How does the sliding window translation work?

SubtleSubtitle's proprietary sliding window uses 25-segment context windows with 10-segment overlap in a three-phase translation process (Past-Present-Future). Each subtitle segment is translated with awareness of surrounding context, preventing the inconsistencies and context loss common in sentence-by-sentence translation tools.

AI-Powered Subtitling

The Subtle Art of Subtitles

SubtleSubtitle uses advanced speech models to achieve 95%+ transcription accuracy, then translates using a proprietary 25-segment sliding window algorithm with Past-Present-Future context awareness. From transcription to stylized bilingual subtitles in under 3 minutes.

50+ Lifetime Users

1,000+ Paid Users

10,000+ Subtitles Generated

PROJECT_V01.MP4

“The art of subtlety.”

Ai Processing

How Does SubtleSubtitle Generate Subtitles?

SubtleSubtitle uses a 5-step AI pipeline to transcribe, understand context, confirm terminology, segment semantically, and translate with sliding-window context awareness — ensuring every word is captured and translated with full narrative understanding.

Precision Transcription

Context Extraction

LLM analyzes video background and context, enhanced by web search for domain-specific accuracy.

Term Confirmation

Intelligent extraction of key terms with user control over translation strategy before final output.

Semantic Segmentation

Sentences split by meaning and rhythm using LLM analysis, not just punctuation marks.

Sliding Window Translation

Proprietary 25-segment context window with 10-segment overlap ensures narrative consistency across your entire video.

Why Choose SubtleSubtitle?

SubtleSubtitle is the only AI subtitle tool with a proprietary sliding-window translation algorithm, user-controlled terminology management, and tone customization — built for creators who demand context-aware bilingual subtitles, not word-by-word machine translation.

Sliding Window Algorithm

An industry-first 3-stage context window (Past-Present-Future) with 25-segment windows and 10-segment overlap ensures every sentence is translated with full awareness of the narrative flow — unlike tools that translate sentence by sentence.

Active

Term Control System

Don't let AI guess your jargon. Review, keep, or translate specific technical terms before the final generation. According to Common Sense Advisory, 75% of consumers prefer content in their native language — SubtleSubtitle ensures that content is accurate.

Keep

Translate

Tone Customization

From formal education to humorous vlogging — define the persona of your subtitles to match your video's soul. SubtleSubtitle adapts translation style to your content type.

Multi-Format Export

Export standard SRT for captions or advanced ASS for stylized, bilingual typography. SubtleSubtitle supports all major video platforms including YouTube, Vimeo, and Bilibili.

SRT

ASS

How Much Does SubtleSubtitle Cost?

SubtleSubtitle offers one-time quota packs starting at $5.99. No subscriptions, no monthly fees. 1 quota covers up to 30 minutes of video and never expires.

Pay as you go

When package quota is exhausted, upload first and pay by video duration. Alipay only.

Price per minute

¥1.20

Minimum per video

¥2.40

Starter

¥39

up to 300 mins

avg. ¥0.13/min

Perfect for trying out subtitle generation.

10 quota included
High-quality transcription
Bilingual subtitle output
SRT & ASS export

Best Value

Standard

¥99

up to 900 mins

avg. ¥0.11/min

Ideal for regular content creators.

30 quota included
Everything in Starter
Priority processing
Term confirmation system
Tone customization

Studio Pack

Professional

¥299

up to 3000 mins

avg. ¥0.10/min

For power users and studios.

100 quota included
Everything in Standard
Highest priority processing
Dedicated support

How Does SubtleSubtitle Compare to Alternatives?

SubtleSubtitle is purpose-built for bilingual subtitle creation with context-aware AI translation. Here's how it compares to general-purpose tools that offer subtitles as a secondary feature.

	SubtleSubtitle	Descript	Happy Scribe	Kapwing
Bilingual EN↔CN Subtitles	Full support	Limited	Partial	Limited
Sliding Window Translation	25-segment window	None	None	None
Terminology Management	User-controlled	None	None	None
SRT Upload & Translation	One-click	Basic	Supported	Partial
Tone Customization	4 styles	None	None	None
Context-Aware Translation	3-phase pipeline	Basic	Basic	None
Starting Price	$5.99	$24/mo	$17/mo	$16/mo
Pricing Model	One-time credits	Subscription	Subscription	Subscription

Frequently Asked Questions

SubtleSubtitle is an AI-powered subtitle and caption generator that automatically transcribes video and audio files, generates properly segmented subtitles using LLM-based semantic splitting, and translates them into bilingual formats (English and Chinese). It features a proprietary sliding-window translation algorithm for narrative consistency and a terminology management system for domain-specific accuracy.

Each processed file consumes 1 file credit. Videos over 30 minutes cost 1 credit per 30-minute segment (rounded up). SRT-only translation consumes 1 credit regardless of length. After package quota is used up, you can continue via pay-as-you-go at ¥1.20 per minute with a ¥2.40 minimum per video.

SubtleSubtitle's proprietary sliding window uses 25-segment context windows with 10-segment overlap in a three-phase translation process (Past-Present-Future). This means each subtitle segment is translated with awareness of surrounding context, preventing the inconsistencies and context loss common in sentence-by-sentence translation tools.

Unlike Descript and Kapwing, which treat subtitles as a secondary feature inside broader editing suites, SubtleSubtitle is purpose-built for bilingual subtitle creation. It combines context-aware sliding-window translation, terminology control, and one-time credit pricing starting at $5.99.

Yes. SubtleSubtitle processes files through secure pipelines, and your video content is not used for model training. The terminology confirmation step ensures domain-specific accuracy for corporate training, compliance, and educational content.

SubtleSubtitle supports transcription in 15+ languages using advanced speech models and specializes in English-Chinese bilingual subtitle translation. The translation pipeline is optimized for Chinese-English language pairs with full support for simplified Chinese, traditional Chinese, and English.

A typical 30-minute video is processed in under 3 minutes, including transcription, context extraction, and translation. SubtleSubtitle uses parallel processing with 3 workers for faster output. Priority processing is available for Standard and above plans.

Yes. SubtleSubtitle supports a dedicated SRT upload workflow. Upload your existing .srt file, and the system will run background extraction, terminology review, and the full translation pipeline — producing bilingual subtitles from your existing transcript.

No. All purchased credits are lifetime and never expire. Use them whenever you need — there are no monthly limits or expiration dates. This is a key difference from subscription-based competitors.

SubtleSubtitle exports in SRT (SubRip Subtitle) for standard captions and ASS (Advanced SubStation Alpha) for stylized bilingual typography with custom fonts, colors, and positioning. Both formats are compatible with YouTube, Vimeo, Bilibili, and all major video platforms.

SubtleSubtitle supports all major video formats including MP4, MOV, MKV, AVI, and WebM, as well as audio formats including MP3, WAV, AAC, and FLAC.

Yes. SubtleSubtitle offers tone customization — choose from formal, casual, educational, or humorous translation styles to match your content. The terminology confirmation step also lets you control how specific technical terms are translated.