Google Video no longer able to retrieve captions?

Question

As of 4 days ago, you were able to send a GET request to or visit https://video.google.com/timedtext?lang=en&v={youtubeVideoId} and receive an xml response containing the caption track of a given youtube video. Does anyone know if this support has been removed, because as of tonight, it no longer provides the xml response with the captions, the page is simply empty for every video. There were numerous videos this worked for 4 days ago that no longer work. Thanks in advance

Answer 1

The following Python scripts use Protobuf encoding scheme and more precisely blackboxprotobuf library.

Change the VIDEO_ID parameter with the one interesting you.

Automatic captions in the given language:

import requests
import blackboxprotobuf
import base64
import json

VIDEO_ID = 'qQV6guvFmM0'

def getBase64Protobuf(message, typedef):
    data = blackboxprotobuf.encode_message(message, typedef)
    return base64.b64encode(data).decode('ascii')

message = {
    '1': 'asr',
    '2': 'en',
}

typedef = {
    '1': {
        'type': 'string'
    },
    '2': {
        'type': 'string'
    },
}

two = getBase64Protobuf(message, typedef)

message = {
    '1': VIDEO_ID,
    '2': two,
}

typedef = {
    '1': {
        'type': 'string'
    },
    '2': {
        'type': 'string'
    },
}

params = getBase64Protobuf(message, typedef)

url = 'https://www.youtube.com/youtubei/v1/get_transcript'
headers = {
    'Content-Type': 'application/json'
}
data = {
    'context': {
        'client': {
            'clientName': 'WEB',
            'clientVersion': '2.20240313'
        }
    },
    'params': params
}

data = requests.post(url, headers = headers, json = data).json()
print(json.dumps(data, indent = 4))

Captions in desired language if available:

import requests
import blackboxprotobuf
import base64
import json

VIDEO_ID = 'lo0X2ZdElQ4'
LANGUAGE_INITIALS = 'ru'

def getBase64Protobuf(message, typedef):
    data = blackboxprotobuf.encode_message(message, typedef)
    return base64.b64encode(data).decode('ascii')

requestsParams = {
    'key': 'AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8'
}
url = 'https://www.youtube.com/youtubei/v1/get_transcript'
headers = {
    'Content-Type': 'application/json'
}

message = {
    '2': LANGUAGE_INITIALS,
}

typedef = {
    '2': {
        'type': 'string'
    },
}

two = getBase64Protobuf(message, typedef)

message = {
    '1': VIDEO_ID,
    '2': two
}

typedef = {
    '1': {
        'type': 'string'
    },
    '2': {
        'type': 'string'
    }
}

params = getBase64Protobuf(message, typedef)

data = {
    'context': {
        'client': {
            'clientName': 'WEB',
            'clientVersion': '2.20240313'
        }
    },
    'params': params
}

data = requests.post(url, params = requestsParams, headers = headers, json = data).json()
print(json.dumps(data, indent = 4))

Change the LANGUAGE_INITIALS parameter with the one interesting you.

Note: the key isn't a YouTube Data API v3 one, it is the first public (tested on some computers in different countries) one coming if you curl https://www.youtube.com/ | grep AIzaSy

Note: If interested in how I reverse-engineered this YouTube feature, say it in the comments and I would write a paragraph to explain

Answer 2

I recommend that anyone who uses python to try the module youtube_transcript_api. I used to send GET request to https://video.google.com/timedtext?lang=en&v={videoId}, but now the page is blank. The following is the code example. In addition, this method does not need api key.

from youtube_transcript_api import YouTubeTranscriptApi
srt = YouTubeTranscriptApi.get_transcript("videoId",languages=['en'])

Answer 3

The YouTube API change around captions caused me a lot of hassle, which I circumvented through use of youtube-dl, which has won GitHub legal support and is now again available for download/clone.

The software is available as source or binary download for all major platforms, details on their GitHub page, linked above.

Sample use is this simple:

youtube-dl --write-sub --sub-lang en --skip-download --sub-format vtt https://www.youtube.com/watch?v=E-lZ8lCG7WY

Answer 4

This is a working Python implementation of the CURL answer provided by Benjamin Loison. Replace ZhT6BeHNmvo with your video ID.

import base64
import json
import requests

base64_string = base64.b64encode("\n\vZhT6BeHNmvo".encode("utf-8")).decode("utf-8")

headers = {
    "Content-Type": "application/json",
}

body = json.dumps(
    {
        "context": {"client": {"clientName": "WEB", "clientVersion": "2.9999099"}},
        "params": base64_string,
    }
)

response = requests.post(
    "https://www.youtube.com/youtubei/v1/get_transcript?key=AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8",
    headers=headers,
    data=body,
)

print(response.text)

Answer 5

Old API currently returns 404 on every request. And YouTube right now uses new version of this API:

https://www.youtube.com/api/timedtext?v={youtubeVideoId}&asr_langs=de%2Cen%2Ces%2Cfr%2Cid%2Cit%2Cja%2Cko%2Cnl%2Cpt%2Cru%2Ctr%2Cvi&caps=asr&exp=xftt%2Cxctw&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1637102374&sparams=ip%2Cipbits%2Cexpire%2Cv%2Casr_langs%2Ccaps%2Cexp%2Cxoaf&signature=0BEBD68A2638D8A18A5BC78E1851D28300247F93.7D5E6D26397D8E8A93F65CCA97260D090C870462&key=yt8&kind=asr&lang=en&fmt=json3

The main problem with this API is to calculate the signature field of request. Unfortunately I couldn't find its algorithm. Maybe someone can reverse engineered it from YouTube player.