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Old Official Forum » Projects » Video Thumbnails Maker by Scorp » MD5 in comment field
MD5 in comment field
enderDate: Tuesday, 2011-06-21, 5:46 AM | Message # 1
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I would love to be able to put a hash of the video in the comment field. This can obviously be accomplished if you directly implement the feature as a [MD5] and maybe a [SHA256] variable (as .Net makes those sorts of crypto functions easy to implement).

Alternatively, a more general flexible approach for adding custom comments would be if you implemented a commandline "-comment" switch and vtm could be called using a variable that iterates over a file list and can pass the hashes to vtm that way.

It would be very useful to be able to tag videos with hashes to make it easy to verify their integrity (or to make it easy to tell if you have a file already even if the filename is different).

Thanks biggrin
 
suu-designDate: Friday, 2011-06-24, 11:45 AM | Message # 2
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Quote (ender)
I would love to be able to put a hash of the video in the comment field. This can obviously be accomplished if you directly implement the feature as a [MD5] and maybe a [SHA256] variable (as .Net makes those sorts of crypto functions easy to implement).

nice idea

please let me know if i will forget to include that feature in the future release
 
suu-designDate: Wednesday, 2011-07-27, 1:36 PM | Message # 3
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[md5] done
 
enderDate: Wednesday, 2011-08-03, 10:59 PM | Message # 4
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Quote (suu-design)
[M] [MD5] tag is added to the "Comment" option. It allows you to add MD5 hash string to the picture (is calculated for the first kilobyte of video-file).

Based on the changelog, it looks like [md5] only takes into account the first kilobyte of a video. It would be great if you could make this configurable or include a second [md5full] tag or something along those lines to take the md5 of the *entire* file. I understand it will take longer to calculate the hashes of all the videos, but the reason I wanted to include this information in the first place is to detect file corruption. Using a fast hash of the first kilobyte is fine for identification, but it doesn't let you detect incomplete transfers or file corruption (if the first 50% of a file downloaded fine, and the second 50% got messed up, the filesize might match up, but the corruption wouldn't be obvious from the hash).

The other alternative as I mentioned before is if you included a commandline switch for the comment field. Then I could preprocess a list of files, calculate their md5's, and run vtm within a loop from a batch script and pipe it the md5's for the comment field that way.

Since you already coded the md5, I think adding an md5full tag should be pretty quick, but either way works fine. Thanks again and good luck with the new pornizer program wink


Message edited by ender - Wednesday, 2011-08-03, 11:05 PM
 
suu-designDate: Thursday, 2011-08-04, 2:30 PM | Message # 5
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is it handy to compare MD5 reading it from the picture (screenlist)?
 
enderDate: Friday, 2011-08-05, 5:49 AM | Message # 6
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Quote (suu-design)
is it handy to compare MD5 reading it from the picture (screenlist)?

There are two reasons I think it is useful to have the hash of the "full" file vs just a quick (1kb) hash.

Hashing the full file is the most common convention:
- Popular hash utilities like HashTab and HashCheck return the md5 of the *full* file (having only partial hashes means people can't use these types of utilities to check the hash).
- Almost any websites that host videos and include the hash or name a video by the hash give the hash of the *full* file.

The second reason is that as I mentioned, full hashes let you confirm file integrity (partial hashes don't).

As far as it being handy to compare MD5's from the picture. True, if it's in a picture (vs in a txt file or xml file) you can't automatically compare the MD5 (maybe you could add the md5 to the xml/txt/etc list in the options *if* the md5 tag is detected in the comments). That said, for the reasons I already mentioned, I think if you have *any* hash in the comments, having a "full" MD5 is much more useful than a partial one. It is a common practice with many websites to name files using their MD5 hash (to prevent duplicates), and as I mentioned it's the only way to be sure that a file is the file you expect. If I have a video and split it in half without modifying anything. It will have the same 1kb hash but be missing half the video.

As a specific use case, I have a website where I automatically generate thumbsheets for uploaded videos and list the MD5 of the file that was uploaded. I would love to include the MD5 of the video in the thumbsheet because that way. someone who downloads a thumbsheet collection from my site, can easily search for a video on my site even if the title of a video was changed for some reason (the md5 always stays the same).


Message edited by ender - Friday, 2011-08-05, 6:01 AM
 
Old Official Forum » Projects » Video Thumbnails Maker by Scorp » MD5 in comment field
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