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Solve : Dude uploads video to YouTube, rips it, uploads again a thous...?

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Pretty fascinating. Didn't think that the compression would cause that much of an issue, even at 1,000 times.

What happens when you upload a video to YouTube, then rip it from YouTube, and repeat that process again, a thousand times. The final digitally-distilled product bears little resemblance to the original, and becomes something of its own.

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My Computer Science teacher did something similar with a Visual Basic program saving and loading the same jpeg over and over.

First, we did it with a blue square overlapped by a red circle. after a while it just because a purple blur.

for a photo it just became a bunch of splotches.


I guess this is a sort of mpeg version of that jpeg experiment, Wow. I think this is called "too much free time".Quote from: rthompson80819 on June 04, 2010, 03:41:37 PM

Wow. I think this is called "too much free time".
Just make a macro.Quote from: rthompson80819 on June 04, 2010, 03:41:37 PM
Wow. I think this is called "too much free time".


Fun to play with... I played around with Imagemagick's command line converter, convert.exe. Two things govern the degradation: the number of conversions, and the compression (quality) setting. I found that with 80% quality even 1000 cycles didn't do much; on the other hand if I chose 1% (very severe compression) quality, the changes happen more quickly. There COMES a POINT where the image settles down and doesn't degrade much more as you can SEE...

Original


System specs Shuttle SN78SH7, 4 GB DDR2 RAM, 3.0 GHz AMD Phenom II 945 (quad core), Windows 7 Pro 64 bit, images stored on a USB 2.0 external hard drive, converted with ImageMagick 6.6.2-2, image size 401x433, 24 bit colour.

Converted 10 times at 1% quality setting (0.61 seconds)



Converted 100 times at 1% quality setting (6.4 seconds)



Converted 5000 times at 1% quality setting (240.38 seconds)


the script I used (a QUICK hack, I know)

jpegloop.bat
Code: [Select]@echo off
setlocal enabledelayedexpansion
set limit=%2
set quality=%3
set /a stop=%limit%-1
del "%~n1-converted-*.jpg"
copy "%~n1.jpg" "%~n1-converted-0.jpg"
set stime=%time%
for /l %%N in (0,1,%stop%) do (
set num1=%%N
set /a num2=!num1!+1
echo !num2!.jpg
convert %~n1-converted-!num1!.jpg -quality %quality%%% %~n1-converted-!num2!.jpg
if %%N LSS %stop% del %~n1-converted-!num1!.jpg
)
del %~n1-converted-%num1%.jpg
set etime=%time%
echo start %stime%
echo end %etime%

command line example

Code: [Select]jpegloop.bat face.jpg 5000 1






By the way, after 10 compressions, the file size went from 23 KB to 3 KB and stayed there.


Very nice post Salmon Trout. Very interesting and good fast way of playing around with it.Salmon Trout's post should be the post of the month. I'd agree if we had some type of SETUP that would allow that. Maybe something that could be thought out and added to the community.


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