DDS to HRZ Converter

Turn DDS into HRZ format quickly online

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Data Safety First

All uploaded DDS data is wiped after processing. Converted HRZ results expire from the server within 24 hours automatically.

Bulk Conversion

Upload multiple DDS files and convert them all to HRZ in one session. Each processes independently — download all results at once.

Format Versatility

Beyond HRZ, Convertio supports dozens of output formats for your DDS files. One tool handles all your conversion needs.

How to convert DDS to HRZ

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose hrz or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your hrz file right afterwards

About formats

DDS (DirectDraw Surface) is a container format for storing compressed and uncompressed textures, cube maps, volume textures, and mipmap chains, introduced by Microsoft with DirectX 7.0 on September 22, 1999. DDS files are designed for GPU-native consumption: the pixel data is stored in formats that graphics hardware can decompress directly during rendering — primarily S3TC/DXTn block compression (DXT1, DXT3, DXT5), and in later DirectX versions BC4 through BC7 — eliminating the CPU-side decompression step required by formats like PNG or JPEG. The file structure begins with a magic number and a 124-byte header specifying width, height, pixel format, mipmap count, and optional DX10 extended header for newer compression modes, followed by the raw surface data. DDS supports 2D textures, cube maps (six faces for environment mapping), volume/3D textures, and texture arrays, each with pre-computed mipmap chains that allow the GPU to sample appropriately sized versions at different distances. One advantage is rendering performance: because the GPU reads DDS data directly without decompression overhead, texture loading is dramatically faster than with traditional image formats, and the compressed data stays compressed in video memory, allowing more textures to fit in VRAM simultaneously. The format's dominance in game development is another key strength — DDS is the standard texture format for DirectX applications, supported natively by Unreal Engine, Unity, and virtually every PC game engine, as well as by image editors like GIMP (with plugin), Paint.NET, Photoshop (via NVIDIA plugin), and ImageMagick.
Developer: Microsoft
Initial release: September 22, 1999
HRZ is a simple raster image format associated with slow-scan television (SSTV), a method of transmitting still images over radio frequencies used by amateur radio operators since the late 1950s when Copthorne Macdonald pioneered the technology. HRZ files store images at a fixed resolution of 256x240 pixels in raw RGB format, with each pixel represented as three bytes (red, green, blue) at 8 bits per channel, producing uncompressed files of exactly 184,320 bytes. The format has no header, no metadata, and no compression — the file is simply a sequential dump of raw pixel data in row-major order. This extreme simplicity reflects the format's origins in the amateur radio community, where SSTV images are transmitted as audio tones encoding luminance and chrominance values over narrow-bandwidth HF (shortwave) radio channels. The fixed 256x240 resolution corresponds to common SSTV transmission modes, and HRZ files serve as the digital capture or storage medium for received SSTV transmissions. One advantage is the format's zero-overhead structure: with no parsing, decompression, or metadata processing required, HRZ files can be read by any program capable of reading raw pixel data with known dimensions — a single function call in virtually any programming language. The format's connection to amateur radio SSTV culture is another notable aspect: HRZ files document a unique form of image communication where operators transmit photographs over thousands of miles using nothing but radio waves and audio encoding, a practice that continues today alongside digital modes. HRZ files can be opened by ImageMagick, GIMP, and specialized SSTV software.
Developer: SSTV Community
Initial release: 1985

Frequently Asked Questions

Why convert DDS to HRZ?

DDS mipmap chains and compression make files hard to share with non-technical colleagues. HRZ is universally readable.

What programs open HRZ files?

ImageMagick and slow-scan television (SSTV) software open HRZ radio image format files

Does DDS to HRZ conversion preserve quality?

The converter optimizes for best visual fidelity. HRZ may apply compression

Will the converted HRZ keep the original resolution?

Yes — the default conversion preserves the original pixel dimensions

Does the conversion preserve transparency?

HRZ does not support transparency natively. Alpha channel data from DDS will be flattened against a solid background during conversion.

Can I batch convert multiple DDS files to HRZ?

Upload several DDS files at once. Each one converts to HRZ independently — download them individually or together when all are done.