How to Set rav1e Encoder Speed in FFmpeg

This article provides a quick guide on how to configure the speed parameter for the rav1e AV1 video encoder using FFmpeg. You will learn the correct command-line syntax, the range of available speed values, and how to balance encoding velocity against compression efficiency to get the best results for your video projects.

To adjust the encoding speed of the rav1e encoder in FFmpeg, you must use the -speed private option. The speed scale for rav1e ranges from 0 to 10, where lower numbers prioritize compression efficiency (resulting in smaller files but extremely slow encode times) and higher numbers prioritize processing speed (resulting in faster encodes but lower compression efficiency).

The FFmpeg Command Syntax

Here is the basic command template to set the speed parameter:

ffmpeg -i input.mp4 -c:v librav1e -speed 5 output.mp4

Understanding the Speed Values

• 0 (Slowest): Offers the maximum compression efficiency and visual quality. This level is extremely resource-intensive and is typically used only for archival purposes or benchmarking.
• 5 to 6 (Balanced default): This range is the recommended sweet spot for general use, offering a reasonable compromise between encoding time and output quality.
• 10 (Fastest): The fastest encoding speed. This is ideal for rapid testing or real-time streaming experiments, though it will result in larger file sizes.

Combining Speed with Quality Controls

When configuring the speed, you should also define your quality target. In FFmpeg, rav1e supports quality control using the Quantizer Parameter (-qp). The -qp scale ranges from 0 to 255 (where lower values mean higher quality).

For example, to encode a video with a balanced speed of 6 and a high-quality target QP of 80, use the following command:

ffmpeg -i input.mp4 -c:v librav1e -speed 6 -qp 80 output.mp4