.. -*- coding: utf-8; mode: rst -*- .. include:: .. _v4l2spec: ############################ Part I - Video for Linux API ############################ This part describes the Video for Linux API version 2 (V4L2 API) specification. **Revision 4.5** .. class:: toc-title Table of Contents .. toctree:: :numbered: :maxdepth: 5 common pixfmt io devices driver libv4l compat user-func common-defs videodev capture-example v4l2grab-example biblio ********************** Revision and Copyright ********************** Authors, in alphabetical order: - Ailus, Sakari - Subdev selections API. - Carvalho Chehab, Mauro - Documented libv4l, designed and added v4l2grab example, Remote Controller chapter. - Dirks, Bill - Original author of the V4L2 API and documentation. - H Schimek, Michael - Original author of the V4L2 API and documentation. - Karicheri, Muralidharan - Documented the Digital Video timings API. - Osciak, Pawel - Designed and documented the multi-planar API. - Palosaari, Antti - SDR API. - Ribalda, Ricardo - Introduce HSV formats and other minor changes. - Rubli, Martin - Designed and documented the VIDIOC_ENUM_FRAMESIZES and VIDIOC_ENUM_FRAMEINTERVALS ioctls. - Walls, Andy - Documented the fielded V4L2_MPEG_STREAM_VBI_FMT_IVTV MPEG stream embedded, sliced VBI data format in this specification. - Verkuil, Hans - Designed and documented the VIDIOC_LOG_STATUS ioctl, the extended control ioctls, major parts of the sliced VBI API, the MPEG encoder and decoder APIs and the DV Timings API. **Copyright** |copy| 1999-2016: Bill Dirks, Michael H. Schimek, Hans Verkuil, Martin Rubli, Andy Walls, Muralidharan Karicheri, Mauro Carvalho Chehab, Pawel Osciak, Sakari Ailus & Antti Palosaari. Except when explicitly stated as GPL, programming examples within this part can be used and distributed without restrictions. **************** Revision History **************** :revision: 4.10 / 2016-07-15 (*rr*) Introduce HSV formats. :revision: 4.5 / 2015-10-29 (*rr*) Extend VIDIOC_G_EXT_CTRLS;. Replace ctrl_class with a new union with ctrl_class and which. Which is used to select the current value of the control or the default value. :revision: 4.4 / 2015-05-26 (*ap*) Renamed V4L2_TUNER_ADC to V4L2_TUNER_SDR. Added V4L2_CID_RF_TUNER_RF_GAIN control. Added transmitter support for Software Defined Radio (SDR) Interface. :revision: 4.1 / 2015-02-13 (*mcc*) Fix documentation for media controller device nodes and add support for DVB device nodes. Add support for Tuner sub-device. :revision: 3.19 / 2014-12-05 (*hv*) Rewrote Colorspace chapter, added new enum :c:type:`v4l2_ycbcr_encoding` and enum :c:type:`v4l2_quantization` fields to struct :c:type:`v4l2_pix_format`, struct :c:type:`v4l2_pix_format_mplane` and struct :c:type:`v4l2_mbus_framefmt`. :revision: 3.17 / 2014-08-04 (*lp, hv*) Extended struct :c:type:`v4l2_pix_format`. Added format flags. Added compound control types and VIDIOC_QUERY_EXT_CTRL. :revision: 3.15 / 2014-02-03 (*hv, ap*) Update several sections of "Common API Elements": "Opening and Closing Devices" "Querying Capabilities", "Application Priority", "Video Inputs and Outputs", "Audio Inputs and Outputs" "Tuners and Modulators", "Video Standards" and "Digital Video (DV) Timings". Added SDR API. :revision: 3.14 / 2013-11-25 (*rr*) Set width and height as unsigned on v4l2_rect. :revision: 3.11 / 2013-05-26 (*hv*) Remove obsolete VIDIOC_DBG_G_CHIP_IDENT ioctl. :revision: 3.10 / 2013-03-25 (*hv*) Remove obsolete and unused DV_PRESET ioctls: VIDIOC_G_DV_PRESET, VIDIOC_S_DV_PRESET, VIDIOC_QUERY_DV_PRESET and VIDIOC_ENUM_DV_PRESET. Remove the related v4l2_input/output capability flags V4L2_IN_CAP_PRESETS and V4L2_OUT_CAP_PRESETS. Added VIDIOC_DBG_G_CHIP_INFO. :revision: 3.9 / 2012-12-03 (*sa, sn*) Added timestamp types to v4l2_buffer. Added V4L2_EVENT_CTRL_CH_RANGE control event changes flag. :revision: 3.6 / 2012-07-02 (*hv*) Added VIDIOC_ENUM_FREQ_BANDS. :revision: 3.5 / 2012-05-07 (*sa, sn, hv*) Added V4L2_CTRL_TYPE_INTEGER_MENU and V4L2 subdev selections API. Improved the description of V4L2_CID_COLORFX control, added V4L2_CID_COLORFX_CBCR control. Added camera controls V4L2_CID_AUTO_EXPOSURE_BIAS, V4L2_CID_AUTO_N_PRESET_WHITE_BALANCE, V4L2_CID_IMAGE_STABILIZATION, V4L2_CID_ISO_SENSITIVITY, V4L2_CID_ISO_SENSITIVITY_AUTO, V4L2_CID_EXPOSURE_METERING, V4L2_CID_SCENE_MODE, V4L2_CID_3A_LOCK, V4L2_CID_AUTO_FOCUS_START, V4L2_CID_AUTO_FOCUS_STOP, V4L2_CID_AUTO_FOCUS_STATUS and V4L2_CID_AUTO_FOCUS_RANGE. Added VIDIOC_ENUM_DV_TIMINGS, VIDIOC_QUERY_DV_TIMINGS and VIDIOC_DV_TIMINGS_CAP. :revision: 3.4 / 2012-01-25 (*sn*) Added :ref:`JPEG compression control class. ` :revision: 3.3 / 2012-01-11 (*hv*) Added device_caps field to struct v4l2_capabilities. :revision: 3.2 / 2011-08-26 (*hv*) Added V4L2_CTRL_FLAG_VOLATILE. :revision: 3.1 / 2011-06-27 (*mcc, po, hv*) Documented that VIDIOC_QUERYCAP now returns a per-subsystem version instead of a per-driver one. Standardize an error code for invalid ioctl. Added V4L2_CTRL_TYPE_BITMASK. :revision: 2.6.39 / 2011-03-01 (*mcc, po*) Removed VIDIOC_*_OLD from videodev2.h header and update it to reflect latest changes. Added the :ref:`multi-planar API `. :revision: 2.6.37 / 2010-08-06 (*hv*) Removed obsolete vtx (videotext) API. :revision: 2.6.33 / 2009-12-03 (*mk*) Added documentation for the Digital Video timings API. :revision: 2.6.32 / 2009-08-31 (*mcc*) Now, revisions will match the kernel version where the V4L2 API changes will be used by the Linux Kernel. Also added Remote Controller chapter. :revision: 0.29 / 2009-08-26 (*ev*) Added documentation for string controls and for FM Transmitter controls. :revision: 0.28 / 2009-08-26 (*gl*) Added V4L2_CID_BAND_STOP_FILTER documentation. :revision: 0.27 / 2009-08-15 (*mcc*) Added libv4l and Remote Controller documentation; added v4l2grab and keytable application examples. :revision: 0.26 / 2009-07-23 (*hv*) Finalized the RDS capture API. Added modulator and RDS encoder capabilities. Added support for string controls. :revision: 0.25 / 2009-01-18 (*hv*) Added pixel formats VYUY, NV16 and NV61, and changed the debug ioctls VIDIOC_DBG_G/S_REGISTER and VIDIOC_DBG_G_CHIP_IDENT. Added camera controls V4L2_CID_ZOOM_ABSOLUTE, V4L2_CID_ZOOM_RELATIVE, V4L2_CID_ZOOM_CONTINUOUS and V4L2_CID_PRIVACY. :revision: 0.24 / 2008-03-04 (*mhs*) Added pixel formats Y16 and SBGGR16, new controls and a camera controls class. Removed VIDIOC_G/S_MPEGCOMP. :revision: 0.23 / 2007-08-30 (*mhs*) Fixed a typo in VIDIOC_DBG_G/S_REGISTER. Clarified the byte order of packed pixel formats. :revision: 0.22 / 2007-08-29 (*mhs*) Added the Video Output Overlay interface, new MPEG controls, V4L2_FIELD_INTERLACED_TB and V4L2_FIELD_INTERLACED_BT, VIDIOC_DBG_G/S_REGISTER, VIDIOC\_(TRY\_)ENCODER_CMD, VIDIOC_G_CHIP_IDENT, VIDIOC_G_ENC_INDEX, new pixel formats. Clarifications in the cropping chapter, about RGB pixel formats, the mmap(), poll(), select(), read() and write() functions. Typographical fixes. :revision: 0.21 / 2006-12-19 (*mhs*) Fixed a link in the VIDIOC_G_EXT_CTRLS section. :revision: 0.20 / 2006-11-24 (*mhs*) Clarified the purpose of the audioset field in struct v4l2_input and v4l2_output. :revision: 0.19 / 2006-10-19 (*mhs*) Documented V4L2_PIX_FMT_RGB444. :revision: 0.18 / 2006-10-18 (*mhs*) Added the description of extended controls by Hans Verkuil. Linked V4L2_PIX_FMT_MPEG to V4L2_CID_MPEG_STREAM_TYPE. :revision: 0.17 / 2006-10-12 (*mhs*) Corrected V4L2_PIX_FMT_HM12 description. :revision: 0.16 / 2006-10-08 (*mhs*) VIDIOC_ENUM_FRAMESIZES and VIDIOC_ENUM_FRAMEINTERVALS are now part of the API. :revision: 0.15 / 2006-09-23 (*mhs*) Cleaned up the bibliography, added BT.653 and BT.1119. capture.c/start_capturing() for user pointer I/O did not initialize the buffer index. Documented the V4L MPEG and MJPEG VID_TYPEs and V4L2_PIX_FMT_SBGGR8. Updated the list of reserved pixel formats. See the history chapter for API changes. :revision: 0.14 / 2006-09-14 (*mr*) Added VIDIOC_ENUM_FRAMESIZES and VIDIOC_ENUM_FRAMEINTERVALS proposal for frame format enumeration of digital devices. :revision: 0.13 / 2006-04-07 (*mhs*) Corrected the description of struct v4l2_window clips. New V4L2_STD\_ and V4L2_TUNER_MODE_LANG1_LANG2 defines. :revision: 0.12 / 2006-02-03 (*mhs*) Corrected the description of struct v4l2_captureparm and v4l2_outputparm. :revision: 0.11 / 2006-01-27 (*mhs*) Improved the description of struct v4l2_tuner. :revision: 0.10 / 2006-01-10 (*mhs*) VIDIOC_G_INPUT and VIDIOC_S_PARM clarifications. :revision: 0.9 / 2005-11-27 (*mhs*) Improved the 525 line numbering diagram. Hans Verkuil and I rewrote the sliced VBI section. He also contributed a VIDIOC_LOG_STATUS page. Fixed VIDIOC_S_STD call in the video standard selection example. Various updates. :revision: 0.8 / 2004-10-04 (*mhs*) Somehow a piece of junk slipped into the capture example, removed. :revision: 0.7 / 2004-09-19 (*mhs*) Fixed video standard selection, control enumeration, downscaling and aspect example. Added read and user pointer i/o to video capture example. :revision: 0.6 / 2004-08-01 (*mhs*) v4l2_buffer changes, added video capture example, various corrections. :revision: 0.5 / 2003-11-05 (*mhs*) Pixel format erratum. :revision: 0.4 / 2003-09-17 (*mhs*) Corrected source and Makefile to generate a PDF. SGML fixes. Added latest API changes. Closed gaps in the history chapter. :revision: 0.3 / 2003-02-05 (*mhs*) Another draft, more corrections. :revision: 0.2 / 2003-01-15 (*mhs*) Second draft, with corrections pointed out by Gerd Knorr. :revision: 0.1 / 2002-12-01 (*mhs*) First draft, based on documentation by Bill Dirks and discussions on the V4L mailing list.