23 Oct 2026 · 6 min read
Steam will not let you release without a trailer, and it is one of the first things a visitor sees. Here is everything Valve asks for in one place: the upload spec, how the order of your trailers decides what plays first, how the microtrailer is made, and what to do when a trailer is stuck on converting. Checked against the Steamworks documentation on 23 Oct 2026.
Upload in the Store Page Admin, on the Trailers tab. Steam re-encodes every file, so send the best master you have rather than a small web export.
| Setting | What Steam asks for |
|---|---|
| Resolution | The highest you have, up to 1920 x 1080 |
| Aspect ratio | 16:9 preferred, 4:3 accepted |
| Frame rate | 30 (29.97) or 60 (59.94) fps |
| Bitrate | 5,000 kbps or more. Valve's own encoder preset uses 20 Mbps |
| Container | .mp4, .mov or .wmv |
| Codecs | H.264 video and AAC audio preferred; Steam can transcode many others |
| Audio | 44 or 48 kHz sample rate. Surround is mixed down to stereo |
| Custom poster | A frame from the video, 1920 x 1080, .jpg or .png |
If your editor has no Steam preset, this ffmpeg command turns a master into a file that matches the spec. It keeps your frame rate, pads anything that is not 16:9 instead of stretching it, and uses the same 20 Mbps and 192 kbps AAC as Valve's preset:
ffmpeg -i master.mov \ -vf "scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2" \ -c:v libx264 -preset slow -b:v 20M -maxrate 20M -bufsize 40M -pix_fmt yuv420p \ -c:a aac -b:a 192k -ar 48000 -ac 2 \ -movflags +faststart trailer-steam.mp4
The Steamworks docs set no maximum length. What Valve does say is more useful: in the Discovery Queue you may have less than 10 seconds to make an impression, and many people watch without sound. So show the game being played in the opening seconds, and make sure it still makes sense on mute.
While processing, Steam generates a 600 x 380 poster that shows until the video starts, and a 232 x 130 thumbnail for the trailer list. To use your own, it must be a frame from the video itself at 1920 x 1080. Valve suggests a frame that shows something unique, without text.
DE,FR,US,CA,MX.Upload trailers days before you need them, not on launch morning or the first day of Next Fest. The queue is shared with everyone else releasing that week.
The trailer is a file Steam hosts and plays on request. A store page broadcast is a live stream at the very top of the page, above the screenshots, and it has its own spec: a constant bitrate of at most 7,000 kbps, so a 20 Mbps trailer master cannot be streamed as it is. Steam broadcast video specs has the numbers. Many developers air a longer gameplay cut as the broadcast, so the page offers something the trailer does not. What a store broadcast is explains how it works, and Loopcast keeps one live around the clock from our servers, so no PC has to stay on.
Next up for your page: the capsule art sizes and the full store page checklist.
Sources: Trailers, Review process, Setting up a broadcast. Checked 23 Oct 2026. Valve updates these pages; the Steamworks docs always win.