1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2
3.. _packed-yuv:
4
5******************
6Packed YUV formats
7******************
8
9Similarly to the packed RGB formats, the packed YUV formats store the Y, Cb and
10Cr components consecutively in memory. They may apply subsampling to the chroma
11components and thus differ in how they interlave the three components.
12
13.. note::
14
15   - In all the tables that follow, bit 7 is the most significant bit in a byte.
16   - 'Y', 'Cb' and 'Cr' denote bits of the luma, blue chroma (also known as
17     'U') and red chroma (also known as 'V') components respectively. 'A'
18     denotes bits of the alpha component (if supported by the format), and 'X'
19     denotes padding bits.
20
21
224:4:4 Subsampling
23=================
24
25These formats do not subsample the chroma components and store each pixels as a
26full triplet of Y, Cb and Cr values.
27
28The next table lists the packed YUV 4:4:4 formats with less than 8 bits per
29component. They are named based on the order of the Y, Cb and Cr components as
30seen in a 16-bit word, which is then stored in memory in little endian byte
31order, and on the number of bits for each component. For instance the YUV565
32format stores a pixel in a 16-bit word [15:0] laid out at as [Y'\ :sub:`4-0`
33Cb\ :sub:`5-0` Cr\ :sub:`4-0`], and stored in memory in two bytes,
34[Cb\ :sub:`2-0` Cr\ :sub:`4-0`] followed by [Y'\ :sub:`4-0` Cb\ :sub:`5-3`].
35
36.. raw:: latex
37
38    \begingroup
39    \scriptsize
40    \setlength{\tabcolsep}{2pt}
41
42.. tabularcolumns:: |p{3.5cm}|p{0.96cm}|p{0.52cm}|p{0.52cm}|p{0.52cm}|p{0.52cm}|p{0.52cm}|p{0.52cm}|p{0.52cm}|p{0.52cm}|p{0.52cm}|p{0.52cm}|p{0.52cm}|p{0.52cm}|p{0.52cm}|p{0.52cm}|p{0.52cm}|p{0.52cm}|
43
44.. flat-table:: Packed YUV 4:4:4 Image Formats (less than 8bpc)
45    :header-rows:  2
46    :stub-columns: 0
47
48    * - Identifier
49      - Code
50
51      - :cspan:`7` Byte 0 in memory
52
53      - :cspan:`7` Byte 1
54
55    * -
56      -
57      - 7
58      - 6
59      - 5
60      - 4
61      - 3
62      - 2
63      - 1
64      - 0
65
66      - 7
67      - 6
68      - 5
69      - 4
70      - 3
71      - 2
72      - 1
73      - 0
74
75    * .. _V4L2-PIX-FMT-YUV444:
76
77      - ``V4L2_PIX_FMT_YUV444``
78      - 'Y444'
79
80      - Cb\ :sub:`3`
81      - Cb\ :sub:`2`
82      - Cb\ :sub:`1`
83      - Cb\ :sub:`0`
84      - Cr\ :sub:`3`
85      - Cr\ :sub:`2`
86      - Cr\ :sub:`1`
87      - Cr\ :sub:`0`
88
89      - a\ :sub:`3`
90      - a\ :sub:`2`
91      - a\ :sub:`1`
92      - a\ :sub:`0`
93      - Y'\ :sub:`3`
94      - Y'\ :sub:`2`
95      - Y'\ :sub:`1`
96      - Y'\ :sub:`0`
97
98    * .. _V4L2-PIX-FMT-YUV555:
99
100      - ``V4L2_PIX_FMT_YUV555``
101      - 'YUVO'
102
103      - Cb\ :sub:`2`
104      - Cb\ :sub:`1`
105      - Cb\ :sub:`0`
106      - Cr\ :sub:`4`
107      - Cr\ :sub:`3`
108      - Cr\ :sub:`2`
109      - Cr\ :sub:`1`
110      - Cr\ :sub:`0`
111
112      - a
113      - Y'\ :sub:`4`
114      - Y'\ :sub:`3`
115      - Y'\ :sub:`2`
116      - Y'\ :sub:`1`
117      - Y'\ :sub:`0`
118      - Cb\ :sub:`4`
119      - Cb\ :sub:`3`
120
121    * .. _V4L2-PIX-FMT-YUV565:
122
123      - ``V4L2_PIX_FMT_YUV565``
124      - 'YUVP'
125
126      - Cb\ :sub:`2`
127      - Cb\ :sub:`1`
128      - Cb\ :sub:`0`
129      - Cr\ :sub:`4`
130      - Cr\ :sub:`3`
131      - Cr\ :sub:`2`
132      - Cr\ :sub:`1`
133      - Cr\ :sub:`0`
134
135      - Y'\ :sub:`4`
136      - Y'\ :sub:`3`
137      - Y'\ :sub:`2`
138      - Y'\ :sub:`1`
139      - Y'\ :sub:`0`
140      - Cb\ :sub:`5`
141      - Cb\ :sub:`4`
142      - Cb\ :sub:`3`
143
144.. raw:: latex
145
146    \endgroup
147
148.. note::
149
150    For the YUV444 and YUV555 formats, the value of alpha bits is undefined
151    when reading from the driver, ignored when writing to the driver, except
152    when alpha blending has been negotiated for a :ref:`Video Overlay
153    <overlay>` or :ref:`Video Output Overlay <osd>`.
154
155
156The next table lists the packed YUV 4:4:4 formats with 8 bits per component.
157They are named based on the order of the Y, Cb and Cr components as stored in
158memory, and on the total number of bits per pixel. For instance, the VUYX32
159format stores a pixel with Cr\ :sub:`7-0` in the first byte, Cb\ :sub:`7-0` in
160the second byte and Y'\ :sub:`7-0` in the third byte.
161
162.. flat-table:: Packed YUV Image Formats (8bpc)
163    :header-rows: 1
164    :stub-columns: 0
165
166    * - Identifier
167      - Code
168      - Byte 0
169      - Byte 1
170      - Byte 2
171      - Byte 3
172
173    * .. _V4L2-PIX-FMT-YUV32:
174
175      - ``V4L2_PIX_FMT_YUV32``
176      - 'YUV4'
177
178      - A\ :sub:`7-0`
179      - Y'\ :sub:`7-0`
180      - Cb\ :sub:`7-0`
181      - Cr\ :sub:`7-0`
182
183    * .. _V4L2-PIX-FMT-AYUV32:
184
185      - ``V4L2_PIX_FMT_AYUV32``
186      - 'AYUV'
187
188      - A\ :sub:`7-0`
189      - Y'\ :sub:`7-0`
190      - Cb\ :sub:`7-0`
191      - Cr\ :sub:`7-0`
192
193    * .. _V4L2-PIX-FMT-XYUV32:
194
195      - ``V4L2_PIX_FMT_XYUV32``
196      - 'XYUV'
197
198      - X\ :sub:`7-0`
199      - Y'\ :sub:`7-0`
200      - Cb\ :sub:`7-0`
201      - Cr\ :sub:`7-0`
202
203    * .. _V4L2-PIX-FMT-VUYA32:
204
205      - ``V4L2_PIX_FMT_VUYA32``
206      - 'VUYA'
207
208      - Cr\ :sub:`7-0`
209      - Cb\ :sub:`7-0`
210      - Y'\ :sub:`7-0`
211      - A\ :sub:`7-0`
212
213    * .. _V4L2-PIX-FMT-VUYX32:
214
215      - ``V4L2_PIX_FMT_VUYX32``
216      - 'VUYX'
217
218      - Cr\ :sub:`7-0`
219      - Cb\ :sub:`7-0`
220      - Y'\ :sub:`7-0`
221      - X\ :sub:`7-0`
222
223.. note::
224
225    - The alpha component is expected to contain a meaningful value that can be
226      used by drivers and applications.
227    - The padding bits contain undefined values that must be ignored by all
228      applications and drivers.
229
230
2314:2:2 Subsampling
232=================
233
234These formats, commonly referred to as YUYV or YUY2, subsample the chroma
235components horizontally by 2, storing 2 pixels in 4 bytes.
236
237.. raw:: latex
238
239    \footnotesize
240
241.. tabularcolumns:: |p{3.4cm}|p{1.2cm}|p{0.8cm}|p{0.8cm}|p{0.8cm}|p{0.8cm}|p{0.8cm}|p{0.8cm}|p{0.8cm}|p{0.8cm}|
242
243.. flat-table:: Packed YUV 4:2:2 Formats
244    :header-rows: 1
245    :stub-columns: 0
246
247    * - Identifier
248      - Code
249      - Byte 0
250      - Byte 1
251      - Byte 2
252      - Byte 3
253      - Byte 4
254      - Byte 5
255      - Byte 6
256      - Byte 7
257    * .. _V4L2-PIX-FMT-UYVY:
258
259      - ``V4L2_PIX_FMT_UYVY``
260      - 'UYVY'
261
262      - Cb\ :sub:`0`
263      - Y'\ :sub:`0`
264      - Cr\ :sub:`0`
265      - Y'\ :sub:`1`
266      - Cb\ :sub:`2`
267      - Y'\ :sub:`2`
268      - Cr\ :sub:`2`
269      - Y'\ :sub:`3`
270    * .. _V4L2-PIX-FMT-VYUY:
271
272      - ``V4L2_PIX_FMT_VYUY``
273      - 'VYUY'
274
275      - Cr\ :sub:`0`
276      - Y'\ :sub:`0`
277      - Cb\ :sub:`0`
278      - Y'\ :sub:`1`
279      - Cr\ :sub:`2`
280      - Y'\ :sub:`2`
281      - Cb\ :sub:`2`
282      - Y'\ :sub:`3`
283    * .. _V4L2-PIX-FMT-YUYV:
284
285      - ``V4L2_PIX_FMT_YUYV``
286      - 'YUYV'
287
288      - Y'\ :sub:`0`
289      - Cb\ :sub:`0`
290      - Y'\ :sub:`1`
291      - Cr\ :sub:`0`
292      - Y'\ :sub:`2`
293      - Cb\ :sub:`2`
294      - Y'\ :sub:`3`
295      - Cr\ :sub:`2`
296    * .. _V4L2-PIX-FMT-YVYU:
297
298      - ``V4L2_PIX_FMT_YVYU``
299      - 'YVYU'
300
301      - Y'\ :sub:`0`
302      - Cr\ :sub:`0`
303      - Y'\ :sub:`1`
304      - Cb\ :sub:`0`
305      - Y'\ :sub:`2`
306      - Cr\ :sub:`2`
307      - Y'\ :sub:`3`
308      - Cb\ :sub:`2`
309
310.. raw:: latex
311
312    \normalsize
313
314**Color Sample Location:**
315Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
316horizontally.
317
318
3194:1:1 Subsampling
320=================
321
322This format subsamples the chroma components horizontally by 4, storing 8
323pixels in 12 bytes.
324
325.. raw:: latex
326
327    \scriptsize
328
329.. tabularcolumns:: |p{2.9cm}|p{0.8cm}|p{0.5cm}|p{0.5cm}|p{0.5cm}|p{0.5cm}|p{0.5cm}|p{0.5cm}|p{0.5cm}|p{0.5cm}|p{0.5cm}|p{0.5cm}|p{0.5cm}|p{0.5cm}|
330
331.. flat-table:: Packed YUV 4:1:1 Formats
332    :header-rows: 1
333    :stub-columns: 0
334
335    * - Identifier
336      - Code
337      - Byte 0
338      - Byte 1
339      - Byte 2
340      - Byte 3
341      - Byte 4
342      - Byte 5
343      - Byte 6
344      - Byte 7
345      - Byte 8
346      - Byte 9
347      - Byte 10
348      - Byte 11
349    * .. _V4L2-PIX-FMT-Y41P:
350
351      - ``V4L2_PIX_FMT_Y41P``
352      - 'Y41P'
353
354      - Cb\ :sub:`0`
355      - Y'\ :sub:`0`
356      - Cr\ :sub:`0`
357      - Y'\ :sub:`1`
358      - Cb\ :sub:`4`
359      - Y'\ :sub:`2`
360      - Cr\ :sub:`4`
361      - Y'\ :sub:`3`
362      - Y'\ :sub:`4`
363      - Y'\ :sub:`5`
364      - Y'\ :sub:`6`
365      - Y'\ :sub:`7`
366
367.. raw:: latex
368
369    \normalsize
370
371.. note::
372
373    Do not confuse ``V4L2_PIX_FMT_Y41P`` with
374    :ref:`V4L2_PIX_FMT_YUV411P <V4L2-PIX-FMT-YUV411P>`. Y41P is derived from
375    "YUV 4:1:1 **packed**", while YUV411P stands for "YUV 4:1:1 **planar**".
376
377**Color Sample Location:**
378Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
379horizontally.
380