View source for WebM

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[[File:WebM logo.svg.png|160px|left]]
'''WebM''' (file extension <code>.webm</code>) is a video file format developed by {{wiki|Google}}, based upon the {{w|Matroska}} (MKV) container format. WebM was originally designed to be used on webpages to save bandwidth, but it also has some benefits when it comes to video games and many other applications.

In Source and Source 2 games, WebM is being used in {{csgo|1}} and {{cs2|1}} as menu backgrounds. And in {{tf2|1}} (since 2024 engine update), aswell as {{hl1|1}} (25th anniversary), for Valve intro during startup.

The biggest benefit of WebM over [[BIK|Bink]] (or [[AVI]]) for games is that of file size; a WebM video will be significantly smaller than that of a similar-quality Bink file as WebM has better compression than Bink. For example, the installation size of {{hdtf|4.1}} decreased by 5.7 GB when switching its FMV cutscenes from Bink to WebM{{cite|1}}. Furthermore, WebM is much more common and easier to make than the Bink file format, as Bink requires the RAD Video Tools software that only takes AVI files (MP4 initially required QuickTime until the requirement was eventually removed as QuickTime for Windows is no longer supported by Apple), and may fail to convert MP4 to BIK (with "Unable to open file" error) on some systems.

WebM is supported in the following games, engines, and engine branches:
{| class="wikitable"
|-
! <!--this cell intentionally left blank-->
! colspan=3 | Video codecs
! colspan=2 | Audio codecs
|-
! Implementation 
! [[w:VP8|VP8]] !! [[w:VP9|VP9]] !! [[w:AV1|AV1]] !! [[w:Vorbis|Vorbis]] !! [[w:Opus (audio format)|Opus]]
|-
| {{src2|4.1}} ({{cs2}} tested)
| {{Yes}} || {{Yes}} || {{No}} || {{Yes|Yes**}} || {{Yes|Yes**}}
|-
| {{gldsrc|4.1}}<br>(since 25th anniversary update; intro video only)
| {{Yes}} || {{Yes}} || {{No}} || {{Yes|Yes*}} || {{Yes|Yes*}}
|-
| {{csgo|4.1}}<br>(since 2018 Panorama update)
| {{Yes}} || {{Yes}} || {{No}} || {{Yes|Yes***}} || {{No}}
|-
| {{tf2branch|4.1}}****</br>(64-bit only)
| {{Yes}} || {{Yes}} || {{No}} || {{Yes}} || {{No}}
|-
| {{strata|4.1}}
| {{Yes}} || {{Yes}} || {{No}} || {{Yes}} || {{No}}
|-
| '''[https://github.com/nooodles-ahh/video_services/tree/master WebM Video Services]''' for {{src13}}<br>(used by {{hdtf|4.1}})
| {{Yes}} || {{Yes}} || {{No}} || {{Yes}} || {{Yes}}
|-
|}
:<nowiki>*</nowiki>Audio is read, but muted. {{file|<moddir>/sound/ui/valve_sound|wav}} is used instead.
:<nowiki>**</nowiki>Audio is read, but muted. {{only|{{cs2}}}} If the video was unable to play due to incompatible codecs or other codecs issue, then part of the intro sounds ({{file|sounds/ui/logo_startup|vsnd_c}}, which is played separately) will not play or likely be played in lower volume.
:<nowiki>***</nowiki>Sometimes audio plays in slower speed and lower pitch.
:<nowiki>****</nowiki>Support added in {{tf2}} since April 18, 2024/64-bit update. Later, {{hl2dm}} 20th anniversary, and all remaining {{src13mp|1}} games ({{css}}, {{dods}} and {{hldms}}) upgraded to the {{tf2branch|1}}, which now adds WebM support, however, these upgraded games (aside from TF2), still only ship with the Valve intro in [[Bink]] format. This meant that you will need to launch the game in 32-bit to play the intro, as 64-bit version now requires WebM, and these games (except TF2) do not ship with WebM version of Valve intro, causing the game to skip it. This also meant that the 64-bit binaries was coded to use WebM, while 32-bit versions still support and use Bink.

To convert a 1080p MP4 file to a WebM that will reliably play in the the above games and have reasonable quality and encoding speed, use the following {{w|ffmpeg}} script:
{{codeblock|ffmpeg -i input.mp4 -acodec libvorbis -ab 128k -vb 0 -crf 31 output.webm}}
* To increase audio quality, increase {{code|-ab}}.
* To increase video quality, reduce {{code|-crf}}. Lower values may be necessary for higher ''and'' lower resolutions to reduce macroblocking artefacts.

{{References|1=
{{Ref2|cite id=1|1=[https://store.steampowered.com/news/app/723390/view/5409426666000801989?l=english Hunt Down The Freeman - July blog: where we're at + looking for team members! - Steam News]
{{quote|Bink video is replaced with webm (like CSGO and Source 2) and has successfully freed up 5.7GB of space}}}}
}}

== External links==
*{{Wiki|WebM|WebM on Wikipedia}}
[[Category:File formats]]
[[Category:Valve Open Source]]