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Line 21 Live Captions

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Line 21 is an intelligent captioning solution that combines professional human captioners with advanced AI technology. It offers real-time captioning, live translation in over 120 languages, AI-powered proofreading, and automatic speech recognition (ASR). Designed for live events, broadcasts, and meetings, it ensures fast, accurate, and accessible content delivery to global audiences across platforms like YouTube, Zoom, and Teams.

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Added on: 2025-08-05
Price Type Is Paid
Monthly Traffic: 814

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Line 21 Live Captions Overview

Line 21 Live Captions is a state-of-the-art, all-in-one platform designed to make live content accessible to a global audience. It uniquely merges the expertise of professional human captioners with the power of advanced AI technologies to deliver dynamic, accurate, and fast captioning and translation solutions. This hybrid approach ensures that content for corporate events, concerts, screenings, and online broadcasts is not only accessible but also contextually accurate and engaging for viewers worldwide.

The platform is built around the philosophy of 'Human + AI' collaboration. It empowers human captioners with tools like an AI Proofreader and automated translations, while also offering fully automated solutions like Automatic Speech Recognition (ASR). With support for over 120 languages and seamless integration with major streaming and video conferencing platforms, Line 21 provides a comprehensive solution for any organization looking to expand its reach and comply with accessibility standards.

How to use Line 21 Live Captions

Using Line 21 is a streamlined process designed for both technical and non-technical users. First, you book the required services, choosing between professional human captioners for maximum accuracy or the high-performance ASR for automated captioning. You can then connect your existing captioning software or audio source to the Line 21 platform using their dedicated desktop app or a simple keyboard macro. During the event, captions are created and can be enhanced in real-time with the AI Proofreader, which corrects typos and name errors. If needed, captions can be automatically translated into any of the 120+ supported languages. Finally, the captions are delivered to your chosen destinations, such as YouTube Live, Zoom, Facebook Live, or a custom web player. After the event, you can download full transcripts in various formats (.txt, .srt, .webvtt) for repurposing or archival.

Core Features of Line 21 Live Captions

  • AI Proofreader: An innovative, context-aware AI that acts as a dynamic safeguard, correcting typos and name-errors in real-time to ensure caption accuracy and professionalism.
  • AI Translations: Automatically translate live captions into over 120 languages using high-performance language models, breaking down language barriers for international audiences.
  • Automatic Speech Recognition (ASR): A powerful speech-to-text engine that generates captions with up to 97% accuracy. It supports custom glossaries to improve context understanding for specialized terminology.
  • CEA-608/708 Caption Encoding: Seamlessly encode captions directly into your video streams (RTMP and HLS), ensuring compatibility with broadcast standards and platforms like YouTube, Twitch, and Vimeo.
  • Low-Latency Delivery: Captions are delivered to viewers with an average speed of ~144ms, ensuring a synchronized and smooth viewing experience.
  • Multi-Destination Delivery: Distribute captions simultaneously to a wide range of endpoints, including major social media platforms, video conferencing tools, custom RTMP servers, and a dedicated overlay app.
  • Customizable Caption Display: Offer viewers flexible display options, including a browser link or a downloadable overlay. The display is fully customizable and includes a color contrast checker to ensure accessibility compliance.
  • Post-Event Transcripts: Downloadable transcripts of the entire session are available in multiple formats and languages, included as a standard feature for all events.

Use Cases for Line 21 Live Captions

Line 21 is ideal for a wide range of live events. For corporate town halls and international conferences, it ensures all employees and attendees can participate, regardless of their language or hearing ability. In media and broadcasting, it provides reliable, low-latency captions for live news and sports. Educational institutions use it for lectures and webinars to create an inclusive learning environment. Concerts and cultural events can leverage it to reach a broader, more diverse audience by providing real-time captions and translations.

Advantages of Line 21 Live Captions

The primary advantage of Line 21 is its unique Human + AI hybrid model, which offers the nuance and accuracy of professional captioners enhanced by the speed and scale of AI. This results in superior quality captions. The platform is an all-in-one solution, eliminating the need for multiple tools for captioning, translation, and encoding. Its extensive language support makes it a truly global tool. Furthermore, its high performance, reliability, and flexible pay-per-minute pricing make it an accessible and cost-effective choice for organizations of all sizes.

Pricing and Plans

Line 21 operates on a transparent, pay-as-you-go pricing model, allowing users to pay only for the services they use. There are no subscriptions or hidden fees. Key pricing points include:

  • Human Captioner Booking: From $120 per hour.
  • AI Services: AI Proofreader at $0.35/min, AI Translations at $0.15/min, and ASR at $0.25/min.
  • Platform Usage (with own captioner): $0.05 per minute.
  • Video Streaming & Encoding: RTMP Encoding at $0.40/min and HLS Streaming at $0.002/min.
  • Live Support: Dedicated event support is available from $100 per hour or $300 per day.
This flexible structure makes it suitable for both one-off events and agencies that require regular captioning services for their clients.

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