TTS Voice Over Skill

Generates per-slide WAV voice-over files from YAML speaker_notes using Azure Speech SDK with SSML pronunciation control.

Overview

This skill reads content.yaml files from a PowerPoint skill content directory, extracts speaker_notes fields, applies SSML acronym aliases for correct pronunciation of technical terms, and produces one WAV file per slide. Supports dry-run mode for SSML template verification without Azure credentials.

Prerequisites

• Azure Speech resource — Free tier provides 500K characters per month.
• Authentication — Key-based (SPEECH_KEY) or Microsoft Entra ID (SPEECH_RESOURCE_ID).
• Python 3.11+ with uv for virtual environment management.
• Data handling note — Speaker-notes content is transmitted to the configured SPEECH_REGION for synthesis. Operators must pin an approved region and avoid sending regulated or confidential narration.

Key-Based Auth

export SPEECH_KEY="your-speech-key"
export SPEECH_REGION="eastus"

Microsoft Entra ID Auth

Requires a custom domain on the Speech resource and Cognitive Services Speech User role.

export SPEECH_RESOURCE_ID="/subscriptions/.../Microsoft.CognitiveServices/accounts/your-resource"
export SPEECH_REGION="eastus"

Install dependencies:

# run from this skill folder
uv sync

Quick Start

Verify SSML templates without generating audio:

uv run scripts/generate_voiceover.py --dry-run --content-dir path/to/content

Generate voice-over WAV files:

uv run scripts/generate_voiceover.py --content-dir path/to/content --output-dir voice-over

Embed audio into a PPTX deck:

uv run scripts/embed_audio.py --input deck.pptx --audio-dir voice-over --output deck-narrated.pptx

Parameters Reference

generate_voiceover.py

Parameter	Type	Default	Description
--dry-run	flag	false	Print SSML templates without generating audio
--voice	string	en-US-Andrew:DragonHDLatestNeural	Azure TTS voice name
--rate	string	+10%	Speech prosody rate
--content-dir	path	content	Path to slide content directory
--output-dir	path	voice-over	Path to WAV output directory
--lexicon	path	(auto-detect)	Custom acronyms.yaml path
--collapse-newlines	flag	false	Collapse newlines and whitespace runs in speaker notes into single spaces before synthesis
--verbose / -v	flag	false	Enable verbose (DEBUG) logging output

embed_audio.py

Embeds WAV files into corresponding PPTX slides and adds narration timing
XML so PowerPoint recognizes the audio for video export via
File > Export > Create a Video > Use Recorded Timings and Narrations.

Parameter	Type	Default	Description
--input	path	(required)	Source PPTX file path
--audio-dir	path	voice-over	Directory with slide-NNN.wav
--output	path	*-narrated.pptx	Output PPTX file path
--verbose / -v	flag	false	Enable verbose (DEBUG) logging output

Script Reference

Generate with custom voice and rate:

uv run scripts/generate_voiceover.py \
  --content-dir content \
  --output-dir voice-over \
  --voice "en-US-Jenny:DragonHDLatestNeural" \
  --rate "+5%"

Use a custom lexicon:

uv run scripts/generate_voiceover.py \
  --content-dir content \
  --lexicon custom-acronyms.yaml

Collapse newlines in speaker notes (recommended for block-scalar | notes,
whose line breaks are otherwise spoken as pauses):

uv run scripts/generate_voiceover.py \
  --content-dir content \
  --collapse-newlines

Embed generated audio:

uv run scripts/embed_audio.py \
  --input slide-deck/presentation.pptx \
  --audio-dir voice-over \
  --output slide-deck/presentation-narrated.pptx

Acronym Lexicon

The lexicon controls SSML <sub alias> replacements for acronyms and technical terms. Create an acronyms.yaml file:

acronyms:
  HVE-Core: "H V E Core"
  OWASP: "Oh wasp"
  SBOM: "S Bomb"
  SLSA: "Salsa"
  CI/CD: "C I C D"

Lexicon resolution order:

1. Path specified via --lexicon argument.
2. acronyms.yaml in the content directory.
3. Built-in defaults covering common technical acronyms.

SSML Template

Each slide produces an SSML document:

<speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis"
 xmlns:mstts="http://www.w3.org/2001/mstts" xml:lang="en-US">
  <voice name="en-US-Andrew:DragonHDLatestNeural">
    <prosody rate="+10%">
      Text with <sub alias="Oh wasp">OWASP</sub> aliases applied.
    </prosody>
  </voice>
</speak>

Integration with PowerPoint Skill

This skill reads from the PowerPoint skill's content directory structure:

content/
├── slide-001/
│   └── content.yaml    # Must include speaker_notes: field
├── slide-002/
│   └── content.yaml
└── ...

Each content.yaml should contain a speaker_notes: field with the narration text. The generated WAV files are named slide-NNN.wav matching the directory names.

Troubleshooting

Issue	Solution
Set SPEECH_KEY ... or SPEECH_RESOURCE_ID	Export SPEECH_KEY (key auth) or SPEECH_RESOURCE_ID (Entra ID) with SPEECH_REGION.
401 with Entra ID auth	Verify custom domain on the Speech resource and Cognitive Services Speech User role. RBAC propagation takes up to 5 minutes.
Empty WAV files or skipped slides	Verify speaker_notes: is present and non-empty in content.yaml.
Mispronounced acronyms	Add entries to acronyms.yaml with phonetic aliases.
azure-cognitiveservices-speech package is required	Run uv sync in the skill directory.
Audio icon visible in PPTX	Reposition or resize the audio object in PowerPoint after embedding.
Authored slide animations missing after embedding	embed_audio.py replaces existing p:timing with narration timing; re-apply animations in PowerPoint after embedding audio.
Slides no longer advance on click after embedding	embed_audio.py sets advClick="0" for auto-advance. To re-enable, select all slides in PowerPoint and check Advance Slide > On Mouse Click in the Transitions tab.
Video export shows "No timings recorded"	Re-embed audio with the updated embed_audio.py which adds narration timing XML automatically.