A more detailed ffmpeg command ffmpeg -i input.mp4 -c:v libvpx-vp9 -b:v 1M -c:a libopus output.webm If the filename has spaces you need to enclose it in quotes: -i "my file.mkv" output.webm The name of the converted WebM. i input.mkv The file you want to convert. In order to make good quality WebMs, we need to add extra options to fine-tune it.įirst, let's examine the structure of an ffmpeg command:įfmpeg Starts the ffmpeg program you have on your computer. However, this will give you a really shitty WebM that everyone will mock you for. OS X Users: The homebrew version of ffmpeg doesn't include WebM support by default, try brew install ffmpeg -with-libvpx.Ĭommand line options The basic command ffmpeg -i input.mkv output.webm Make sure you know which one you are using. Note: avconv and ffmpeg are not entirely drop-in replacements. No audio streams except on /gif/ and /wsg/.Maximum resolution is 2048x2048 pixels.Maximum duration is 300 seconds (5 minutes).Maximum file size is 4096KB for /gif/ and 6144KB for /wsg/.See a list of useful archived 4chan threads further down the pageĬurrent limits for WebM files on 4chan are: This wiki page is meant to serve as an instructional tool to help you get started converting your content to WebM for posting. WebM also supports the new AV1 video codec, but 4chan currently does not. In 2013, it was updated to accommodate VP9 video and Opus audio, however it took 4chan until July 2022 to implement it.
WebM initially supported VP8 video and Vorbis audio streams. The WebM container is based on a profile of Matroska. On imageboards WebMs serve the same purpose as GIFs, that is, to encode short clips of anime, pornography and cartel beheading videos. The development of WebM is unfortunately sponsored by Google, and the corresponding software is distributed under some BSD license. It has a sister project, WebP, which is a shitty image format that nobody cares about.
It is primarily intended to offer a royalty-free alternative to use in the HTML5 video and the HTML5 audio elements. WebM is an audiovisual media file format. 4.1 Manipulating individual video, audio and subtitle streams.2.3 Calculating the best bitrate to fit within the size limit.