lossy-compression

JPEG is a lossy compression scheme, so decompression-manipulation-recompression normally reduces the image quality further for each step. Is it possible to rotate a JPEG image without incurring further loss? From what little I know of the JPEG algorithm, it naively seems possible to avoid further loss with a bit of effort. Which common image manipulation programs (e.g. GIMP, Paint Shop Pro, Windows Photo Gallery) and graphic libraries cause quality loss when performing a rotation and which don't? Boojum Yes, it is possible for certain cases: 90-degree rotations and flips on images. The heart

The JPEG compression encoding process splits a given image into blocks of 8x8 pixels, working with these blocks in future lossy and lossless compressions. [source] It is also mentioned that if the image is a multiple 1MCU block (defined as a Minimum Coded Unit, 'usually 16 pixels in both directions') that lossless alterations to a JPEG can be performed. [source] I am working with product images and would like to know both if, and how much benefit can be derived from using multiples of 16 in my final image size (say, using an image with size 480px by 360px) vs. a non-multiple of 16 (such as

This question might be very basic Is there a way to reduce the frame size/rate of Lossy compressed (WMV, MPEG) format, to get a smaller video, of lesser size, with same format. Are there any open source or proprietary apis for this? Jason B ffmpeg provides this functionality. All you need to do is run someting like ffmpeg -i <inputfilename> -s 640x480 -b 512k -vcodec mpeg1video -acodec copy <outputfilename> For newer versions of ffmpeg you need to change -b to -b:v : ffmpeg -i <inputfilename> -s 640x480 -b:v 512k -vcodec mpeg1video -acodec copy <outputfilename> to convert the input video file

On Android, how do I save an image file as a JPEG at 30% quality? In standard Java, I would use ImageIO to read the image as a BufferedImage , then save it as a JPEG file using an IIOImage instance: http://www.universalwebservices.net/web-programming-resources/java/adjust-jpeg-image-compression-quality-when-saving-images-in-java . It appears, however, that Android lacks the javax.imageio package. Phyrum Tea You can store your bitmap in the JPEG format by calling compress and setting the second parameter: Bitmap bm2 = createBitmap(); OutputStream stream = new FileOutputStream("/sdcard/test.jpg"