Remove the background from a video, keep the alpha channel.
Most tools that claim this hand back an MP4 with a colour behind your subject. That is a different, much less useful thing. Here is the distinction and why it decides your workflow.
Removed, or replaced?
The word "remove" is doing a lot of work in this category. Two products can both claim it and give you results that are not remotely interchangeable.
Replaced background
The tool cuts your subject and puts white, or black, or a stock beach behind it, then encodes the result as a normal MP4. The background is gone in the sense that it is no longer visible. It is also gone in the sense that you can never change it.
Removed background
Each pixel can be fully visible, partly transparent, or invisible. That transparency is stored in an alpha channel alongside the file’s red, green, and blue colour channels. Nothing is behind your subject. You can add a color, blur, image, or video in Change Background and export an MP4, or keep the transparent WebM for an external editor.
How to tell which you got
Open the file in a browser or drop it on a coloured layer in any editor. If the subject sits on your colour, it is a real alpha channel. If it sits on a white rectangle, it was replaced.
Why the file format matters
An MP4 with H.264 cannot carry alpha at all. If a tool exports MP4 only, it has already flattened your matte, whatever the marketing says. WebM VP9 can carry it, which is what BGRemove exports.
Flattened export against alpha export
Flattened MP4
The background colour is baked into the pixels permanently
Changing that colour means processing the whole clip again
Edges arrive pre-blended against whichever colour was chosen
A dark subject exported on a white fill shows a light fringe at the edge
A flattened export cannot be used as a layer in a composite
Smaller file size, which is the only advantage it has
Alpha channel
Nothing at all sits behind the subject
The background is chosen in the edit, instantly and at no cost
Edges carry real partial transparency, so hair and blur survive
The clip composites cleanly onto any colour or any footage
It works as a layer, which was the entire point
Larger file size, and worth it for what it preserves
Questions people actually ask
Which format should I download?
Transparent WebM using VP9 with a real alpha channel. Whether that transparency shows depends on what opens it: browsers differ, and editors differ by version and platform. If yours will not read WebM alpha, convert to a transparent format its own documentation lists — renaming the file does nothing.
Why is the WebM file so much bigger than my MP4?
It is carrying a fourth channel of data that the MP4 never had, and VP9 with alpha does not compress as aggressively as H.264. This is the cost of keeping the matte.
Can I get an MP4 with a white background instead?
Yes. Open the finished clip in Change Background, choose white under Colour, and export an MP4. Keep the transparent WebM if you may want another background later.
What resolutions are supported?
Output preserves the source video’s dimensions, including vertical and square.
Your next transparent video is one upload away.
Turn real footage into a reusable transparent video with stable motion edges and a real alpha channel.
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