Kernel drivers expect vpud to run in userspace. Encoding and decoding won't work without vpud.
VCU and VPU
VCU (Video Communication Unit) and VPU (Video Processor Unit) are used for encoding and decoding videos. Both terms can be used interchangeably, but VPU is a more prevalent term, it will be used throughout this book.
API
Mediatek provides V4L2 M2M API for high-level VPU operations.
/dev/vcu and /dev/vpu devices are meant for vpud and don't have any relevant encoding/decoding interfaces.
DMA
Most kernel configurations enable CONFIG_VB2_MEDIATEK_DMA_CONTIG. When this config is enabled, kernel drivers use their own mtk_dma_contig_memops, this struct lacks VB2_MMAP and VB2_USERPTR support, which breaks many applications that use these modes.
Devices
/dev/video0- Decoding./dev/video1- Encoding.
Decoding Support
| SoC | AVC | HEVC | VP8 | VP9 | AV1 |
|---|---|---|---|---|---|
| MT6768 | ✅ | ✅ | ✅ | ✅ | ❌ |
Encoding Support
| SoC | AVC | HEVC | VP8 | VP9 | AV1 |
|---|---|---|---|---|---|
| MT6768 | ✅ | ✅ | ❌ | ❌ | ❌ |