How X compresses your uploads, and the settings that survive it best

You spent an hour editing a clip. It looks crisp on your phone. You post it to X and, a minute later, it looks soft, blocky in the dark parts, and smeared whenever something moves. Did you do something wrong?

Usually not. Every major social platform re-encodes uploads, and X is no exception. But how you prepare your file makes a real difference to how well it survives. This guide explains what's happening and what you can control. We run a video tool, so we look at a lot of files after X has processed them. That's where the practical advice here comes from. We don't have access to X's internal encoder settings, so we describe behaviour and stick to X's published guidance, noting where limits are "at the time of writing".

What X does to your upload

When you post a video, X:

1. Accepts your file if it meets its upload requirements (format, size, duration, dimensions).
2. Transcodes it into several versions at different resolutions and bitrates (a "bitrate ladder"), so viewers on slow connections can still play it.
3. Serves those versions to viewers, mostly by adaptive streaming (HLS), so the player can switch quality based on connection speed.

Your original file isn't what people watch. They watch X's re-encodes. Our video formats guide explains the delivery side in detail.

Re-encoding is "lossy": the encoder throws away detail it thinks you won't notice in order to hit a target bitrate. When the target is low relative to how complex your video is, you notice.

Which details suffer most

From what we've seen, these are hardest for any platform's encoder:

• Fast motion and camera shake. Every frame is different, so there's less to reuse between frames.
• Fine texture: grass, gravel, water, fabric, hair, crowds, confetti, rain.
• Film grain and sensor noise, especially in low-light footage. The encoder wastes bits trying to keep random noise.
• Dark scenes and smooth gradients (skies, studio backdrops), which show "banding" and blocky shadows.
• Small text and thin lines in screen recordings, which blur when downscaled.
• Already-compressed sources. A video that went through WhatsApp, a screen recorder or another platform first gets compressed again, and the damage compounds.

Know the upload requirements (and check them yourself)

X publishes its media requirements in its help center. At the time of writing, the commonly cited guidance for standard accounts includes MP4 or MOV files, H.264 video with AAC audio recommended, a maximum file size of 512 MB, a maximum length of 2 minutes 20 seconds, and dimensions within a range that tops out around 1920×1200 (or 1200×1900 vertical), with aspect ratios between roughly 1:2.39 and 2.39:1. Subscribers to X's paid tiers can, at the time of writing, upload longer and larger videos, and the exact limits have changed several times.

Because these numbers change, check X's current "media upload" help page before a big upload rather than relying on any guide, including this one.

The settings that give the best result

These recommendations follow from how encoders work. They aren't secret X settings.

Resolution: 1080p, at the right shape

• Export 1920×1080 for landscape, 1080×1920 for vertical, or 1080×1080 for square.
• Don't upload 4K hoping for better quality. X won't serve 4K for ordinary posts, and your file will be downscaled anyway, often by a lower-quality path than your editing app would use. Downscale yourself, with a good scaler, before uploading.
• Avoid odd sizes like 1918×1078 from cropping. Stick to standard dimensions with even numbers.

Frame rate: keep it native, usually 30

• Export at the same frame rate you recorded: 30 fps for most phone footage, 25 fps if you shot for PAL broadcast, 24 for cinematic footage.
• Higher frame rates (50/60) mean more frames sharing the same bitrate. For gaming or sport, 60 fps can look great if X keeps it for your post. For talking heads, 30 fps gives each frame more data.
• Don't convert between rates unnecessarily (e.g. 25 → 30). It causes judder.

Bitrate: generous, but not absurd

Give X a clean, high-quality source to work from. For 1080p H.264:

• Around 8–15 Mbps for 30 fps is a sensible range for most content. Go higher for grainy or high-motion footage.
• Keep within the size limit: bitrate (Mbps) × duration (s) ÷ 8 ≈ file size in MB. A 2-minute video at 12 Mbps is about 180 MB, comfortably under 512 MB.
• Use VBR (variable bitrate), 2-pass if your app offers it, or a high-quality constant-quality setting.

Uploading 100 Mbps doesn't make X's output better than 15 Mbps. Past a point, you're only making the upload slower.

Codec: H.264 is the safe choice

• H.264 (AVC), High profile, in MP4 is the most predictable choice.
• iPhones record HEVC (H.265) by default. X accepts uploads from the iPhone app, but if you export from an editor, H.264 removes one variable.
• Audio: AAC, 128–320 kbps, 48 kHz stereo.

HDR: usually turn it off for X

Recent phones record HDR video by default. HDR on social platforms is inconsistent: depending on the device, app and viewer, HDR clips can look washed out or oddly bright after processing. Unless you've confirmed HDR looks right on X for your workflow, export SDR (Rec. 709).

Habits that help as much as settings

1. Upload the original, not a forwarded copy. Export from your editor or camera roll directly. Never upload a file you downloaded from a messaging app.
2. Shoot with enough light. Low-light noise is the single biggest quality killer we see. A brighter, cleaner image compresses much better.
3. Stabilise. Use a tripod, a gimbal or your phone's stabilisation, or stabilise in the edit. Less shake means fewer bits wasted on motion.
4. Light denoising before export can help grainy footage. Don't overdo it, or skin turns plastic.
5. Make text big. On-screen captions and titles should be readable on a phone after downscaling. Avoid very thin fonts.
6. Upload on a stable connection. Interrupted uploads can fail or need restarting.
7. Wait a minute before judging. Higher-quality versions can take a little longer to become available after posting, and the player may show a lower rung while buffering.

How to check what X actually made

After posting, you can examine the result:

• Watch it on a large screen at full quality on a fast connection, not just in a feed preview.
• Download your own post with our tool and open it in MediaInfo or VLC to see the resolution and bitrate X kept. This is the most objective comparison with your export.

Troubleshooting

The upload is rejected. Check duration, size and dimensions against X's current help page. Re-export as MP4 (H.264/AAC). Unusual formats like ProRes, MKV or WebM may be rejected.

The video is stuck "processing". Long or large files take time. If it never finishes, re-export at a lower bitrate and try again, and check your connection.

It's sideways or cropped. Make sure the export's dimensions match the intended orientation, not just a rotation flag. Most editors have a "vertical 9:16" canvas option.

Colours look different on X. Probably HDR or a colour-space mismatch. Export SDR Rec. 709.

My video is only 720p on X. Either your export wasn't 1080p, the video was processed at a lower top rung, or the account's upload path limited it. See why 1080p isn't always available.

A note on others' videos

These settings are for your own uploads. If you're re-uploading someone else's video, quality is the least of the issues. Read our fair use guide first, and consider reposting or quoting the original instead.