1 .. SPDX-License-Identifier: GFDL-1.1-no-invari
2
3 .. _yuv-formats:
4
5 ***********
6 YUV Formats
7 ***********
8
9 YUV is the format native to TV broadcast and c
10 separates the brightness information (Y) from
11 and V or Cb and Cr). The color information con
12 *color difference* signals, this way the green
13 reconstructed by subtracting from the brightne
14 :ref:`colorspaces` for conversion examples. YU
15 early television would only transmit brightnes
16 color in a way compatible with existing receiv
17 was added to transmit the color difference sig
18
19
20 Subsampling
21 ===========
22
23 YUV formats commonly encode images with a lowe
24 components than for the luma component. This c
25 advantage of the human eye being more sensitiv
26 differences, is called chroma subsampling.
27
28 While many combinations of subsampling factors
29 direction are possible, common factors are 1 (
30 horizontal subsampling always larger than or e
31 Common combinations are named as follows.
32
33 - `4:4:4`: No subsampling
34 - `4:2:2`: Horizontal subsampling by 2, no ver
35 - `4:2:0`: Horizontal subsampling by 2, vertic
36 - `4:1:1`: Horizontal subsampling by 4, no ver
37 - `4:1:0`: Horizontal subsampling by 4, vertic
38
39 Subsampling the chroma component effectively c
40 located in different spatial locations:
41
42 - .. _yuv-chroma-centered:
43
44 The subsampled chroma value may be calculate
45 value of two consecutive pixels. It effectiv
46 sited between the two original pixels. This
47 interstitially sited chroma.
48
49 - .. _yuv-chroma-cosited:
50
51 The other option is to subsample chroma valu
52 the same spatial sites as the pixels. This m
53 other chroma sample (creating aliasing artif
54 odd number of taps. This is referred to as c
55
56 The following examples show different combinat
57 image.
58
59 .. flat-table:: 4:2:2 subsampling, interstitia
60 :header-rows: 1
61 :stub-columns: 1
62
63 * -
64 - 0
65 -
66 - 1
67 -
68 - 2
69 -
70 - 3
71 * - 0
72 - Y
73 - C
74 - Y
75 -
76 - Y
77 - C
78 - Y
79 * - 1
80 - Y
81 - C
82 - Y
83 -
84 - Y
85 - C
86 - Y
87 * - 2
88 - Y
89 - C
90 - Y
91 -
92 - Y
93 - C
94 - Y
95 * - 3
96 - Y
97 - C
98 - Y
99 -
100 - Y
101 - C
102 - Y
103
104 .. flat-table:: 4:2:2 subsampling, co-sited
105 :header-rows: 1
106 :stub-columns: 1
107
108 * -
109 - 0
110 -
111 - 1
112 -
113 - 2
114 -
115 - 3
116 * - 0
117 - Y/C
118 -
119 - Y
120 -
121 - Y/C
122 -
123 - Y
124 * - 1
125 - Y/C
126 -
127 - Y
128 -
129 - Y/C
130 -
131 - Y
132 * - 2
133 - Y/C
134 -
135 - Y
136 -
137 - Y/C
138 -
139 - Y
140 * - 3
141 - Y/C
142 -
143 - Y
144 -
145 - Y/C
146 -
147 - Y
148
149 .. flat-table:: 4:2:0 subsampling, horizontall
150 :header-rows: 1
151 :stub-columns: 1
152
153 * -
154 - 0
155 -
156 - 1
157 -
158 - 2
159 -
160 - 3
161 * - 0
162 - Y
163 - C
164 - Y
165 -
166 - Y
167 - C
168 - Y
169 * - 1
170 - Y
171 -
172 - Y
173 -
174 - Y
175 -
176 - Y
177 * - 2
178 - Y
179 - C
180 - Y
181 -
182 - Y
183 - C
184 - Y
185 * - 3
186 - Y
187 -
188 - Y
189 -
190 - Y
191 -
192 - Y
193
194 .. flat-table:: 4:1:0 subsampling, horizontall
195 :header-rows: 1
196 :stub-columns: 1
197
198 * -
199 - 0
200 -
201 - 1
202 -
203 - 2
204 -
205 - 3
206 * - 0
207 - Y
208 -
209 - Y
210 -
211 - Y
212 -
213 - Y
214 * -
215 -
216 -
217 -
218 -
219 -
220 -
221 -
222 * - 1
223 - Y
224 -
225 - Y
226 -
227 - Y
228 -
229 - Y
230 * -
231 -
232 -
233 -
234 - C
235 -
236 -
237 -
238 * - 2
239 - Y
240 -
241 - Y
242 -
243 - Y
244 -
245 - Y
246 * -
247 -
248 -
249 -
250 -
251 -
252 -
253 -
254 * - 3
255 - Y
256 -
257 - Y
258 -
259 - Y
260 -
261 - Y
262
263
264 .. toctree::
265 :maxdepth: 1
266
267 pixfmt-packed-yuv
268 pixfmt-yuv-planar
269 pixfmt-yuv-luma
270 pixfmt-y8i
271 pixfmt-y12i
272 pixfmt-uv8
273 pixfmt-m420
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