YUV pixel formats

9/21/2010 7:46:59 PM

http://www.fourcc.org/yuv.php（摘自此页面）

YUV formats fall into two distinct groups, the packed formats where Y, U (Cb) and V (Cr) samples are packed together into macropixels which are stored in a single array, and the planar formats where each component is stored as a separate array, the final image being a fusing of the three separate planes. （分为两种形式packed formats 和planar formats，packed formats 降YUV都压缩进一个数组，而planar formats将YUV分别压缩为一个数组，即Y数组、U数组、V数组分别存放）。

In the diagrams below, the numerical suffix attached to each Y, U or V sample indicates the sampling position across the image line, so, for example, V0 indicates the leftmost V sample and Yn indicates the Y sample at the (n+1)th pixel from the left.

Subsampling intervals in the horizontal and vertical directions may merit some explanation. The horizontal subsampling interval describes how frequently across a line a sample of that component is taken while the vertical interval describes on which lines samples are taken. For example, UYVY format has a horizontal subsampling period of 2 for both the U and V components indicating that U and V samples are taken for every second pixel across a line.(UYVY 意思是针对一个像素取一个U和Y，然后下一个像素取一个V和Y，这样相对于整个行就是Y是每个像素都取值，而U和V都是隔一个像素取一次) Their vertical subsampling period is 1 indicating that U and V samples are taken on each line of the image. （UYVY 则每一行都是按这个规则，也就是每行都是按上面的规则取。）

For YVU9, though, the vertical subsampling interval is 4. This indicates that U and V samples are only taken on every fourth line of the original image. Since the horizontal sampling period is also 4, a single U and a single V sample are taken for each square block of 16 image pixels.

Also, if you are interested in YCrCb to RGB conversion, you may find this page helpful.

People reading this page may be interested in a freeware codec（codec 的意思是compress and decompress)from Drastic Technologies which allegedly handles the vast majority of YUV formats listed here. I've not tried it but you can find it here.

Packed YUV Formats

Label	FOURCC in Hex	Bits per pixel	Description
AYUV	0x56555941	32	Combined YUV and alpha
CLJR	0x524A4C43	8	Cirrus Logic format with 4 pixels packed into a u_int32. A form of YUV 4:1:1 wiht less than 8 bits per Y, U and V sample.
cyuv	0x76757963	16	Essentially a copy of UYVY except that the sense of the height is reversed - the image is upside down with respect to the UYVY version.
GREY	0x59455247	8	Apparently a duplicate of Y800 (and also, presumably, "Y8 ")
IRAW	0x57615349	?	Intel uncompressed YUV. I have no information on this format - can you help?
IUYV	0x56595549	16	Interlaced version of UYVY (line order 0, 2, 4,....,1, 3, 5....) registered by Silviu Brinzei of LEAD Technologies.
IY41	0x31345949	12	Interlaced version of Y41P (line order 0, 2, 4,....,1, 3, 5....) registered by Silviu Brinzei of LEAD Technologies.
IYU1	0x31555949	12	12 bit format used in mode 2 of the IEEE 1394 Digital Camera 1.04 spec. This is equivalent to Y411
IYU2	0x32555949	24	24 bit format used in mode 0 of the IEEE 1394 Digital Camera 1.04 spec
HDYC	0x43594448	16	YUV 4:2:2 (Y sample at every pixel, U and V sampled at every second pixel horizontally on each line). A macropixel contains 2 pixels in 1 u_int32. This is a suplicate of UYVY except that the color components use the BT709 color space (as used in HD video).
UYNV	0x564E5955	16	A direct copy of UYVY registered by NVidia to work around problems in some old codecs which did not like hardware which offered more than 2 UYVY surfaces.
UYVP	0x50565955	24?	YCbCr 4:2:2 extended precision 10-bits per component in U0Y0V0Y1 order. Registered by Rich Ehlers of Evans & Sutherland. (Awaiting confirmation of component packing structure)
UYVY	0x59565955	16	YUV 4:2:2 (Y sample at every pixel, U and V sampled at every second pixel horizontally on each line). A macropixel （JUN:像素宏单元可以认为是一个最小的非重复的单元）contains 2 pixels in 1 u_int32.
V210	0x30313256	32	10-bit 4:2:2 YCrCb equivalent to the Quicktime format of the same name.
V422	0x32323456	16	I am told that this is an upside down version of UYVY.
V655	0x35353656	16?	16 bit YUV 4:2:2 （JUN:16-bit 是指一个packed像素占用的位数，而4：2：2指的是下采样比例）format registered by Vitec Multimedia. I have no information on the component ordering or packing.
VYUY	0x59555956	?	ATI Packed YUV Data (format unknown but you can get hold of a codec supporting it here)
Y422	0x32323459	16	Direct copy of UYVY as used by ADS Technologies Pyro WebCam firewire camera.
YUY2	0x32595559	16	YUV 4:2:2 as for UYVY but with different component ordering within the u_int32 macropixel.
YUYV	0x56595559	16	Duplicate of YUY2
YUNV	0x564E5559	16	A direct copy of YUY2 registered by NVidia to work around problems in some old codecs which did not like hardware which offered more than 2 YUY2 surfaces.
YVYU	0x55595659	16	YUV 4:2:2 as for UYVY but with different component ordering within the u_int32 macropixel.
Y41P	0x50313459	12	YUV 4:1:1 (Y sample at every pixel, U and V sampled at every fourth pixel horizontally on each line). A macropixel contains 8 pixels in 3 u_int32s.
Y411	0x31313459	12	YUV 4:1:1 with a packed, 6 byte/4 pixel macroblock structure.
Y211	0x31313259	8	Packed YUV format with Y sampled at every second pixel across each line and U and V sampled at every fourth pixel.
Y41T	0x54313459	12	Format as for Y41P but the lsb of each Y component is used to signal pixel transparency .
Y42T	0x54323459	16	Format as for UYVY but the lsb of each Y component is used to signal pixel transparency .
YUVP	0x50565559	24?	YCbCr 4:2:2 extended precision 10-bits per component in Y0U0Y1V0 order. Registered by Rich Ehlers of Evans & Sutherland.
Y800	0x30303859	8	Simple, single Y plane for monochrome images.
Y8	0x20203859	8	Duplicate of Y800 as far as I can see.
Y16	0x20363159	16	16-bit uncompressed greyscale image.

Planar YUV Formats

Label	FOURCC in Hex	Bits per pixel	Description
YVU9	0x39555659	9	8 bit Y plane followed by 8 bit 4x4 subsampled V and U planes. Registered by Intel.
YUV9	0x39565559	9?	Registered by Intel., this is the format used internally by Indeo video code
IF09	0x39304649	9.5	As YVU9 but an additional 4x4 subsampled plane is appended containing delta information relative to the last frame. (Bpp is reported as 9)
YV16	0x36315659	16	8 bit Y plane followed by 8 bit 2x1 subsampled V and U planes.
YV12	0x32315659	12	8 bit Y plane followed by 8 bit 2x2 subsampled V and U planes.
I420	0x30323449	12	8 bit Y plane followed by 8 bit 2x2 subsampled U and V planes.
IYUV	0x56555949	12	Duplicate FOURCC, identical to I420.
NV12	0x3231564E	12	8-bit Y plane followed by an interleaved U/V plane with 2x2 subsampling
NV21	0x3132564E	12	As NV12 with U and V reversed in the interleaved plane
IMC1	0x31434D49	12	As YV12 except the U and V planes each have the same stride as the Y plane
IMC2	0x32434D49	12	Similar to IMC1 except that the U and V lines are interleaved at half stride boundaries
IMC3	0x33434D49	12	As IMC1 except that U and V are swapped
IMC4	0x34434D49	12	As IMC2 except that U and V are swapped
CLPL	0x4C504C43	12	Format similar to YV12 but including a level of indirection.
Y41B	0x42313459	12?	Weitek format listed as "YUV 4:1:1 planar". I have no other information on this format.
Y42B	0x42323459	16?	Weitek format listed as "YUV 4:2:2 planar". I have no other information on this format.
Y800	0x30303859	8	Simple, single Y plane for monochrome images.
Y8	0x20203859	8	Duplicate of Y800 as far as I can see.
CXY1	0x31595843	12	Awaiting clarification of format.
CXY2	0x32595842	16	Awaiting clarification of format.

IF09

A derivative of YVU9, IF09 contains the basic 3 planes for Y, V and U followed by an additional (N/4)x(N/4) plane of "skip blocks". This final plane forms a basic delta encoding scheme which can be used by a displayer to decide which pixels in the image are unchanged from the previous displayed frame. The strange number of bits per pixel listed for the format results from the fact that an NxN image is described using N²+3(N/4)² bytes.

This format is generated by Intel's Indeo codecs though users should beware - the original 32 bit Indeo 3.2 shipped with Windows 95 and the beta levels of Indeo 4.1 contain bugs which cause them to generate protection faults when using IF09. Fixed versions of these codecs are available from Intel.

	Horizontal	Vertical
Y Sample Period	1	1
V Sample Period	4	4
U Sample Period	4	4

Positive biHeight implies top-down image (top line first)

Delta plane definition

To be completed...

YV12

This is the format of choice for many software MPEG codecs. It comprises an NxM Y plane followed by (N/2)x(M/2) V and U planes.

	Horizontal	Vertical
Y Sample Period	1	1
V Sample Period	2	2
U Sample Period	2	2

Positive biHeight implies top-down image (top line first)

ATI says they have a download which contains this codec but I can't find it on their site. If you would like something similar for Quicktime, try here.

YV16

This format is basically a version of YV12 with higher chroma resolution. It comprises an NxM Y plane followed by (N/2)xM U and V planes.

	Horizontal	Vertical
Y Sample Period	1	1
V Sample Period	2	1
U Sample Period	2	1

IYUV and I420

These formats are identical to YV12 except that the U and V plane order is reversed. They comprise an NxN Y plane followed by (N/2)x(N/2) U and V planes. Full marks to Intel for registering the same format twice and full marks to Microsoft for not picking up on this and rejecting the second registration.

(Note:There is some confusion over these formats thanks to the definitions on Microsoft's site which tend to suggest that the two FOURCCs are different. One is described as a 4:2:0 format while the other is described as 4:1:1. Later, however, the same page states that YV12 is the same as both of these with the U and V plane order reversed. I would consider 4:2:0 to imply 1 chroma sample for every 2x2 luma block and 4:1:1 to imply 1 chroma sample for every 4x1 luma block but it seems as if the Microsoft writer may have been using the terms interchangeably. If you know these formats, please could you let me know whether the definition here is correct or whether Ineed to update one or other?)

	Horizontal	Vertical
Y Sample Period	1	1
V Sample Period	2	2
U Sample Period	2	2

Positive biHeight implies top-down image (top line first)

Y16

This format contains only a single, 16 bit Y plane for monochrome images. Each pixel is represented by a 16 bit, little endian luminance sample.

	Horizontal	Vertical
Y Sample Period	1	1
V Sample Period	N/A	N/A
U Sample Period	N/A	N/A

NV12

YUV 4:2:0 image with a plane of 8 bit Y samples followed by an interleaved U/V plane containing 8 bit 2x2 subsampled colour difference samples.

	Horizontal	Vertical
Y Sample Period	1	1
V (Cr) Sample Period	2	2
U (Cb) Sample Period	2	2

Microsoft defines this format as follows:

"A format in which all Y samples are found first in memory as an array of unsigned char with an even number of lines (possibly with a larger stride for memory alignment), followed immediately by an array of unsigned char containing interleaved Cb and Cr samples (such that if addressed as a little-endian WORD type, Cb would be in the LSBs and Cr would be in the MSBs) with the same total stride as the Y samples. This is the preferred 4:2:0 pixel format."