1# Introduction 2 3Formats (FOURCC) supported by libyuv are detailed here. 4 5# Core Formats 6 7There are 2 core formats supported by libyuv - I420 and ARGB. All YUV formats can be converted to/from I420. All RGB formats can be converted to/from ARGB. 8 9Filtering functions such as scaling and planar functions work on I420 and/or ARGB. 10 11# OSX Core Media Pixel Formats 12 13This is how OSX formats map to libyuv 14 15 enum { 16 kCMPixelFormat_32ARGB = 32, FOURCC_BGRA 17 kCMPixelFormat_32BGRA = 'BGRA', FOURCC_ARGB 18 kCMPixelFormat_24RGB = 24, FOURCC_RAW 19 kCMPixelFormat_16BE555 = 16, Not supported. 20 kCMPixelFormat_16BE565 = 'B565', Not supported. 21 kCMPixelFormat_16LE555 = 'L555', FOURCC_RGBO 22 kCMPixelFormat_16LE565 = 'L565', FOURCC_RGBP 23 kCMPixelFormat_16LE5551 = '5551', FOURCC_RGBO 24 kCMPixelFormat_422YpCbCr8 = '2vuy', FOURCC_UYVY 25 kCMPixelFormat_422YpCbCr8_yuvs = 'yuvs', FOURCC_YUY2 26 kCMPixelFormat_444YpCbCr8 = 'v308', FOURCC_I444 ? 27 kCMPixelFormat_4444YpCbCrA8 = 'v408', Not supported. 28 kCMPixelFormat_422YpCbCr16 = 'v216', Not supported. 29 kCMPixelFormat_422YpCbCr10 = 'v210', FOURCC_V210 previously. Removed now. 30 kCMPixelFormat_444YpCbCr10 = 'v410', Not supported. 31 kCMPixelFormat_8IndexedGray_WhiteIsZero = 0x00000028, Not supported. 32 }; 33 34 35# FOURCC (Four Charactacter Code) List 36 37The following is extracted from video_common.h as a complete list of formats supported by libyuv. 38 enum FourCC { 39 // 9 Primary YUV formats: 5 planar, 2 biplanar, 2 packed. 40 FOURCC_I420 = FOURCC('I', '4', '2', '0'), 41 FOURCC_I422 = FOURCC('I', '4', '2', '2'), 42 FOURCC_I444 = FOURCC('I', '4', '4', '4'), 43 FOURCC_I400 = FOURCC('I', '4', '0', '0'), 44 FOURCC_NV21 = FOURCC('N', 'V', '2', '1'), 45 FOURCC_NV12 = FOURCC('N', 'V', '1', '2'), 46 FOURCC_YUY2 = FOURCC('Y', 'U', 'Y', '2'), 47 FOURCC_UYVY = FOURCC('U', 'Y', 'V', 'Y'), 48 FOURCC_H010 = FOURCC('H', '0', '1', '0'), // unofficial fourcc. 10 bit lsb 49 50 // 1 Secondary YUV format: row biplanar. 51 FOURCC_M420 = FOURCC('M', '4', '2', '0'), 52 53 // 11 Primary RGB formats: 4 32 bpp, 2 24 bpp, 3 16 bpp, 1 10 bpc 54 FOURCC_ARGB = FOURCC('A', 'R', 'G', 'B'), 55 FOURCC_BGRA = FOURCC('B', 'G', 'R', 'A'), 56 FOURCC_ABGR = FOURCC('A', 'B', 'G', 'R'), 57 FOURCC_AR30 = FOURCC('A', 'R', '3', '0'), // 10 bit per channel. 2101010. 58 FOURCC_AB30 = FOURCC('A', 'B', '3', '0'), // ABGR version of 10 bit 59 FOURCC_24BG = FOURCC('2', '4', 'B', 'G'), 60 FOURCC_RAW = FOURCC('r', 'a', 'w', ' '), 61 FOURCC_RGBA = FOURCC('R', 'G', 'B', 'A'), 62 FOURCC_RGBP = FOURCC('R', 'G', 'B', 'P'), // rgb565 LE. 63 FOURCC_RGBO = FOURCC('R', 'G', 'B', 'O'), // argb1555 LE. 64 FOURCC_R444 = FOURCC('R', '4', '4', '4'), // argb4444 LE. 65 66 // 1 Primary Compressed YUV format. 67 FOURCC_MJPG = FOURCC('M', 'J', 'P', 'G'), 68 69 // 8 Auxiliary YUV variations: 3 with U and V planes are swapped, 1 Alias. 70 FOURCC_YV12 = FOURCC('Y', 'V', '1', '2'), 71 FOURCC_YV16 = FOURCC('Y', 'V', '1', '6'), 72 FOURCC_YV24 = FOURCC('Y', 'V', '2', '4'), 73 FOURCC_YU12 = FOURCC('Y', 'U', '1', '2'), // Linux version of I420. 74 FOURCC_J420 = FOURCC('J', '4', '2', '0'), 75 FOURCC_J400 = FOURCC('J', '4', '0', '0'), // unofficial fourcc 76 FOURCC_H420 = FOURCC('H', '4', '2', '0'), // unofficial fourcc 77 FOURCC_H422 = FOURCC('H', '4', '2', '2'), // unofficial fourcc 78 79 // 14 Auxiliary aliases. CanonicalFourCC() maps these to canonical fourcc. 80 FOURCC_IYUV = FOURCC('I', 'Y', 'U', 'V'), // Alias for I420. 81 FOURCC_YU16 = FOURCC('Y', 'U', '1', '6'), // Alias for I422. 82 FOURCC_YU24 = FOURCC('Y', 'U', '2', '4'), // Alias for I444. 83 FOURCC_YUYV = FOURCC('Y', 'U', 'Y', 'V'), // Alias for YUY2. 84 FOURCC_YUVS = FOURCC('y', 'u', 'v', 's'), // Alias for YUY2 on Mac. 85 FOURCC_HDYC = FOURCC('H', 'D', 'Y', 'C'), // Alias for UYVY. 86 FOURCC_2VUY = FOURCC('2', 'v', 'u', 'y'), // Alias for UYVY on Mac. 87 FOURCC_JPEG = FOURCC('J', 'P', 'E', 'G'), // Alias for MJPG. 88 FOURCC_DMB1 = FOURCC('d', 'm', 'b', '1'), // Alias for MJPG on Mac. 89 FOURCC_BA81 = FOURCC('B', 'A', '8', '1'), // Alias for BGGR. 90 FOURCC_RGB3 = FOURCC('R', 'G', 'B', '3'), // Alias for RAW. 91 FOURCC_BGR3 = FOURCC('B', 'G', 'R', '3'), // Alias for 24BG. 92 FOURCC_CM32 = FOURCC(0, 0, 0, 32), // Alias for BGRA kCMPixelFormat_32ARGB 93 FOURCC_CM24 = FOURCC(0, 0, 0, 24), // Alias for RAW kCMPixelFormat_24RGB 94 FOURCC_L555 = FOURCC('L', '5', '5', '5'), // Alias for RGBO. 95 FOURCC_L565 = FOURCC('L', '5', '6', '5'), // Alias for RGBP. 96 FOURCC_5551 = FOURCC('5', '5', '5', '1'), // Alias for RGBO. 97 98# Planar YUV 99 The following formats contains a full size Y plane followed by 1 or 2 100 planes for UV: I420, I422, I444, I400, NV21, NV12, I400 101 The size (subsampling) of the UV varies. 102 I420, NV12 and NV21 are half width, half height 103 I422, NV16 and NV61 are half width, full height 104 I444, NV24 and NV42 are full width, full height 105 I400 and J400 have no chroma channel. 106 107# The ARGB FOURCC 108 109There are 4 ARGB layouts - ARGB, BGRA, ABGR and RGBA. ARGB is most common by far, used for screen formats, and windows webcam drivers. 110 111The fourcc describes the order of channels in a ***register***. 112 113A fourcc provided by capturer, can be thought of string, e.g. "ARGB". 114 115On little endian machines, as an int, this would have 'A' in the lowest byte. The FOURCC macro reverses the order: 116 117 #define FOURCC(a, b, c, d) (((uint32)(a)) | ((uint32)(b) << 8) | ((uint32)(c) << 16) | ((uint32)(d) << 24)) 118 119So the "ARGB" string, read as an uint32, is 120 121 FOURCC_ARGB = FOURCC('A', 'R', 'G', 'B') 122 123If you were to read ARGB pixels as uint32's, the alpha would be in the high byte, and the blue in the lowest byte. In memory, these are stored little endian, so 'B' is first, then 'G', 'R' and 'A' last. 124 125When calling conversion functions, the names match the FOURCC, so in this case it would be I420ToARGB(). 126 127All formats can be converted to/from ARGB. 128 129Most 'planar_functions' work on ARGB (e.g. ARGBBlend). 130 131Some are channel order agnostic (e.g. ARGBScale). 132 133Some functions are symmetric (e.g. ARGBToBGRA is the same as BGRAToARGB, so its a macro). 134 135ARGBBlend expects preattenuated ARGB. The R,G,B are premultiplied by alpha. Other functions don't care. 136 137# RGB24 and RAW 138 139There are 2 RGB layouts - RGB24 (aka 24BG) and RAW 140 141RGB24 is B,G,R in memory 142RAW is R,G,B in memory 143 144# AR30 and XR30 145 146AR30 is 2 10 10 10 ARGB stored in little endian order. 147The 2 bit alpha has 4 values. Here are the comparable 8 bit alpha values. 1480 - 0. 00000000b = 0x00 = 0 1491 - 33%. 01010101b = 0x55 = 85 1502 - 66%. 10101010b = 0xaa = 170 1513 - 100%. 11111111b = 0xff = 255 152The 10 bit RGB values range from 0 to 1023. 153XR30 is the same as AR30 but with no alpha channel. 154 155# NV12 and NV21 156 157NV12 is a biplanar format with a full sized Y plane followed by a single 158chroma plane with weaved U and V values. 159NV21 is the same but with weaved V and U values. 160The 12 in NV12 refers to 12 bits per pixel. NV12 has a half width and half 161height chroma channel, and therefore is a 420 subsampling. 162NV16 is 16 bits per pixel, with half width and full height. aka 422. 163NV24 is 24 bits per pixel with full sized chroma channel. aka 444. 164