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I want to edit some .avi videos (cut them, to be precise) in VirtualDub but it failed to open the files. They are encoded in xvid, which I have installed, and play in KMPlayer without problem. Also, all other xvid videos can be opened and cut just fine by VirtualDub.

I suspect there's something wrong in the first few bytes of these particular videos (the magic number?). This means I have to open the offending files in a hex editor and make some necessary adjustments to the header. Problem is, they are very large (> 3 GB each) and take very long time to open in UltraEdit.

Can UltraEdit open just the first few bytes of a file? If not, do you know of an application that can do that?

Edit: I'm using Windows XP.

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I suspect you're trying to put the cart before the horse. Maybe you could try to fix the video (e.g. by letting ffmpeg put it in another container first)? – slhck Jun 26 '11 at 14:23
It does indeed take a long time. After selecting "Disable temporary files when opening large files (greater than 47 MB) for this edit section only" it took 22 seconds for a 1.0 GB file and 243 seconds (4 minutes) for a 3.3 GB file. Tested on Windows XP 64-bit with 8 GB of RAM and UltraEdit v. 16.2. – Peter Mortensen Jun 26 '11 at 15:13
Larssend, Is it 32-bit or 64-bit Windows XP? – Peter Mortensen Jul 20 '11 at 14:57
up vote 3 down vote accepted

No, to the best of my knowledge (UltraEdit user since 1998) UltraEdit reads the entire file into memory and there are also some inefficiencies as documented in the comments to this question (and further inefficiencies when opening large HTML files).

However, if your system is up to it (64-bit Windows and enough RAM) and temporary files are disabled for large files (menu Advanced/Configuration/File Handling/Temporary Files/"Disable temporary files when opening large files (greater than 2 MB)") then it should work given a little patience.

Hex editors for large files

  1. HxD. From Features: "Instant opening regardless of file-size. Opening and editing is very fast"

  2. From a list of hex editors I found wxHexEditor which look promising:

    • It does NOT copy the whole file to your RAM.
    • Memory usage: Currently ~25 MB while opened multiple > ~8 GB files.
    • You can work with delete/insert bytes to file, more than once, without creating a temporary file!
    • It supports files up to 2^64 bytes. Besides Linux it can be used with other OS'es such as Windows, and Mac OS.

I have not tested them, though.

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Recently I published Hexinator which is a free hex editor for Windows and Linux that allows you to open files of unlimited size instantly -- only the visible part is loaded to memory.

The non-free part allows you to apply a "grammar" to binary files which lets you decode files automatically. There is already a (free) grammar for WAV files available which is based on RIFF like AVI. You could try to apply this grammar and see where it doesn't parse well.

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