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Dumping raw input (demux=dump) not working?

Posted: 15 Jun 2010 14:59
by gxyz
I am trying to figure out a way how to just dump a raw input stream to a file, something that should be supported by vlc. In some cases it works, in other cases it doesn't. Specifically, when the source is a video dvd, it always fails with recent vlc versions. Given for example an iso dvd image file "test.iso", as far as I could figure out, the following command line:

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vlc dvd://test.iso@1 --demux=dump --demuxdump-file=test.mpg
should dump track 1 to file test.mpg - instead it plays the track. The same happens when using the GUI:

- Choose the track with menu option "Media|Convert/Save|Disk".
- Click on the "Convert/Save" Button
- enter a destination file
- ignore the "Profile" option and instead
- mark the "Dump raw input" checkbox
- and finally click on "Start"

The GUI is a little confusing in this respect, but I guess the problem is a bug somewhere and not just a misunderstanding, because when the input source is a local file or the destination is to be transcoded the same thing works, only the combination of dvd:// input and dumpfile doesn't.

With vlc 0.8.6, I can get the desired result, but only when using the "wizard" menu option (which is gone in newer vlc versions); when using "File/Open Disc" the result is the same as in current versions.

[I don't expect this to be OS-specific, but for completeness: I am using Debian 5.0 and tried vlc 0.8.6, both self-compiled and Debian package and a self-compiled vlc 1.0.6
It's a probably a little silly because it seems to happen with any dvd, but I also uploaded a minimal dvd image named "test.iso" to ftp://streams.videolan.org/incoming/ if someone wants to try it]

Any ideas?

Re: Dumping raw input (demux=dump) not working?

Posted: 12 Oct 2010 23:00
by rjwilmsi
I've been having exactly the same problem. VLC 1.1.2 on opensuse 11.3.

Re: Dumping raw input (demux=dump) not working?

Posted: 12 Oct 2010 23:21
by rjwilmsi
In comparison the following method works correctly: choose stream (Ctrl+S), choose disk, press stream button: the stream output dialogue opens. Now Press the Add button beside the File destination picklist, choose your file. Then back at the stream output dialogue uncheck "activate transcoding" and then finally press the Stream button. I notice that when transcoding is unchecked the Profile picklist is still enabled, when it would seem it should not be.

The above seems logically identical to the convert method described by the OP, is there a reason why they're different?

Also, does anybody know the command line equivalent of the streaming method I describe?

Re: Dumping raw input (demux=dump) not working?

Posted: 13 Oct 2010 17:11
by RĂ©mi Denis-Courmont
Dumping a raw DVD is best done as an ISO image, rather than with VLC, e.g. on Linux:

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dd if=/dev/dvd of=MyDVD.iso
--demux dump does not work with DVD's because those are not considered as bytes streams in the VLC architecture. This only works for bytes streams, e.g. http, ftp, smb, file... not dvd.