[FFmpeg-devel] Detecting encrypted DVDs

Måns Rullgård mans
Sat Jan 10 14:26:03 CET 2009

Andres Mejia <mcitadel at gmail.com> writes:

> Hello,
> Is there some way that ffmpeg gives a notice that it's trying to read an 
> encrypted DVD. I saw that ffmpeg handled encrypted streams differently until 
> this commit was made. 
> http://lists.mplayerhq.hu/pipermail/ffmpeg-cvslog/2006-June/002486.html
> And here's the reason.
> http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2006-June/011950.html
> For comparison, xine uses the PES scrambling control field to detect an 
> encrypted stream.

Encrypted DVDs give low-level read errors unless the drive has been
properly set up, e.g. by libdvdcss.  I don't know of anything unlocks
the drive without also decrypting the stream.

There are of course other sources of encrypted MPEG streams than DVDs.
The ISO spec does not assign any meaning to the scrambling control
field, and we've seen files that set it to a non-zero value even
though there is no encryption, so acting on this field is not

M?ns Rullg?rd
mans at mansr.com

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