If you want to try our beta version, follow the instruction in the release note below.
Note: The video version of "What is MulmoCast?" is available on X, which is created by MulmoCast itself.
MulmoCast is a next-generation presentation platform, purpose-built for a world where AI and humans collaborate to create and share ideas.
Unlike traditional tools like PowerPoint or Keynote—both designed in the pre-AI era for human creators—MulmoCast is AI-native: reimagined from the ground up to work hand-in-hand with generative AI that understands and produces natural language, images, audio, and video.
As AI takes on an increasingly central role in content creation, it needs more than raw capability—it needs an environment designed for its strengths. MulmoCast provides that environment, empowering AI to generate rich, coherent presentations across multiple formats, while keeping humans in the creative loop.
At the core of MulmoCast is MulmoScript, a JSON-based intermediate language that functions like a screenplay or web markup. Generated by large language models, MulmoScript defines everything from narrative structure to visuals, making it easy to produce presentations that adapt seamlessly across formats.
flowchart TD
S_TextEditor["Creator"] <--> S_AIChat2("LLM")
S_AIChat2 --> MulmoScript["MulmoScript"]
MulmoScript --> MulmoCast["MulmoCast"]
MulmoCast --> O_Video("Video") & O_Podcast("Podcast") & O_Slideshow("Slideshow") & O_PDF("PDF") & O_Manga("Manga") & O_SwipeAnime("Swipe Anime")
MulmoScript@{ shape: div-proc}
MulmoCast@{ shape: trap-t}
S_TextEditor:::StoryInput
S_AIChat2:::ScriptInput
O_Video:::ScriptOutput
O_Podcast:::ScriptOutput
O_Slideshow:::ScriptOutput
O_PDF:::ScriptOutput
O_Manga:::ScriptOutput
O_SwipeAnime:::ScriptOutput
classDef StoryInput stroke-width:1px, stroke-dasharray:none, stroke:#46EDC8, fill:#DEFFF8, color:#378E7A
classDef ScriptInput stroke-width:1px, stroke-dasharray:none, stroke:#374D7C, fill:#E2EBFF, color:#374D7C
classDef ScriptOutput stroke-width:1px, stroke-dasharray:none, stroke:#FBB35A, fill:#FFEFDB, color:#8F632D
In today’s world, people consume information through many channels—on Zoom calls, in Slack threads, via videos on the go, or through podcasts during commutes. Presentations can no longer be confined to a single format or device. That’s why MulmoCast is built to be truly multi-modal, enabling output not only as slide decks but also as videos, podcasts, manga-style comics, and PDF documents.
Whether you're building a podcast from a research report or turning a business pitch into a narrated video, MulmoCast transforms source material into dynamic, multi-format content with the help of state-of-the-art AI like ChatGPT and Claude.
MulmoCast isn't just a tool. It’s a new foundation for communication—one where humans and AI co-create across every mode of expression.
MulmoScript is a simple JSON/YAML format for describing multi-modal content.
You can define speakers, text, images, and layout — all in one script.
Here is the "Hello World" in MulmoScript.
{
"$mulmocast": {
"version": "1.0"
},
"beats": [
{ "text": "Hello World" }
]
}See MulmoScript Format for details on the structure.
npm install -g mulmocastYou'll also need to install ffmpeg:
# For macOS with Homebrew
brew install ffmpeg
# For other platforms
# Visit https://ffmpeg.org/download.htmlYou can also use Dockerfile which helps you install the pre-requisits.
docker build -t mulmo-cli .
You can use the Docker image like this:
docker run -e OPENAI_API_KEY=<your_openai_api_key> -it mulmo-cli mulmo tool scripting -i -t children_book -o ./ -s story
Create a .env file in your project directory with the following API keys:
OPENAI_API_KEY=your_openai_api_keyDEFAULT_OPENAI_IMAGE_MODEL=gpt-image-1 # for the advanced image generation modelGOOGLE_PROJECT_ID=your_google_project_idSee also pre-requisites for Google's image generation model
# For Anthropic Claude (htmlPrompt feature)
ANTHROPIC_API_TOKEN=your_anthropic_api_tokenFor htmlPrompt configuration, see docs/image.md.
REPLICATE_API_TOKEN=your_replicate_api_key# For Nijivoice TTS
NIJIVOICE_API_KEY=your_nijivoice_api_key
# For ElevenLabs TTS
ELEVENLABS_API_KEY=your_elevenlabs_api_keyBROWSERLESS_API_TOKEN=your_browserless_api_token # to access web in mulmo tool- Create a MulmoScript JSON file with
mulmo tool scripting - Generate audio with
mulmo audio - Generate images with
mulmo images - Create final video with
mulmo movie
-
Step 1-1: Run the script generation command
mulmo tool scripting -i -t children_book -o ./ -s story
This will initiate the script creation process.
-
Step 1-2: Interactive conversation with AI
After running the command, you'll engage in an interactive conversation with the AI to create your story script. The AI will guide you through the process and help shape your content based on your inputs. Once completed, a JSON file (like
story-1746600802426.json) will be generated.
mulmo movie {generated_script_file}Replace {generated_script_file} with the output file from STEP 1, such as story-1746600802426.json.
Optionally, you can specify __clipboard as the script file name to paste the script from the clipboard, which is generated by other interactive environment such as ChatGPT or Claude.
Click the image above to watch an example of what you can create
Verify your .env file contains:
OPENAI_API_KEY=your_openai_api_key
DEFAULT_OPENAI_IMAGE_MODEL=gpt-image-1 # required for high-quality Ghibli-style imagesNote: Ensure your OpenAI organization is verified to access the gpt-image-1 model. Visit https://platform.openai.com/settings/organization/general and complete the "Verifications" section.
mulmo tool scripting -i -t ghibli_comic -o ./ -s storyThis will initiate an interactive conversation with the AI to create your Ghibli-inspired story. Once completed, a JSON file (e.g., story-1747834931950.json) will be generated.
mulmo translate {generated_script_file_from_step_2}mulmo movie {generated_script_file_from_step_2} -c jaThe -c ja flag adds Japanese subtitles to your video.
When the process completes, the CLI will display the path to your generated video file:
Video created successfully! 14.939 sec
writing: /Users/username/path/to/output/story-1747834931950__ja.mp4# Generate script from web content (requires Browserless API KEY)
mulmo tool scripting -u https://example.com
# Generate script from local file
mulmo tool scripting --input-file story.txt
# Generate script with interactive mode
mulmo tool scripting -iNote:
- When using the
sensei_and_tarotemplate, a Nijivoice API key is required - When -i is specified, --input-file value will be ignored
- When --input-file is specified, -u value will be ignored
Mulmo provides several commands to handle different aspects of content creation:
# Generate audio from script
mulmo audio script.json
# Generate images for script
mulmo images script.json
# Generate both audio and images, then combine into video
mulmo movie script.json
# Translate script to Japanese
mulmo translate script.jsonWhen running the same mulmo command multiple times, previously generated files are treated as cache. For example, audio or image files will not be regenerated if they already exist.
To force regeneration, delete the old files — including temporary files — under the output directory before re-running the command or use -f (force) option.
If you modify the text or instruction fields in a MulmoScript, mulmo will automatically detect the changes and regenerate the corresponding audio content upon re-run.
MulmoScript is a JSON format to define podcast or video scripts: Schema definition: schema.ts
https://github.com/receptron/mulmocast-cli/tree/main/scripts
| Directory | Description |
|---|---|
output/ |
Artifacts generated by commands — e.g., .json, audio, and video files |
output/audio/ |
Temporary audio fragments used in the final audio assembly |
output/images/ |
Image files generated by the images command |
output/cache/ |
Internal cache files for various processing steps |
These directories are automatically created as needed by the
mulmocommands.
CLI Usage
mulmo <command> [options]
Commands:
mulmo translate <file> Translate Mulmo script
mulmo audio <file> Generate audio files
mulmo images <file> Generate image files
mulmo movie <file> Generate movie file
mulmo pdf <file> Generate PDF files
mulmo tool <command> Generate Mulmo script and other tools
Options:
--version Show version number [boolean]
-v, --verbose verbose log [boolean] [required] [default: false]
-h, --help Show help [boolean]
mulmo translate <file>
Translate Mulmo script
Positionals:
file Mulmo Script File [string] [required]
Options:
--version Show version number [boolean]
-v, --verbose verbose log [boolean] [required] [default: false]
-h, --help Show help [boolean]
-o, --outdir output dir [string]
-b, --basedir base dir [string]
-l, --lang target language [string] [choices: "en", "ja"]
-f, --force Force regenerate [boolean] [default: false]
mulmo audio <file>
Generate audio files
Positionals:
file Mulmo Script File [string] [required]
Options:
--version Show version number [boolean]
-v, --verbose verbose log [boolean] [required] [default: false]
-h, --help Show help [boolean]
-o, --outdir output dir [string]
-b, --basedir base dir [string]
-l, --lang target language [string] [choices: "en", "ja"]
-f, --force Force regenerate [boolean] [default: false]
-p, --presentationStyle Presentation Style [string]
-a, --audiodir Audio output directory [string]
mulmo images <file>
Generate image files
Positionals:
file Mulmo Script File [string] [required]
Options:
--version Show version number [boolean]
-v, --verbose verbose log [boolean] [required] [default: false]
-h, --help Show help [boolean]
-o, --outdir output dir [string]
-b, --basedir base dir [string]
-l, --lang target language [string] [choices: "en", "ja"]
-f, --force Force regenerate [boolean] [default: false]
-p, --presentationStyle Presentation Style [string]
-i, --imagedir Image output directory [string]
mulmo movie <file>
Generate movie file
Positionals:
file Mulmo Script File [string] [required]
Options:
--version Show version number [boolean]
-v, --verbose verbose log [boolean] [required] [default: false]
-h, --help Show help [boolean]
-o, --outdir output dir [string]
-b, --basedir base dir [string]
-l, --lang target language [string] [choices: "en", "ja"]
-f, --force Force regenerate [boolean] [default: false]
-p, --presentationStyle Presentation Style [string]
-a, --audiodir Audio output directory [string]
-i, --imagedir Image output directory [string]
-c, --caption Video captions [string] [choices: "en", "ja"]
mulmo pdf <file>
Generate PDF files
Positionals:
file Mulmo Script File [string] [required]
Options:
--version Show version number [boolean]
-v, --verbose verbose log [boolean] [required] [default: false]
-h, --help Show help [boolean]
-o, --outdir output dir [string]
-b, --basedir base dir [string]
-l, --lang target language [string] [choices: "en", "ja"]
-f, --force Force regenerate [boolean] [default: false]
--dryRun Dry run [boolean] [default: false]
-p, --presentationStyle Presentation Style [string]
-i, --imagedir Image output directory [string]
--pdf_mode PDF mode
[string] [choices: "slide", "talk", "handout"] [default: "slide"]
--pdf_size PDF paper size (default: letter)
[choices: "letter", "a4"] [default: "letter"]
mulmo tool <command>
Generate Mulmo script and other tools
Commands:
mulmo tool scripting Generate mulmocast script
mulmo tool prompt Dump prompt from template
mulmo tool schema Dump mulmocast schema
Options:
--version Show version number [boolean]
-v, --verbose verbose log [boolean] [required] [default: false]
-h, --help Show help [boolean]
mulmo tool scripting
Generate mulmocast script
Options:
--version Show version number [boolean]
-v, --verbose verbose log [boolean] [required] [default: false]
-h, --help Show help [boolean]
-o, --outdir output dir [string]
-b, --basedir base dir [string]
-u, --url URLs to reference (required when not in interactive mode)
[array] [default: []]
--input-file input file name [string]
-i, --interactive Generate script in interactive mode with user prompts
[boolean]
-t, --template Template name to use
[string] [choices: "akira_comic", "business", "children_book", "coding",
"comic_strips", "drslump_comic", "ghibli_comic", "ghibli_image_only",
"ghibli_shorts", "ghost_comic", "onepiece_comic", "podcast_standard",
"portrait_movie", "realistic_movie", "sensei_and_taro", "shorts",
"text_and_image", "text_only", "trailer"]
-c, --cache cache dir [string]
-s, --script script filename [string] [default: "script"]
--llm llm
[string] [choices: "openai", "anthropic", "gemini", "groq"]
--llm_model llm model [string]
mulmo tool story_to_script <file>
Generate Mulmo script from story
Positionals:
file story file path [string] [required]
Options:
--version Show version number [boolean]
-v, --verbose verbose log [boolean] [required] [default: false]
-h, --help Show help [boolean]
-o, --outdir output dir [string]
-b, --basedir base dir [string]
-t, --template Template name to use
[string] [choices: "business", "children_book", "coding", "comic_strips",
"ghibli_strips", "podcast_standard", "sensei_and_taro"]
-s, --script script filename [string] [default: "script"]
--beats_per_scene beats per scene [number] [default: 3]
--llm llm
[string] [choices: "openAI", "anthropic", "gemini", "groq"]
--llm_model llm model [string]
--mode story to script generation mode
[string] [choices: "step_wise", "one_step"] [default: "step_wise"]
mulmo tool prompt
Dump prompt from template
Options:
--version Show version number [boolean]
-v, --verbose verbose log [boolean] [required] [default: false]
-h, --help Show help [boolean]
-t, --template Template name to use
[string] [choices: "business", "children_book", "coding", "comic_strips",
"ghibli_strips", "podcast_standard", "sensei_and_taro"]
mulmo tool schema
Dump mulmocast schema
Options:
--version Show version number [boolean]
-v, --verbose verbose log [boolean] [required] [default: false]
-h, --help Show help [boolean]
For developers interested in contributing to this project, please see CONTRIBUTING.md.