BC7 is the quality champion of the block compression family. If DXT1 and DXT5 are the reliable workhorses, BC7 is the format you reach for when a texture simply has to look its best. This guide explains what BC7 is and when the larger file is worth it.
What BC7 is
BC7 is a modern block compression format introduced with DirectX 11. Like the DXT formats it works on 4 by 4 pixel blocks, but it stores each block with far more flexibility. It supports high quality colour and a full alpha channel in the same 16 bytes per block that DXT5 uses, yet it produces noticeably cleaner results.
How BC7 works
The clever part of BC7 is that it can pick from several internal modes for each block. One block might use more bits for colour, another might split into two colour regions to capture a sharp edge, and another might dedicate precision to alpha. By choosing the best mode per block, BC7 avoids many of the artifacts that older formats show on gradients and detailed areas.
BC7 versus DXT
| Format | Quality | Size | Alpha |
|---|---|---|---|
| DXT1 | Good | Smallest | 1 bit |
| DXT5 | Good | Medium | Full |
| BC7 | Excellent | Same as DXT5 | Full |
At the same size as DXT5, BC7 gives smoother gradients and fewer blocky artifacts. The catch is that encoding a true BC7 file is far more computationally demanding, which is why some fast tools offer a high quality uncompressed stand in instead.
When to use BC7
Use BC7 for hero assets: character faces, close up props, detailed skyboxes, and anything a player will study up close. For background textures that are rarely seen in detail, DXT1 or DXT5 usually save space with no visible downside. Choosing PNG to DDS high-quality output where it counts, and lighter formats elsewhere, is how experienced artists balance a texture budget.
BC7 in the browser
Full BC7 block compression is heavy to compute, so our browser converter writes a high quality, visually lossless surface inside a DDS container when you choose the BC7 option. It opens where BC7 is expected and looks pristine, though the file is larger than a true BC7 encode. When you need the smallest compressed file, DXT1 or DXT5 remain the right call.
Frequently Asked Questions
In quality, yes. At the same file size BC7 shows smoother gradients and fewer artifacts. It costs much more to encode, which is its main trade off.
Yes, BC7 stores a full alpha channel, so it handles smooth transparency as well as high quality colour.
For background or rarely seen textures, DXT1 or DXT5 usually look fine and save space and encoding time.
