Create video preview thumbnails. Big Media folder? Make smaller video preview thumbnails! .

Create video preview thumbnails A recent requirement to make a LOT of contact sheets for a LOT of videos has me looking at a command line option so I can do these in batches. js. Video Thumbnails Maker by Scorp allows you to make thumbnails (caps, previews) of video files. You've just wrapped up an epic video that’s ready to take the internet by storm — now it's time to make sure it gets the spotlight it deserves. mp4". 2831 Player Version#: N/A I have both “Generate video preview thumbnails” and, after today’s update, “Generate intro video markers” set as a scheduled task. Trusted by designers at. frame-grab's features are 100% client-side. For example if you include a file input element, or a drop zone on your page. MICRO_KIND for 96 x 96 Thumbnails. jpg. How it works: First select the image output with: -V image or - It has meaningful defaults. Thanks everyone! The real issue here is that there is no easy way to really add in a good thumbnail preview system to the existing web client. js, Flowplayer, Fluid Player, and more, use this format for showing the thumbnails. Optimize your video's click-through rate by seeing how your thumbnails appear across different devices and layouts. Take a look at these screenshots. var player = videojs('my-video'); // setup 160x90 thumbnails in 5 days ago · Generate thumbnails from any video with Anycript Video to Thumbnail Generator tool. Thumbnails. Customize your thumbnail creation to fit your specific needs with various options. Learn more about Labs. over the network, or from a form if you're doing this from ASP), an attacker may be able to leverage this code to get code execution on your system. And only video thumbnails. It supports wide range of video formats, such as, avi, wmv, rm, rmvb, mpg, flv, mov, vob, 3gp and mkv. Fortunately, we’ve made everything super easy for you! Thanks to our editor, you can effortlessly To create video preview thumbnails for all your movies, type "Plex Media Scanner. ffmpeg -i input -filter_comp This tutorial will show you how to enable or disable thumbnail previews in File Explorer for your account, all users, Goodday, I want to ask if any of you knows how to just shows the thumbnail of files e. With Customizable Layout Options, Interactive Time Markers, and Auto Step 4: Create Thumbnails With the video paused at your chosen frame, click on the "Create Thumbnail" button to generate the thumbnail instantly. Simply insert the picture at the beginning in your video, make sure that it lasts 1 frame and the website should pick it up. Therefore; I want to create my own thumbnail for that video and set it t YouTube Thumbnail Preview Tool. C:\ drive), I would still like to benefit from using the “Video Preview Thumbnails” feature. It utilizes multi-threaded processes and leverages NVIDIA/AMD GPUs and CPUs for maximum throughput. exe" -b --section 5 For TV shows type "Plex Media Scanner. png Get early access and see previews of new features. Its been about 3 days now. is on an NVME drive. This post discusses creating video thumbnail previews - merge all videos in 1 single video thumbnail preview -> final. The ultimate You can create preview of a video like this: String videoFile = "/sdcard/blonde. It spoiled the results of a sporting event for me. Is it possible to create a If I enable Video Preview Thumbnails for my Library's where are these saved if I don't "Tick" the option Save video preview thumbnails into media folders I Don't want them in with the media for space saving reason however the Emby Metadata folder is on its own dedicated SSD so I am hoping much li Case in point, the fixed value of "take image of first 10% into the video" can create awkward thumbnails like people blinking mid-sentence. When I look at the video on my desktop I see that it has a thumbnail that does not match the main contents of my video. Confirm your thumbnail selection and tap SELECT. This is a code example: Guys, I already see the video previews/thumbnails in explorer, I always did, what I want is, instead of that ugly low contrast yellow icon on the bottom right of the thumbnail, I want in it's place the filetype potplayer icon for that file, purple for mp4, light blue for MKV, etc, like it The other answers are fine but for most "video" content, JPEG is a more space-efficient choice for a thumbnail image. Make it Create video thumbnails via kde dolphin or the command line simply and conveniently, using technologies such as 🎬 ffmpeg and 🧙‍♂️ imagemagick. e. Ask Question Asked 14 years, 11 months ago. In Premiere Pro, open the Essential Graphics panel and hover scrub over your . I hope this solution helps anyone else out there that needs to dynamically generate thumbnails for their video player. the sample code is given below. The README file doesn't contain enough It's like Windows has lost the ability to create video thumbnails. That setup has proven to be extremely effective in increasing engagement, leading to more views of the full video. I’ve “turned on” this feature in Plex by having my Plex server (Synology NAS DS918+) work during nights only to create the thumbnails. However For Others. Updated Dec 5, 2021; Thumbnail/Preview generator for 450 different filetypes in python. Go to you video and see the thumbnail preview appear for all videos. Would like to see a way where this feature can have it’s own storage path for Sure, many tiny files takes longer to copy than one bigger file. I had to swap some episodes around and now they contain the incorrect video preview thumbnails. count is ignored when timemarks or timestamps is specified. Tell us what you think, your feedback is appreciated! I think that as long as you still have the setting for "Generate video preview thumbnails" set to "as a scheduled task", Plex should automatically regenerate the thumbnails at your next scheduled maintenance window. Cheers! A library that allows you to generate an image to serve as a thumbnail from a video file. HDR tonemapping for video preview thumbnails Create Short Preview from Video Online. 320px on the Hello I'm on a PC - Windows 10 OS - ADOBE PREMIERE C 2017, and I made my video and saved it to my desktop. python screenshot pypi python3 pip video-thumbnail thumbnail thumbnail-generator. Just create StatefulWidget as like item (if you want to show in list use that widget as item). How to create thumbnail of video using C#. Additionally, if have the setting for "Generate video preview thumbnails" set to "as a scheduled task and when media is added", and then do the Plex Dance for whatever ThumbnailMe makes a contact sheet of this size virtually instantaneously. A well-designed thumbnail can make all the I have "generate chapter thumbnails" turned on as a scheduled task, however when watching videos through Chrome or on my PS4 using the Plex app, I never see the chapter thumbnails. Blog Changelog Star Us on GitHub. Tap SAVE. Before we go any further, here is an example of what the final output will look like: Phin2001. It can be used to create preview images of individual video files, videos located in a directory and optionally its subdirectories. Ensure that your thumbnails and video titles are optimized for various devices and screen sizes. See your YouTube Titles and Thumbnails in context of the current YouTube feed and layout. " In the library itself, Advanced > "Enable video preview thumbnails" is turned off. ffmpeg kde thumbnails kde-plasma-5 arch-linux shell-script kdialog image Create a video thumbnail. So to play the movie and at the same time make the thumbnails, you will need a 160 megabit connection, have to wait longer for the generation or your video will buffer. And often you'll want to specify the thumbnail size - the below command will scale the video down to fit in a 320x320 box (maintaining the aspect ratio by decreasing the smaller edge -- i. quoting the documentation: "count: specifies how many thumbnails to generate. e get a frame of exactly after 1 min) and display them as thumbnails as in youtube Get early access and see previews of new features. So you can just start creating your first preview thumbnails image of an individual video file by invoking: pyvideothumbnailer [VIDEO FILE] or to create thumbnails of all video files I think that as long as you still have the setting for "Generate video preview thumbnails" set to "as a scheduled task", Plex should automatically regenerate the thumbnails at your next scheduled maintenance window. - hhtznr/pyvideothumbnailer When VLC media player runs it 'plays' the video for one second without actually showing the video on screen, and then quits, leaving us with a file named 'snap000000. MICRO_KIND for 96 x 96 It's among the most efficient way to generate and display a video thumbnail for a local video file. The argument to target an entire library is "-c X" where X is the ID of the desired library. 19. Make sure the ALWAYS SHOW ICONS, NEVER THUMBNAILS IS OFF BY DEFAULT. There are a number of best practices to consider when creating a good video thumbnail. Should I generate thumbnails on the backend and save them in the storage and then send them when the videos are requested? Currently, I am finding solutions on how to generate thumbnails on the frontend or how to save them but no one is discussing which is the best way to do it. I mean folders, generally, stay as icon only, no preview of whats in it. Alternatively, if you've generated multiple thumbnails and want to You could play a short preview of the video content on thumbnail hover. 0033 -vf scale=-1:120 -vcodec png capture-%002d. However the list became extremely hard to scroll. In the first one you can see that a OneDrive connected folder can most definitely show thumbnails of photos. Home Guides EAS Reference Learn. Make your own YouTube thumbnails for free. Ive always known the first option can potentially create a large cache collection under AppData (win10), so it's been set to NEVER since the start. My HDD array stores the video files, artwork images and currently the Video Preview Thumbnails. In the past, when I’d download a new TV show (or movie), I’d often analyze them to manually generate the video preview thumbnails, rather than waiting overnight for the . You have several tabs to go through: In the Settings tab, you can set the quality of the thumbnails generated by Media Preview. Creating youtube video preview thumbnails in videojs. 0' I am trying to create thumbnail of a video using javascript. A community to discuss Synology NAS and networking devices Members Online. @gNazi I tested with thumbnails generated using a video with 10 minutes when I generate the thumbnails I see a video end time equal to 00:20: Video previews have become a standard feature on most media platforms and applications. In Server > Settings -> Library, "Generate video preview thumbnails" is set to "never. To create a By utilizing minimal resources, you can generate more in less time. With new VLC versions (VLC 1. Follow along with the commit! Step 3: Automatically generating a video thumbnail to use as a poster with Cloudinary. i found some articles, some projects to create thumbnail of a video, using ffmpeg. Next we’ll see how we can autogenerate a poster (or thumbnail) that we can use for our video. id. 1. To create video preview thumbnails for all your movies, type "Plex Media Scanner. ffmpeg -i MOVIE. And with a user-friendly CLI and a convenient Python API, this tool is the ultimate solution for efficient and streamlined Create video thumbnails via kde dolphin or the command line simply and conveniently, using technologies such as 🎬 ffmpeg and 🧙‍♂️ imagemagick. Use our free YouTube thumbnail and title mockup tool to preview how your videos will look when they appear on YouTube. Is there a better way to It sounds like you're not seeing preview thumbnails for MP4 video files, and we're happy to help. There, they display a Big Media folder? Make smaller video preview thumbnails! Loading Test and preview your YouTube thumbnails in real-time with our YouTube Thumbnail Tester. You can also use "-h" to display a help screen with all available commands. mogrt to see it animate. if there's a lot of 5 minute videos and the page fits 10 images across easily, take a thumbnail from every 30 seconds through the video. Then, in a cmd window, navigate to the folder with your tv shows (ie, type in: cd d:\tv shows) and then you can use the command he mentioned. github. This answer discusses JPEG quality settings. In the second one you can see the settings in the OPTIONS>VIEW menu. exe" -b --section 6 After it's complete enable real-time antivirus detection Bear in mind that all video preview thumbnails (*. How to display local video thumbnails with glide WITHOUT slowing down the listview? Ask Question I'm trying to display local video thumbnail in this way, it did show the thumbnail in the list. I am able to generate thumbnails using FFmpeg as follows. These tiny preview images are roughly the size of a thumbnail, which is how they got their name. You should, at minimum, run both of those parameters through Path. - AntonioNarcilio/generate-thumbnails Mar 15, 2020 · How to create a thumbnail from a video. r/synology. The HTML video tag comes with a feature called a poster Video Thumbnail Preview Free offers an array of advanced features like Dynamic Frame Selection and Hover Scrub Technology, tailored to boost user engagement and simplify video navigation. So I would like to use this VTT file and the thumbs I e. Just add this line to your gradle file : compile 'com. Navigate through the video, Select your desired export format, and create stunning 6 days ago · Video Thumbnails Maker is free tool for Windows that takes multiple screenshots of the video and then create a thumbnail out of it. 0 and above), the thumbnails are generated with scene video filter vlc C:\video\to\process. 1)using jpg instead of png, much smaller sprites, 2)added adjustment to better sync the snapshot image to the start time in vtt file, to offset time drift occurring in ffmpeg; 3)omitting first image (0seconds) from sprite because JwPlayer doesn't show it anyway; 4) configurable snapshot timing now via command Get early access and see previews of new features. Picsart’s free online thumbnail maker makes @scaryguy, please do! I checked in latest to github with several key updates. Command line tool for creating video preview thumbnails. I would like to skip only until the time I want and extract the time frames as mp4 To make the video preview thumbnails your client needs to load in future parts of the video to make them. WebVTT is a format for displaying timed text tracks (such as subtitles or captions). Open-source video players such as Plyr, Video. Select an auto-generated thumbnail or tap Custom thumbnail to create a custom video thumbnail from an image on your device. When using this option, thumbnails are generated at regular intervals in the video (for example, when requesting 3 thumbnails, at 25%, 50% and 75% of the video length). Create video thumbnails via kde dolphin or the command line simply and conveniently, using technologies such as 🎬 ffmpeg and 🧙‍♂️ imagemagick. This is a Select the Include video preview checkbox to create a video preview, or deselect it to create a static thumbnail. MINI_KIND for 512 x 384 px. Video preview thumbnails not always working on FireStick 4K upvotes r/synology. Video. " – When you fast forward a movie on Netflix or YouTube there are thumbnails of the movie on the screen but on Plex I was always having to guess at where I was during a fast forward. Install the plugin. 2 SSD, so it would be pretty negligible in this scenario, even an old HDD would be able to write that amount of data in 1-2 seconds. Giri Aakula About; Blog; Projects; Contact; Videojs: How To Create Preview Thumbnails April 17, 2021 3-minute read videojs. Server Version#: 1. Use video player plugin as thumbnail. Python Video Thumbnailer. This way it could be a nice compromise for the few videos 52 minutes ago, chef said: Do you have any layout ideas? For a chapter editor you dont need to show lists or pages of items, just one item and its chapters with a way of selecting or searching for an item you want to edit. A library that allows you to generate an image to serve as a thumbnail from a video file. Image compression Mar 23, 2021 · In this tutorial, we will learn how to create a video thumbnail preview from a full video using FFmpeg & PHP. something look like you tube thumbnails or AMT – Auto-Movie-Thumbnailer is a free video thumbnail sheet maker software for Windows 10. Here’s how to do that: I am creating a custom video player, I would like to add a video preview when the user hovers a progress bar. Additionally, if have the setting for "Generate video preview thumbnails" set to "as a scheduled task and when media is added", and then do the Plex Dance for whatever Create YouTube thumbnails that grab your audience's attention. The appdata/emby folder containing user settings, cache, plugins, etc. Edit: It seems the video preview files are there, but the thumbnail image for each episode within the season page is missing. mp4 -r 0. provider. A thumbnail is an image preview of the actual video, as shown in the image below:. While it may be technically possible to transfer the generated thumbnails from one plex library/ server to another (cross platform no less) it’s probably going to be less hassle to just let the pi chug away at generating Is it possible to store video preview thumbnails in an external HDD? I'd like to see if the feature is worth using but I sincerely doubt the SSD that Plex is installed on has a large enough capacity. Thumbnails; We can get two preview thumbnail sizes from the video: Thumbnails. The utility can be used for home-video cataloging and Apr 17, 2021 · There is this awesome plugin called videojs-sprite-thumbnails which will seamlessly integrate sprites into our player. It will be a single low-resolution file containing a sequence of 2-second clips from various parts of the original i want to display thumbnails or preview panels for videos listed on my site, i want to fetch a single frame from a video (from a particular time i. I've tried a couple different ways to make the thumbnails from the command line: ffmpeg -ss 300 -i myvideo. 3. The scenario is when the user select a video from the gallery it will create a preview thumbnail of the selected video as a single image like this. Docs. Edit 2: solved, the Plex dance worked! See comments below. . Hello! I work as a professional software developer but haven&#39;t really participated in open source projects thus far. Installing plex on the gaming pc and generating the thumbnails there will only allow you to have thumbnails when connected to the gaming pc plex installation. Reference version. mp4 but my big problem to do this is, ffmpeg needs to iterate over all video to extract this parts, so it can take some time and later when I will have longer videos of 2h it will take more you know. Topics. Hence, I am looking for software in the form of some kind of organizer or file system viewer for Windows that would allow me to 'mouse over' video files and preview by either - A) Scanning their timeline by moving the mouse along and seeing stills from the video, or The good news is that even if you’re a design newbie, you can create unique YouTube thumbnails for your hobby, side hustle, or business that make a good impression on potential viewers. Images. Configuration files. It will be used as the preview image in the embedded player. avi -vf fps=1/300 %d In this tutorial, we will learn how to create a video thumbnail preview from a full video using FFmpeg & PHP. These images are used by some Plex apps when you move back and forward in the app with the timeline scrubber. The Media Preview user interface is now loaded. photos and videos but not the folders. MINI_KIND); Now you can show it in an ImageView: ImageView imageView = (ImageView) findViewById(R. If Totem can't play the video file, then I get no thumbnail. 1. At the end of this tutorial, we will learn how to use Cloudinary’s AI-Based video preview feature to generate video previews that I am creating a custom video player, I would like to add a video preview when the user hovers a progress bar. jpg', containing an image of the first frame of the video. YouTube provides a perfect example where a user is presented with a video preview when the mouse pointer hovers over the thumbnail. Python application that can be used to generate video thumbnail for mp4 and mkv file types. Similar to creating thumbnails, generating short video previews is often a manual, time-consuming process. And then say APPLY TO FOLDERS> I'm sure For me having the thumbnail previews justified allocating a dedicated 2tb SSD for Plex (though only at about 600gb, so 1tb would probably have done) Video Tour of /u/spaceinvaderone 's Studio where he creates all the great Unraid resources and content you enjoy! Names and thumbnails often only go so far when you have this many files. It will be a single low-resolution file containing a sequence of 2-second clips from various parts of the original video. hi guys . This simple tool will create a video preview from your full video. Any help would be apprecia A new potential developer, wishing to implement video preview thumbnails and fuzzy search. preview thumbnail thumbnail-generator preview-generator. I would like to skip only until the time I want and extract the time frames as mp4 Some websites (For example LinkedIn did this for a long time) create thumbnails by taking the first frame of your video. It is based on PyAV, MediaInfo and PIL/Pillow. createVideoThumbnail(videoFile, MediaStore. Looking at my video files, the total If you take the video or thumbnail parameters from an untrusted source (e. Is there a way to force plex to redo the thumbnails even if it thinks it has already been done? Edit: fixed typo How to generate video preview thumbnails using nodejs and ffmpeg? Hot Network Questions What does "in any reasonable manner" of the Creative Commons Attribution clause mean? Can I use an A or D string on my violin in place of a G string? In a single elimination tournament, each match can end with 1 loser or two losers. 7. Try Canva's free, easy design editor with hundreds of templates. Pull out the image captures (these are 100 pixels tall, and keep aspect ratio), the rate (-r) is per-second (this yields one frame every ~5 minutes), this also adds time stamp to output image. Share This script is designed to speed up the process of generating preview thumbnails for your Plex media library. bif) are saved on the drive that your Plex Media Server is installed. Step 5: Export Your Thumbnail Once you've created the thumbnail, simply click on the exported thumbnail to save it to your device. When telling plex to analyze the videos it appears to run a quick check but does not proceed to generate the thumbnails again. I have seen plex create video previews for other files though in the mean time. I also don't get any video previews in Windows Explorer's Preview Pane; but again I do get previews for On Windows, while I prefer to have the Plex Media Server installed in its default location (i. Video Preview Thumbnails (also known sometimes as “media index files” or “BIF” index files) are basically a series of low-resolution images from a media item. I know it's possible to change the interval of which the thumbnails are generated, but I'd rather install them on an external drive anyway. If it's a folder of hour+ videos it'd be handy to have multiple rows for one video so you can set it to do a thumbnail every 60 seconds and you can preview longer videos for interesting clips that way, I had to swap some episodes around and now they contain the incorrect video preview thumbnails. If you copied it off of the post, you can right-click and choose "paste" to paste the Is there a way to FORCE video preview thumbnails - Plex Forum Loading I am trying to make a video preview of a movie using ffmpeg. GetFullPath(), and then compare each canonical path to a known Modern web video players use the WebVTT formatted files to preview thumbnails at a pointed time. Modified 11 years, 9 months ago. i realy need a way ( or a third party software) that makes windows explorer video thumbnails playing a few seconds of the video file in thumbnail. So you can basically upload a thumbnail just by making it the first frame of your video. Using it, you can create thumbnails for a batch of videos. The following are two common options: I am currently looking at options to load the video first, generate the thumbnails in the background, and incorporate it into the video source once ready. Initiate the plugin. Thank you guys in advance! Video Previews for Resources. But we're talking about a total of 10-50 mb worth of files written to a M. As for the screenshot creator - you have to have all 3 of the linked files in the c:\windows\system32 folder. MediaStore. And, with the use of external plugins, Video. ffmpeg kde thumbnails kde-plasma-5 arch-linux shell-script kdialog image-magick linux-debian antonio-narcilio dolphin-context-menu generate-thumbnails e. Is there a Thumbnails are small images that act as a preview for a picture or video. Search. I need to create thumbnails from video on video load and show it in a canvas. It'll likely be Vue client only if it's added (to start, guessing other clients will add it eventually). GetFullPath(), and then compare each canonical path to a known Is there a way to make VLC generate the video-thumbnails instead of having to rely on the buggy gstreamer/totem? I made VLC my default video player but this had no effect on the display of video-thumbnails. Canva lets you create a stunning video cover for your masterpiece with readily available and professionally designed templates that even non-designers can tweak and make their own using Canva’s easy drag-and-drop Should I generate thumbnails on the backend and save them in the storage and then send them when the videos are requested? Currently, I am finding solutions on how to generate thumbnails on the frontend or how to save them but no one is discussing which is the best way to do it. Problem is, this feature uses the default installation path, and ends up filling up the OS / Program drive. It's very efficient compared to those libraries and also works for iOS. glide:glide:3. ds416play - streaming 4k video (direct play) remotely upvotes · comments. They act like billboards to help people decide to watch your videos – encouraging viewers to click and engage with your content. Have you ever wondered how youtube shows the preview of Plex > Library List > Edit (per library) > Advanced Tab > Enable Video Preview Thumbnails -Where by default is checked, and a large RED button to delete the preview thumbnails. exe, expression encoder but when i The argument to generate video preview thumbnails is "-b", it says its depreciated but it still works at the time of writing. Create Video Thumbnail of All Files in a Directory via FFmpeg and PHP. Some of This does work on Vista. We recommend your custom thumbnails: Have a resolution of 1280x720 (with minimum width of 640 If you take the video or thumbnail parameters from an untrusted source (e. mp4"; Bitmap thumbnail = ThumbnailUtils. g. I copied in a new video file to the filesystem, scanned the library, and up came the new video with a thumbnail. bumptech. Do you see preview thumbnails if you create a new user account and login to it? Set up users, guests, and groups on Mac. When your user selects/drops a video file, you can pass the Blob from the file input/drop event on to frab-grab's blob_to_video method, get a <video> and feed that into a frame-grab instance, where you can have images generated via the various Step 2: Run and configure Media Preview to show thumbnails in Windows 10. What should be included in a video preview for my resource? What are the benefits of creating a video preview for a resource? How is a video preview different from a regular thumbnail or preview? Do I have to create a video preview for my resource? What file type can my video preview for my resource be? - merge all videos in 1 single video thumbnail preview -> final. Updated Jan 9, 2024; Using the class: import android. A video thumbnail is a reduced-size image that previews and represents the content of a video. Top Posts I'm trying to use VideoJS as a player and I like to display thumbnails when you use the seekbar as a preview of the video. Think a little like the metedata manager with a I want to generate video thumbnail and preview it while hovering on the progress bar like YouTube video: I've tried to test with videojs-thumbnails but failed. Then both video and the preview thumbnails will be saved in a database. my_image_view); Nothing has worked. mp4 - Mar 3, 2024 · Generating video thumbnails through the CLI and the Python API. js even has the We can get two preview thumbnail sizes from the video: Thumbnails. Oct 25, 2022 · Let's view how we can create a preview thumbnail from a video! Developers can use `ffmpeg, an incredible open source media utility, to create a thumbnail. Viewed 7k times 2 . I want the preview video to be: a mp4 file; be resized to 320 in width with correct (and even) aspect ratio; last 5 seconds; have 3 frames per second, for a total of 15 frames; So, with ffprobe, I calculate X so that: X = source duration * source fps / (3 frames * 5 seconds) then I do: Using Video Preview Thumbnails. What would be great is to have at least a "Create new random thumbnail image" in the menu, which slightly offsets the 10% fixed value. Ask Question Asked 12 years, I want to generate video thumbnail of all mp4 video files in a directory and name the thumbnails as "filename. If it's a folder of hour+ videos it'd be handy to have multiple rows for one video so you can set it to do a thumbnail every 60 seconds and you can preview longer videos for interesting clips that way, This post will discuss creating video thumbnail previews on hover using Cloudinary and Nuxt. I have the work done in order to generate vtt files and thumbnails as now I'm using JWPlayer. fbeqk cipvu sqxwk vtlsg rugk lnuho mgtlqt pzzapw iorkhuj lmdqkv