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Questions tagged [jpeg]

JPEG is a commonly used method of lossy compression for digital photography (image).

The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality.

JPEG compression is used in a number of image file formats. JPEG/Exif is the most common image format used by digital cameras and other photographic image capture devices; along with JPEG/JFIF, it is the most common format for storing and transmitting photographic images on the World Wide Web.[citation needed] These format variations are often not distinguished, and are simply called JPEG.

The term "JPEG" is an acronym for the Joint Photographic Experts Group which created the standard. The MIME media type for JPEG is image/jpeg (defined in RFC 1341), except in Internet Explorer, which provides a MIME type of image/pjpeg when uploading JPEG images.

More information at Wikipedia page of JPEG

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Cannot decode jpeg using JpegBitmapDecoder

I have the following two functions to convert bytes to image and display on Image in WPF private JpegBitmapDecoder ConvertBytestoImageStream(byte[] imageData) { Stream imageStreamSource = new MemoryStream(imageData); …
xaria
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Histogram using Chart2D

I want to draw coefficient histogram of JPEG. I'm searching on Google for hours to know how to use Chart2D library, but there is no tutorial with examples. The array which I want to draw is hist[]. I created an object of LBChart2D, but I don't know…
muhannad
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drawing histogram

I want to draw a JPEG coefficient histogram //coeff[] is the coefficients array int hist[]=new int[25]; for(int i=0;i
muhannad
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EXIF fraction calculation

I am modifying jpeg EXIF data. Some data requires to be defined as a fractions. Here, I have two problems: 1.) Which is the correct fraction "format"? For instance when I have an exposure time ("ExposureTime") of 30000µs and store it as…
Hyndrix
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Decoding a jpg in the background in WP7

I have a bunch of apps in the marketplace, and so far I have been able, by changing my functionality or going the extra mile, to work around the issue of being unable to decode a jpg in the background into a WriteableBitmap. I am finding a situation…
Shahar Prish
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Using jpegoptim with PIL in easy-thumbnails

I'd like to process all JPEG thumbnails generated with easy-thumbnail via PIL thru jpegoptim. Using PIL's optimization: image.save(..,optimize=1,...) isn't optimizing much at all. For example: with PIL: 123KB with PIL + optimize: 112KB with PIL +…
Steve McKinney
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Resize PNG and convert to JPG image in PHP

This is the code i just wrote. It takes an image crops it and then creates a jpg image. If i give it a jpg file it works fine but does not works for png (transparent) images. It just makes a blank image with black background. I'm using the GD…
Ameer
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Converting PDF Byte Array to jpg image(JAVA Project)

We are trying to convert PDF Byte Array to image(jpg format) in a JAVA project. We initially used PDFBox library but we are facing issues with the output. The generated PDF documents generated by PDFBox are ok but sometimes the images generated are…
Rishabh Ohri
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JPEG estimating file size

I'm writing an application that needs to compress and scale an image before sending it as an mms which has a maximum file size of 600kb. I'm looking for an algorithm that will help estimate the maximum surface area of a jpeg with a file size < 600kb…
alex.m.brown
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Can I read a part of jpeg image (rectangle) decompressing it up to DCT parameters?

I need to use some part of a jpeg image (a rectangle in the center) decompressing it up to DCT coeficients. Is this possible with libjpeg , or some other open source tool ?
Dimitar Slavchev
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How to define photo from camera is rotated

Is there any standard meta-data field in JPEG or other formats that defines photo is made rotated +-90° (i mean camera was rotated). Some graphic viewers displays this photos correctly. So, i guess they read some image format headers.
radistao
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How do I parse every html file in a directory for images?

I have a directory full of html files, each of which has a clinical image of a psoriasis patient in it. I want to open each file, find the image, and save it in the same directory. import os, os.path import Image from BeautifulSoup import…
Wandering Sophist
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Uploaded ZIP archive. Convert only PNG to JPEG in PHP

For the life of me, I cant figure out how to code part of this process: Ive Already Completed These Steps: 1. Upload ZIP archive (containing only photos in gif, png, and jpg) 2. Unpack to folder 3. Scan folder for filenames + file extentions I…
blbaker
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Java PNG to JPG Bug

I am trying to convert a PNG image to a JPEG image following this tutorial. But I encounter a problem. The resulting image has a pink layer. Does anyone have a solution for this problem? Or what code should I use in order to convert the image into…
Ionut Ungureanu
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JPEG Image from Serial Camera not loading with C# BitmapImage

I am writing a program which grabs JPEG images from a camera which is connected via Serial Port. I want to programmatically define an image in WPF, in order to display it once it is retreived, using the Source attribute of Image. I have found that…
Luke
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