V4l2 formats. I use e Lattis FPGA to convert the SubLVDS to MIPI CSI2.

V4l2 formats $ v4l2-ctl -d /dev/video2 --list-formats-ext The information may 2. NV15 and NV20 is 10-bit 4:2:0/4:2:2 semi-planar YUV formats similar to NV12 and NV16, using 10-bit components with no padding between each component. This class describes the image format and resolution to be programmed on a V4L2 video device. mode_type = “yuv”; pixel_phase = “uyvy”; csi_pixel_bit_depth = “16”; I get the following from v4l2-ctl --list-formats The Gstreamer and V4L2 Formats are described in this section. Each colour component is stored in a 16-bit word, with 4 unused high bits filled with zeros. The VIDIOC_S_FMT ioctl is a major turning-point in the initialization sequence. Does anybody know how this works? The supported pixel formats can be obtained by using the ioctl VIDIOC_ENUM_FMT function. The contents of struct v4l2_pix_format and struct v4l2_pix_format_mplane are discussed in Image Formats. Upon return the struct v4l2_subdev_format contains the current format as would be returned by a VIDIOC_SUBDEV_G_FMT call. The command "v4l2-ctl --list-formats-ext --device $ {path-to-video_device}" is used to list all the supported video formats and capabilities of a video device using the v4l2-ctl tool. Single-planar format structure View page source A V4L2 codec device is a device that can compress, decompress, transform, or otherwise convert video data from one format into another format, in memory. libv4lconvert libv4lconvert is a library that converts several different pixelformats found in V4L2 drivers into a few common RGB and YUY formats. Although I cannot get formats list from v4l2 api, nvarguscamerasrc can get correct information. 5. AndyWalls Documented the fielded V4L2_MPEG_STREAM_VBI_FMT_IVTV MPEG stream embedded, sliced VBI data format in this specification. 5 fps, but I'm not able to test that for sure. Contribute to Genymobile/scrcpy development by creating an account on GitHub. Compressed Formats ¶ Docs » Linux Media Subsystem Documentation » Linux Media Infrastructure userspace API » Part I - Video for Linux API » 2. They are identified by an ‘M’ suffix in their name (such as in V4L2_PIX_FMT_NV12M). Aug 15, 2019 · For above modes of imx185, v4l2-ctl will outputs 2 formats, (1920x1080 @30fps and 1920x1080 @30fps) I looked into the related v4l2 api in camera_common. The struct v4l2_plane_pix_format structures define size and layout for each of the planes in a multi-planar format. To query the current image format applications set the type field of a struct v4l2_format to V4L2_BUF_TYPE_VIDEO_OUTPUT and call the VIDIOC_G_FMT ioctl with a pointer to this structure. For a closer look at image formats see Image Formats. 16. Query the camera’s formats and capabilities whose device number is 2. Usually this angle is measured in degrees, i. Can you suggest how to debug this issu May 30, 2021 · Hi, I am developing encoding program using combination of 03_video_cuda_enc 12_camera_v4l2_cuda My problem is that 12_camera_v4l2_cuda have only case of YUV422 interlaced single-planar, but I want to capture by NV12/YU12/YV12 color format witch is multi-planar format. Instead, a group of 4 luminance/chrominance samples are stored over 5 bytes in little endian order: YYYY = UVUV = 4 * 10 Members flags media bus (V4L2_MBUS_*) flags data_lanes an array of physical data lane indexes clock_lane physical lane index of the clock lane num_data_lanes number of data lanes lane_polarities polarity of the lanes. The order is the same of the physical lanes. How can I force the gstreamer pipeline to use MJPG 1920x1080 and enable higher frame rates? New structures for describing multi-planar formats are added: struct v4l2_pix_format_mplane and struct v4l2_plane_pix_format. Some planar formats allow planes to be placed in independent memory locations. To compile all examples, simply navigate into this directory and run the following command: The contents of struct v4l2_pix_format and struct v4l2_pix_format_mplane are discussed in Image Formats. V4L2 Linux kernel interface The kernel provides a set of structures and helper functions for convenient V4L2 drivers development. V4L2 includes several such formats, and this section is intended to be an unambiguous specification of the standard image data formats in V4L2. 31. For now until I look into the V4L2 documentation I am unsure what v4l2_mbus_pixelcode does. I did the necessary in the device tree to have the following format : MEDIA_BUS_FMT_UYVY8_1X16. V4L2 common functions and data structures int v4l2_ctrl_query_fill(struct v4l2_queryctrl * qctrl, s32 min, s32 max, s32 step, s32 def) Fill in a struct v4l2_queryctrl Parameters struct v4l2_queryctrl * qctrl pointer to the struct v4l2_queryctrl to be filled s32 min minimum value for the control s32 max maximum value for the control s32 step control step s32 def default value for the Oct 25, 2021 · After execution of the gstreamer pipeline, v4l2-ctl confirms that the video format reverted to YUYV. However, seems the API does not display the correct parameters as were set by the OS. Apr 3, 2015 · So the v4l2-ctl --list-formats-ext says I can capture at 15 fps, but I won't be able to play it at the right speed. com Dec 17, 2024 · The v4l2-ctl command is a versatile tool used for controlling video devices on Linux systems. e. They occupy 8, 16, 24 or 32 bits per pixel. type field depend on the type of frame sizes the device supports. Contribute to torvalds/linux development by creating an account on GitHub. RGB Formats ¶ These formats encode each pixel as a triplet of RGB values. 7k次，点赞2次，收藏7次。本文详细介绍了Linux V4L2 (Video for Linux 2) 中的像素格式定义及其各种具体的PixelFormat，包括RGB、灰度、YUV等格式，并列举了特定的FourCC代码。 I got 60fps using mjpeg, I only needed 30. On HSV formats the Hue is defined as the angle on the cylindrical color representation. ) Table 2. I am currently customizing the ov5693 driver and the device tree for it to work with our own sensor. Standard Image Formats In order to exchange images between drivers and applications, it is necessary to have standard image data formats which both sides will interpret the same way. The default yuyv gave a miserable 5fps. Single-planar format structure ¶ type v4l2_pix_format ¶ V4L2 Reference Video4Linux (V4L for short) is a collection of device drivers and an API for supporting realtime video capture on Linux systems. Strange if wrong resolution has different behavior on root vs video, but might as well fix your code and rule it out? Docs » Linux Media Subsystem Documentation » Linux Media Infrastructure userspace API » Part I - Video for Linux API » 2. V4L2 sub-devices Many drivers need to communicate with sub-devices. The former is used with the single-planar API, while the latter is used with the multi-planar version (see Single- and multi-planar APIs). See also the Wikipedia article on Bayer filter. It looks like you are trying to use h264, so you are probably looking for something along these lines: ffmpeg Aug 2, 2020 · "v4l2-ctl --list-formats" will list all the formats that the V4L2 device supports. h. Sep 21, 2023 · The deprecated legacy camera stack would expose processed formats such as YUV420, RGB (of various flavours), or having passed it through either H264 or MJPEG encoders. The v4l2_pix_format structure defines the format and layout of an image in memory. While there is a relationship between image formats on buses and image Jun 1, 2010 · 2. The encoder needs to know the memory layout of pixel at input side for reading the raw data, so the corresponding video format needs to be specifi Apr 11, 2020 · V4L2 API Video4Linux, V4L for short, is a collection of device drivers and an API for supporting real-time video capture on Linux systems. VIDIOC_QBUF, VIDIOC_DQBUF, VIDIOC_QUERYBUF A new struct v4l2_plane structure for describing planes is added. Single-planar format structure — The Linux Kernel documentationSingle-planar format structure type v4l2_pix_format ¶ Linux kernel source tree. Oct 3, 2025 · Interlace, Color formats, Resolution and Framerate are translated from v4l2 space to bare metal drivers space. Description These ioctls are used to negotiate the format of data (typically image format) exchanged between driver and application. Applications can query the device capabilities by setting the which to V4L2_SUBDEV_FORMAT_TRY. Once the configuration is parsed and verified, the input and output streams are configured. Dec 1, 2002 · Part I - Video for Linux API ¶ This part describes the Video for Linux API version 2 (V4L2 API) specification. 2. May 29, 2025 · The Gstreamer and V4L2 Formats are described in this section. V4L2 sub-devices ¶ Many drivers need to communicate with sub-devices. One luminance and one chrominance plane with alternating chroma samples as opposed to V4L2_PIX_FMT_YVU420 V4L2_PIX_FMT_NV42 Formats with full horizontal and vertical chroma resolutions, also known as YUV 4:4:4. The v4l2-ctl tool is used to control video4linux devices, either video, vbi, radio or swradio, both input and output. [1] Installation The v4l2 drivers should have been integrated with the kernel in most recent Linux distributions. 7. May 8, 2021 · I’ve heard of v4l-ctl or v4l2-ctl, a command line utility. ffmpeg -f v4l2 -input_format mjpeg -i /dev/video0 -c:v copy output. Image Formats ¶ The V4L2 API was primarily designed for devices exchanging image data with applications. exception v4l2ctl. struct v4l2_pix_format 2. Compressed Formats — The Linux Kernel documentation2. Feb 15, 2024 · The TAPPAS application use the v4l2 / Video4Linux driver to support many cameras. se> Add NV15 and NV20 pixel formats used by the Rockchip Video Decoder for 10-bit buffers. The V4L2 API was primarily designed for devices exchanging image data with applications. Image formats, as defined EMULATED = 2 ¶ This format is not native to the device but emulated through software (usually libv4l2), where possible try to use a native format instead for better performance. The default is however YU12 which can be queried with --get-fmt-video option. List supported video formats and resolutions of default video device /dev/video0 4. This article gives information about the Linux®V4L2 video codec framework. Depending on your device, v4l2 can provide video in several different formats (for example, raw video like yuv420p, or compressed video like h264, possibly via a hardware accelerator). Bullseye has switched to libcamera where /dev/video0 presents the raw typically Bayer frames from the image sensor, and libcamera then passes those through the ISP to create YUV or RGB images. I am coding in c++ and my goal is to capture raw UNCOMPRESSED picture from the webcam. These formats are designed to match the pixel formats of typical PC graphics frame buffers. The struct v4l2_pix_format_mplane structure contains information common to all planes (such as image width and height) and an array of struct v4l2_plane_pix_format structures, describing all planes of that format. dat I get the following output on the Nano (seen in a hex editor): FF 0F FF 0F … This is consistent 2. Apr 4, 2024 · v4l2:///dev/video0 \ --v4l2-width 1920 \ --v4l2-height 1080 \ --v4l2-chroma h264 \ --v4l2-fps 30 \ --v4l2-hflip 1 \ --v4l2-vflip 1 \ --sout '#standard {access=http,mux=ts,dst=:8554/}' \ -I dummy Streaming Video with VLC [RTSP & HTTP] using raspivid This is a guideline to streaming video on a Raspberry Pi 2 with raspivid and VLC. In order to provide the driver with a consistent interface to these sub-devices the 2. 264: ffmpeg -f v4l2 -input_format yuyv422 -i /dev/video0 -c:v libx264 -vf format=yuv420p output. The V4L2Subdevice class provides an API to the "Sub-device interface" as described in section 4. This example shows two connected webcams: /dev/video0 and /dev/video1. Generic V4L2 applications do not need to use the API described in this section. See also the specification of the VIDIOC_G_FMT, VIDIOC_S_FMT and VIDIOC_TRY_FMT ioctls for details. But you may need to install the utils separately. Compressed Formats View page source 2. I use e Lattis FPGA to convert the SubLVDS to MIPI CSI2. Drivers fill the struct v4l2_pix_format pix member of the fmt union. To query the current parameters applications set the type field of a struct v4l2_format to the respective buffer (stream) type. 4. The The target rectangle is given either by the width and height fields of struct v4l2_pix_format or the width and height fields of the struct v4l2_rect w substructure of struct v4l2_window. I guess the same applies for 27. Raw Bayer Formats ¶ 2. List devices To list the supported, connected capture devices you can use the v4l-ctl tool. Four formats are defined, two 16-bits per pixel, one 24 bpp, and one 32 bpp. The MIPI signal is connected to an imx6. Contribute to v4l2loopback/v4l2loopback development by creating an account on GitHub. ("sudo apt install v4l-utils" first if it doesn't happen to be installed on your system). Image formats are negotiated with Contribute to gjasny/v4l-utils development by creating an account on GitHub. Media Bus Pixel Codes ¶ The media bus pixel codes describe image formats as flowing over physical buses (both between separate physical components and inside SoC devices). The former is used with the single-planar API, while the latter is used with the multi-planar version (see the section called “Single- and multi-planar APIs”). // a capture instance // device, resolution, pixel format , and callback function this should be known in advance you can use // v4l2-ctl command to figure that out. 2 Query the supported formats and capabilities of the camera by v4l2-ctl tool. com> Add initial support for V4L2 stateless video decoder There are several tools, one is v4l2-ctl, definitely on ubuntu and linux, read more here List camera device devices: v4l2-ctl --list-devices List supported video formats and resolutions of default video device /dev/video0: v4l2-ctl --list-formats-ext List supported video formats and resolutions of a specific video device: v4l2-ctl --list-formats-ext --device /dev/video0 Get all details of a Aug 12, 2018 · Hello, my goal is to produce multiple virtual copies of the raspberry pi camera (uses v4l2 with interface /dev/video0) with v4l2loopback in order to stream the copy via rtp with ffmpeg to multiple receivers simultaneously. See the v4l2 input device documentation for more information. Image Formats The V4L2 API was primarily designed for devices exchanging image data with applications. Image formats, as defined 4. Each n-pixel row contains n/2 green samples and n/2 blue or red samples, with alternating red and blue rows. To request different parameters applications set the type field of a struct v4l2_format as above and initialize all fields of the struct v4l2_vbi_format vbi member of the fmt union, or better just modify the results of VIDIOC_G_FMT, and call the VIDIOC_S_FMT ioctl with a pointer to this structure. c and found that this behavior is expected from the code. 6. 2. In order to provide the driver with a consistent interface to these sub-devices The data formats supported by the V4L2 API are covered in the respective device section in Interfaces. Description ¶ The raw Bayer formats are used by image sensors before much if any processing is performed on the image. Image formats are 2. There is also however a --set-fmt-video option. g. Here is a breakdown of the command and its components: "v4l2-ctl": This is the name of the command-line tool used for controlling video devices in Linux. These interface elements must be present on the sub-device represents the CSI-2 transmitter. Description These formats are designed to match the pixel formats of typical PC graphics frame buffers. It provides a standardized API for video capture, making it the go-to interface for Linux-based video application development. Those formats are intended to be used only in drivers and applications that support the multi-planar API, described in Single- and multi-planar APIs. I configure the MIPI with "mipi_csi2_set_datatype(mipi_csi2_info,MIPI_DT_ They take a pointer to a struct v4l2_format as argument, here the struct v4l2_pix_format named pix of its fmt union is used. Jan 5, 2021 · Hi, I am working with a jetson tx2 on an auvidea J120 carrier board. Note that v4l2 devices support one or more pixel formats, and various resolutions and framerates for each format. 0 PC CAMERA (usb-0000:00:1d. 0-360. There is a tool available that can list all formats supported by v4l2 devices. To use the Data Formats ioctls applications set the type field of the v4l2_format structure to V4L2_BUF_TYPE_META Nov 24, 2023 · I checked the failed reason for ‘duplicate format 59565955’, it is that V4L2_PIX_FMT_UYVY support 2 bus types: MEDIA_BUS_FMT_UYVY8_1X16 & MEDIA_BUS_FMT_UYVY8_2X8, the default enum mbus function have no way to identify them by mode setting. Oct 3, 2025 · . The return value and the content of the v4l2_frmsizeenum. v4l-utils / utils / v4l2-compliance / v4l2-test-formats. I have things on the way to working now that I have worked out that I need to set all the fields of hdvpss_capture_sdev_info in ti81xx_vpss. Mar 21, 2014 · In Linux, command line utility v4l2-ctl displays all of a webcam's natively supported formats -- install it with sudo apt-get install v4l-utils, run it with v4l2-ctl -dX --list-formats-ext where X is the camera index as in /dev/videoX. They are conventionally described as GRGR The contents of struct v4l2_pix_format and struct v4l2_pix_format_mplane are discussed in Image Formats. 3. A single mechanism exists to negotiate all data formats using the aggregate struct v4l2_format and the VIDIOC_G_FMT and VIDIOC_S_FMT ioctls. 264 and mjpg. V4L2_PIX_FMT_MT2110T is one of Mediatek packed 10bit YUV 4:2:0 formats. 1. Jul 10, 2017 · I have a gray scale Image Sensor with SubLVDS. Mar 19, 2017 · I'm trying to set a V4L2 camera's parameters according to the V4L2 API. When the number of bits required to store a pixel is not aligned to a byte boundary, the data is padded with additional bits to fill the remaining byte. The devices shows up as /dev/video* and supports the following operations: open () - Open a video device close () - Close a video device ioctl () - Send ioctl commands to the device mmap () - Map memory to a driver allocated buffer read () - Read from video device write () - Write to the device The V4L2 Jun 3, 2014 · Linux Uses the video4linux2 (or simply v4l2) input device to capture live input such as from a webcam. 5 Table of Contents Jan 24, 2007 · An application can fill out a v4l2_pix_format structure asking for just about any sort of format that a user-space developer can imagine. Bytes are stored in memory in little endian order. These include the V4L2_CID_LINK_FREQ and V4L2_CID_PIXEL_RATE controls and (v4l2_subdev_video_ops ->s_stream () callback). 14 hours ago · From: Zhentao Guo <zhentao. It seems that v4l2_mbus_pixelcode doesn't matter too much for me at this moment in time. 15 of the "Linux Media Infrastructure userspace API" chapter of the Linux Kernel documentation. Dec 23, 2015 · $ ls /dev/video* if it outputs the list of /dev/video* device, it means good. V4L2_PIX_FMT_NV21 Formats with ½ horizontal and vertical chroma resolution, also known as YUV 4:2:0. Dec 10, 2022 · In Video Capture Formats Options there is --list-formats-ext which shows all the formats the device supports. guo@amlogic. Each example directory contains a Makefile for compiling its respective example. [DSx_All_App] How to connect a USB camera in DeepStream? 28. cpp Cannot retrieve latest commit at this time. This should not be confused with the V4L2 pixel formats that describe, using four character codes, image formats as stored in memory. 8. Firstly i checked what formats are supported via command v4l2 2. The metadata buffer content format is bound to that selected format. 1. Now i write a V4L2 modul. 4. The 1. Compressed Formats ¶ NAME v4l2-ctl - An application to control video4linux drivers SYNOPSIS v4l2-ctl [-h] [-d <dev>] [many other options] DESCRIPTION The v4l2-ctl tool is used to control video4linux devices, either video, vbi, radio or swradio, both input and output. The encoder needs to know the memory layout of pixel at input side for reading the raw data, so the corresponding video format needs to be specifi Mar 19, 2023 · V4L2 user space API Video devices is represented by character devices in a Linux system. Description These four pixel formats are raw sRGB / Bayer formats with 12 bits per colour. . Data Format Negotiation The metadata device uses the Data Formats ioctls to select the capture format. 0 V4L2 sub-devices ---------------- Many drivers need to communicate with sub-devices. For webcams common sub-devices are sensors and camera controllers. It is fully packed 10bit 4:2:0 format like NV15 (15 bits per pixel), except that the lower two bits data is stored in separate partitions. Jan 10, 2013 · Detailed Description struct v4l2_format - stream data format : enum v4l2_buf_type; type of the data stream : definition of an image format : definition of a multiplanar image format : definition of an overlaid image : raw VBI capture or output parameters : sliced VBI capture or output parameters : placeholder for future extensions and custom See full list on afrantzis. Most part of implementations of these functions is located in drivers Jan 10, 2013 · Detailed Description struct v4l2_subdev_format - Pad-level media bus format : format type (from enum v4l2_subdev_format_whence) : pad number, as reported by the media API : media bus format (format code and frame size) Definition at line 47 of file v4l2-subdev. The formats contain green, red and blue components, with alternating lines of red and green, and blue and green pixels in different orders. Description ¶ These formats are designed to match the pixel formats of typical PC graphics frame buffers. mp4 Same as above but manually choose frame rate and video size (v4l2-ctl --list-formats-ext for available frame rate and video sizes): Warning Pad-level formats are only applicable to very complex devices that need to expose low-level format configuration to user space. These four pixel formats are raw sRGB / Bayer formats with 10 bits per sample. Image formats are negotiated with the VIDIOC_S_FMT ioctl. can you please try to answer the specific questions above ? Thanks ! Display and control your Android device. It provides various options to configure and get 1. It applies at the encoder input and the decoder output side. OPTIONS -A, --list-devices List all v4l devices. IoctlError(device, name, request, return_code, extra_msg=None) ¶ Raised when ioctl () returns a non-zero value. see if you can set the device’s pixel format using that. The client may use VIDIOC_ENUM_FRAMEINTERVALS() to detect supported frame intervals for a given format and resolution, passing the desired pixel format in v4l2_frmivalenum pixel_format and the resolution in v4l2_frmivalenum width and v4l2_frmivalenum height. Standard Image Formats ¶ In order to exchange images between drivers and applications, it is necessary to have standard image data formats which both sides will interpret the same way. These formats signify the memory layout of pixels. Revision 4. ) v4l2_timecode Sep 20, 2020 · You can tell FFmpeg to use video4linux2 (v4l2) as an input "device" (which it treats like a demuxer). I configure the camera to create a very bright image (to better see the data), and using the command v4l2-ctl --stream-mmap --stream-count=1 --stream-to=raw. h> contains declarations of base structures and functions, required for registering V4L2 driver and its work. In order to provide the driver with a consistent interface to these sub-devices Mar 25, 2025 · From: Jonas Karlman <jonas@kwiboo. 6. These devices can do all sort of tasks, but most commonly they handle audio and/or video muxing, encoding or decoding. Install vlc: Most of the time only the colorspace field of struct v4l2_pix_format or struct v4l2_pix_format_mplane needs to be filled in. The v4l2_pix_format and v4l2_pix_format_mplane structures define the format and layout of an image in memory. Image Formats » 2. The V4L2_CID Oct 10, 2023 · Thank you for your replay. Each sample is stored in a 16-bit word, with 6 unused high bits filled with zeros. Drivers may define new multi-planar formats, which have distinct FourCC codes from the existing single-planar ones. try getting CAP_PROP_FORMAT and see if that’s an interesting value. A lightweight C application to query and display the capabilities of Video4Linux2 (V4L2) devices. These are all packed-pixel formats, meaning all the data for a pixel lie next to each other in memory. 25. This article delves into the memory management mechanisms V4L2 offers and demonstrates how to capture video from a USB camera with reference code. It is able to control almost any aspect of such devices covering the full V4L2 API. If the depth value in those entries differs from the depth value in the formats array then the packing and unpacking should be set up correctly. v4l2_format sturcture is to be used to change image format. Feb 11, 2021 · I am comparing the output of the raw data captured through v4l2 on the Xavier NX and Nano platforms, and found an unexpected difference. $ v4l2-ctl --list-devices USB2. we might need to process the data in memeory as well, and i try to understand the format of the data returned by v4l2. These devices typically include webcams, TV tuners, capture cards, and other video input/output hardware. 7. Feb 13, 2025 · Video4Linux2 (V4L2) is a robust framework in the Linux kernel for handling video devices, including USB cameras. To use these functions one has to include the following header files: media/v4l2-dev. Examples that demonstrate the Video for Linux version 2 (V4L2) API. For more information about the V4L2 read interface see Read/Write. When the application calls the VIDIOC_S_FMT ioctl with a pointer to a struct v4l2_format structure the driver checks and adjusts the parameters against hardware abilities. I configure the sensor to 10Bit and the FPGA to RAW10. When I run v4l2-ctl --list-formats -d /dev/video0 it lists all available formats for the rpi cam including h. These ioctls are used to negotiate the format of data (typically image format) exchanged between driver and application. Jan 8, 2013 · The V4L2 video device image format and sizes. It provides a command-line interface to the V4L2 API, allowing users to query device capabilities, list supported video formats, set 2. Pad-level Formats Warning Pad-level formats are only applicable to very complex devices that need to expose low-level format configuration to user space. 10. One luminance and one chrominance plane with alternating chroma samples as opposed to V4L2_PIX_FMT_YVU420. 13. Applications send data to be converted to the driver through the write () call, and receive the converted data through the read () call. The image format is defined by a fourcc code (as specified by the V4L2 API with the V4L2_PIX_FMT_* macros), a resolution (width and height) and one to three planes with configurable line stride and a total per-plane size in bytes. NONE = 0 ¶ No flags are set. Jul 18, 2022 · v4l2-ctl –list-formats-ext 可列出所有支援的影像格式及尺寸、FPS，例如，/dev/video0支援的MJPG格式如下，會發現，如果我們使用最大畫質4096×2160錄影，它的速度其實最快可支援30 FPS。 2. To query the supported output format of the camera, we use v4l2-ctl, Warning Pad-level formats are only applicable to very complex devices that need to expose low-level format configuration to user space. Part I - Video for Linux API This part describes the Video for Linux API version 2 (V4L2 API) specification. (The explanations here focus on video capturing and output, for overlay frame buffer formats see also VIDIOC_G_FBUF. Jan 8, 2013 · A V4L2 subdevice as exposed by the Linux kernel. In sample code 12_camera_v4l2_cuda is /* TODO: add multi-planar support Currently only supports YUV422 interlaced single-planar Warning Pad-level formats are only applicable to very complex devices that need to expose low-level format configuration to user space. Also note that /dev/video0 is The v4l2-ctl command is a versatile utility from the v4l-utils package, designed to interact with and configure Video4Linux2 (V4L2) compliant devices. $ sudo apt install v4l-utils && v4l2-ctl --list-devices 28. 15. Aug 24, 2018 · In unicam_async_bound we enumerate the formats that the sensor subdevice advertises and make up a list of our supported formats via unicam_add_active_format. If -z was given The contents of struct v4l2_pix_format and struct v4l2_pix_format_mplane are discussed in Image Formats. The struct v4l2_pix_format and struct v4l2_pix_format_mplane structures define the format and layout of an image in memory. In order to provide the driver with a Jan 30, 2025 · 28. 11, “Image Cropping, Insertion and Scaling”. They are packed formats, meaning that the RGB values for one pixel are stored consecutively in memory and each pixel consumes an integer number of bytes. Sep 4, 2025 · 文章浏览阅读8. Usually these are I2C devices, but not necessarily. c appropriately. v4l2-ctl -d 10 --list-formats-ext does list NV12 as an option. Sep 19, 2021 · I have a webcam connected to beaglebone via usb. 9. It retrieves details like supported formats, frame sizes, and device inputs, helping developers und 3. Single-planar format structure ¶ type v4l2_pix_format ¶ V4L2_PIX_FMT_NV12_10BE_8L128 is similar to V4L2_PIX_FMT_NV12M_10BE_8L128 but stores two planes in one memory. (struct struct timeval timestamps are stored in struct v4l2_buffer field timestamp. On the driver side, however, things have to be restrained to the formats the hardware can work with. 1 Query the device number by the v4l2-ctl tool E. 7-1 Jun 25, 2013 · V4L2 provides an easy interface to check the image formats and colorspace that your webcam supports and provide. SPDX-License-Identifier: GPL-2. V4L2 is the second version of V4L Capturing a frame Dec 19, 2024 · v4l2-ctl --list-devices List supported video formats and resolutions of default video device /dev/video0: v4l2-ctl --list-formats-ext List supported video formats and resolutions of a specific video device: v4l2-ctl --list-formats-ext --device {{path/to/video_device}} Get all details of a video device: v4l2-ctl --all --device {{path/to/video v4l2-loopback device . Additionally the VIDIOC_TRY_FMT ioctl can be used to examine what the hardware could do, without actually selecting a new data format. Dec 30, 2017 · And 2592x1944 is for Camera Module V1 but your v4l2-ctl --list-formats-ext indicates this is Camera Module V2 (3280x2464), plus you said it's the Sony module. Now use ffmpeg to list the capabilities of the camera and get the matching codec: ffmpeg -f v4l2 -list_formats all -i /dev/video0 #use your camera here from step 2 In the output you'll see something like this: An example is given in Section 1. Transmitter drivers CSI-2 transmitter, such as a sensor or a TV tuner, drivers need to provide the CSI-2 receiver with information on the CSI-2 bus configuration. 5 May 7, 2023 · v4l2-ctl --list-formats-ext: This command also lists all supported video formats and frame sizes for a given device but provides more detailed information about each video format, including the May 21, 2020 · pixel formats, framesizes, and framerates ¶ You can use v4l2-ctl to show what pixel formats a video device supports and select a desired format. A V4L2 utility relying on media controller Linux kernel interface [2] aiming to configure and link each sub devices composing the camera subsystem to configure it. Timecodes The struct v4l2_timecode structure is designed to hold a SMPTE 12M or similar timecode. In addition to the basic Data Formats ioctls, the VIDIOC_ENUM_FMT() ioctl must be supported as well. mkv Re-encode the raw webcam video to H. Many thanks to Jun for the heads up on the pixel formats void v4l2_fill_mbus_format(struct v4l2_mbus_framefmt * mbus_fmt, const struct v4l2_pix_format * pix_fmt, u32 code) ¶ Ancillary routine that fills a struct v4l2_mbus_framefmt from a struct v4l2_pix_format and a data format code. To enumerate image formats applications initialize the type and index field of struct v4l2_fmtdesc and call the ioctl VIDIOC_ENUM_FMT ioctl with a pointer to this structure. This command can list video devices, query their formats and capabilities, capture video frames, and control device settings. 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