JPEG DCT, Discrete Cosine Transform (JPEG Pt2)- Computerphile
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DCT is the secret to JPEG's compression. Image Analyst Mike Pound explains how the compression works. Colourspaces: https://youtu.be/LFXN9PiOGtY JPEG 'files' & Colour: https://youtu.be/n_uNPbdenRs Computer That Changed Everything (Altair 8800): https://youtu.be/6LYRgrqJgDc Problems with JPEG: COMING SOON Upside Down Trees (Huffman Encoding): https://youtu.be/umTbivyJoiI Colourspaces: https://youtu.be/LFXN9PiOGtY JPEG isn't a file format - JPEG pt1: https://youtu.be/n_uNPbdenRs Upside Down Trees (Huffman Encoding): https://youtu.be/umTbivyJoiI Problems with JPEG: COMING SOON! Computer That Changed Everything (Altair 8800): https://youtu.be/6LYRgrqJgDc http://www.facebook.com/computerphile https://twitter.com/computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: http://bit.ly/nottscomputer Computerphile is a sister project to Brady Haran's Numberphile. More at http://www.bradyharan.com
Kommentare
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Could anyone help me please in plotting the 64 basis waves of Cos! I need that ! Thank you
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Exactly how my turbo encabulator winds up the pentametric fans.
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Thank you sir, excellent demonstration on JPEG topic!!!
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You addressed the meaning of frequency in images, which others completely miss out . Thanks.
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Really great
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Great video! Thanks a lot
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Absolutely amazing video! Thank you so much for this!
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If the quantization table is different used by different applications as you told like PS uses different how is it able to show the image. It there any standard quantization tables?
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How do you calculate your DCT coefficients?
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DCT is very similar to FFT as it converts samples from a time domain to a frequency domain. MP3 also uses DCT but with windowing.
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Just out of curiosity, if you've watched this just now, and you haven't had any exposure to Fourier analysis, does the explanation make sense? I'm wondering what I would have made of this prior to university: would the image he pulls out at 3:42 have made any sense to me without seeing it as a grid of basis functions for a Fourier transform?
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So the "minus" sign means that You have to invert the image, and then apply it to the square?
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you look like spider man
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the greatest video ever created tbh
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Well, that was much easier than reading 5 pages of the book. Thanks.
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Great great video!! I wish you were my professor!!
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I explore some about DCT's article on internet, do you have utilize DC,AC values coding, or you are coding directly?
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How do you get the coefficients from the DCT?
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I'd love a detail explanation of the magic part where you calculate the DTC coefficients for one block of 8x8. What's the algorithm?
For example the top left blank block is approximately 50% the same as the bottom right checkerboard block so by weighting these two together you are wasting some data.
I do understand that the blocks also carry positional information but I still think there is information overlap which means it is not as efficient as possible.
Any explanations?