The Linux Foundation: Implementing a Stateless V4L2 Decoder Driver: Architecture and Lessons Learned - SungHo Lee & Media

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Implementing a Stateless V4L2 Decoder Driver: Architecture and Lessons Learned - SungHo Lee, Chips&Media

Stateless video decoding has become the standard approach in V4L2 using the Request API, but implementing a stateless decoder driver remains complex. It requires careful handling of codec parameters, buffer management, and coordination between userspace and the kernel.

This session presents a practical overview of implementing a stateless V4L2 decoder driver based on real development experience. It covers how SPS/PPS and per-frame parameters are passed from userspace, how reference frames are managed, and how hardware constraints are handled within a generic V4L2 framework.

We also discuss common pitfalls such as synchronization issues and buffer lifecycle management, and highlight key differences from traditional stateful decoders.

Attendees will gain a clear understanding of stateless decoder architecture and practical insights for developing robust V4L2 drivers.