Transcribe videos with google colab and openai whisper

Google colab provides powerful GPUs with 12G of VRAM even at free tier. I foud this very useful to first generate srt files of chinese youtube videos and then translate the chinese srt files into english srt files.

Sample yt-dlp command to download video

# proxy, cookies, format and output name are not compulsory.
yt-dlp --proxy socks5://localhost:1080/ --cookies /tmp/cookies.txt -f "bestvideo[height=720]+bestaudio" 'https://www.youtube.com/watch?v=XlmWtg4ksaw' -o '藏南的诅咒：困死在喜马拉雅南坡的印度'

Sample ffmpeg command to extract audio from video

ffmpeg -i input.webm -vn -acodec libmp3lame -ab 192k output.mp3

First visit https://colab.research.google.com/

File
    > New notebook in Drive

Set the runtime type

Runtime
    > Change runtime type

Select python3 as interpreter and t4 gpu as hardware accelator

Each code bock below is inserted by pressing the +Code button in the UI first and then entering the text. Lines that beings with ! is run in the os shell environment, while the rest are run in the selected interpreter (here python3). After typing in each code blocks, press the run button:

The codeblocks (run in sequence)

!pip install openai-whisper

from google.colab import files

uploaded = files.upload() # (1)

1. Click on Choose Files, navigate to and select file.

filename = list(uploaded.keys())[0]
print(f"Uploaded file: {filename}")
import os
os.environ['FNAME'] = filename

!whisper "$FNAME" --output_format srt --language zh --model turbo

Note

Replace zh with the spoken language in the uploaded audio file

filename_without_ext = os.path.splitext(os.environ['FNAME'])[0]
files.download(f"{filename_without_ext}.srt")

Note

1. The generated srt file has the same name but different srt as extension.

Translate with google translate

At https://translate.google.com, in Documents tab you see that google only supports .docx, .pdf, .pptx, .xlsx.

To work around this limitation, use libreoffice.

libreoffice --convert-to "docx:MS Word 2007 XML" output.srt

This creates output.docx. Get it translated at google translate and download the resulting docx. Convert it back with

libreoffice --convert-to "txt:Text" output-eng.docx

Rename this file to your "video name.srt" and you're good to go!

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