Two ways to run an encoder
Encoding a video is a heavy calculation, and it can be done in two broad ways.
Software encoding runs the encoder as a program on the general-purpose processor (CPU). The best-known open-source examples are x264 for H.264 and x265 for HEVC. The same code can run on many machines, and developers can keep tuning the algorithms.
Hardware encoding uses circuitry built to do the job. Often this is a dedicated media engine inside a graphics card or a processor, or a block in a phone chip. Vendors provide interfaces to it, such as NVENC on Nvidia graphics cards, Quick Sync on Intel processors, VideoToolbox on Apple platforms and AMD’s encoding blocks. Feature sets differ between hardware generations, so what one chip can do, another may not.
A third term, GPU-accelerated encoding, can be confusing. In most products “GPU encoding” refers to the dedicated encoder block sitting on the graphics chip, not to the general shader cores. Some software encoders also offload parts of the work to the GPU, which is a different thing.
Speed
Hardware encoders are typically much faster than software encoders running at comparable settings. Because the logic is fixed in silicon, they can handle high-resolution video in real time or faster while leaving the CPU free for other tasks. That is why hardware encoding is the default in many camera apps, screen recorders, video calls and editing exports.
Software encoders offer a range of presets. Fast presets approach hardware speeds with lower efficiency, while slow presets spend much more time searching for savings. The wait for a slow software encode can be long, particularly for modern codecs such as AV1.
Quality and efficiency
Here the trade-off tends to run the other way. At the same bitrate, a well-tuned software encoder on a slow preset commonly delivers better visual quality than a hardware encoder, because it can test many more options for each block of the picture. Put another way, it can reach similar quality with fewer bits, which affects file size and the cost of delivery.
The gap is not fixed. Hardware encoders have improved with each generation, and for many uses the difference is small, especially at higher bitrates. It also varies by codec, vendor and settings, so general claims should be read as tendencies. If quality matters, compare the two on your own footage.
Software encoders also offer more control. They typically expose a larger set of tuning options and rate control modes, which can matter for specialised work.
Power and heat
Hardware encoding generally uses less energy per frame than doing the same job on the CPU. On a laptop, that can mean quieter fans and longer battery life. On a phone it is often the only practical way to record high-resolution video without overheating. Software encoding at heavy settings can keep a CPU at full load for long periods.
Who benefits from which
Live streaming and game capture. Streamers often run a game and an encoder on the same machine. Hardware encoding uses little CPU, so the game runs more smoothly. Software encoding can give a cleaner picture at a given bitrate, but it takes processing power away from the game unless a second computer handles the encoding. Platforms limit the upload bitrate, so efficiency matters. A fast but well-tuned hardware encoder is a frequent compromise. Each choice also affects stream latency, since the encoder is one stage of the delay.
Video editing. Editing software commonly uses hardware encoders for quick exports and previews. For a final delivery master, some editors prefer a slower software encode for better efficiency, though hardware results are often entirely acceptable.
Archiving and large libraries. When a video will be stored for a long time or watched many times, spending extra encoding time to save bits can be worthwhile. A streaming service encoding a large catalogue may choose slow software encoders for that reason, because the time is spent once while the savings repeat for each viewer. Hardware options also exist at data-centre scale, trading some efficiency for throughput.
Mobile and cameras. Recording on a phone or camera nearly always uses a hardware encoder. The device has no spare power budget for software encoding at that resolution, and the quality is designed around the chip.
Video calls. Real-time communication relies on fast, low-delay encoders, and hardware support helps keep calls smooth. See WebRTC calls for more.
Compatibility and limits
Hardware encoders support only the codecs and features their silicon includes. A graphics card may encode H.264 and HEVC but lack AV1 encoding, or support them only in newer models. Some setups cannot use particular bit depths, colour formats or high dynamic range modes in hardware. Software encoders are not limited in that way; if a codec exists, someone can usually run it in software, however slowly.
Driver and software versions also influence results. It is common for the same graphics card to perform differently after an update, so older advice can become outdated.
A practical rule of thumb
- Choose hardware when speed, responsiveness or battery life matter most, and when slightly larger files are acceptable.
- Choose software when you want the best quality for a given file size and can wait.
- If you are not sure, test a short clip both ways at the same bitrate and compare the hard scenes. Check file size, visual quality and encoding time together, since improving one often costs another.
Neither approach is universally better. They are tools suited to different constraints, and many workflows use both, drafting with hardware and finishing with software.