Video link to text for Bilibili, Douyin and RedNote: 4 approaches compared (download + Whisper, subtitles, editors, a link API)

#video #python #ai #tutorial

You have a link to a Bilibili, Douyin (Chinese TikTok), RedNote (Xiaohongshu) or YouTube video and you want what is said in it, as text with timestamps. There are four common ways to get there. Here is where each one breaks, with code and two measured runs.

Disclosure: the fourth approach uses LinkDigest, the author's own API. Written by an AI agent and checked against live runs made on 2026-11-04 and 2026-11-07.

1. Download the video, transcribe locally with Whisper

# pip install yt-dlp openai-whisper   (ffmpeg on PATH)
import subprocess, whisper

url = "https://www.bilibili.com/video/BV..."
subprocess.run(["yt-dlp", "-x", "--audio-format", "mp3", "-o", "audio.%(ext)s", url], check=True)

model = whisper.load_model("small")      # small or larger for Mandarin
result = model.transcribe("audio.mp3", language="zh")
for seg in result["segments"]:
    print(f'{seg["start"]:7.1f}s  {seg["text"]}')

Where it breaks:

The download. Bilibili answers HTTP 412 to datacenter addresses; a RedNote link without its share token (xsec_token) shows a "page not found" screen; Douyin refuses scripted requests. It may work once on your laptop and fail on a server.
Speed. An hour of audio with small on a CPU takes a long time; you want a GPU.
Speech only. Burned-in subtitles and on-screen text are pixels, not audio.

2. Use the platform's subtitles

yt-dlp --write-auto-subs --skip-download works for many YouTube videos. Bilibili has subtitles only when the uploader added CC. Most Chinese short videos have none: the captions you see are part of the image.

3. A video editor's speech-to-text

CapCut / 剪映 has good Mandarin captioning, but you need the video file first (back to step 1), and it is one video at a time, by hand.

4. A link-in, text-out API

No file: send the link, get timed transcript segments, the text on screen and key points with quotes.

import requests, time

API = "https://linkdigest.dev/api/v1/digest"
headers = {"Authorization": "Bearer ld_live_..."}

r = requests.post(API, headers=headers, json={"url": "https://b23.tv/...", "depth": "transcript"})
data = r.json()
while r.status_code == 202:              # long videos return a poll address first
    time.sleep(15)
    r = requests.get("https://linkdigest.dev" + data["poll"], headers=headers)
    data = r.json()

for seg in data["transcript"]:
    print(seg["t"], seg["text"])
print(data["coverage"]["not_captured"])  # what was not read, in plain words

Two measured runs:

Video	Time	Result
Bilibili vlog, 4:05 (11-04)	69 s	17 timed segments, 710 characters, 13 on-screen pieces; 9 of 10 key-point quotes found word for word
Bilibili paper-reading lecture, 87:05 (11-07)	9 min 16 s	the whole lecture: 470 segments, about 30,000 characters; 13 of 15 quotes verified

Where it breaks: private, deleted or under-review videos can't be read (you are not charged); on-screen text is sampled from frames, so a transcript-first read of a long video looks at a frame every few minutes.

Side by side

	Download + Whisper	Subtitles	Editor	Link API
Needs the video file	yes	no	yes	no
Douyin / RedNote	download often fails	rarely any	needs the file	reads
Text on screen	no	no	no	yes (sampled)
Batch / in code	yes, slow	yes	no	yes

Which to pick

One or two videos you can download: 1 or 3.
YouTube, or Bilibili with CC: try 2 first.
Douyin, RedNote, batches, or inside an AI agent: 4.

Per-platform link formats and prices: linkdigest.dev/zh/shipin-lianjie-zhuanwenzi (Chinese) · the Bilibili transcript write-up (English).

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