langflow Failed to get YouTube transcripts: list index out of range

Bug Description

The output of the tool should be the video transcripts.

Failed to get YouTube transcripts: list index out of range

ERROR at the red dot of the youtube tool

Reproduction

Below is the exported flow file.
Checkout the data output from the youtube tool.

Expected behavior

The transcripts for the youtube video for which the URL has been pass.

Who can help?

No response

Operating System

Ubuntu 22.04

Langflow Version

1.1

Python Version

3.11

Screenshot

No response

Flow File

youtube chat summerizer.json

Dec 30 '24 17:12 mrtushartiwari

@mrtushartiwari Hello there! I'm here to help you with bug fixes, questions, or becoming a contributor. Let's squash those bugs together! 🤖

To resolve the "list index out of range" error when using the YouTube Transcription node, ensure that the transcripts list is not empty before attempting to access its elements. This error likely occurs when transcripts[0] is accessed without checking if the list contains any elements. You can add a check to handle this case:

transcripts = loader.load()

if not transcripts:
    return Message(text="No transcripts available for the provided video URL.")

if self.transcript_format == "text":
    # Extract only the page_content from the Document
    result = transcripts[0].page_content
    return Message(text=result)

# For chunks, format the output with timestamps
formatted_chunks = []
for doc in transcripts:
    start_seconds = int(doc.metadata["start_seconds"])
    start_minutes = start_seconds // 60
    start_seconds %= 60
    timestamp = f"{start_minutes:02d}:{start_seconds:02d}"
    formatted_chunks.append(f"{timestamp} {doc.page_content}")
result = "\n".join(formatted_chunks)
return Message(text=result)

This code snippet checks if the transcripts list is empty and returns a message indicating that no transcripts are available, preventing the "list index out of range" error ^[1].

To continue talking to Dosu, mention @dosu.

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Dec 30 '24 17:12 dosubot[bot]

I'm having this issue as well. It seems to be a problem with DataStax, as I've run the Youtube Transcript component on a local build and it worked.

I tried with a bare-bone custom component using what the Official Component does, which is the "youtube_transcript_api".

# from langflow.field_typing import Data
from langflow.custom import Component
from langflow.io import MessageTextInput, Output
from langflow.schema import Message
from youtube_transcript_api import YouTubeTranscriptApi

class CustomComponent(Component):
    display_name = "Custom Component"
    description = "Use as a template to create your own component."
    icon = "code"
    name = "CustomComponent"

    inputs = [
        MessageTextInput(
            name="video_id",
            display_name="Video ID",
        ),
    ]

    outputs = [
        Output(name="message", display_name="Transcript", method="get_message_output"),
    ]

    def get_message_output(self) -> Message:
        transcript = YouTubeTranscriptApi.get_transcript(self.video_id)
        
        return Message(text=transcript)

It returned me the error

Error building Component Custom Component: Could not retrieve a transcript for the video https://www.youtube.com/watch?v=[Video ID]! This is most likely caused by: Subtitles are disabled for this video If you are sure that the described cause is not responsible for this error and that a transcript should be retrievable, please create an issue at https://github.com/jdepoix/youtube-transcript-api/issues. Please add which version of youtube_transcript_api you are using and provide the information needed to replicate the error. Also make sure that there are no open issues which already describe your problem!

The thing is, this component builds and runs fine on my local build. My theory is that Youtube has blocked Datastax requests, but I ain't no expert, just waiting this to be fixed. For that reason the Datastax component fails to retrieve the transcript and because of that when the component tries to accerss transcript[0] it finds it is empty (because the api did not work) and returns the index error.

Mar 04 '25 16:03 leafranger

Hi,

Confirming I'm also encountering the IndexError: list index out of range with YouTubeTranscriptsComponent when running Langflow deployed on Hugging Face Spaces.

Further supporting the theory of an environmental/IP blocking issue: I integrated yt-dlp directly into this same Hugging Face Space environment to fetch media URLs. When attempting to get a YouTube URL, yt-dlp failed with the following

error: ERROR: [youtube] xxx: Sign in to confirm you’re not a bot. Use --cookies-from-browser or --cookies for the authentication...

This yt-dlp error strongly suggests YouTube is requiring authentication or blocking requests from the Hugging Face server IPs, likely due to bot detection measures.

It's reasonable to assume the youtube-transcript-api library used by YouTubeTranscriptsComponent is facing the same block. This would cause it to fail retrieving transcripts (returning an empty list), leading directly to the IndexError when the component tries to access transcripts[0].

Therefore, the root cause seems to be YouTube blocking requests from cloud provider IPs (like Hugging Face and likely DataStax as mentioned earlier), rather than just an issue within the component itself.

Apr 20 '25 22:04 fucn569

Hi @mrtushartiwari,

Thank you for reporting this YouTube Transcripts issue. I can help you resolve this "list index out of range" error.

Root Cause Analysis

This error occurs because:

YouTube IP Blocking: YouTube has implemented bot detection that blocks requests from cloud provider IPs (DataStax, Hugging Face Spaces, etc.)
Empty Response: When blocked, the youtube-transcript-api returns an empty list instead of transcripts
Missing Error Handling: The component tries to access transcripts[0] without checking if the list is empty

This has been confirmed by multiple community members (@leafranger and @fucn569) - the component works fine locally but fails in cloud environments.

Current Component Status

The current YouTube Transcripts component in Langflow does have error handling for specific YouTube API exceptions:

TranscriptsDisabled
NoTranscriptFound
CouldNotRetrieveTranscript

However, it still has a vulnerability in the get_message_output() method at line 84 where it directly accesses transcripts[0].page_content without checking if the list is empty.

Solutions

Solution 1: Use Alternative Output Method

Try using the "Transcript + Source" output instead of the "Transcript" output. This method has better error handling and checks for empty transcripts:

if not transcripts:
    default_data["error"] = "No transcripts found."
    return Data(data=default_data)

Solution 2: Use AssemblyAI Components (Recommended)

For reliable transcription across all environments, switch to AssemblyAI components:

AssemblyAI Start Transcript - Submit audio/video for transcription
AssemblyAI Poll Transcript - Wait for completion
AssemblyAI Get Subtitles - Generate SRT/VTT format

AssemblyAI works consistently in cloud deployments and doesn't face YouTube's IP blocking issues.

Why This Happens in Cloud Environments

As confirmed by community members:

@leafranger: "It seems to be a problem with DataStax, as I've run the Youtube Transcript component on a local build and it worked."
@fucn569: "YouTube is requiring authentication or blocking requests from cloud provider IPs... YouTube blocking requests from cloud provider IPs (like Hugging Face and likely DataStax)"

YouTube's anti-bot measures specifically target cloud provider IP ranges. The error message you'd see locally would be:

"Sign in to confirm you're not a bot. Use --cookies-from-browser or --cookies for the authentication"

Immediate Workarounds

Option 1: Test Locally First

If you're developing locally, the YouTube component should work fine since your home IP isn't blocked.

Option 2: Switch to AssemblyAI

Replace your YouTube Transcripts component with AssemblyAI components for cloud deployments.

Option 3: Handle the Error Gracefully

If you must use YouTube transcripts, wrap your flow with error handling to catch when transcripts aren't available.

Version Note

The current latest version is 1.5.0.post2. Consider upgrading to the latest version for better error handling and bug fixes.

Next Steps

Short-term: Switch to using the "Transcript + Source" output method
Long-term: Use AssemblyAI components for production transcription workflows
Testing: If deploying locally, the YouTube component should work fine

The core issue is YouTube's IP blocking of cloud providers rather than a bug in Langflow itself.

Let me know if you need help setting up AssemblyAI components or have other questions!

Best regards

Aug 26 '25 18:08 Vigtu