Why a GIF from X downloads as an MP4, and what a real .gif costs

You found a GIF on X, saved it, and got a file ending in .mp4. Nothing went wrong. This page explains what X does to a GIF, shows what we measured on 8 real GIFs on 5 October 2026, and helps you decide when a real .gif is worth its size.

What X does to a GIF

X serves every GIF as a short MP4 video with no sound. When you watch a GIF on X, your phone or browser is playing a video on a loop. There is no .gif file on the page, so a downloader has none to give you. It gives you the MP4 that X plays.

We checked this on 8 GIFs from five accounts, posted between 2018 and 2026 (GIPHY, NASA, MSNBC, a four-GIF post by MewZe, and Hidden Power Podcast). Every one came back the same way:

• One file, one size. A video on X comes in several sizes. A GIF comes as a single MP4.
• H.264 video, no sound track. Not a quiet track: no sound track at all.
• Small pictures. The largest was 680 by 382 pixels; two were only 220 pixels wide.
• A .mp4 address. For NASA's post, the file was video.twimg.com/tweet_video/...mp4.

For comparison, a real video post we read the same day (West Bromwich Albion, 5 seconds, 1080 by 1920) offered four sizes plus a separate sound track. That difference is how you can tell, from the download alone, whether someone posted a GIF or a video.

Many guides now say the same thing: X turns GIFs into MP4. None of the top results we read gave a single number for it. The rest of this page is the numbers.

How much bigger a real .gif is

A real .gif of the same clip was 5 to 63 times bigger than the MP4 X serves, in our test. We took each MP4 and made two GIFs with ffmpeg:

• Raptor's GIF: the settings our Animated GIF button uses: 10 frames a second, at most 480 pixels wide (never enlarged), and a palette of 128 colours made for that clip.
• Full GIF: the same size and frame rate as the MP4, with one 256-colour palette, the most a GIF frame can hold.

Sizes are in thousands and millions of bytes. The script that made this table is measure_x_gif.py in our tooling, run on our test computer with yt-dlp 2026.08.19 and ffmpeg.

Three things stand out:

• Even a cut-down GIF is far bigger. Dropping to 10 frames a second and 128 colours still left every GIF at least 4.9 times the MP4.
• Smooth clips cost the most. The MSNBC clip runs at about 34 frames a second. As a full GIF it grew to 11.2 MB, from 351 KB.
• Real videos are worse. The 5-second video from West Bromwich Albion is 2.98 MB as an MP4. As a full-size GIF it was 109 MB. Raptor's GIF of it was 7.36 MB, but only because it shrank the picture to 480 by 854 and kept 10 frames a second.

Why the gap is so big: the GIF format stores every frame as its own picture, squeezed one picture at a time. H.264 in an MP4 mostly stores what changed since the last frame. A loop where little moves is almost free in MP4 and still costs a full picture per frame in GIF.

What the GIF format cannot do

A GIF frame holds 256 colours at most, and its timing works in hundredths of a second. Both limits come from the GIF specification itself, dated 31 July 1990.

Colours. The colour table in a GIF has 2 to the power of (a 3-bit number + 1) entries, so 256 at the very most. MDN, the reference for web developers, says the same: each palette "has 2, 4, 8, 16, 32, 64, or 256 entries", and "to simulate more than 255 or 256 colors, dithering is generally used". Dithering is the fine dot pattern you see in GIFs of skies, skin and shadows. An MP4 frame has no palette, so it keeps smooth colour.

Timing. The specification defines the delay between frames as "the number of hundredths (1/100) of a second to wait". A clip at 15 frames a second needs 6.67 hundredths per frame, which a GIF cannot store. Our measurements show the result: the GIPHY and NASA clips, about 15 frames a second as MP4s, came out at 16.67 as full GIFs (6 hundredths per frame). The 34-frame MSNBC clip came out at 33.33. A GIF can only play at speeds like 50, 33.3, 25, 20, 16.7 or 10 frames a second.

Sound. GIF has no place for sound. That fits X, whose GIFs have none anyway.

X's own limits for posting a GIF

X's developer documentation sets four limits for an animated GIF in a post. They apply when you upload, not when you download:

The pixel rule is the one people miss. At the full 1280 by 1080, each frame has 1,382,400 pixels, so 300 million allows only 217 frames, not 350. That is under 9 seconds at 25 frames a second. And with our measurements in mind, the 15 MB cap is easy to hit with a real .gif even when the same clip as an MP4 would be tiny.

When a real .gif is worth it

Keep the MP4 unless the place you are sending it accepts GIF and nothing else. MP4 is smaller, sharper and plays almost everywhere:

To get a real .gif from an X post with Raptor Downloader, paste the post's link and press Animated GIF. We download the MP4 and make the GIF on our server with the settings above. The button appears for GIF posts and for videos up to 30 seconds. Until 5 October 2026 it did not appear for GIF posts at all, because X gives them no length and our button waited for one; that is fixed.

If you want full control instead, the full-GIF settings from our table are one ffmpeg command:

ffmpeg -i clip.mp4 -vf "split[a][b];[a]palettegen=max_colors=256[p];[b][p]paletteuse" -loop 0 clip.gif

To make the file smaller, add fps=10,scale=480:-2, at the start of the part in quotes (leave out the scale part if the clip is already narrower than 480 pixels, or it gets bigger). Fewer frames and a smaller picture cut the size more than anything else.

What you cannot download

Only public posts can be saved. Posts from protected accounts, and posts X hides behind a sensitive-content warning for logged-out visitors, need a login, and we never log in to anyone's account. A downloader cannot make those public, and it should not try.

The GIF also still belongs to whoever made it. Many reaction GIFs are clips from films, shows or games, so the rights sit with a studio, not with the person who posted it. Keeping one to watch or to send to a friend is a different thing from using it in an advert or your own channel. For anything public, ask first or use an official GIF library that licenses its clips.