Reading YUV images in C

How to read any yuv image?

How can the dimensions of an 开发者_开发问答YUV image be passed for reading to a buffer?

Usually, when people talk about YUV they talk about YUV 4:2:0. Your reference to any YUV image is misleading, because there are a number of different formats, and each is handled differently. For example, raw YUV 4:2:0 (by convention, files with an extension .yuv) doesn't contain any dimension data; whereas y4m files typically do. So you really need to know what sort of image you're dealing with before you start reading it. For YUV 4:2:0, you just open the file and read the luminance (Y') and chrominance (CbCr) components in that order, keeping in mind the chrominance components have been decimated (quarter size of the luminance components). After that you typically convert Y'CbCr to RGB so you can display the image.

From what I've mentioned above, you simply can't determine the dimensions of any YUV image. Often, the dimensions are simply not in the file. You have to know them up front -- this is why most sites listing YUV files for download also list their frame dimensions (and for video, the number of frames). Most YUV files are either CIF (352x288) or QCIF (176x144), although there are some files digitized from analog video that are in the slightly different SIF format. Read about the different formats here.