ssmd 0.2.1

Speech Synthesis Markdown (SSMD) is a lightweight alternative syntax for SSML.

SSMD - Speech Synthesis Markdown

SSMD (Speech Synthesis Markdown) is a lightweight Python library that provides a human-friendly markdown-like syntax for creating SSML (Speech Synthesis Markup Language) documents. It's designed to make TTS (Text-to-Speech) content more readable and maintainable.

Features

✨ Markdown-like syntax - More intuitive than raw SSML 🎯 Full SSML support - All major SSML features covered 🔄 Bidirectional - Convert SSMD↔SSML or strip to plain text 📝 Document-centric - Build, edit, and export TTS documents 🎛️ TTS capabilities - Auto-filter features based on engine support 🎨 Extensible - Custom extensions for platform-specific features 🧪 Spec-driven - Follows the official SSMD specification

Installation

pip install ssmd

Or install from source:

git clone https://github.com/holgern/ssmd.git
cd ssmd
pip install -e .

Quick Start

Basic Usage

import ssmd

# Convert SSMD to SSML
ssml = ssmd.to_ssml("Hello *world*!")
print(ssml)
# Output: <speak>Hello <emphasis>world</emphasis>!</speak>

# Strip SSMD markup for plain text
plain = ssmd.to_text("Hello *world* @marker!")
print(plain)
# Output: Hello world!

# Convert SSML back to SSMD
ssmd_text = ssmd.from_ssml('<speak><emphasis>Hello</emphasis></speak>')
print(ssmd_text)
# Output: *Hello*

Document API - Build TTS Content Incrementally

from ssmd import Document

# Create a document and build it piece by piece
doc = Document()
doc.add_sentence("Hello and *welcome* to SSMD!")
doc.add_sentence("This is a great tool for TTS.")
doc.add_paragraph("Let's start a new paragraph here.")

# Export to different formats
ssml = doc.to_ssml()      # SSML output
markdown = doc.to_ssmd()  # SSMD markdown
text = doc.to_text()      # Plain text

# Access document content
print(doc.ssmd)           # Raw SSMD content
print(len(doc))           # Number of sentences

TTS Streaming Integration

Perfect for streaming TTS where you process sentences one at a time:

from ssmd import Document

# Create document with configuration
doc = Document(
    config={'auto_sentence_tags': True},
    capabilities='pyttsx3'  # Auto-filter for pyttsx3 support
)

# Build the document
doc.add_paragraph("# Chapter 1: Introduction")
doc.add_sentence("Welcome to the *amazing* world of SSMD!")
doc.add_sentence("This makes TTS content much easier to write.")
doc.add_paragraph("# Chapter 2: Features")
doc.add_sentence("You can use all kinds of markup.")
doc.add_sentence("Including ...500ms pauses and [special pronunciations](ph: speSl).")

# Iterate through sentences for TTS
for i, sentence in enumerate(doc.sentences(), 1):
    print(f"Sentence {i}: {sentence}")
    # Your TTS engine here:
    # tts_engine.speak(sentence)
    # await tts_engine.wait_until_done()

# Or access specific sentences
print(f"Total sentences: {len(doc)}")
print(f"First sentence: {doc[0]}")
print(f"Last sentence: {doc[-1]}")

Document Editing

from ssmd import Document

# Load from existing content
doc = Document("First sentence. Second sentence. Third sentence.")

# Edit like a list
doc[0] = "Modified first sentence."
del doc[1]  # Remove second sentence

# String operations
doc.replace("sentence", "line")

# Merge documents
doc2 = Document("Additional content.")
doc.merge(doc2)

# Split into individual sentences
sentences = doc.split()  # Returns list of Document objects

TTS Engine Capabilities

SSMD can automatically filter SSML features based on your TTS engine's capabilities. This ensures compatibility by stripping unsupported tags to plain text.

Using Presets

from ssmd import Document

# Use a preset for your TTS engine
doc = Document("*Hello* [world](en)!", capabilities='pyttsx3')
ssml = doc.to_ssml()

# pyttsx3 doesn't support emphasis or language tags, so they're stripped:
# <speak>Hello world!</speak>

Available Presets:

• minimal - Plain text only (no SSML)
• pyttsx3 - Minimal support (basic prosody only)
• espeak - Moderate support (breaks, language, prosody, phonemes)
• google / azure / microsoft - Full SSML support
• polly / amazon - Full support + Amazon extensions (whisper, DRC)
• full - All features enabled

Custom Capabilities

from ssmd import Document, TTSCapabilities

# Define exactly what your TTS supports
caps = TTSCapabilities(
    emphasis=False,      # No <emphasis> support
    break_tags=True,     # Supports <break>
    paragraph=True,      # Supports <p>
    language=False,      # No language switching
    prosody=True,        # Supports volume/rate/pitch
    say_as=False,        # No <say-as>
    audio=False,         # No audio files
    mark=False,          # No markers
)

doc = Document("*Hello* world!", capabilities=caps)

Capability-Aware Streaming

from ssmd import Document

# Create document for specific TTS engine
doc = Document(capabilities='espeak')

# Build content with various features
doc.add_paragraph("# Welcome")
doc.add_sentence("*Hello* world!")
doc.add_sentence("[Bonjour](fr) everyone!")

# All sentences are filtered for eSpeak compatibility
for sentence in doc.sentences():
    # Features eSpeak doesn't support are automatically removed
    tts_engine.speak(sentence)

Comparison of Engine Outputs:

Same input: *Hello* world... [this is loud](v: 5)!

Engine	Output
minimal	<speak>Hello world... this is loud!</speak>
pyttsx3	<speak>Hello world... <prosody volume="x-loud">this is loud</prosody>!</speak>
espeak	<speak>Hello world<break time="1000ms"/> <prosody volume="x-loud">this is loud</prosody>!</speak>
google	<speak><p><emphasis>Hello</emphasis> world<break time="1000ms"/> <prosody volume="x-loud">this is loud</prosody>!</p></speak>

See examples/tts_with_capabilities.py for a complete demonstration.

SSMD Syntax Reference

Text & Emphasis

# Emphasis
ssmd.to_ssml("*emphasized text*")
# → <speak><emphasis>emphasized text</emphasis></speak>

Breaks & Pauses

# Specific time (required - bare ... is preserved as ellipsis)
ssmd.to_ssml("Hello ...500ms world")
ssmd.to_ssml("Hello ...2s world")
ssmd.to_ssml("Hello ...1s world")

# Strength-based
ssmd.to_ssml("Hello ...n world")  # none
ssmd.to_ssml("Hello ...w world")  # weak (x-weak)
ssmd.to_ssml("Hello ...c world")  # comma (medium)
ssmd.to_ssml("Hello ...s world")  # sentence (strong)
ssmd.to_ssml("Hello ...p world")  # paragraph (x-strong)

Paragraphs

text = """First paragraph here.
Second line of first paragraph.

Second paragraph starts here."""

ssmd.to_ssml(text)
# → <speak><p>First paragraph here.
#    Second line of first paragraph.</p><p>Second paragraph starts here.</p></speak>

Language

# Auto-complete language codes
ssmd.to_ssml('[Bonjour](fr) world')
# → <speak><lang xml:lang="fr-FR">Bonjour</lang> world</speak>

# Explicit locale
ssmd.to_ssml('[Cheerio](en-GB)')
# → <speak><lang xml:lang="en-GB">Cheerio</lang></speak>

Voice Selection

# Simple voice name
ssmd.to_ssml('[Hello](voice: Joanna)')
# → <speak><voice name="Joanna">Hello</voice></speak>

# Cloud TTS voice name (e.g., Google Wavenet)
ssmd.to_ssml('[Hello](voice: en-US-Wavenet-A)')
# → <speak><voice name="en-US-Wavenet-A">Hello</voice></speak>

# Language and gender
ssmd.to_ssml('[Bonjour](voice: fr-FR, gender: female)')
# → <speak><voice language="fr-FR" gender="female">Bonjour</voice></speak>

# All attributes (language, gender, variant)
ssmd.to_ssml('[Text](voice: en-GB, gender: male, variant: 1)')
# → <speak><voice language="en-GB" gender="male" variant="1">Text</voice></speak>

Phonetic Pronunciation

# X-SAMPA notation (converted to IPA automatically)
ssmd.to_ssml('[tomato](ph: t@meItoU)')

# Direct IPA
ssmd.to_ssml('[tomato](ipa: təˈmeɪtoʊ)')

# Output: <speak><phoneme alphabet="ipa" ph="təˈmeɪtoʊ">tomato</phoneme></speak>

Prosody (Volume, Rate, Pitch)

Shorthand Notation

# Volume
ssmd.to_ssml("~silent~")      # silent
ssmd.to_ssml("--whisper--")   # x-soft
ssmd.to_ssml("-soft-")        # soft
ssmd.to_ssml("+loud+")        # loud
ssmd.to_ssml("++very loud++") # x-loud

# Rate
ssmd.to_ssml("<<very slow<<")  # x-slow
ssmd.to_ssml("<slow<")         # slow
ssmd.to_ssml(">fast>")         # fast
ssmd.to_ssml(">>very fast>>")  # x-fast

# Pitch
ssmd.to_ssml("__very low__")   # x-low
ssmd.to_ssml("_low_")          # low
ssmd.to_ssml("^high^")         # high
ssmd.to_ssml("^^very high^^")  # x-high

Explicit Notation

# Combined (volume, rate, pitch)
ssmd.to_ssml('[loud and fast](vrp: 555)')
# → <prosody volume="x-loud" rate="x-fast" pitch="x-high">loud and fast</prosody>

# Individual attributes
ssmd.to_ssml('[text](v: 5, r: 3, p: 1)')
# → <prosody volume="x-loud" rate="medium" pitch="x-low">text</prosody>

# Relative values
ssmd.to_ssml('[louder](v: +10dB)')
ssmd.to_ssml('[higher](p: +20%)')

Substitution (Aliases)

ssmd.to_ssml('[H2O](sub: water)')
# → <speak><sub alias="water">H2O</sub></speak>

ssmd.to_ssml('[AWS](sub: Amazon Web Services)')
# → <speak><sub alias="Amazon Web Services">AWS</sub></speak>

Say-As

# Telephone numbers
ssmd.to_ssml('[[phone]](as: telephone)')

# Dates with format
ssmd.to_ssml('[31.12.2024](as: date, format: "dd.mm.yyyy")')

# Spell out
ssmd.to_ssml('[NASA](as: character)')

# Numbers
ssmd.to_ssml('[123](as: cardinal)')
ssmd.to_ssml('[1st](as: ordinal)')

# Expletives (beeped)
ssmd.to_ssml('[damn](as: expletive)')

Audio Files

# With description
ssmd.to_ssml('[doorbell](https://example.com/sounds/bell.mp3)')
# → <audio src="https://example.com/sounds/bell.mp3"><desc>doorbell</desc></audio>

# With fallback text
ssmd.to_ssml('[cat purring](cat.ogg Sound file not loaded)')
# → <audio src="cat.ogg"><desc>cat purring</desc>Sound file not loaded</audio>

# No description
ssmd.to_ssml('[](beep.mp3)')
# → <audio src="beep.mp3"></audio>

Markers

ssmd.to_ssml('I always wanted a @animal cat as a pet.')
# → <speak>I always wanted a <mark name="animal"/> cat as a pet.</speak>

# Markers are removed in plain text (with smart whitespace handling)
ssmd.to_text('word @marker word')
# → "word word" (not "word  word")

Headings

doc = Document(config={
    'heading_levels': {
        1: [('emphasis', 'strong'), ('pause', '300ms')],
        2: [('emphasis', 'moderate'), ('pause', '75ms')],
        3: [('prosody', {'rate': 'slow'}), ('pause', '50ms')],
    }
})

doc.add("""
# Chapter 1
## Section 1.1
### Subsection
""")

ssml = doc.to_ssml()

Extensions (Platform-Specific)

# Amazon Polly whisper effect
ssmd.to_ssml('[whispered text](ext: whisper)')
# → <speak><amazon:effect name="whispered">whispered text</amazon:effect></speak>

# Custom extensions
doc = Document(config={
    'extensions': {
        'custom': lambda text: f'<custom-tag>{text}</custom-tag>'
    }
})

API Reference

Module Functions

ssmd.to_ssml(ssmd_text, **config) → str

Convert SSMD markup to SSML.

Parameters:

• ssmd_text (str): SSMD markdown text
• **config: Optional configuration parameters

Returns: SSML string

ssmd.to_text(ssmd_text, **config) → str

Convert SSMD to plain text (strips all markup).

Parameters:

• ssmd_text (str): SSMD markdown text
• **config: Optional configuration parameters

Returns: Plain text string

ssmd.from_ssml(ssml_text, **config) → str

Convert SSML to SSMD format.

Parameters:

• ssml_text (str): SSML XML string
• **config: Optional configuration parameters

Returns: SSMD markdown string

Document Class

Document(content="", config=None, capabilities=None)

Main document container for building and managing TTS content.

Parameters:

• content (str): Optional initial SSMD content
• config (dict): Configuration options
• capabilities (TTSCapabilities | str): TTS capabilities preset or object

Building Methods:

• add(text) → Add text without separator (returns self for chaining)
• add_sentence(text) → Add text with \n separator
• add_paragraph(text) → Add text with \n\n separator

Export Methods:

• to_ssml() → Export to SSML string
• to_ssmd() → Export to SSMD string
• to_text() → Export to plain text

Class Methods:

• Document.from_ssml(ssml, **config) → Create from SSML
• Document.from_text(text, **config) → Create from text

Properties:

• ssmd → Raw SSMD content
• config → Configuration dict
• capabilities → TTS capabilities

List-like Interface:

• len(doc) → Number of sentences
• doc[i] → Get sentence by index (SSML)
• doc[i] = text → Replace sentence
• del doc[i] → Delete sentence
• doc += text → Append content

Iteration:

• sentences() → Iterator yielding SSML sentences
• sentences(as_documents=True) → Iterator yielding Document objects

Editing Methods:

• insert(index, text, separator="") → Insert text at index
• remove(index) → Remove sentence
• clear() → Remove all content
• replace(old, new, count=-1) → Replace text

Advanced Methods:

• merge(other_doc, separator="\n\n") → Merge another document
• split() → Split into sentence Documents
• get_fragment(index) → Get raw fragment by index

Real-World TTS Example

import asyncio
from ssmd import Document

# Your TTS engine (example with pyttsx3, kokoro-tts, etc.)
class TTSEngine:
    async def speak(self, ssml: str):
        """Speak SSML text."""
        # Implementation depends on your TTS engine
        pass

    async def wait_until_done(self):
        """Wait for speech to complete."""
        pass

async def read_document(content: str, tts: TTSEngine):
    """Read an SSMD document sentence by sentence."""
    doc = Document(content, config={'auto_sentence_tags': True})

    print(f"Reading document with {len(doc)} sentences...")

    for i in range(len(doc)):
        sentence = doc[i]
        print(f"[{i+1}/{len(doc)}] Speaking...")
        await tts.speak(sentence)
        await tts.wait_until_done()

    print("Done!")

# Usage
document = """
# Welcome
Hello and *welcome* to our presentation!
Today we'll discuss some exciting topics.

# Topic 1
First ...500ms let's talk about SSMD.
It makes writing TTS content [much easier](v: 4, p: 4)!

# Conclusion
Thank you for listening @end_marker!
"""

# Run async
# await read_document(document, tts_engine)

Development

Running Tests

# Install dev dependencies
pip install -e ".[dev]"

# Run all tests
pytest

# Run with coverage
pytest --cov=ssmd --cov-report=html

# Run specific test file
pytest tests/test_basic.py -v

Code Quality

# Format with ruff
ruff format ssmd/ tests/

# Lint
ruff check ssmd/ tests/

# Type check
mypy ssmd/

Specification

This implementation follows the SSMD Specification with additional features inspired by the JavaScript implementation.

Implemented Features

✅ Text ✅ Emphasis (*text*) ✅ Break (...500ms, ...2s, ...n/w/c/s/p) ✅ Language ([text](en), [text](en-GB)) ✅ Voice ([text](voice: Joanna), [text](voice: en-US, gender: female)) ✅ Mark (@marker) ✅ Paragraph (\n\n) ✅ Phoneme ([text](ph: xsampa), [text](ipa: ipa)) ✅ Prosody shorthand (++loud++, >>fast>>, ^^high^^) ✅ Prosody explicit ([text](vrp: 555), [text](v: 5)) ✅ Substitution ([text](sub: alias)) ✅ Say-as ([text](as: telephone)) ✅ Audio ([desc](url.mp3 alt)) ✅ Headings (# ## ###) ✅ Extensions ([text](ext: whisper)) ✅ Auto-sentence tags (<s>) ✅ SSML ↔ SSMD bidirectional conversion

Related Projects

• SSMD (Ruby) - Original reference implementation
• SSMD (JavaScript) - JavaScript implementation
• Speech Markdown - Alternative specification

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT - see the LICENSE file for details.

Acknowledgments

• Original SSMD specification by machisuji
• JavaScript implementation by fabien88
• X-SAMPA to IPA conversion table from the Ruby implementation

Links

• Homepage: https://github.com/holgern/ssmd
• PyPI: https://pypi.org/project/ssmd/
• Issues: https://github.com/holgern/ssmd/issues
• Documentation: https://ssmd.readthedocs.io/