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    * .. _V4L2-PIX-FMT-YUVA32:
224
225      - ``V4L2_PIX_FMT_YUVA32``
226      - 'YUVA'
227
228      - Y'\ :sub:`7-0`
229      - Cb\ :sub:`7-0`
230      - Cr\ :sub:`7-0`
231      - A\ :sub:`7-0`
232
233    * .. _V4L2-PIX-FMT-YUVX32:
234
235      - ``V4L2_PIX_FMT_YUVX32``
236      - 'YUVX'
237
238      - Y'\ :sub:`7-0`
239      - Cb\ :sub:`7-0`
240      - Cr\ :sub:`7-0`
241      - X\ :sub:`7-0`
242
243    * .. _V4L2-PIX-FMT-YUV24:
244
245      - ``V4L2_PIX_FMT_YUV24``
246      - 'YUV3'
247
248      - Y'\ :sub:`7-0`
249      - Cb\ :sub:`7-0`
250      - Cr\ :sub:`7-0`
251      - -\
252
253.. note::
254
255    - The alpha component is expected to contain a meaningful value that can be
256      used by drivers and applications.
257    - The padding bits contain undefined values that must be ignored by all
258      applications and drivers.
259
260
2614:2:2 Subsampling
262=================
263
264These formats, commonly referred to as YUYV or YUY2, subsample the chroma
265components horizontally by 2, storing 2 pixels in 4 bytes.
266
267.. raw:: latex
268
269    \footnotesize
270
271.. 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}|
272
273.. flat-table:: Packed YUV 4:2:2 Formats
274    :header-rows: 1
275    :stub-columns: 0
276
277    * - Identifier
278      - Code
279      - Byte 0
280      - Byte 1
281      - Byte 2
282      - Byte 3
283      - Byte 4
284      - Byte 5
285      - Byte 6
286      - Byte 7
287    * .. _V4L2-PIX-FMT-UYVY:
288
289      - ``V4L2_PIX_FMT_UYVY``
290      - 'UYVY'
291
292      - Cb\ :sub:`0`
293      - Y'\ :sub:`0`
294      - Cr\ :sub:`0`
295      - Y'\ :sub:`1`
296      - Cb\ :sub:`2`
297      - Y'\ :sub:`2`
298      - Cr\ :sub:`2`
299      - Y'\ :sub:`3`
300    * .. _V4L2-PIX-FMT-VYUY:
301
302      - ``V4L2_PIX_FMT_VYUY``
303      - 'VYUY'
304
305      - Cr\ :sub:`0`
306      - Y'\ :sub:`0`
307      - Cb\ :sub:`0`
308      - Y'\ :sub:`1`
309      - Cr\ :sub:`2`
310      - Y'\ :sub:`2`
311      - Cb\ :sub:`2`
312      - Y'\ :sub:`3`
313    * .. _V4L2-PIX-FMT-YUYV:
314
315      - ``V4L2_PIX_FMT_YUYV``
316      - 'YUYV'
317
318      - Y'\ :sub:`0`
319      - Cb\ :sub:`0`
320      - Y'\ :sub:`1`
321      - Cr\ :sub:`0`
322      - Y'\ :sub:`2`
323      - Cb\ :sub:`2`
324      - Y'\ :sub:`3`
325      - Cr\ :sub:`2`
326    * .. _V4L2-PIX-FMT-YVYU:
327
328      - ``V4L2_PIX_FMT_YVYU``
329      - 'YVYU'
330
331      - Y'\ :sub:`0`
332      - Cr\ :sub:`0`
333      - Y'\ :sub:`1`
334      - Cb\ :sub:`0`
335      - Y'\ :sub:`2`
336      - Cr\ :sub:`2`
337      - Y'\ :sub:`3`
338      - Cb\ :sub:`2`
339
340.. raw:: latex
341
342    \normalsize
343
344**Color Sample Location:**
345Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
346horizontally.
347
348
3494:1:1 Subsampling
350=================
351
352This format subsamples the chroma components horizontally by 4, storing 8
353pixels in 12 bytes.
354
355.. raw:: latex
356
357    \scriptsize
358
359.. 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}|
360
361.. flat-table:: Packed YUV 4:1:1 Formats
362    :header-rows: 1
363    :stub-columns: 0
364
365    * - Identifier
366      - Code
367      - Byte 0
368      - Byte 1
369      - Byte 2
370      - Byte 3
371      - Byte 4
372      - Byte 5
373      - Byte 6
374      - Byte 7
375      - Byte 8
376      - Byte 9
377      - Byte 10
378      - Byte 11
379    * .. _V4L2-PIX-FMT-Y41P:
380
381      - ``V4L2_PIX_FMT_Y41P``
382      - 'Y41P'
383
384      - Cb\ :sub:`0`
385      - Y'\ :sub:`0`
386      - Cr\ :sub:`0`
387      - Y'\ :sub:`1`
388      - Cb\ :sub:`4`
389      - Y'\ :sub:`2`
390      - Cr\ :sub:`4`
391      - Y'\ :sub:`3`
392      - Y'\ :sub:`4`
393      - Y'\ :sub:`5`
394      - Y'\ :sub:`6`
395      - Y'\ :sub:`7`
396
397.. raw:: latex
398
399    \normalsize
400
401.. note::
402
403    Do not confuse ``V4L2_PIX_FMT_Y41P`` with
404    :ref:`V4L2_PIX_FMT_YUV411P <V4L2-PIX-FMT-YUV411P>`. Y41P is derived from
405    "YUV 4:1:1 **packed**", while YUV411P stands for "YUV 4:1:1 **planar**".
406
407**Color Sample Location:**
408Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
409horizontally.
410