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As the title suggest, I have a video(.mp4) protected by widevin DRM and license
URL of it? How can I decrypt my video?

Nguyên Phương
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You don’t decrypt it. You configure the CDM with the correct values, and the CDM decrypts, decodes and plays.

If you have the key, then the file is simply CENC, and most tools like ffmpeg and mp4 box can decrypt it for you.

szatmary
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  • I downloaded mp4 from mpd with ffmpeg and i have License URL of it, How can i decrypt? – Nguyên Phương Nov 12 '19 at 03:49
  • License URL is worthless. It is public information and does not leak any security parameters. The license is encrypted by the DRM server and only the CDM can decrypt it. You need the raw key. You either have it or not. There is no way around it. – szatmary Nov 12 '19 at 06:54
  • So, are there any way to download it? – Nguyên Phương Nov 12 '19 at 10:30
  • Download what, the key? No. unless this is clear key encryption, allowing anything but the CDM access to the key is literally what DRM exists to prevent. You can download the key in an encrypted Form, but then only the CDM can decrypt it. – szatmary Nov 12 '19 at 14:24