Extract Image from WMV using HEX values?

[phatz]

HI,

Not sure where I shouldpost this so went for the newbie option.

I have been able to extract Jpg images from .EXE files in the past using a HEX editor for example like ultraedit and knowing what the image header binary values are etc for the headers.

However I am having trouble trying to do the same with WMV files?

I can find what seems to be the relevant headers but cannot extract them out of the WMV file?

I have seen that you can get WMV to Jpg apps but looks like this is done with a frame capture process.

I want to know if it is possible to extract a jpeg that has been added to a WMV file, bascially if 10 jpg files went in to the WMV file then I assume I can extract these using a hex editor and get 10 jpgs back out or is this more difficult then i think?

Any advice tips help that anyone can give me.

THanks phatz

[VegasBud]

phatz,

An image in an exe or dll is stored intact as a resource for the program to use. An image in a wmv, or other video format, isn't the original image anymore. It's a representation of the image which is compatible with the properties of the video. It's encoded into the video, as part of the video. At that point, there's nothing left to extract...except by capturing the video frame(s).

As to:

I can find what seems to be the relevant headers...

The probability of finding a specific byte sequence in a wmv file (which may or may not be influenced by other factors than random occurence...I just don't know) is going to increase as you use fewer bytes for the search. For example, if you searched using just the first two byte values (FF D8) of a JFIF header, you're going to get more matches than if you used the full 11 byte values (FF D8 FF E0 ?? ?? 4A 46 49 46 00). I wouldn't think you would find the 11 byte sequence very often in a wmv file. If you are, let me know, and I'll see what I can find out about why that would be.

I see this was your first post here, so welcome to VideoHelp.

[JohnnyMalaria]

I would expect that when you "add" JPEGs to a WMV, they are recompressed as WMV format. I don't think Windows Media supports embedded different formats within the WMV file.

[jagabo]

Most frames in a WMV file are not complete images. Most of them only encode the differences between frames. To extract a particular image you have to go to an earlier key frame, then decode all the frames between that key frame and the frame you want.

[phatz]

Thanks everyone for the feedback. Looks like it will be the frame capture way of things for wmv. FFD8 does occur too many time as opposed to the full byte sequence for a jfiff header.