diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-10-10 22:04:49 -0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-10-10 22:04:49 -0400 |
commit | 4d9708ea5e5a45973df7cf965805fdfb185dd5bf (patch) | |
tree | 833a918e85f1e3bff8cb182517707d12836d10a8 /Documentation/video4linux | |
parent | 754c780953397dd5ee5191b7b3ca67e09088ce7a (diff) | |
parent | a66d05d504a24894a8fdf11e4569752f313e5764 (diff) |
Merge tag 'media/v3.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media updates from Mauro Carvalho Chehab:
- new IR driver: hix5hd2-ir
- the virtual test driver (vivi) was replaced by vivid, with has an
almost complete set of features to emulate most v4l2 devices and
properly test all sorts of userspace apps
- the as102 driver had several bugs fixed and was properly split into a
frontend and a core driver. With that, it got promoted from staging
into mainstream
- one new CI driver got added for CIMaX SP2/SP2HF (sp2 driver)
- one new frontend driver for Toshiba ISDB-T/ISDB-S demod (tc90522)
- one new PCI driver for ISDB-T/ISDB-S (pt3 driver)
- saa7134 driver got support for go7007-based devices
- added a new PCI driver for Techwell 68xx chipsets (tw68)
- a new platform driver was added (coda)
- new tuner drivers: mxl301rf and qm1d1c0042
- a new DVB USB driver was added for DVBSky S860 & similar devices
- added a new SDR driver (hackrf)
- usbtv got audio support
- several platform drivers are now compiled with COMPILE_TEST
- a series of compiler fixup patches, making sparse/spatch happier with
the media stuff and removing several warnings, especially on those
platform drivers that didn't use to compile on x86
- Support for several new modern devices got added
- lots of other fixes, improvements and cleanups
* tag 'media/v3.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (544 commits)
[media] ir-hix5hd2: fix build on c6x arch
[media] pt3: fix DTV FE I2C driver load error paths
Revert "[media] media: em28xx - remove reset_resume interface"
[media] exynos4-is: fix some warnings when compiling on arm64
[media] usb drivers: use %zu instead of %zd
[media] pci drivers: use %zu instead of %zd
[media] dvb-frontends: use %zu instead of %zd
[media] s5p-mfc: Fix several printk warnings
[media] s5p_mfc_opr: Fix warnings
[media] ti-vpe: Fix typecast
[media] s3c-camif: fix dma_addr_t printks
[media] s5p_mfc_opr_v6: get rid of warnings when compiled with 64 bits
[media] s5p_mfc_opr_v5: Fix lots of warnings on x86_64
[media] em28xx: Fix identation
[media] drxd: remove a dead code
[media] saa7146: remove return after BUG()
[media] cx88: remove return after BUG()
[media] cx88: fix cards table CodingStyle
[media] radio-sf16fmr2: declare some structs as static
[media] radio-sf16fmi: declare pnp_attached as static
...
Diffstat (limited to 'Documentation/video4linux')
-rw-r--r-- | Documentation/video4linux/vivid.txt | 1111 |
1 files changed, 1111 insertions, 0 deletions
diff --git a/Documentation/video4linux/vivid.txt b/Documentation/video4linux/vivid.txt new file mode 100644 index 000000000000..eeb11a28e4fc --- /dev/null +++ b/Documentation/video4linux/vivid.txt | |||
@@ -0,0 +1,1111 @@ | |||
1 | vivid: Virtual Video Test Driver | ||
2 | ================================ | ||
3 | |||
4 | This driver emulates video4linux hardware of various types: video capture, video | ||
5 | output, vbi capture and output, radio receivers and transmitters and a software | ||
6 | defined radio receiver. In addition a simple framebuffer device is available for | ||
7 | testing capture and output overlays. | ||
8 | |||
9 | Up to 64 vivid instances can be created, each with up to 16 inputs and 16 outputs. | ||
10 | |||
11 | Each input can be a webcam, TV capture device, S-Video capture device or an HDMI | ||
12 | capture device. Each output can be an S-Video output device or an HDMI output | ||
13 | device. | ||
14 | |||
15 | These inputs and outputs act exactly as a real hardware device would behave. This | ||
16 | allows you to use this driver as a test input for application development, since | ||
17 | you can test the various features without requiring special hardware. | ||
18 | |||
19 | This document describes the features implemented by this driver: | ||
20 | |||
21 | - Support for read()/write(), MMAP, USERPTR and DMABUF streaming I/O. | ||
22 | - A large list of test patterns and variations thereof | ||
23 | - Working brightness, contrast, saturation and hue controls | ||
24 | - Support for the alpha color component | ||
25 | - Full colorspace support, including limited/full RGB range | ||
26 | - All possible control types are present | ||
27 | - Support for various pixel aspect ratios and video aspect ratios | ||
28 | - Error injection to test what happens if errors occur | ||
29 | - Supports crop/compose/scale in any combination for both input and output | ||
30 | - Can emulate up to 4K resolutions | ||
31 | - All Field settings are supported for testing interlaced capturing | ||
32 | - Supports all standard YUV and RGB formats, including two multiplanar YUV formats | ||
33 | - Raw and Sliced VBI capture and output support | ||
34 | - Radio receiver and transmitter support, including RDS support | ||
35 | - Software defined radio (SDR) support | ||
36 | - Capture and output overlay support | ||
37 | |||
38 | These features will be described in more detail below. | ||
39 | |||
40 | |||
41 | Table of Contents | ||
42 | ----------------- | ||
43 | |||
44 | Section 1: Configuring the driver | ||
45 | Section 2: Video Capture | ||
46 | Section 2.1: Webcam Input | ||
47 | Section 2.2: TV and S-Video Inputs | ||
48 | Section 2.3: HDMI Input | ||
49 | Section 3: Video Output | ||
50 | Section 3.1: S-Video Output | ||
51 | Section 3.2: HDMI Output | ||
52 | Section 4: VBI Capture | ||
53 | Section 5: VBI Output | ||
54 | Section 6: Radio Receiver | ||
55 | Section 7: Radio Transmitter | ||
56 | Section 8: Software Defined Radio Receiver | ||
57 | Section 9: Controls | ||
58 | Section 9.1: User Controls - Test Controls | ||
59 | Section 9.2: User Controls - Video Capture | ||
60 | Section 9.3: User Controls - Audio | ||
61 | Section 9.4: Vivid Controls | ||
62 | Section 9.4.1: Test Pattern Controls | ||
63 | Section 9.4.2: Capture Feature Selection Controls | ||
64 | Section 9.4.3: Output Feature Selection Controls | ||
65 | Section 9.4.4: Error Injection Controls | ||
66 | Section 9.4.5: VBI Raw Capture Controls | ||
67 | Section 9.5: Digital Video Controls | ||
68 | Section 9.6: FM Radio Receiver Controls | ||
69 | Section 9.7: FM Radio Modulator | ||
70 | Section 10: Video, VBI and RDS Looping | ||
71 | Section 10.1: Video and Sliced VBI looping | ||
72 | Section 10.2: Radio & RDS Looping | ||
73 | Section 11: Cropping, Composing, Scaling | ||
74 | Section 12: Formats | ||
75 | Section 13: Capture Overlay | ||
76 | Section 14: Output Overlay | ||
77 | Section 15: Some Future Improvements | ||
78 | |||
79 | |||
80 | Section 1: Configuring the driver | ||
81 | --------------------------------- | ||
82 | |||
83 | By default the driver will create a single instance that has a video capture | ||
84 | device with webcam, TV, S-Video and HDMI inputs, a video output device with | ||
85 | S-Video and HDMI outputs, one vbi capture device, one vbi output device, one | ||
86 | radio receiver device, one radio transmitter device and one SDR device. | ||
87 | |||
88 | The number of instances, devices, video inputs and outputs and their types are | ||
89 | all configurable using the following module options: | ||
90 | |||
91 | n_devs: number of driver instances to create. By default set to 1. Up to 64 | ||
92 | instances can be created. | ||
93 | |||
94 | node_types: which devices should each driver instance create. An array of | ||
95 | hexadecimal values, one for each instance. The default is 0x1d3d. | ||
96 | Each value is a bitmask with the following meaning: | ||
97 | bit 0: Video Capture node | ||
98 | bit 2-3: VBI Capture node: 0 = none, 1 = raw vbi, 2 = sliced vbi, 3 = both | ||
99 | bit 4: Radio Receiver node | ||
100 | bit 5: Software Defined Radio Receiver node | ||
101 | bit 8: Video Output node | ||
102 | bit 10-11: VBI Output node: 0 = none, 1 = raw vbi, 2 = sliced vbi, 3 = both | ||
103 | bit 12: Radio Transmitter node | ||
104 | bit 16: Framebuffer for testing overlays | ||
105 | |||
106 | So to create four instances, the first two with just one video capture | ||
107 | device, the second two with just one video output device you would pass | ||
108 | these module options to vivid: | ||
109 | |||
110 | n_devs=4 node_types=0x1,0x1,0x100,0x100 | ||
111 | |||
112 | num_inputs: the number of inputs, one for each instance. By default 4 inputs | ||
113 | are created for each video capture device. At most 16 inputs can be created, | ||
114 | and there must be at least one. | ||
115 | |||
116 | input_types: the input types for each instance, the default is 0xe4. This defines | ||
117 | what the type of each input is when the inputs are created for each driver | ||
118 | instance. This is a hexadecimal value with up to 16 pairs of bits, each | ||
119 | pair gives the type and bits 0-1 map to input 0, bits 2-3 map to input 1, | ||
120 | 30-31 map to input 15. Each pair of bits has the following meaning: | ||
121 | |||
122 | 00: this is a webcam input | ||
123 | 01: this is a TV tuner input | ||
124 | 10: this is an S-Video input | ||
125 | 11: this is an HDMI input | ||
126 | |||
127 | So to create a video capture device with 8 inputs where input 0 is a TV | ||
128 | tuner, inputs 1-3 are S-Video inputs and inputs 4-7 are HDMI inputs you | ||
129 | would use the following module options: | ||
130 | |||
131 | num_inputs=8 input_types=0xffa9 | ||
132 | |||
133 | num_outputs: the number of outputs, one for each instance. By default 2 outputs | ||
134 | are created for each video output device. At most 16 outputs can be | ||
135 | created, and there must be at least one. | ||
136 | |||
137 | output_types: the output types for each instance, the default is 0x02. This defines | ||
138 | what the type of each output is when the outputs are created for each | ||
139 | driver instance. This is a hexadecimal value with up to 16 bits, each bit | ||
140 | gives the type and bit 0 maps to output 0, bit 1 maps to output 1, bit | ||
141 | 15 maps to output 15. The meaning of each bit is as follows: | ||
142 | |||
143 | 0: this is an S-Video output | ||
144 | 1: this is an HDMI output | ||
145 | |||
146 | So to create a video output device with 8 outputs where outputs 0-3 are | ||
147 | S-Video outputs and outputs 4-7 are HDMI outputs you would use the | ||
148 | following module options: | ||
149 | |||
150 | num_outputs=8 output_types=0xf0 | ||
151 | |||
152 | vid_cap_nr: give the desired videoX start number for each video capture device. | ||
153 | The default is -1 which will just take the first free number. This allows | ||
154 | you to map capture video nodes to specific videoX device nodes. Example: | ||
155 | |||
156 | n_devs=4 vid_cap_nr=2,4,6,8 | ||
157 | |||
158 | This will attempt to assign /dev/video2 for the video capture device of | ||
159 | the first vivid instance, video4 for the next up to video8 for the last | ||
160 | instance. If it can't succeed, then it will just take the next free | ||
161 | number. | ||
162 | |||
163 | vid_out_nr: give the desired videoX start number for each video output device. | ||
164 | The default is -1 which will just take the first free number. | ||
165 | |||
166 | vbi_cap_nr: give the desired vbiX start number for each vbi capture device. | ||
167 | The default is -1 which will just take the first free number. | ||
168 | |||
169 | vbi_out_nr: give the desired vbiX start number for each vbi output device. | ||
170 | The default is -1 which will just take the first free number. | ||
171 | |||
172 | radio_rx_nr: give the desired radioX start number for each radio receiver device. | ||
173 | The default is -1 which will just take the first free number. | ||
174 | |||
175 | radio_tx_nr: give the desired radioX start number for each radio transmitter | ||
176 | device. The default is -1 which will just take the first free number. | ||
177 | |||
178 | sdr_cap_nr: give the desired swradioX start number for each SDR capture device. | ||
179 | The default is -1 which will just take the first free number. | ||
180 | |||
181 | ccs_cap_mode: specify the allowed video capture crop/compose/scaling combination | ||
182 | for each driver instance. Video capture devices can have any combination | ||
183 | of cropping, composing and scaling capabilities and this will tell the | ||
184 | vivid driver which of those is should emulate. By default the user can | ||
185 | select this through controls. | ||
186 | |||
187 | The value is either -1 (controlled by the user) or a set of three bits, | ||
188 | each enabling (1) or disabling (0) one of the features: | ||
189 | |||
190 | bit 0: Enable crop support. Cropping will take only part of the | ||
191 | incoming picture. | ||
192 | bit 1: Enable compose support. Composing will copy the incoming | ||
193 | picture into a larger buffer. | ||
194 | bit 2: Enable scaling support. Scaling can scale the incoming | ||
195 | picture. The scaler of the vivid driver can enlarge up | ||
196 | or down to four times the original size. The scaler is | ||
197 | very simple and low-quality. Simplicity and speed were | ||
198 | key, not quality. | ||
199 | |||
200 | Note that this value is ignored by webcam inputs: those enumerate | ||
201 | discrete framesizes and that is incompatible with cropping, composing | ||
202 | or scaling. | ||
203 | |||
204 | ccs_out_mode: specify the allowed video output crop/compose/scaling combination | ||
205 | for each driver instance. Video output devices can have any combination | ||
206 | of cropping, composing and scaling capabilities and this will tell the | ||
207 | vivid driver which of those is should emulate. By default the user can | ||
208 | select this through controls. | ||
209 | |||
210 | The value is either -1 (controlled by the user) or a set of three bits, | ||
211 | each enabling (1) or disabling (0) one of the features: | ||
212 | |||
213 | bit 0: Enable crop support. Cropping will take only part of the | ||
214 | outgoing buffer. | ||
215 | bit 1: Enable compose support. Composing will copy the incoming | ||
216 | buffer into a larger picture frame. | ||
217 | bit 2: Enable scaling support. Scaling can scale the incoming | ||
218 | buffer. The scaler of the vivid driver can enlarge up | ||
219 | or down to four times the original size. The scaler is | ||
220 | very simple and low-quality. Simplicity and speed were | ||
221 | key, not quality. | ||
222 | |||
223 | multiplanar: select whether each device instance supports multi-planar formats, | ||
224 | and thus the V4L2 multi-planar API. By default the first device instance | ||
225 | is single-planar, the second multi-planar, and it keeps alternating. | ||
226 | |||
227 | This module option can override that for each instance. Values are: | ||
228 | |||
229 | 0: use alternating single and multi-planar devices. | ||
230 | 1: this is a single-planar instance. | ||
231 | 2: this is a multi-planar instance. | ||
232 | |||
233 | vivid_debug: enable driver debugging info | ||
234 | |||
235 | no_error_inj: if set disable the error injecting controls. This option is | ||
236 | needed in order to run a tool like v4l2-compliance. Tools like that | ||
237 | exercise all controls including a control like 'Disconnect' which | ||
238 | emulates a USB disconnect, making the device inaccessible and so | ||
239 | all tests that v4l2-compliance is doing will fail afterwards. | ||
240 | |||
241 | There may be other situations as well where you want to disable the | ||
242 | error injection support of vivid. When this option is set, then the | ||
243 | controls that select crop, compose and scale behavior are also | ||
244 | removed. Unless overridden by ccs_cap_mode and/or ccs_out_mode the | ||
245 | will default to enabling crop, compose and scaling. | ||
246 | |||
247 | Taken together, all these module options allow you to precisely customize | ||
248 | the driver behavior and test your application with all sorts of permutations. | ||
249 | It is also very suitable to emulate hardware that is not yet available, e.g. | ||
250 | when developing software for a new upcoming device. | ||
251 | |||
252 | |||
253 | Section 2: Video Capture | ||
254 | ------------------------ | ||
255 | |||
256 | This is probably the most frequently used feature. The video capture device | ||
257 | can be configured by using the module options num_inputs, input_types and | ||
258 | ccs_cap_mode (see section 1 for more detailed information), but by default | ||
259 | four inputs are configured: a webcam, a TV tuner, an S-Video and an HDMI | ||
260 | input, one input for each input type. Those are described in more detail | ||
261 | below. | ||
262 | |||
263 | Special attention has been given to the rate at which new frames become | ||
264 | available. The jitter will be around 1 jiffie (that depends on the HZ | ||
265 | configuration of your kernel, so usually 1/100, 1/250 or 1/1000 of a second), | ||
266 | but the long-term behavior is exactly following the framerate. So a | ||
267 | framerate of 59.94 Hz is really different from 60 Hz. If the framerate | ||
268 | exceeds your kernel's HZ value, then you will get dropped frames, but the | ||
269 | frame/field sequence counting will keep track of that so the sequence | ||
270 | count will skip whenever frames are dropped. | ||
271 | |||
272 | |||
273 | Section 2.1: Webcam Input | ||
274 | ------------------------- | ||
275 | |||
276 | The webcam input supports three framesizes: 320x180, 640x360 and 1280x720. It | ||
277 | supports frames per second settings of 10, 15, 25, 30, 50 and 60 fps. Which ones | ||
278 | are available depends on the chosen framesize: the larger the framesize, the | ||
279 | lower the maximum frames per second. | ||
280 | |||
281 | The initially selected colorspace when you switch to the webcam input will be | ||
282 | sRGB. | ||
283 | |||
284 | |||
285 | Section 2.2: TV and S-Video Inputs | ||
286 | ---------------------------------- | ||
287 | |||
288 | The only difference between the TV and S-Video input is that the TV has a | ||
289 | tuner. Otherwise they behave identically. | ||
290 | |||
291 | These inputs support audio inputs as well: one TV and one Line-In. They | ||
292 | both support all TV standards. If the standard is queried, then the Vivid | ||
293 | controls 'Standard Signal Mode' and 'Standard' determine what | ||
294 | the result will be. | ||
295 | |||
296 | These inputs support all combinations of the field setting. Special care has | ||
297 | been taken to faithfully reproduce how fields are handled for the different | ||
298 | TV standards. This is particularly noticable when generating a horizontally | ||
299 | moving image so the temporal effect of using interlaced formats becomes clearly | ||
300 | visible. For 50 Hz standards the top field is the oldest and the bottom field | ||
301 | is the newest in time. For 60 Hz standards that is reversed: the bottom field | ||
302 | is the oldest and the top field is the newest in time. | ||
303 | |||
304 | When you start capturing in V4L2_FIELD_ALTERNATE mode the first buffer will | ||
305 | contain the top field for 50 Hz standards and the bottom field for 60 Hz | ||
306 | standards. This is what capture hardware does as well. | ||
307 | |||
308 | Finally, for PAL/SECAM standards the first half of the top line contains noise. | ||
309 | This simulates the Wide Screen Signal that is commonly placed there. | ||
310 | |||
311 | The initially selected colorspace when you switch to the TV or S-Video input | ||
312 | will be SMPTE-170M. | ||
313 | |||
314 | The pixel aspect ratio will depend on the TV standard. The video aspect ratio | ||
315 | can be selected through the 'Standard Aspect Ratio' Vivid control. | ||
316 | Choices are '4x3', '16x9' which will give letterboxed widescreen video and | ||
317 | '16x9 Anomorphic' which will give full screen squashed anamorphic widescreen | ||
318 | video that will need to be scaled accordingly. | ||
319 | |||
320 | The TV 'tuner' supports a frequency range of 44-958 MHz. Channels are available | ||
321 | every 6 MHz, starting from 49.25 MHz. For each channel the generated image | ||
322 | will be in color for the +/- 0.25 MHz around it, and in grayscale for | ||
323 | +/- 1 MHz around the channel. Beyond that it is just noise. The VIDIOC_G_TUNER | ||
324 | ioctl will return 100% signal strength for +/- 0.25 MHz and 50% for +/- 1 MHz. | ||
325 | It will also return correct afc values to show whether the frequency is too | ||
326 | low or too high. | ||
327 | |||
328 | The audio subchannels that are returned are MONO for the +/- 1 MHz range around | ||
329 | a valid channel frequency. When the frequency is within +/- 0.25 MHz of the | ||
330 | channel it will return either MONO, STEREO, either MONO | SAP (for NTSC) or | ||
331 | LANG1 | LANG2 (for others), or STEREO | SAP. | ||
332 | |||
333 | Which one is returned depends on the chosen channel, each next valid channel | ||
334 | will cycle through the possible audio subchannel combinations. This allows | ||
335 | you to test the various combinations by just switching channels.. | ||
336 | |||
337 | Finally, for these inputs the v4l2_timecode struct is filled in in the | ||
338 | dequeued v4l2_buffer struct. | ||
339 | |||
340 | |||
341 | Section 2.3: HDMI Input | ||
342 | ----------------------- | ||
343 | |||
344 | The HDMI inputs supports all CEA-861 and DMT timings, both progressive and | ||
345 | interlaced, for pixelclock frequencies between 25 and 600 MHz. The field | ||
346 | mode for interlaced formats is always V4L2_FIELD_ALTERNATE. For HDMI the | ||
347 | field order is always top field first, and when you start capturing an | ||
348 | interlaced format you will receive the top field first. | ||
349 | |||
350 | The initially selected colorspace when you switch to the HDMI input or | ||
351 | select an HDMI timing is based on the format resolution: for resolutions | ||
352 | less than or equal to 720x576 the colorspace is set to SMPTE-170M, for | ||
353 | others it is set to REC-709 (CEA-861 timings) or sRGB (VESA DMT timings). | ||
354 | |||
355 | The pixel aspect ratio will depend on the HDMI timing: for 720x480 is it | ||
356 | set as for the NTSC TV standard, for 720x576 it is set as for the PAL TV | ||
357 | standard, and for all others a 1:1 pixel aspect ratio is returned. | ||
358 | |||
359 | The video aspect ratio can be selected through the 'DV Timings Aspect Ratio' | ||
360 | Vivid control. Choices are 'Source Width x Height' (just use the | ||
361 | same ratio as the chosen format), '4x3' or '16x9', either of which can | ||
362 | result in pillarboxed or letterboxed video. | ||
363 | |||
364 | For HDMI inputs it is possible to set the EDID. By default a simple EDID | ||
365 | is provided. You can only set the EDID for HDMI inputs. Internally, however, | ||
366 | the EDID is shared between all HDMI inputs. | ||
367 | |||
368 | No interpretation is done of the EDID data. | ||
369 | |||
370 | |||
371 | Section 3: Video Output | ||
372 | ----------------------- | ||
373 | |||
374 | The video output device can be configured by using the module options | ||
375 | num_outputs, output_types and ccs_out_mode (see section 1 for more detailed | ||
376 | information), but by default two outputs are configured: an S-Video and an | ||
377 | HDMI input, one output for each output type. Those are described in more detail | ||
378 | below. | ||
379 | |||
380 | Like with video capture the framerate is also exact in the long term. | ||
381 | |||
382 | |||
383 | Section 3.1: S-Video Output | ||
384 | --------------------------- | ||
385 | |||
386 | This output supports audio outputs as well: "Line-Out 1" and "Line-Out 2". | ||
387 | The S-Video output supports all TV standards. | ||
388 | |||
389 | This output supports all combinations of the field setting. | ||
390 | |||
391 | The initially selected colorspace when you switch to the TV or S-Video input | ||
392 | will be SMPTE-170M. | ||
393 | |||
394 | |||
395 | Section 3.2: HDMI Output | ||
396 | ------------------------ | ||
397 | |||
398 | The HDMI output supports all CEA-861 and DMT timings, both progressive and | ||
399 | interlaced, for pixelclock frequencies between 25 and 600 MHz. The field | ||
400 | mode for interlaced formats is always V4L2_FIELD_ALTERNATE. | ||
401 | |||
402 | The initially selected colorspace when you switch to the HDMI output or | ||
403 | select an HDMI timing is based on the format resolution: for resolutions | ||
404 | less than or equal to 720x576 the colorspace is set to SMPTE-170M, for | ||
405 | others it is set to REC-709 (CEA-861 timings) or sRGB (VESA DMT timings). | ||
406 | |||
407 | The pixel aspect ratio will depend on the HDMI timing: for 720x480 is it | ||
408 | set as for the NTSC TV standard, for 720x576 it is set as for the PAL TV | ||
409 | standard, and for all others a 1:1 pixel aspect ratio is returned. | ||
410 | |||
411 | An HDMI output has a valid EDID which can be obtained through VIDIOC_G_EDID. | ||
412 | |||
413 | |||
414 | Section 4: VBI Capture | ||
415 | ---------------------- | ||
416 | |||
417 | There are three types of VBI capture devices: those that only support raw | ||
418 | (undecoded) VBI, those that only support sliced (decoded) VBI and those that | ||
419 | support both. This is determined by the node_types module option. In all | ||
420 | cases the driver will generate valid VBI data: for 60 Hz standards it will | ||
421 | generate Closed Caption and XDS data. The closed caption stream will | ||
422 | alternate between "Hello world!" and "Closed captions test" every second. | ||
423 | The XDS stream will give the current time once a minute. For 50 Hz standards | ||
424 | it will generate the Wide Screen Signal which is based on the actual Video | ||
425 | Aspect Ratio control setting and teletext pages 100-159, one page per frame. | ||
426 | |||
427 | The VBI device will only work for the S-Video and TV inputs, it will give | ||
428 | back an error if the current input is a webcam or HDMI. | ||
429 | |||
430 | |||
431 | Section 5: VBI Output | ||
432 | --------------------- | ||
433 | |||
434 | There are three types of VBI output devices: those that only support raw | ||
435 | (undecoded) VBI, those that only support sliced (decoded) VBI and those that | ||
436 | support both. This is determined by the node_types module option. | ||
437 | |||
438 | The sliced VBI output supports the Wide Screen Signal and the teletext signal | ||
439 | for 50 Hz standards and Closed Captioning + XDS for 60 Hz standards. | ||
440 | |||
441 | The VBI device will only work for the S-Video output, it will give | ||
442 | back an error if the current output is HDMI. | ||
443 | |||
444 | |||
445 | Section 6: Radio Receiver | ||
446 | ------------------------- | ||
447 | |||
448 | The radio receiver emulates an FM/AM/SW receiver. The FM band also supports RDS. | ||
449 | The frequency ranges are: | ||
450 | |||
451 | FM: 64 MHz - 108 MHz | ||
452 | AM: 520 kHz - 1710 kHz | ||
453 | SW: 2300 kHz - 26.1 MHz | ||
454 | |||
455 | Valid channels are emulated every 1 MHz for FM and every 100 kHz for AM and SW. | ||
456 | The signal strength decreases the further the frequency is from the valid | ||
457 | frequency until it becomes 0% at +/- 50 kHz (FM) or 5 kHz (AM/SW) from the | ||
458 | ideal frequency. The initial frequency when the driver is loaded is set to | ||
459 | 95 MHz. | ||
460 | |||
461 | The FM receiver supports RDS as well, both using 'Block I/O' and 'Controls' | ||
462 | modes. In the 'Controls' mode the RDS information is stored in read-only | ||
463 | controls. These controls are updated every time the frequency is changed, | ||
464 | or when the tuner status is requested. The Block I/O method uses the read() | ||
465 | interface to pass the RDS blocks on to the application for decoding. | ||
466 | |||
467 | The RDS signal is 'detected' for +/- 12.5 kHz around the channel frequency, | ||
468 | and the further the frequency is away from the valid frequency the more RDS | ||
469 | errors are randomly introduced into the block I/O stream, up to 50% of all | ||
470 | blocks if you are +/- 12.5 kHz from the channel frequency. All four errors | ||
471 | can occur in equal proportions: blocks marked 'CORRECTED', blocks marked | ||
472 | 'ERROR', blocks marked 'INVALID' and dropped blocks. | ||
473 | |||
474 | The generated RDS stream contains all the standard fields contained in a | ||
475 | 0B group, and also radio text and the current time. | ||
476 | |||
477 | The receiver supports HW frequency seek, either in Bounded mode, Wrap Around | ||
478 | mode or both, which is configurable with the "Radio HW Seek Mode" control. | ||
479 | |||
480 | |||
481 | Section 7: Radio Transmitter | ||
482 | ---------------------------- | ||
483 | |||
484 | The radio transmitter emulates an FM/AM/SW transmitter. The FM band also supports RDS. | ||
485 | The frequency ranges are: | ||
486 | |||
487 | FM: 64 MHz - 108 MHz | ||
488 | AM: 520 kHz - 1710 kHz | ||
489 | SW: 2300 kHz - 26.1 MHz | ||
490 | |||
491 | The initial frequency when the driver is loaded is 95.5 MHz. | ||
492 | |||
493 | The FM transmitter supports RDS as well, both using 'Block I/O' and 'Controls' | ||
494 | modes. In the 'Controls' mode the transmitted RDS information is configured | ||
495 | using controls, and in 'Block I/O' mode the blocks are passed to the driver | ||
496 | using write(). | ||
497 | |||
498 | |||
499 | Section 8: Software Defined Radio Receiver | ||
500 | ------------------------------------------ | ||
501 | |||
502 | The SDR receiver has three frequency bands for the ADC tuner: | ||
503 | |||
504 | - 300 kHz | ||
505 | - 900 kHz - 2800 kHz | ||
506 | - 3200 kHz | ||
507 | |||
508 | The RF tuner supports 50 MHz - 2000 MHz. | ||
509 | |||
510 | The generated data contains the In-phase and Quadrature components of a | ||
511 | 1 kHz tone that has an amplitude of sqrt(2). | ||
512 | |||
513 | |||
514 | Section 9: Controls | ||
515 | ------------------- | ||
516 | |||
517 | Different devices support different controls. The sections below will describe | ||
518 | each control and which devices support them. | ||
519 | |||
520 | |||
521 | Section 9.1: User Controls - Test Controls | ||
522 | ------------------------------------------ | ||
523 | |||
524 | The Button, Boolean, Integer 32 Bits, Integer 64 Bits, Menu, String, Bitmask and | ||
525 | Integer Menu are controls that represent all possible control types. The Menu | ||
526 | control and the Integer Menu control both have 'holes' in their menu list, | ||
527 | meaning that one or more menu items return EINVAL when VIDIOC_QUERYMENU is called. | ||
528 | Both menu controls also have a non-zero minimum control value. These features | ||
529 | allow you to check if your application can handle such things correctly. | ||
530 | These controls are supported for every device type. | ||
531 | |||
532 | |||
533 | Section 9.2: User Controls - Video Capture | ||
534 | ------------------------------------------ | ||
535 | |||
536 | The following controls are specific to video capture. | ||
537 | |||
538 | The Brightness, Contrast, Saturation and Hue controls actually work and are | ||
539 | standard. There is one special feature with the Brightness control: each | ||
540 | video input has its own brightness value, so changing input will restore | ||
541 | the brightness for that input. In addition, each video input uses a different | ||
542 | brightness range (minimum and maximum control values). Switching inputs will | ||
543 | cause a control event to be sent with the V4L2_EVENT_CTRL_CH_RANGE flag set. | ||
544 | This allows you to test controls that can change their range. | ||
545 | |||
546 | The 'Gain, Automatic' and Gain controls can be used to test volatile controls: | ||
547 | if 'Gain, Automatic' is set, then the Gain control is volatile and changes | ||
548 | constantly. If 'Gain, Automatic' is cleared, then the Gain control is a normal | ||
549 | control. | ||
550 | |||
551 | The 'Horizontal Flip' and 'Vertical Flip' controls can be used to flip the | ||
552 | image. These combine with the 'Sensor Flipped Horizontally/Vertically' Vivid | ||
553 | controls. | ||
554 | |||
555 | The 'Alpha Component' control can be used to set the alpha component for | ||
556 | formats containing an alpha channel. | ||
557 | |||
558 | |||
559 | Section 9.3: User Controls - Audio | ||
560 | ---------------------------------- | ||
561 | |||
562 | The following controls are specific to video capture and output and radio | ||
563 | receivers and transmitters. | ||
564 | |||
565 | The 'Volume' and 'Mute' audio controls are typical for such devices to | ||
566 | control the volume and mute the audio. They don't actually do anything in | ||
567 | the vivid driver. | ||
568 | |||
569 | |||
570 | Section 9.4: Vivid Controls | ||
571 | --------------------------- | ||
572 | |||
573 | These vivid custom controls control the image generation, error injection, etc. | ||
574 | |||
575 | |||
576 | Section 9.4.1: Test Pattern Controls | ||
577 | ------------------------------------ | ||
578 | |||
579 | The Test Pattern Controls are all specific to video capture. | ||
580 | |||
581 | Test Pattern: selects which test pattern to use. Use the CSC Colorbar for | ||
582 | testing colorspace conversions: the colors used in that test pattern | ||
583 | map to valid colors in all colorspaces. The colorspace conversion | ||
584 | is disabled for the other test patterns. | ||
585 | |||
586 | OSD Text Mode: selects whether the text superimposed on the | ||
587 | test pattern should be shown, and if so, whether only counters should | ||
588 | be displayed or the full text. | ||
589 | |||
590 | Horizontal Movement: selects whether the test pattern should | ||
591 | move to the left or right and at what speed. | ||
592 | |||
593 | Vertical Movement: does the same for the vertical direction. | ||
594 | |||
595 | Show Border: show a two-pixel wide border at the edge of the actual image, | ||
596 | excluding letter or pillarboxing. | ||
597 | |||
598 | Show Square: show a square in the middle of the image. If the image is | ||
599 | displayed with the correct pixel and image aspect ratio corrections, | ||
600 | then the width and height of the square on the monitor should be | ||
601 | the same. | ||
602 | |||
603 | Insert SAV Code in Image: adds a SAV (Start of Active Video) code to the image. | ||
604 | This can be used to check if such codes in the image are inadvertently | ||
605 | interpreted instead of being ignored. | ||
606 | |||
607 | Insert EAV Code in Image: does the same for the EAV (End of Active Video) code. | ||
608 | |||
609 | |||
610 | Section 9.4.2: Capture Feature Selection Controls | ||
611 | ------------------------------------------------- | ||
612 | |||
613 | These controls are all specific to video capture. | ||
614 | |||
615 | Sensor Flipped Horizontally: the image is flipped horizontally and the | ||
616 | V4L2_IN_ST_HFLIP input status flag is set. This emulates the case where | ||
617 | a sensor is for example mounted upside down. | ||
618 | |||
619 | Sensor Flipped Vertically: the image is flipped vertically and the | ||
620 | V4L2_IN_ST_VFLIP input status flag is set. This emulates the case where | ||
621 | a sensor is for example mounted upside down. | ||
622 | |||
623 | Standard Aspect Ratio: selects if the image aspect ratio as used for the TV or | ||
624 | S-Video input should be 4x3, 16x9 or anamorphic widescreen. This may | ||
625 | introduce letterboxing. | ||
626 | |||
627 | DV Timings Aspect Ratio: selects if the image aspect ratio as used for the HDMI | ||
628 | input should be the same as the source width and height ratio, or if | ||
629 | it should be 4x3 or 16x9. This may introduce letter or pillarboxing. | ||
630 | |||
631 | Timestamp Source: selects when the timestamp for each buffer is taken. | ||
632 | |||
633 | Colorspace: selects which colorspace should be used when generating the image. | ||
634 | This only applies if the CSC Colorbar test pattern is selected, | ||
635 | otherwise the test pattern will go through unconverted (except for | ||
636 | the so-called 'Transfer Function' corrections and the R'G'B' to Y'CbCr | ||
637 | conversion). This behavior is also what you want, since a 75% Colorbar | ||
638 | should really have 75% signal intensity and should not be affected | ||
639 | by colorspace conversions. | ||
640 | |||
641 | Changing the colorspace will result in the V4L2_EVENT_SOURCE_CHANGE | ||
642 | to be sent since it emulates a detected colorspace change. | ||
643 | |||
644 | Limited RGB Range (16-235): selects if the RGB range of the HDMI source should | ||
645 | be limited or full range. This combines with the Digital Video 'Rx RGB | ||
646 | Quantization Range' control and can be used to test what happens if | ||
647 | a source provides you with the wrong quantization range information. | ||
648 | See the description of that control for more details. | ||
649 | |||
650 | Apply Alpha To Red Only: apply the alpha channel as set by the 'Alpha Component' | ||
651 | user control to the red color of the test pattern only. | ||
652 | |||
653 | Enable Capture Cropping: enables crop support. This control is only present if | ||
654 | the ccs_cap_mode module option is set to the default value of -1 and if | ||
655 | the no_error_inj module option is set to 0 (the default). | ||
656 | |||
657 | Enable Capture Composing: enables composing support. This control is only | ||
658 | present if the ccs_cap_mode module option is set to the default value of | ||
659 | -1 and if the no_error_inj module option is set to 0 (the default). | ||
660 | |||
661 | Enable Capture Scaler: enables support for a scaler (maximum 4 times upscaling | ||
662 | and downscaling). This control is only present if the ccs_cap_mode | ||
663 | module option is set to the default value of -1 and if the no_error_inj | ||
664 | module option is set to 0 (the default). | ||
665 | |||
666 | Maximum EDID Blocks: determines how many EDID blocks the driver supports. | ||
667 | Note that the vivid driver does not actually interpret new EDID | ||
668 | data, it just stores it. It allows for up to 256 EDID blocks | ||
669 | which is the maximum supported by the standard. | ||
670 | |||
671 | Fill Percentage of Frame: can be used to draw only the top X percent | ||
672 | of the image. Since each frame has to be drawn by the driver, this | ||
673 | demands a lot of the CPU. For large resolutions this becomes | ||
674 | problematic. By drawing only part of the image this CPU load can | ||
675 | be reduced. | ||
676 | |||
677 | |||
678 | Section 9.4.3: Output Feature Selection Controls | ||
679 | ------------------------------------------------ | ||
680 | |||
681 | These controls are all specific to video output. | ||
682 | |||
683 | Enable Output Cropping: enables crop support. This control is only present if | ||
684 | the ccs_out_mode module option is set to the default value of -1 and if | ||
685 | the no_error_inj module option is set to 0 (the default). | ||
686 | |||
687 | Enable Output Composing: enables composing support. This control is only | ||
688 | present if the ccs_out_mode module option is set to the default value of | ||
689 | -1 and if the no_error_inj module option is set to 0 (the default). | ||
690 | |||
691 | Enable Output Scaler: enables support for a scaler (maximum 4 times upscaling | ||
692 | and downscaling). This control is only present if the ccs_out_mode | ||
693 | module option is set to the default value of -1 and if the no_error_inj | ||
694 | module option is set to 0 (the default). | ||
695 | |||
696 | |||
697 | Section 9.4.4: Error Injection Controls | ||
698 | --------------------------------------- | ||
699 | |||
700 | The following two controls are only valid for video and vbi capture. | ||
701 | |||
702 | Standard Signal Mode: selects the behavior of VIDIOC_QUERYSTD: what should | ||
703 | it return? | ||
704 | |||
705 | Changing this control will result in the V4L2_EVENT_SOURCE_CHANGE | ||
706 | to be sent since it emulates a changed input condition (e.g. a cable | ||
707 | was plugged in or out). | ||
708 | |||
709 | Standard: selects the standard that VIDIOC_QUERYSTD should return if the | ||
710 | previous control is set to "Selected Standard". | ||
711 | |||
712 | Changing this control will result in the V4L2_EVENT_SOURCE_CHANGE | ||
713 | to be sent since it emulates a changed input standard. | ||
714 | |||
715 | |||
716 | The following two controls are only valid for video capture. | ||
717 | |||
718 | DV Timings Signal Mode: selects the behavior of VIDIOC_QUERY_DV_TIMINGS: what | ||
719 | should it return? | ||
720 | |||
721 | Changing this control will result in the V4L2_EVENT_SOURCE_CHANGE | ||
722 | to be sent since it emulates a changed input condition (e.g. a cable | ||
723 | was plugged in or out). | ||
724 | |||
725 | DV Timings: selects the timings the VIDIOC_QUERY_DV_TIMINGS should return | ||
726 | if the previous control is set to "Selected DV Timings". | ||
727 | |||
728 | Changing this control will result in the V4L2_EVENT_SOURCE_CHANGE | ||
729 | to be sent since it emulates changed input timings. | ||
730 | |||
731 | |||
732 | The following controls are only present if the no_error_inj module option | ||
733 | is set to 0 (the default). These controls are valid for video and vbi | ||
734 | capture and output streams and for the SDR capture device except for the | ||
735 | Disconnect control which is valid for all devices. | ||
736 | |||
737 | Wrap Sequence Number: test what happens when you wrap the sequence number in | ||
738 | struct v4l2_buffer around. | ||
739 | |||
740 | Wrap Timestamp: test what happens when you wrap the timestamp in struct | ||
741 | v4l2_buffer around. | ||
742 | |||
743 | Percentage of Dropped Buffers: sets the percentage of buffers that | ||
744 | are never returned by the driver (i.e., they are dropped). | ||
745 | |||
746 | Disconnect: emulates a USB disconnect. The device will act as if it has | ||
747 | been disconnected. Only after all open filehandles to the device | ||
748 | node have been closed will the device become 'connected' again. | ||
749 | |||
750 | Inject V4L2_BUF_FLAG_ERROR: when pressed, the next frame returned by | ||
751 | the driver will have the error flag set (i.e. the frame is marked | ||
752 | corrupt). | ||
753 | |||
754 | Inject VIDIOC_REQBUFS Error: when pressed, the next REQBUFS or CREATE_BUFS | ||
755 | ioctl call will fail with an error. To be precise: the videobuf2 | ||
756 | queue_setup() op will return -EINVAL. | ||
757 | |||
758 | Inject VIDIOC_QBUF Error: when pressed, the next VIDIOC_QBUF or | ||
759 | VIDIOC_PREPARE_BUFFER ioctl call will fail with an error. To be | ||
760 | precise: the videobuf2 buf_prepare() op will return -EINVAL. | ||
761 | |||
762 | Inject VIDIOC_STREAMON Error: when pressed, the next VIDIOC_STREAMON ioctl | ||
763 | call will fail with an error. To be precise: the videobuf2 | ||
764 | start_streaming() op will return -EINVAL. | ||
765 | |||
766 | Inject Fatal Streaming Error: when pressed, the streaming core will be | ||
767 | marked as having suffered a fatal error, the only way to recover | ||
768 | from that is to stop streaming. To be precise: the videobuf2 | ||
769 | vb2_queue_error() function is called. | ||
770 | |||
771 | |||
772 | Section 9.4.5: VBI Raw Capture Controls | ||
773 | --------------------------------------- | ||
774 | |||
775 | Interlaced VBI Format: if set, then the raw VBI data will be interlaced instead | ||
776 | of providing it grouped by field. | ||
777 | |||
778 | |||
779 | Section 9.5: Digital Video Controls | ||
780 | ----------------------------------- | ||
781 | |||
782 | Rx RGB Quantization Range: sets the RGB quantization detection of the HDMI | ||
783 | input. This combines with the Vivid 'Limited RGB Range (16-235)' | ||
784 | control and can be used to test what happens if a source provides | ||
785 | you with the wrong quantization range information. This can be tested | ||
786 | by selecting an HDMI input, setting this control to Full or Limited | ||
787 | range and selecting the opposite in the 'Limited RGB Range (16-235)' | ||
788 | control. The effect is easy to see if the 'Gray Ramp' test pattern | ||
789 | is selected. | ||
790 | |||
791 | Tx RGB Quantization Range: sets the RGB quantization detection of the HDMI | ||
792 | output. It is currently not used for anything in vivid, but most HDMI | ||
793 | transmitters would typically have this control. | ||
794 | |||
795 | Transmit Mode: sets the transmit mode of the HDMI output to HDMI or DVI-D. This | ||
796 | affects the reported colorspace since DVI_D outputs will always use | ||
797 | sRGB. | ||
798 | |||
799 | |||
800 | Section 9.6: FM Radio Receiver Controls | ||
801 | --------------------------------------- | ||
802 | |||
803 | RDS Reception: set if the RDS receiver should be enabled. | ||
804 | |||
805 | RDS Program Type: | ||
806 | RDS PS Name: | ||
807 | RDS Radio Text: | ||
808 | RDS Traffic Announcement: | ||
809 | RDS Traffic Program: | ||
810 | RDS Music: these are all read-only controls. If RDS Rx I/O Mode is set to | ||
811 | "Block I/O", then they are inactive as well. If RDS Rx I/O Mode is set | ||
812 | to "Controls", then these controls report the received RDS data. Note | ||
813 | that the vivid implementation of this is pretty basic: they are only | ||
814 | updated when you set a new frequency or when you get the tuner status | ||
815 | (VIDIOC_G_TUNER). | ||
816 | |||
817 | Radio HW Seek Mode: can be one of "Bounded", "Wrap Around" or "Both". This | ||
818 | determines if VIDIOC_S_HW_FREQ_SEEK will be bounded by the frequency | ||
819 | range or wrap-around or if it is selectable by the user. | ||
820 | |||
821 | Radio Programmable HW Seek: if set, then the user can provide the lower and | ||
822 | upper bound of the HW Seek. Otherwise the frequency range boundaries | ||
823 | will be used. | ||
824 | |||
825 | Generate RBDS Instead of RDS: if set, then generate RBDS (the US variant of | ||
826 | RDS) data instead of RDS (European-style RDS). This affects only the | ||
827 | PICODE and PTY codes. | ||
828 | |||
829 | RDS Rx I/O Mode: this can be "Block I/O" where the RDS blocks have to be read() | ||
830 | by the application, or "Controls" where the RDS data is provided by | ||
831 | the RDS controls mentioned above. | ||
832 | |||
833 | |||
834 | Section 9.7: FM Radio Modulator Controls | ||
835 | ---------------------------------------- | ||
836 | |||
837 | RDS Program ID: | ||
838 | RDS Program Type: | ||
839 | RDS PS Name: | ||
840 | RDS Radio Text: | ||
841 | RDS Stereo: | ||
842 | RDS Artificial Head: | ||
843 | RDS Compressed: | ||
844 | RDS Dymanic PTY: | ||
845 | RDS Traffic Announcement: | ||
846 | RDS Traffic Program: | ||
847 | RDS Music: these are all controls that set the RDS data that is transmitted by | ||
848 | the FM modulator. | ||
849 | |||
850 | RDS Tx I/O Mode: this can be "Block I/O" where the application has to use write() | ||
851 | to pass the RDS blocks to the driver, or "Controls" where the RDS data is | ||
852 | provided by the RDS controls mentioned above. | ||
853 | |||
854 | |||
855 | Section 10: Video, VBI and RDS Looping | ||
856 | -------------------------------------- | ||
857 | |||
858 | The vivid driver supports looping of video output to video input, VBI output | ||
859 | to VBI input and RDS output to RDS input. For video/VBI looping this emulates | ||
860 | as if a cable was hooked up between the output and input connector. So video | ||
861 | and VBI looping is only supported between S-Video and HDMI inputs and outputs. | ||
862 | VBI is only valid for S-Video as it makes no sense for HDMI. | ||
863 | |||
864 | Since radio is wireless this looping always happens if the radio receiver | ||
865 | frequency is close to the radio transmitter frequency. In that case the radio | ||
866 | transmitter will 'override' the emulated radio stations. | ||
867 | |||
868 | Looping is currently supported only between devices created by the same | ||
869 | vivid driver instance. | ||
870 | |||
871 | |||
872 | Section 10.1: Video and Sliced VBI looping | ||
873 | ------------------------------------------ | ||
874 | |||
875 | The way to enable video/VBI looping is currently fairly crude. A 'Loop Video' | ||
876 | control is available in the "Vivid" control class of the video | ||
877 | output and VBI output devices. When checked the video looping will be enabled. | ||
878 | Once enabled any video S-Video or HDMI input will show a static test pattern | ||
879 | until the video output has started. At that time the video output will be | ||
880 | looped to the video input provided that: | ||
881 | |||
882 | - the input type matches the output type. So the HDMI input cannot receive | ||
883 | video from the S-Video output. | ||
884 | |||
885 | - the video resolution of the video input must match that of the video output. | ||
886 | So it is not possible to loop a 50 Hz (720x576) S-Video output to a 60 Hz | ||
887 | (720x480) S-Video input, or a 720p60 HDMI output to a 1080p30 input. | ||
888 | |||
889 | - the pixel formats must be identical on both sides. Otherwise the driver would | ||
890 | have to do pixel format conversion as well, and that's taking things too far. | ||
891 | |||
892 | - the field settings must be identical on both sides. Same reason as above: | ||
893 | requiring the driver to convert from one field format to another complicated | ||
894 | matters too much. This also prohibits capturing with 'Field Top' or 'Field | ||
895 | Bottom' when the output video is set to 'Field Alternate'. This combination, | ||
896 | while legal, became too complicated to support. Both sides have to be 'Field | ||
897 | Alternate' for this to work. Also note that for this specific case the | ||
898 | sequence and field counting in struct v4l2_buffer on the capture side may not | ||
899 | be 100% accurate. | ||
900 | |||
901 | - on the input side the "Standard Signal Mode" for the S-Video input or the | ||
902 | "DV Timings Signal Mode" for the HDMI input should be configured so that a | ||
903 | valid signal is passed to the video input. | ||
904 | |||
905 | The framerates do not have to match, although this might change in the future. | ||
906 | |||
907 | By default you will see the OSD text superimposed on top of the looped video. | ||
908 | This can be turned off by changing the "OSD Text Mode" control of the video | ||
909 | capture device. | ||
910 | |||
911 | For VBI looping to work all of the above must be valid and in addition the vbi | ||
912 | output must be configured for sliced VBI. The VBI capture side can be configured | ||
913 | for either raw or sliced VBI. Note that at the moment only CC/XDS (60 Hz formats) | ||
914 | and WSS (50 Hz formats) VBI data is looped. Teletext VBI data is not looped. | ||
915 | |||
916 | |||
917 | Section 10.2: Radio & RDS Looping | ||
918 | --------------------------------- | ||
919 | |||
920 | As mentioned in section 6 the radio receiver emulates stations are regular | ||
921 | frequency intervals. Depending on the frequency of the radio receiver a | ||
922 | signal strength value is calculated (this is returned by VIDIOC_G_TUNER). | ||
923 | However, it will also look at the frequency set by the radio transmitter and | ||
924 | if that results in a higher signal strength than the settings of the radio | ||
925 | transmitter will be used as if it was a valid station. This also includes | ||
926 | the RDS data (if any) that the transmitter 'transmits'. This is received | ||
927 | faithfully on the receiver side. Note that when the driver is loaded the | ||
928 | frequencies of the radio receiver and transmitter are not identical, so | ||
929 | initially no looping takes place. | ||
930 | |||
931 | |||
932 | Section 11: Cropping, Composing, Scaling | ||
933 | ---------------------------------------- | ||
934 | |||
935 | This driver supports cropping, composing and scaling in any combination. Normally | ||
936 | which features are supported can be selected through the Vivid controls, | ||
937 | but it is also possible to hardcode it when the module is loaded through the | ||
938 | ccs_cap_mode and ccs_out_mode module options. See section 1 on the details of | ||
939 | these module options. | ||
940 | |||
941 | This allows you to test your application for all these variations. | ||
942 | |||
943 | Note that the webcam input never supports cropping, composing or scaling. That | ||
944 | only applies to the TV/S-Video/HDMI inputs and outputs. The reason is that | ||
945 | webcams, including this virtual implementation, normally use | ||
946 | VIDIOC_ENUM_FRAMESIZES to list a set of discrete framesizes that it supports. | ||
947 | And that does not combine with cropping, composing or scaling. This is | ||
948 | primarily a limitation of the V4L2 API which is carefully reproduced here. | ||
949 | |||
950 | The minimum and maximum resolutions that the scaler can achieve are 16x16 and | ||
951 | (4096 * 4) x (2160 x 4), but it can only scale up or down by a factor of 4 or | ||
952 | less. So for a source resolution of 1280x720 the minimum the scaler can do is | ||
953 | 320x180 and the maximum is 5120x2880. You can play around with this using the | ||
954 | qv4l2 test tool and you will see these dependencies. | ||
955 | |||
956 | This driver also supports larger 'bytesperline' settings, something that | ||
957 | VIDIOC_S_FMT allows but that few drivers implement. | ||
958 | |||
959 | The scaler is a simple scaler that uses the Coarse Bresenham algorithm. It's | ||
960 | designed for speed and simplicity, not quality. | ||
961 | |||
962 | If the combination of crop, compose and scaling allows it, then it is possible | ||
963 | to change crop and compose rectangles on the fly. | ||
964 | |||
965 | |||
966 | Section 12: Formats | ||
967 | ------------------- | ||
968 | |||
969 | The driver supports all the regular packed YUYV formats, 16, 24 and 32 RGB | ||
970 | packed formats and two multiplanar formats (one luma and one chroma plane). | ||
971 | |||
972 | The alpha component can be set through the 'Alpha Component' User control | ||
973 | for those formats that support it. If the 'Apply Alpha To Red Only' control | ||
974 | is set, then the alpha component is only used for the color red and set to | ||
975 | 0 otherwise. | ||
976 | |||
977 | The driver has to be configured to support the multiplanar formats. By default | ||
978 | the first driver instance is single-planar, the second is multi-planar, and it | ||
979 | keeps alternating. This can be changed by setting the multiplanar module option, | ||
980 | see section 1 for more details on that option. | ||
981 | |||
982 | If the driver instance is using the multiplanar formats/API, then the first | ||
983 | single planar format (YUYV) and the multiplanar NV16M and NV61M formats the | ||
984 | will have a plane that has a non-zero data_offset of 128 bytes. It is rare for | ||
985 | data_offset to be non-zero, so this is a useful feature for testing applications. | ||
986 | |||
987 | Video output will also honor any data_offset that the application set. | ||
988 | |||
989 | |||
990 | Section 13: Capture Overlay | ||
991 | --------------------------- | ||
992 | |||
993 | Note: capture overlay support is implemented primarily to test the existing | ||
994 | V4L2 capture overlay API. In practice few if any GPUs support such overlays | ||
995 | anymore, and neither are they generally needed anymore since modern hardware | ||
996 | is so much more capable. By setting flag 0x10000 in the node_types module | ||
997 | option the vivid driver will create a simple framebuffer device that can be | ||
998 | used for testing this API. Whether this API should be used for new drivers is | ||
999 | questionable. | ||
1000 | |||
1001 | This driver has support for a destructive capture overlay with bitmap clipping | ||
1002 | and list clipping (up to 16 rectangles) capabilities. Overlays are not | ||
1003 | supported for multiplanar formats. It also honors the struct v4l2_window field | ||
1004 | setting: if it is set to FIELD_TOP or FIELD_BOTTOM and the capture setting is | ||
1005 | FIELD_ALTERNATE, then only the top or bottom fields will be copied to the overlay. | ||
1006 | |||
1007 | The overlay only works if you are also capturing at that same time. This is a | ||
1008 | vivid limitation since it copies from a buffer to the overlay instead of | ||
1009 | filling the overlay directly. And if you are not capturing, then no buffers | ||
1010 | are available to fill. | ||
1011 | |||
1012 | In addition, the pixelformat of the capture format and that of the framebuffer | ||
1013 | must be the same for the overlay to work. Otherwise VIDIOC_OVERLAY will return | ||
1014 | an error. | ||
1015 | |||
1016 | In order to really see what it going on you will need to create two vivid | ||
1017 | instances: the first with a framebuffer enabled. You configure the capture | ||
1018 | overlay of the second instance to use the framebuffer of the first, then | ||
1019 | you start capturing in the second instance. For the first instance you setup | ||
1020 | the output overlay for the video output, turn on video looping and capture | ||
1021 | to see the blended framebuffer overlay that's being written to by the second | ||
1022 | instance. This setup would require the following commands: | ||
1023 | |||
1024 | $ sudo modprobe vivid n_devs=2 node_types=0x10101,0x1 multiplanar=1,1 | ||
1025 | $ v4l2-ctl -d1 --find-fb | ||
1026 | /dev/fb1 is the framebuffer associated with base address 0x12800000 | ||
1027 | $ sudo v4l2-ctl -d2 --set-fbuf fb=1 | ||
1028 | $ v4l2-ctl -d1 --set-fbuf fb=1 | ||
1029 | $ v4l2-ctl -d0 --set-fmt-video=pixelformat='AR15' | ||
1030 | $ v4l2-ctl -d1 --set-fmt-video-out=pixelformat='AR15' | ||
1031 | $ v4l2-ctl -d2 --set-fmt-video=pixelformat='AR15' | ||
1032 | $ v4l2-ctl -d0 -i2 | ||
1033 | $ v4l2-ctl -d2 -i2 | ||
1034 | $ v4l2-ctl -d2 -c horizontal_movement=4 | ||
1035 | $ v4l2-ctl -d1 --overlay=1 | ||
1036 | $ v4l2-ctl -d1 -c loop_video=1 | ||
1037 | $ v4l2-ctl -d2 --stream-mmap --overlay=1 | ||
1038 | |||
1039 | And from another console: | ||
1040 | |||
1041 | $ v4l2-ctl -d1 --stream-out-mmap | ||
1042 | |||
1043 | And yet another console: | ||
1044 | |||
1045 | $ qv4l2 | ||
1046 | |||
1047 | and start streaming. | ||
1048 | |||
1049 | As you can see, this is not for the faint of heart... | ||
1050 | |||
1051 | |||
1052 | Section 14: Output Overlay | ||
1053 | -------------------------- | ||
1054 | |||
1055 | Note: output overlays are primarily implemented in order to test the existing | ||
1056 | V4L2 output overlay API. Whether this API should be used for new drivers is | ||
1057 | questionable. | ||
1058 | |||
1059 | This driver has support for an output overlay and is capable of: | ||
1060 | |||
1061 | - bitmap clipping, | ||
1062 | - list clipping (up to 16 rectangles) | ||
1063 | - chromakey | ||
1064 | - source chromakey | ||
1065 | - global alpha | ||
1066 | - local alpha | ||
1067 | - local inverse alpha | ||
1068 | |||
1069 | Output overlays are not supported for multiplanar formats. In addition, the | ||
1070 | pixelformat of the capture format and that of the framebuffer must be the | ||
1071 | same for the overlay to work. Otherwise VIDIOC_OVERLAY will return an error. | ||
1072 | |||
1073 | Output overlays only work if the driver has been configured to create a | ||
1074 | framebuffer by setting flag 0x10000 in the node_types module option. The | ||
1075 | created framebuffer has a size of 720x576 and supports ARGB 1:5:5:5 and | ||
1076 | RGB 5:6:5. | ||
1077 | |||
1078 | In order to see the effects of the various clipping, chromakeying or alpha | ||
1079 | processing capabilities you need to turn on video looping and see the results | ||
1080 | on the capture side. The use of the clipping, chromakeying or alpha processing | ||
1081 | capabilities will slow down the video loop considerably as a lot of checks have | ||
1082 | to be done per pixel. | ||
1083 | |||
1084 | |||
1085 | Section 15: Some Future Improvements | ||
1086 | ------------------------------------ | ||
1087 | |||
1088 | Just as a reminder and in no particular order: | ||
1089 | |||
1090 | - Add a virtual alsa driver to test audio | ||
1091 | - Add virtual sub-devices and media controller support | ||
1092 | - Some support for testing compressed video | ||
1093 | - Add support to loop raw VBI output to raw VBI input | ||
1094 | - Add support to loop teletext sliced VBI output to VBI input | ||
1095 | - Fix sequence/field numbering when looping of video with alternate fields | ||
1096 | - Add support for V4L2_CID_BG_COLOR for video outputs | ||
1097 | - Add ARGB888 overlay support: better testing of the alpha channel | ||
1098 | - Add custom DV timings support | ||
1099 | - Add support for V4L2_DV_FL_REDUCED_FPS | ||
1100 | - Improve pixel aspect support in the tpg code by passing a real v4l2_fract | ||
1101 | - Use per-queue locks and/or per-device locks to improve throughput | ||
1102 | - Add support to loop from a specific output to a specific input across | ||
1103 | vivid instances | ||
1104 | - Add support for VIDIOC_EXPBUF once support for that has been added to vb2 | ||
1105 | - The SDR radio should use the same 'frequencies' for stations as the normal | ||
1106 | radio receiver, and give back noise if the frequency doesn't match up with | ||
1107 | a station frequency | ||
1108 | - Improve the sine generation of the SDR radio. | ||
1109 | - Make a thread for the RDS generation, that would help in particular for the | ||
1110 | "Controls" RDS Rx I/O Mode as the read-only RDS controls could be updated | ||
1111 | in real-time. | ||