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file_hash - how to calculate, to substitute clip

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Thu, 07/01/2010 - 08:57
#1
Daniel06
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Joined: 06/28/2010
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file_hash - how to calculate, to substitute clip

Hi,

I'd like to know what kind of hash function should I use to calculate new 'file_hash' value. I need to substitute some source clips in my project (clip video, length unchanged, only sound repaired), I've just checked sha1sum (and other sha...) md5sum ...

How to calculate hash for a clip? - to substitute clip in my-project.kdenlive file.

Daniel

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Thu, 07/15/2010 - 16:49
#2
ttill
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Joined: 10/14/2009
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Re: file_hash - how to calculate, to substitute clip

What happens if you just delete the hash value?
I think we should maybe add a option to turn of hashing, as this can also lead to some other problems.

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Fri, 09/16/2011 - 13:16
#3
hamoid
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Joined: 09/16/2011
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Re: file_hash - how to calculate, to substitute clip

I was also interested in generating .kdenlive from Python, so I wanted to find out about the file_hash. I downloaded the source code and it looks like it's using the beginning and end of the file, not the whole file: 

        // ... DocClipBase::getFileHash ...

        if (file.size() > 1000000*2) {
            fileData = file.read(1000000);
            if (file.seek(file.size() - 1000000))
                fileData.append(file.readAll());
        } else
            fileData = file.readAll();

        fileHash = QCryptographicHash::hash(fileData, QCryptographicHash::Md5);
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