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Questions tagged [jpeg]

JPEG is a common lossy compression method for digital images. Use this tag for questions about JPEG images using the image/jpeg MIME type.

JPEG is a common lossy compression method for digital images. Use this tag for questions about JPEG images using the image/jpeg MIME type.

See also , , and for other image file formats with JPEG in the name.

More information at the JPEG Wikipedia page.

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Interpreting JPEG Chroma Subsampling read from file

I am trying to find out of which MCU (8x8, 16x8 and 16x16) a pictures is made of. To do this I parse the Start of Frame (SOFn) Marker where the chroma subsampling factors are stored. I have found the following content: Number of Img components =…
ap0
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Canvas.toBlob() saving as PNG even though I specified JPG

I'm saving my canvas using this function: c.toBlob(function(blob) { saveAs(blob, '@Model.DatabaseName' + '.jpg'); }, 'image/jpg'); The extension is .jpg, and I specified the filetype as .jpg. When I view the file in windows explorer, it says…
Erica Stockwell-Alpert
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Converting Flash frame to JPEG

We are attempting to convert a flash frame into a JPEG without using the Flex SDK or other adobe tools. Right now, we have a flash file that passes binary data over to a .cfm page, which uses the following code to change the headers:
dhorn
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Compressing three individual jpeg pics containing temporal redundancy?

I am interfacing an embedded device with a camera module that returns a single jpeg compressed frame each time I trigger it. I would like to take three successive shots (approx 1 frame per 1/4 second) and further compress the images into a single…
michael
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Am I correctly extracting JPEG binary data from this mysqldump?

I have a very old .sql backup of a vbulletin site that I ran around 8 years ago. I am trying to see the file attachments that are stored in the DB. The script below extracts them all and is verified to be JPEG by hex dumping and checking the SOI…
Glenn
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Command line tool to resize image files to max size and change casing

Suppose you have a folder with a lot of images. Filesizes and extensions differ per image and you want to be consistent in the same format. Is there a way to: Make filename uppercase and extension lowercase (if not already): EXAMPLE.jpg Convert…
J3FFK
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Is libjpeg always installed with Android?

Im writing my entire Android project in NDK C/C++, and I now want to open some jpg files. Ive read a lot people suggesting compiling libjpeg or libjpeg-turbo for use with NDK, but others suggesting libjpeg is already in with android is this…
RJButler
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Imagemagick PDF tp JPG bad quality PHP

I have a big pdf file that about >100mb. I want to save that pdf page by page converting to jpg. My php script works well but image quality sucks even quailty set to 100. Jpg output max width set to 1024. Each file size about 2.5mb. I have searched…
Canser Yanbakan
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Does Exif metadata always get stored just after the JFIF header?

In JPEG files, Does the exif metadata always gets stored as the first marker? Or can it be in between other markers? The following has a comment that "After the APP1 Marker area, the other JPEG Markers…
Nitesh Chordiya
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How to make gif images from a set of images in matlab?

How to make '.gif' image from a set of '.jpg' images (say: I1.jpg, I2.jpg,..., I10.jpg) in matlab?
user2771151
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Why are these patterns in Huffman coding bitstreams in (Photoshop-produced?) JPG files?

This is a question, out of curiosity, about some patterns I see in JPG files when I look at them in a hex editor. I guess it is a question about the JPEG file format; why not this part is "random noise" like the rest, when it is supposed to be…
HackeyStack
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Google pagespeed isn't acceping my image as optimized

I'm trying to make my images optimized for google pagespeed test. I have an image with 1200x393 dimensions. When I optimize the image with Photoshop, its size is approximately 250kb and with Corel it becomes 100kb. Google doesn't accept either. It…
nikel
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Error Image::Compare (jpg files)

I'm trying to use Image::Compare in perl to compare two images based on the colors used in the images. Here is the code i'm using: #!/usr/bin/perl use strict; use warnings; use Image::Compare; my ($cmp) = Image::Compare->new(); $cmp->set_image1( …
user2676847
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How can I access the JPEG image pixels as a 3D array like we do in MATLAB?

I want to process an image in C++. How can I access the 3D array representing the JPEG image as is done in MATLAB?
Alan_AI
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Scanner API for iOS

I'm looking for a scanner API library to be embedded in a new app I'm developing in order to give it the feature of scanning documents (in PDF or other formats) using the built-in camera of the iPhone/iPad. Is anybody aware of such a library…
Sergiob
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