Author(s): Sarvesh Khetan

Originally published on Towards AI.

Table of Contents

• Text2Image
• Text2Speech
• Text2Video

Text2Image (TTI) Task / In-Painting / Out-Painting

Idea

We will do text conditioning on Image2Image Models. As seen in the blog, we can use any generative model i.e. Autoencoders / GAN … / DDPMs / DDIMs to perform Image2Image task but here in Text2Image task during inference we won’t have a input image, we will only have an input text hence while training also we will have to use a model which convert noise to image for the image2image task. Hence we can only use models like GANs and Diffusion for Text2Image Task !!

Below I have discussed Text Conditioned Diffusion based models since it gives better results compared to Text Conditioned GAN based models.

Text Conditioned DDPMs Based Models

Now you can do text conditioning in DDPMs in several ways :

a. Vanilla Method to do text conditioning

We have already seen this here, wherein I show diffusion model (CNN based / Transformer based) conditioned with time information. Now the idea is that to condition this with the text information we will just add this text information to the time information!! Below I have shown how to add text information to DiT based model (self attention) but you can use similar logic to add text information to other types of diffusion models discussed in this blog.

b. Classifier Based Guidance to do text conditioning

c. Classifier Free Guidance (works best) to do text conditioning

Prominent Models

Following are some successful models which have been trained using the above method :

• Guided Language-2-Image Diffusion for Generation and Editing (GLIDE) by OPENAI : it had following architecture

• [better than glide] Dall-e2 (or unCLIP) by OPENAI : It had almost similar architecture as of Glide, just that they used CLIP Model to convert image and text into embeddings and it used a UNET style autoencoder based diffusion model.
• [better than dalle2] ImageGEN by GOOGLE : almost similar architecture as Glide, just that the use the pretrained frozen T5-XXL model to encode text.

Text Conditioned Latent DDPMs Based Models (works better)

Same as text conditioned DDPMs just that here we operate on latent space instead of pixel space.

Some famous models based on above architecture are :

• Stable Diffusion
• Titan Image Generator (AWS)
• Midjourney

All these model weights can be downloaded using Hugging Face’s diffusers library, example code available here

Text2Speech Task (TTS) / Speech Synthesis

• Idea : we will perform text conditioning on models which can do Speech2Speech task.
• Now you can solve Speech2Speech task using any generative model like
  a. GANs
  b. Diffusion (works best)
• Some prominent models in this space are :
  a. AudioGen by Facebook
  b. MusicGen by Facebook
  c. Indic-TTS developed by AI4Bharat is capable of generating speech in multiple Indian Languages.

Text2Video Task

• Idea : we will perform text conditioning on models which can do Video2Video task.
• Now you can solve Video2Video task using any generative model like
  a. GANs
  b. Diffusion (works best)
• Some prominent models in this space are :
  a. [2022] Make A Video By Meta => Here is a Blog explaining this paper
  b. [2023] Stable Video Diffusion
  c. [early 2024] Lumiere By Google
  d. [late 2024] SORA by Open AI
  e. [early 2025] Veo2 by Google

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Published via Towards AI