![Zazu baby swing](https://loka.nahovitsyn.com/175.jpg)
The RGB color primaries defined in JFIF via CCIR 601 also differ somewhat from what has become common practice in newer applications (e.g., they differ slightly from the color primaries defined in sRGB). Unlike the "studio range" defined in CCIR 601, in which black is represented by Y=16 and white by Y=235 and values outside of this range are available for signal processing "headroom" and "footroom", JFIF uses all 256 levels of the 8-bit representation, so that Y=0 for black and Y=255 for peak white. ITU-R BT.601), except with a different "full range" scaling of the Y, Cb and Cr components. JFIF defines the color model to be used: either Y for greyscale, or YCbCr derived from RGB color primaries as defined in CCIR 601 (now known as Rec. The JPEG standard used for the compression coding in JFIF files does not define which color encoding is to be used for images. Exif images recorded by digital cameras generally do not include this segment, but typically comply in all other respects with the JFIF standard.
![binary header for ipicture format binary header for ipicture format](https://venturebeat.com/wp-content/uploads/2017/12/uspresidentssiri.jpg)
It uses Application Segment #0, with a segment header consisting of the null-terminated string spelling "JFIF" in ASCII followed by a byte equal to 0, and specifies that this must be the first segment in the file, hence making it simple to recognize a JFIF file. JFIF provides resolution or aspect ratio information using an application segment extension to JPEG. The JPEG standard does not include any method of coding the resolution or aspect ratio of an image. The information which produces pixels, is rendered with the expectation of indicating rectangles by their centeroid, rather than being pixel data directly, or being 'first corner and flood', etc. JPEG allows multiple components (such as Y, Cb, and Cr) to have different resolutions, but it does not define how those differing sample arrays (which render bitmaps) should be aligned.
#Binary header for ipicture format registration
JFIF defines a number of details that are left unspecified by the JPEG Part 1 standard ( ISO/ IEC 10918-1, ITU-T Recommendation T.81.) Component sample registration
![Zazu baby swing](https://loka.nahovitsyn.com/175.jpg)