Hardware decoding uses dedicated or supported device acceleration to turn compressed media into pictures or sound. It can reduce general processor load for formats the hardware and application support. Compatibility still depends on the actual stream properties and software path, so enabling acceleration does not guarantee that every codec, profile or resolution can be decoded successfully.
A practical example
A compatible television box may play a supported high-resolution stream smoothly using its media hardware. Another format may require software decoding or fail because the necessary acceleration path is unavailable to the particular app installed on that device.
A common misunderstanding
Do not treat hardware decoding as an always-correct setting for every source. A source-specific or implementation problem may need a controlled alternative test while preserving the original configuration for comparison.
Related terms
Stable technical definition. Editorial approach