Frequently Asked Questions

This page collects the questions the standards desk receives most often. Each answer is written to be useful on its own, and each links to the page that treats the subject in depth.

Does this site focus on a single encoder project?

No. This is an independent engineering-analytical reference. It documents compression standards, codec architecture and planning methods. Where specific interfaces are compared, they are compared objectively in a single technical table with no recommendation attached.

Which codec should I use?

There is no universal answer. H.264 maximises compatibility, HEVC offers a strong efficiency step at moderate complexity, and AV1 offers the best efficiency where encoder time and player support allow. Choose against your device population and delivery target, then validate with measurement.

What is a rate factor?

It is a dimensionless quality control. A lower value preserves more detail and produces a larger stream; a higher value compresses harder. It does not fix a bitrate, so the resulting rate follows scene complexity. See constant-quality modes.

Does the container affect quality?

No. The container is storage and indexing logic. Quality is decided by the encoder that produced the streams inside it. See container formats compared.

Is hardware encoding worse than processor-based encoding?

Slightly less efficient at equal quality, in most cases. The gap has narrowed, and for high-volume or live work the throughput gain usually outweighs the efficiency difference. For archival masters, processor-based paths remain preferable.

How do I know my settings are good?

Measure. Build a small representative clip set, encode at several dial values, score with a signal metric and a perceptual metric, and inspect the worst frames by eye. Record the conditions alongside every number.

Do you recommend particular values?

We publish anchor values as starting points, always with the conditions attached. Your content and audience decide the final tuning. See the 1080p and 4K profiles.

Why does a dial value not transfer between encoders?

Because each implementation maps the dial to quantisation differently. A value of twenty in one engine and twenty in another are not the same operating point. Re-measure whenever you switch engines.

What is a bitrate ladder?

An ordered set of renditions at descending resolution and bitrate, letting an adaptive player match current network capacity. Planning guidance is on the ladder page.

Where can I read the definitions?

The glossary lists the terms used across the desk, from macroblock to rate factor.