🚀 YouTube Transcript Indexing Backend for Pinecone 🎥💾

This tutorial explains how to build the backend workflow in n8n that indexes YouTube video transcripts into a Pinecone vector database. Note: This workflow handles the processing and indexing of transcripts only—the retrieval agent (which searches these embeddings) is implemented separately.

📋 Workflow Overview

This backend workflow performs the following tasks:

1. Fetch Video Records from Airtable 📥
   Retrieves video URLs and related metadata.

2. Scrape YouTube Transcripts Using Apify 🎬
   Triggers an Apify actor to scrape transcripts with timestamps from each video.

3. Update Airtable with Transcript Data 🔄
   Stores the fetched transcript JSON back in Airtable linked via video ID.

4. Process & Chunk Transcripts ✂️
   Parses the transcript JSON, converts "mm:ss" timestamps to seconds, and groups entries into meaningful chunks. Each chunk is enriched with metadata—such as video title, description, start/end timestamps, and a direct URL linking to that video moment.

5. Generate Embeddings & Index in Pinecone 💾
   Uses OpenAI to create vector embeddings for each transcript chunk and indexes them in Pinecone. This enables efficient semantic searches later by a separate retrieval agent.

🔧 Step-by-Step Guide

Step 1: Retrieve Video Records from Airtable 📥

• Airtable Search Node:

  • Setup: Configure the node to fetch video records (with essential fields like url and metadata) from your Airtable base.

• Loop Over Items:

  • Use a SplitInBatches node to process each video record individually.

Step 2: Scrape YouTube Transcripts Using Apify 🎬

• Trigger Apify Actor:

  • HTTP Request Node ("Apify NinjaPost"):

    • Method: POST

    • Endpoint: https://api.apify.com/v2/acts/topaz_sharingan~youtube-transcript-scraper-1/runs?token=<YOUR_TOKEN>

    • Payload Example:

                  {
        "includeTimestamps": "Yes",
        "startUrls": ["{{ $json.url }}"]
      }
      

  • Purpose: Initiates transcript scraping for each video URL.

• Wait for Processing:

  • Wait Node:
    • Duration: Approximately 1 minute to allow Apify to generate the transcript.

• Retrieve Transcript Data:

  • HTTP Request Node ("Get JSON TS"):
    • Method: GET
    • Endpoint: https://api.apify.com/v2/acts/topaz_sharingan~youtube-transcript-scraper-1/runs/last/dataset/items?token=<YOUR_TOKEN>

Step 3: Update Airtable with Transcript Data 🔄

• Format Transcript Data:

  • Code Node ("Code"):

    • Task: Convert the fetched transcript JSON into a formatted string.

                  const jsonObject = items[0].json;
      const jsonString = JSON.stringify(jsonObject, null, 2);
      return { json: { stringifiedJson: jsonString } };
      

• Extract the Video ID:

  • Set Node ("Edit Fields"):

    • Expression:

                  {{$json.url.split('v=')[1].split('&')[0]}}
      

• Update Airtable Record:

  • Airtable Update Node ("Airtable1"):
    • Updates:
      • ts: Stores the transcript string.
      • videoid: Uses the extracted video ID to match the record.

Step 4: Process Transcripts into Semantic Chunks ✂️

• Retrieve Updated Records:

  • Airtable Search Node ("Airtable2"):
    • Purpose: Fetch records that now contain transcript data.

• Parse and Chunk Transcripts:

  • Code Node ("Code4"):
    • Functionality:
      • Parses transcript JSON.
      • Converts "mm:ss" timestamps to seconds.
      • Groups transcript entries into chunks based on a 3-second gap.
      • Creates an object for each chunk that includes:
        • Text: The transcript segment.
        • Video Metadata: Video ID, title, description, published date, thumbnail.
        • Chunk Details: Start and end timestamps.
        • Direct URL: A link to the exact moment in the video (e.g., https://youtube.com/watch?v=VIDEOID&t=XXs).

• Enrich & Split Text:

  • Default Data Loader Node:
    • Attaches additional metadata (e.g., video title, description) to each chunk.
  • Recursive Character Text Splitter Node:
    • Settings: Typically set to 500-character chunks with a 50-character overlap.
    • Purpose: Ensures long transcript texts are broken into manageable segments for embedding.

Step 5: Generate Embeddings & Index in Pinecone 💾

• Generate Embeddings:

  • Embeddings OpenAI Node:
    • Task: Convert each transcript chunk into a vector embedding.
    • Tip: Adjust the batch size (e.g., 512) based on your data volume.

• Index in Pinecone:

  • Pinecone Vector Store Node:
    • Configuration:
      • Index: Specify your Pinecone index (e.g., "videos").
      • Namespace: Use a dedicated namespace (e.g., "transcripts").
    • Outcome: Each enriched transcript chunk is stored in Pinecone, ready for semantic retrieval by a separate retrieval agent.

🎉 Final Thoughts

This backend workflow is dedicated to processing and indexing YouTube video transcripts so that a separate retrieval agent can perform efficient semantic searches. With this setup:

• Transcripts Are Indexed:
  Chunks of transcripts are enriched with metadata and stored as vector embeddings.

• Instant Topic Retrieval:
  A retrieval agent (implemented separately) can later query Pinecone to find the exact moment in a video where a topic is discussed, thanks to the direct URL and metadata stored with each chunk.

• Scalable & Modular:
  The separation between indexing and retrieval allows for easy updates and scalability.

Happy automating and enjoy building powerful search capabilities with your YouTube content! 🎉