-specific terminology.
Provide custom dictionaries and pronunciation guidance.
Allow authorized glossary creation and management.
Share approved terminology across authorized sessions.
Improve recognition and translation consistency.

Recording and Media Archiving

Support authorized session recording.
Associate recordings with transcript segments and timestamps.
Provide configurable media retention.
Support searchable media archives.
Maintain appropriate consent and access controls.

Collaboration and Shared Review

Allow authorized participants to review transcripts together.
Support shared corrections and suggestions.
Provide collaborative translation review.
Track changes and contributor acknowledgments.
Support permission-based collaboration.

Analytics and Performance Monitoring

Provide configurable captioning and session analytics.
Monitor transcription latency and service availability.
Evaluate recognition and translation performance.
Support usage reporting where authorized.
Provide privacy-conscious operational insights.

Language Learning and Education

Support language learning through live captions and translations.
Provide vocabulary highlighting and terminology explanations.
Allow comparison of original and translated speech.
Support educational transcript review.
Provide configurable learning and comprehension assistance.

Accessibility Integrations

Connect with compatible accessibility tools and services.
Support additional assistive technology workflows.
Integrate with accessible notification and communication systems.
Provide specialized caption presentation options.
Extend accessibility functionality through independent integrations.

Human Interpreter and Captioner Integration

Connect users with supported human interpretation services.
Support human captioner workflows.
Allow authorized human review of machine-generated captions.
Support corrections and interpretation feedback.
Distinguish human-reviewed content from automated output.

Caption Broadcasting and Public Displays

Provide captions for public displays and shared environments.
Support multiple display destinations.
Offer configurable presentation layouts.
Support multilingual public captioning.
Provide authorized broadcast and distribution controls.

Emergency and Public Announcement Captioning

Support captioning of compatible public announcements.
Identify relevant emergency audio events where supported.
Provide clear and readable announcement captions.
Support multilingual announcement presentation.
Prioritize timely delivery while clearly identifying uncertain recognition results.

Plugin Marketplace and Extensions

Provide a framework for discovering and managing optional plugins.
Support independently maintained integrations.
Document plugin permissions and dependencies.
Allow users to enable, disable, update, and remove plugins.
Support plugin compatibility information.
Maintain security and privacy requirements for all extensions.

Cross-Module Capabilities

Consistent User Preferences

Maintain consistent language, caption, and accessibility preferences across core modules.
Allow authorized preferences to be shared across connected devices.
Support session-specific settings without unexpectedly changing personal defaults.

Independent Module Operation

Keep essential captioning functionality independent of optional integrations wherever possible.
Allow individual modules to operate without requiring unrelated modules.
Support independent configuration and capability management.
Provide graceful degradation when optional services are unavailable.

Shared Terminology and Language Context

Maintain consistent terminology across transcription, translation, and interpretation.
Support approved vocabulary and glossaries across authorized modules.
Preserve language and regional preferences throughout a session.

Specification Branding License (SBL)

Standard

Fully AGPL-3.0+ compliant system
Copyleft enforced for network deployments
Required attribution:
- Roxanne Ardary
- https://www.roxanneardary.com/

Optional

Specification Branding License (SBL)
- Attribution-free commercial deployment
- Pricing based on scale, usage, and deployment scope
- https://roxanneardary.com/livecaptioner/

License & Notice Requirements

LiveCaptioner is released under the GNU Affero General Public License v3.0 or later (AGPL-3.0+).
By contributing to any Open Arsenal project, you agree that your contributions will also be released under this license.

Please note the following:

All contributions must comply with the AGPL-3.0+ terms.
Under Section 7 of the license, all redistributions, forks, and derivative works must preserve attribution to:
Roxanne Ardary and roxanneardary.com.
LiveCaptioner specifications are free to use with attribution. A Specification Branding License can be negotiated upon request.
The project’s notice.md file tracks attribution requirements and contributor acknowledgments.
Any update that adds new contributors or modifies attribution should also update notice.md.
When submitting a pull request, ensure that any new files maintain the attribution headers where applicable.
Network-deployed versions of this software must also remain fully AGPL-3.0+ compliant, including exposure of source code modifications when applicable under the license.

For full legal details, please refer to the AGPL-3.0+ license and the project’s notice.md file.

Notice – LiveCaptioner

Attribution Requirement: Under Section 7 of the AGPL 3.0+ license, all redistributions, forks, and derivative works, including network-deployed versions of this project, must provide attribution to Roxanne Ardary and roxanneardary.com.

Contributors

This file tracks contributors and their specific contributions to the project.

Roxanne Ardary, roxanneardary.com – November 1, 2026
Created the repository for LiveCaptioner. Developed the project concept and specification for an accessible, modular live captioning platform supporting real-time transcription, multilingual communication, two-way conversation, and personalized accessibility features.
Add other contributors here – [Date]
[Describe contribution in one sentence]

License – LiveCaptioner

This repository is licensed under the GNU Affero General Public License v3.0 or later (AGPL-3.0+).

Key Points:

You are free to use, modify, and distribute the code.
All redistributions, forks, and derivative works or network-deployed versions must also be licensed under AGPL-3.0+ and provide attribution to Roxanne Ardary and roxanneardary.com as required under Section 7 of the license.
The software is provided “as is,” without warranty of any kind.

For the full license text, see GNU AGPL-3.0 License.