Technical Overview

Broadcast-Grade Live Captioning Engine

Txtplay is engineered for on-air use in live broadcast environments where latency, accuracy, and reliability are critical. The captioning engine delivers 1–2 seconds end-to-end latency, keeping subtitles in sync with live speech for news, sports, and event programming. Subtitle delivery supports European broadcast standards, including Teletext (via Newfor) and TTML/EBU-TT-D.

The solution is designed for 24/7 playout operations, supporting continuous channel output, live editorial environments, and dynamic programme changes. Txtplay integrates with both SDI and SMPTE 2110/IP infrastructures, allowing deployment in legacy or fully IP broadcast facilities without disrupting existing signal chains.

ASR-Agnostic Speech-to-Text Layer

Txtplay operates independently of any single ASR vendor and supports integration with multiple broadcast-grade ASR engines, ensuring flexibility in accuracy, language coverage, and commercial choice. The ASR component can be deployed in the cloud, on-prem, or in a hybrid configuration, enabling broadcasters to align captioning architecture with internal security, latency, and data-handling policies.

Hybrid deployments allow Txtplay to run on-prem for full control of ingest and output, while ASR operates in the cloud for scalability. For high-security or air-gapped environments, both the Txtplay application and the ASR engine can be deployed fully on-premises. This model supports low-latency processing and eliminates external data exposure, meeting strict compliance requirements.

Subtitle Formatting, Filtering & Editorial Controls

Txtplay provides a broadcast-specific subtitle formatting layer that adapts raw ASR output to on-air captioning standards. Operators can configure segmentation, timing, reading-speed limits, and character-per-line rules to ensure subtitles remain readable within broadcast editorial guidelines. Multiple rendering modes are available, including pop-on, rolling line (“snake”) and multi-line layouts, with per-channel configuration.

The system includes custom dictionaries with real-time update capability for names, terminology, and event-specific vocabulary (e.g., sports, elections). Filtering algorithms improve readability by removing filler words, repeated phrases, false starts, and hesitations. Profanity filtering is included for compliance in live output. Automatic casing, punctuation, and sentence-boundary correction produces cleaner subtitles with reduced operator intervention. Broadcasters can apply language-specific profiles to tailor formatting rules per channel or territory.

Txtplay includes an operator interface for channel monitoring, real-time dictionary updates, and on-air formatting adjustments, allowing editorial teams to intervene when necessary without interrupting output.

Integration Into Broadcast Workflows

Txtplay integrates natively into live production and playout environments and is compatible with industry-standard broadcast captioning and graphics systems, including Pixel Power, BroadStream, Evertz, and Newfor. The solution can operate at either the production or playout stage and supports both SDI and SMPTE 2110/IP caption insertion, depending on the facility architecture.

For linear TV distribution, Txtplay supports Teletext subtitles (via Newfor) for compatibility with traditional broadcast delivery across European markets. Txtplay also supports TTML/EBU-TT-D for modern and future-ready subtitle workflows. Output can be passed to existing caption encoder infrastructure for insertion into the outgoing signal chain, ensuring full compatibility with current broadcast systems.

The integration design enables automated or human-assisted operation, supporting workflows with or without existing respeaker involvement.

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Deployment & Architecture Options

The Txtplay application is installed on-premises within the broadcaster’s environment, ensuring direct control of ingest, processing, latency, and output routing. Broadcasters can run the ASR engine in the cloud or on-prem, depending on operational, security, and regulatory requirements.

A typical hybrid architecture runs Txtplay on-prem for deterministic performance and local resilience, with ASR in the cloud for scalability and continuous model updates. For secure or air-gapped environments, full on-prem deployments of both Txtplay and ASR are supported. This architecture enables deterministic latency, internal data retention, and integration with broadcaster IT and MCR security policies.