biblical-guide.com/TEXT_TO_SPEECH_IMPLEMENTATION_PLAN.md

Text-to-Speech (TTS) - Implementation Plan

📋 Overview

Implement a full-featured Text-to-Speech system for the Bible reader, allowing users to listen to Scripture while reading, driving, exercising, or multitasking.

Status: Planning Phase Priority: 🔴 High Estimated Time: 2-3 weeks (80-120 hours) Target Completion: TBD

---

🎯 Goals & Objectives

Primary Goals

1. Provide accessible audio playback of Bible content
2. Support multiple voices and languages
3. Enable hands-free Bible reading
4. Improve accessibility for visually impaired users
5. Allow multitasking while consuming Scripture

User Value Proposition

• For visually impaired users: Full accessibility to Bible content
• For commuters: Listen during driving/transit
• For learners: Audio reinforcement of reading
• For multitaskers: Listen while doing other activities
• For language learners: Hear correct pronunciation

---

✨ Feature Specifications

1. Core TTS Functionality

Web Speech API (Free Tier)

• Uses browser's built-in speech synthesis
• No API costs
• Works offline after initial load
• Variable quality depending on OS/browser

Premium Voices (Optional - Phase 2)

• Amazon Polly integration
• Google Cloud Text-to-Speech
• Higher quality, more natural voices
• Multiple accents and styles
• Costs: ~$4 per 1 million characters

2. Voice Selection

interface Voice {
  id: string
  name: string
  language: string
  gender: 'male' | 'female' | 'neutral'
  quality: 'standard' | 'premium'
  provider: 'browser' | 'polly' | 'google'
  isDefault: boolean
  localeName: string // e.g., "en-US", "es-ES"
}

interface TTSConfig {
  // Voice
  selectedVoiceId: string

  // Playback
  rate: number        // 0.5 - 2.0 (speed)
  pitch: number       // 0.5 - 2.0 (pitch)
  volume: number      // 0 - 1

  // Behavior
  autoAdvanceChapter: boolean
  highlightCurrentVerse: boolean
  pauseBetweenVerses: number  // 0-2000ms
  pauseBetweenChapters: number // 0-5000ms

  // Display
  showFloatingPlayer: boolean
  showProgress: boolean
  minimizeWhenPlaying: boolean
}

3. Playback Controls

Player UI Components

┌─────────────────────────────────────────────────┐
│ 🔊 Genesis 1:1-31                          ⚙️ 📍 │
├─────────────────────────────────────────────────┤
│ ⏮ ⏪ ▶️ ⏩ ⏭                              1.0x 🔈│
├─────────────────────────────────────────────────┤
│ ━━━━━━━━━●━━━━━━━━━━━━━━━━━━━━              65% │
│ Verse 15 of 31 • 2:34 / 6:12                   │
└─────────────────────────────────────────────────┘

Controls:

• Play/Pause
• Previous/Next Verse
• Previous/Next Chapter
• Skip Backward 10s / Forward 10s
• Speed Control (0.5x, 0.75x, 1.0x, 1.25x, 1.5x, 2.0x)
• Volume Control
• Settings Menu
• Pin/Unpin Player

Keyboard Shortcuts

const shortcuts = {
  'Space': 'Play/Pause',
  'ArrowLeft': 'Previous verse',
  'ArrowRight': 'Next verse',
  'Shift+ArrowLeft': 'Previous chapter',
  'Shift+ArrowRight': 'Next chapter',
  'ArrowUp': 'Increase speed by 0.25x',
  'ArrowDown': 'Decrease speed by 0.25x',
  '[': 'Skip backward 10s',
  ']': 'Skip forward 10s',
  'M': 'Mute/Unmute',
  'Escape': 'Stop playback'
}

4. Visual Feedback

Active Verse Highlighting

interface HighlightConfig {
  enabled: boolean
  style: 'background' | 'border' | 'underline' | 'bold'
  color: string
  scrollToVerse: boolean
  scrollBehavior: 'auto' | 'smooth'
  centerVerse: boolean
}

// CSS Example
.verse-playing {
  background-color: rgba(var(--primary-rgb), 0.1);
  border-left: 4px solid var(--primary-color);
  padding-left: 12px;
  margin-left: -16px;
  scroll-margin-top: 100px; /* For scroll-into-view */
  transition: all 0.3s ease;
}

Progress Visualization

• Linear progress bar
• Circular progress (for floating player)
• Time elapsed / total time
• Verse counter (current / total)
• Visual waveform (optional, premium)

5. Verse-Level Navigation

interface VersePosition {
  book: string
  chapter: number
  verse: number
  verseText: string
  startTime: number  // ms from chapter start
  duration: number   // ms for this verse
}

class VerseNavigator {
  private verses: VersePosition[]
  private currentIndex: number

  getCurrentVerse(): VersePosition
  nextVerse(): VersePosition
  previousVerse(): VersePosition
  jumpToVerse(verseNum: number): void
  getProgress(): number // 0-100%
}

6. Background Playback

Service Worker Integration

// Support for background playback on mobile
// Uses Media Session API

if ('mediaSession' in navigator) {
  navigator.mediaSession.metadata = new MediaMetadata({
    title: 'Genesis 1:1-31',
    artist: 'Bible Reader',
    album: 'Old Testament',
    artwork: [
      { src: '/icons/bible-96.png', sizes: '96x96', type: 'image/png' },
      { src: '/icons/bible-256.png', sizes: '256x256', type: 'image/png' }
    ]
  })

  navigator.mediaSession.setActionHandler('play', handlePlay)
  navigator.mediaSession.setActionHandler('pause', handlePause)
  navigator.mediaSession.setActionHandler('previoustrack', handlePreviousVerse)
  navigator.mediaSession.setActionHandler('nexttrack', handleNextVerse)
  navigator.mediaSession.setActionHandler('seekbackward', () => seek(-10))
  navigator.mediaSession.setActionHandler('seekforward', () => seek(10))
}

7. Persistent Player Bar

Floating Player States

1. Full Player - All controls visible
2. Mini Player - Compact view with play/pause and progress
3. Hidden - Only show icon in corner
4. Minimized to Tab - Shows in browser tab title

type PlayerSize = 'full' | 'mini' | 'icon' | 'hidden'

interface PlayerPosition {
  size: PlayerSize
  position: 'top' | 'bottom'
  sticky: boolean // Stays visible when scrolling
  docked: 'left' | 'center' | 'right'
}

---

🏗️ Technical Implementation

File Structure

/components/bible-reader/
├── tts/
│   ├── TTSProvider.tsx              # Context provider
│   ├── TTSPlayer.tsx                # Main player component
│   ├── TTSControls.tsx              # Playback controls
│   ├── TTSSettings.tsx              # Settings panel
│   ├── VoiceSelector.tsx            # Voice selection UI
│   ├── FloatingPlayer.tsx           # Floating/sticky player
│   ├── VerseHighlighter.tsx         # Active verse highlighting
│   ├── PlaybackProgress.tsx         # Progress bar/circle
│   ├── engines/
│   │   ├── WebSpeechEngine.ts      # Browser TTS
│   │   ├── PollyEngine.ts          # Amazon Polly (Phase 2)
│   │   └── GoogleTTSEngine.ts      # Google TTS (Phase 2)
│   └── hooks/
│       ├── useTTS.ts                # Main TTS hook
│       ├── useVoices.ts             # Voice management
│       ├── usePlayback.ts           # Playback state
│       ├── useVerseTracking.ts     # Track current verse
│       └── useMediaSession.ts       # Background playback
└── reader.tsx                        # Updated main reader

Core TTS Engine (Web Speech API)

// engines/WebSpeechEngine.ts
export class WebSpeechEngine {
  private synth: SpeechSynthesis
  private utterance: SpeechSynthesisUtterance | null = null
  private currentVerseIndex: number = 0
  private verses: string[] = []
  private isPaused: boolean = false

  constructor() {
    this.synth = window.speechSynthesis
  }

  async getVoices(): Promise<Voice[]> {
    return new Promise((resolve) => {
      const voices = this.synth.getVoices()

      if (voices.length > 0) {
        resolve(this.mapVoices(voices))
      } else {
        // Some browsers load voices asynchronously
        this.synth.onvoiceschanged = () => {
          resolve(this.mapVoices(this.synth.getVoices()))
        }
      }
    })
  }

  private mapVoices(synthVoices: SpeechSynthesisVoice[]): Voice[] {
    return synthVoices.map(v => ({
      id: v.voiceURI,
      name: v.name,
      language: v.lang,
      gender: this.detectGender(v.name),
      quality: 'standard',
      provider: 'browser',
      isDefault: v.default,
      localeName: v.lang
    }))
  }

  private detectGender(name: string): 'male' | 'female' | 'neutral' {
    const lower = name.toLowerCase()
    if (lower.includes('female') || lower.includes('woman')) return 'female'
    if (lower.includes('male') || lower.includes('man')) return 'male'
    return 'neutral'
  }

  async speak(
    text: string,
    config: TTSConfig,
    onBoundary?: (charIndex: number) => void,
    onEnd?: () => void
  ): Promise<void> {
    return new Promise((resolve, reject) => {
      // Cancel any existing speech
      this.synth.cancel()

      this.utterance = new SpeechSynthesisUtterance(text)

      // Find selected voice
      const voices = this.synth.getVoices()
      const voice = voices.find(v => v.voiceURI === config.selectedVoiceId)
      if (voice) {
        this.utterance.voice = voice
      }

      // Apply settings
      this.utterance.rate = config.rate
      this.utterance.pitch = config.pitch
      this.utterance.volume = config.volume

      // Event handlers
      this.utterance.onboundary = (event) => {
        if (onBoundary) onBoundary(event.charIndex)
      }

      this.utterance.onend = () => {
        if (onEnd) onEnd()
        resolve()
      }

      this.utterance.onerror = (event) => {
        console.error('Speech error:', event)
        reject(event)
      }

      // Start speaking
      this.synth.speak(this.utterance)
    })
  }

  pause(): void {
    if (this.synth.speaking && !this.synth.paused) {
      this.synth.pause()
      this.isPaused = true
    }
  }

  resume(): void {
    if (this.synth.paused) {
      this.synth.resume()
      this.isPaused = false
    }
  }

  stop(): void {
    this.synth.cancel()
    this.isPaused = false
  }

  isSpeaking(): boolean {
    return this.synth.speaking && !this.synth.paused
  }

  isPausedState(): boolean {
    return this.isPaused
  }
}

TTS Context Provider

// TTSProvider.tsx
interface TTSContextType {
  // State
  isPlaying: boolean
  isPaused: boolean
  currentVerse: VersePosition | null
  config: TTSConfig
  voices: Voice[]
  progress: number // 0-100

  // Actions
  play(): Promise<void>
  pause(): void
  resume(): void
  stop(): void
  nextVerse(): void
  previousVerse(): void
  nextChapter(): void
  previousChapter(): void
  jumpToVerse(verseNum: number): void
  setSpeed(rate: number): void
  setVoice(voiceId: string): void
  setVolume(volume: number): void
  updateConfig(config: Partial<TTSConfig>): void
}

export const TTSProvider: React.FC<{ children: React.ReactNode }> = ({ children }) => {
  const [engine] = useState(() => new WebSpeechEngine())
  const [isPlaying, setIsPlaying] = useState(false)
  const [isPaused, setIsPaused] = useState(false)
  const [config, setConfig] = useState<TTSConfig>(loadConfig())
  const [voices, setVoices] = useState<Voice[]>([])
  const [currentVerse, setCurrentVerse] = useState<VersePosition | null>(null)
  const [verses, setVerses] = useState<VersePosition[]>([])
  const [progress, setProgress] = useState(0)

  // Load voices on mount
  useEffect(() => {
    engine.getVoices().then(setVoices)
  }, [engine])

  // Save config to localStorage
  useEffect(() => {
    localStorage.setItem('tts-config', JSON.stringify(config))
  }, [config])

  const play = async () => {
    if (verses.length === 0) return

    setIsPlaying(true)
    setIsPaused(false)

    const playVerse = async (index: number) => {
      if (index >= verses.length) {
        if (config.autoAdvanceChapter) {
          // Load next chapter
          await loadNextChapter()
        } else {
          stop()
        }
        return
      }

      const verse = verses[index]
      setCurrentVerse(verse)
      setProgress((index / verses.length) * 100)

      try {
        await engine.speak(
          verse.verseText,
          config,
          undefined,
          () => {
            // Verse completed
            if (config.pauseBetweenVerses > 0) {
              setTimeout(() => {
                playVerse(index + 1)
              }, config.pauseBetweenVerses)
            } else {
              playVerse(index + 1)
            }
          }
        )
      } catch (error) {
        console.error('TTS error:', error)
        stop()
      }
    }

    playVerse(currentVerse ? verses.indexOf(currentVerse) : 0)
  }

  const pause = () => {
    engine.pause()
    setIsPaused(true)
  }

  const resume = () => {
    engine.resume()
    setIsPaused(false)
  }

  const stop = () => {
    engine.stop()
    setIsPlaying(false)
    setIsPaused(false)
    setCurrentVerse(null)
    setProgress(0)
  }

  const nextVerse = () => {
    if (!currentVerse) return
    const currentIndex = verses.indexOf(currentVerse)
    if (currentIndex < verses.length - 1) {
      const wasPlaying = isPlaying
      stop()
      setCurrentVerse(verses[currentIndex + 1])
      if (wasPlaying) play()
    }
  }

  const previousVerse = () => {
    if (!currentVerse) return
    const currentIndex = verses.indexOf(currentVerse)
    if (currentIndex > 0) {
      const wasPlaying = isPlaying
      stop()
      setCurrentVerse(verses[currentIndex - 1])
      if (wasPlaying) play()
    }
  }

  // ... more methods

  return (
    <TTSContext.Provider value={{
      isPlaying,
      isPaused,
      currentVerse,
      config,
      voices,
      progress,
      play,
      pause,
      resume,
      stop,
      nextVerse,
      previousVerse,
      nextChapter,
      previousChapter,
      jumpToVerse,
      setSpeed,
      setVoice,
      setVolume,
      updateConfig
    }}>
      {children}
    </TTSContext.Provider>
  )
}

TTS Player UI Component

// TTSPlayer.tsx
export const TTSPlayer: React.FC = () => {
  const {
    isPlaying,
    isPaused,
    currentVerse,
    config,
    progress,
    play,
    pause,
    resume,
    stop,
    nextVerse,
    previousVerse,
    setSpeed
  } = useTTS()

  const [playerSize, setPlayerSize] = useState<PlayerSize>('full')
  const [isVisible, setIsVisible] = useState(false)

  // Show player when playback starts
  useEffect(() => {
    if (isPlaying) {
      setIsVisible(true)
    }
  }, [isPlaying])

  if (!isVisible) return null

  const handlePlayPause = () => {
    if (isPlaying && !isPaused) {
      pause()
    } else if (isPaused) {
      resume()
    } else {
      play()
    }
  }

  const speeds = [0.5, 0.75, 1.0, 1.25, 1.5, 1.75, 2.0]
  const currentSpeedIndex = speeds.indexOf(config.rate)

  const cycleSpeed = () => {
    const nextIndex = (currentSpeedIndex + 1) % speeds.length
    setSpeed(speeds[nextIndex])
  }

  if (playerSize === 'mini') {
    return (
      <Box className="tts-player mini" sx={{
        position: 'fixed',
        bottom: 20,
        right: 20,
        bgcolor: 'background.paper',
        borderRadius: 2,
        boxShadow: 3,
        p: 2,
        minWidth: 200
      }}>
        <Box display="flex" alignItems="center" gap={1}>
          <IconButton size="small" onClick={handlePlayPause}>
            {isPlaying && !isPaused ? <PauseIcon /> : <PlayArrowIcon />}
          </IconButton>
          <Box flex={1}>
            <LinearProgress variant="determinate" value={progress} />
            <Typography variant="caption">
              {currentVerse?.book} {currentVerse?.chapter}:{currentVerse?.verse}
            </Typography>
          </Box>
          <IconButton size="small" onClick={() => setPlayerSize('full')}>
            <ExpandLessIcon />
          </IconButton>
        </Box>
      </Box>
    )
  }

  return (
    <Card className="tts-player full" sx={{
      position: 'fixed',
      bottom: 0,
      left: 0,
      right: 0,
      zIndex: 1300,
      borderRadius: 0,
      boxShadow: 6
    }}>
      <CardContent>
        {/* Header */}
        <Box display="flex" justifyContent="space-between" alignItems="center" mb={2}>
          <Box display="flex" alignItems="center" gap={1}>
            <HeadphonesIcon color="primary" />
            <Typography variant="h6">
              {currentVerse?.book} {currentVerse?.chapter}:1-{verses.length}
            </Typography>
          </Box>
          <Box>
            <IconButton size="small" onClick={() => setPlayerSize('mini')}>
              <MinimizeIcon />
            </IconButton>
            <IconButton size="small" onClick={stop}>
              <CloseIcon />
            </IconButton>
          </Box>
        </Box>

        {/* Main Controls */}
        <Box display="flex" justifyContent="center" alignItems="center" gap={2} mb={2}>
          <IconButton onClick={previousChapter}>
            <SkipPreviousIcon />
          </IconButton>
          <IconButton onClick={previousVerse}>
            <FastRewindIcon />
          </IconButton>
          <IconButton onClick={handlePlayPause} size="large" color="primary">
            {isPlaying && !isPaused ? <PauseIcon /> : <PlayArrowIcon />}
          </IconButton>
          <IconButton onClick={nextVerse}>
            <FastForwardIcon />
          </IconButton>
          <IconButton onClick={nextChapter}>
            <SkipNextIcon />
          </IconButton>
        </Box>

        {/* Progress Bar */}
        <Box mb={2}>
          <LinearProgress variant="determinate" value={progress} sx={{ height: 6, borderRadius: 1 }} />
          <Box display="flex" justifyContent="space-between" mt={1}>
            <Typography variant="caption" color="text.secondary">
              Verse {currentVerse?.verse} of {verses.length}
            </Typography>
            <Typography variant="caption" color="text.secondary">
              {Math.round(progress)}%
            </Typography>
          </Box>
        </Box>

        {/* Secondary Controls */}
        <Box display="flex" justifyContent="space-between" alignItems="center">
          <Button
            size="small"
            startIcon={<SpeedIcon />}
            onClick={cycleSpeed}
          >
            {config.rate}x
          </Button>

          <Box display="flex" alignItems="center" gap={1}>
            <VolumeUpIcon />
            <Slider
              value={config.volume}
              onChange={(_, value) => setVolume(value as number)}
              min={0}
              max={1}
              step={0.1}
              sx={{ width: 100 }}
            />
          </Box>

          <IconButton size="small">
            <SettingsIcon />
          </IconButton>
        </Box>
      </CardContent>
    </Card>
  )
}

Verse Highlighting

// VerseHighlighter.tsx
export const VerseHighlighter: React.FC = () => {
  const { currentVerse, config } = useTTS()

  useEffect(() => {
    if (!currentVerse || !config.highlightCurrentVerse) return

    const verseElement = document.querySelector(
      `[data-verse="${currentVerse.verse}"]`
    )

    if (verseElement) {
      // Add playing class
      verseElement.classList.add('verse-playing')

      // Scroll into view
      if (config.scrollToVerse) {
        verseElement.scrollIntoView({
          behavior: 'smooth',
          block: 'center'
        })
      }

      // Cleanup
      return () => {
        verseElement.classList.remove('verse-playing')
      }
    }
  }, [currentVerse, config])

  return null // Pure effect component
}

Media Session API (Background Playback)

// hooks/useMediaSession.ts
export const useMediaSession = () => {
  const {
    currentVerse,
    isPlaying,
    play,
    pause,
    nextVerse,
    previousVerse
  } = useTTS()

  useEffect(() => {
    if (!('mediaSession' in navigator)) return

    if (currentVerse) {
      navigator.mediaSession.metadata = new MediaMetadata({
        title: `${currentVerse.book} ${currentVerse.chapter}:${currentVerse.verse}`,
        artist: 'Bible Reader',
        album: currentVerse.book,
        artwork: [
          { src: '/icons/bible-96.png', sizes: '96x96', type: 'image/png' },
          { src: '/icons/bible-192.png', sizes: '192x192', type: 'image/png' },
          { src: '/icons/bible-512.png', sizes: '512x512', type: 'image/png' }
        ]
      })
    }

    // Set up action handlers
    navigator.mediaSession.setActionHandler('play', () => play())
    navigator.mediaSession.setActionHandler('pause', () => pause())
    navigator.mediaSession.setActionHandler('previoustrack', () => previousVerse())
    navigator.mediaSession.setActionHandler('nexttrack', () => nextVerse())

    // Update playback state
    navigator.mediaSession.playbackState = isPlaying ? 'playing' : 'paused'

    return () => {
      navigator.mediaSession.setActionHandler('play', null)
      navigator.mediaSession.setActionHandler('pause', null)
      navigator.mediaSession.setActionHandler('previoustrack', null)
      navigator.mediaSession.setActionHandler('nexttrack', null)
    }
  }, [currentVerse, isPlaying, play, pause, nextVerse, previousVerse])
}

---

💾 Data Persistence

LocalStorage Schema

interface TTSStorage {
  version: number
  config: TTSConfig
  recentVoices: string[] // Voice IDs
  lastPlayedVerse: {
    book: string
    chapter: number
    verse: number
  } | null
  stats: {
    totalListeningTime: number // seconds
    chaptersCompleted: number
    favoriteVoice: string
  }
}

// Key: 'bible-reader:tts'

User Preferences API

// Add to UserPreference model
model UserPreference {
  // ... existing fields
  ttsConfig Json?
  ttsVoiceId String?
  ttsRate Float? @default(1.0)
}

// Sync endpoint
POST /api/user/preferences/tts
Body: Partial<TTSConfig>

---

📊 API Endpoints

For Premium Voices (Phase 2)

// /api/tts/voices
GET /api/tts/voices
Response: {
  voices: Voice[]
  providers: {
    browser: Voice[]
    polly: Voice[]
    google: Voice[]
  }
}

// /api/tts/synthesize
POST /api/tts/synthesize
Body: {
  text: string
  voiceId: string
  provider: 'polly' | 'google'
  config: TTSConfig
}
Response: {
  audioUrl: string // Signed URL to audio file
  duration: number // seconds
}

---

🧪 Testing Strategy

Unit Tests

// __tests__/tts/web-speech-engine.test.ts
describe('WebSpeechEngine', () => {
  it('should load available voices', async () => {
    const engine = new WebSpeechEngine()
    const voices = await engine.getVoices()
    expect(voices.length).toBeGreaterThan(0)
  })

  it('should speak text with config', async () => {
    const engine = new WebSpeechEngine()
    const mockSynth = jest.spyOn(window.speechSynthesis, 'speak')

    await engine.speak('Test', defaultConfig)
    expect(mockSynth).toHaveBeenCalled()
  })

  it('should pause and resume correctly', () => {
    const engine = new WebSpeechEngine()
    engine.pause()
    expect(engine.isPausedState()).toBe(true)
    engine.resume()
    expect(engine.isPausedState()).toBe(false)
  })
})

Integration Tests

// __tests__/tts/integration.test.tsx
describe('TTS Integration', () => {
  it('should play verse and highlight it', async () => {
    render(
      <TTSProvider>
        <BibleReader />
        <TTSPlayer />
      </TTSProvider>
    )

    const playButton = screen.getByRole('button', { name: /play/i })
    fireEvent.click(playButton)

    await waitFor(() => {
      expect(screen.getByText(/Genesis 1:1/)).toHaveClass('verse-playing')
    })
  })
})

Manual Testing Checklist

• All voices load correctly
• Playback works across browsers (Chrome, Firefox, Safari)
• Speed adjustment works (0.5x - 2.0x)
• Volume control works
• Verse highlighting syncs with audio
• Auto-advance to next verse works
• Auto-advance to next chapter works
• Background playback works on mobile
• Media controls in notification shade work
• Settings persist across sessions
• Player UI is responsive on mobile
• Keyboard shortcuts work correctly
• No memory leaks during long playback

---

📅 Implementation Timeline

Phase 1: Core TTS (Week 1)

Day 1-2: Foundation

• Create TTS context provider
• Implement Web Speech API engine
• Build voice selector component
• Add basic play/pause controls

Day 3-4: Player UI

• Design and build full player UI
• Implement mini player mode
• Add progress bar and tracking
• Create settings panel

Day 5: Verse Navigation

• Implement verse-by-verse playback
• Add next/previous verse controls
• Build verse position tracking
• Test chapter boundaries

Deliverable: Working TTS with basic controls

Phase 2: Enhanced Features (Week 2)

Day 1-2: Visual Feedback

• Implement verse highlighting
• Add scroll-to-verse
• Create speed controls
• Build volume controls

Day 3-4: Advanced Controls

• Add keyboard shortcuts
• Implement skip forward/backward
• Create chapter navigation
• Add auto-advance features

Day 5: Mobile & Background

• Implement Media Session API
• Test background playback
• Optimize for mobile
• Add floating player

Deliverable: Full-featured TTS system

Phase 3: Premium Voices (Week 3 - Optional)

Day 1-2: Backend Integration

• Set up Amazon Polly API
• Create synthesis endpoint
• Implement audio caching
• Build voice preview

Day 3-4: Frontend Integration

• Add premium voice selector
• Implement streaming playback
• Handle API errors gracefully
• Add loading states

Day 5: Polish & Testing

• Test premium voices
• Optimize API usage
• Add cost monitoring
• Documentation

Deliverable: Premium TTS with high-quality voices

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🚀 Deployment Plan

Pre-Launch Checklist

• All unit tests passing
• Integration tests passing
• Cross-browser testing complete
• Mobile testing complete (iOS + Android)
• Accessibility audit passed
• Performance benchmarks met
• User documentation created
• Analytics events configured

Rollout Strategy

1. Beta (Week 1): 10% of users, Web Speech API only
2. Staged (Week 2): 50% of users, collect feedback
3. Full (Week 3): 100% of users
4. Premium (Week 4): Launch premium voices for subscribers

Browser Support

• ✅ Chrome 33+ (excellent support)
• ✅ Edge 14+ (excellent support)
• ✅ Safari 7+ (good support)
• ⚠️ Firefox 49+ (limited voices)
• ❌ IE 11 (not supported)

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💰 Cost Analysis (Premium Voices)

Amazon Polly Pricing

• Standard voices: $4.00 per 1 million characters
• Neural voices: $16.00 per 1 million characters
• Average Bible: ~4 million characters
• Cost to read entire Bible: ~$16-64

Optimization Strategies

1. Caching: Cache synthesized audio (reduce repeat costs)
2. Compression: Use MP3 (smaller file sizes)
3. Lazy Loading: Only synthesize on-demand
4. Rate Limiting: Prevent abuse
5. Subscription Gating: Premium voices for paid users only

Expected Monthly Costs

• 1,000 users × 10 chapters/month × 5,000 chars = 50M chars
• Cost: $200-800/month (depending on voice quality)

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📚 Documentation

User Documentation

• "Getting Started with Text-to-Speech"
• "Choosing the Right Voice"
• "Keyboard Shortcuts Guide"
• "Background Playback on Mobile"
• "Premium Voices: What's the Difference?"

Developer Documentation

• TTS Engine Architecture
• Adding New Voice Providers
• Custom Voice Integration Guide
• Performance Optimization Tips

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🔄 Future Enhancements

Phase 3+ Features

• Offline audio download (pre-synthesize chapters)
• Playlist creation (custom reading lists)
• Sleep timer
• Bookmarks/favorites for audio
• Sharing audio clips
• Customizable voice profiles (pitch + rate presets)
• Synchronized multi-device playback
• Audio effects (reverb, echo)
• Speed training (gradually increase WPM)
• Comprehension quizzes after listening

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📝 Notes & Considerations

Performance

• Keep player UI lightweight (<50ms render time)
• Use Web Workers for audio processing (Phase 2)
• Implement audio buffering for smooth playback
• Monitor memory usage during long sessions

Accessibility

• Ensure screen reader compatibility
• Provide text alternatives for all controls
• Maintain keyboard accessibility
• Test with assistive technologies

Legal Considerations

• Bible text copyright (check version licenses)
• Voice cloning regulations (only use licensed voices)
• COPPA compliance (children under 13)
• GDPR compliance (store user preferences correctly)

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Document Version: 1.0 Last Updated: 2025-10-13 Owner: Development Team Status: Ready for Implementation