i.MX ProcessorsのトピックDecoder Initialization Failed with hevcdec on i.MX8MP (imx-vpu-hantro)

Decoder Initialization Failed with hevcdec on i.MX8MP (imx-vpu-hantro)

Hariharan1 — Mon, 06 Oct 2025 07:16:33 GMT

Hi,

I'm working with the i.MX8M Plus platform and using the `imx-vpu-hantro` package for hardware-accelerated video decoding. While testing the HEVC decoder using the provided testbench (`hevcdec` from `decoder_sw`), I'm encountering a decoder initialization failure.

Here are the details:

- Platform: i.MX8MP
- Kernel: 6.6.52
- Package: imx-vpu-hantro
- Testbench: hevcdec
- Input stream: Animation.h265 (valid HEVC stream)
- CMA: Enabled (`CmaTotal: 983040 kB`, `CmaFree: 945624 kB`)
- Driver: `hantro_vpu` found
- DTS: VPU node status is `"okay"`

**Console Output:**

./hevcdec Animation.h265 Hevc SW build: 196609 - HW build: 67323088 Decoder Macro Block Error Concealment 0 Decoder RLC 0 Decoder Clock Gating 1 Decoder Clock Gating Runtime0 Decoder Data Discard 0 Decoder Latency Compensation 0 Decoder Output Picture Endian 1 Decoder Bus Burst Length 16 Decoder Asic Service Priority 0 Decoder Output Format 0 TB Packet by Packet 0 TB Nal Unit Stream 0 TB Seed Rnd 1 TB Stream Truncate 0 TB Stream Header Corrupt 0 TB Stream Bit Swap 0; odds 0 TB Stream Packet Loss 0; odds 0 DWL Before:0 DWL After:0 DECODER INITIALIZATION FAILED Decoding ended, flush the DPB Releasing 0 external frame buffers Output file: out.yuv OUTPUT_SIZE 0 SW_PERFORMANCE 0.00001 DECODING DONE

It appears the DWL layer is failing to initialize, possibly due to missing hardware bindings or driver registration. I’ve verified that CMA is available, but the Hantro VPU driver may not be loaded or built correctly.

Could you please advise on:
- Required kernel config options for Hantro HEVC decoding
- Device tree bindings for enabling the VPU
- Whether `hevcdec` requires `/dev/videoX` nodes or specific firmware
- Any known issues with `imx-vpu-hantro` on recent kernels

Any guidance would be greatly appreciated.

Thank you.

Re: Decoder Initialization Failed with hevcdec on i.MX8MP (imx-vpu-hantro)

Bio_TICFSL — Mon, 06 Oct 2025 14:26:25 GMT

Hello,

Please refer to the Section 6.6 "Video Processing Unit (VPU)" document. Also, what exactly unit_test flow did you use?

Check this from gstreamer:

https://github.com/Freescale/gstreamer-imx/issues/296

Please specify in more details.

Regards

Re: Decoder Initialization Failed with hevcdec on i.MX8MP (imx-vpu-hantro)

Hariharan1 — Thu, 09 Oct 2025 04:17:22 GMT

I was trying to get clk_summary of vpu. i was getting vpu_g1 set has Y but vpu_g2 set has N. What could be the reason. Is that the reason i am getting more cpu load like 85% when i was decoding H265 whereas H264 decoding was taking just 7% CPU Load.

cat /sys/kernel/debug/clk/clk_summary | grep vpu

vpu_g1 0 0 0 800000000 0 0 50000 Y deviceless no_connection_id
vpu_g1_root_clk 0 0 0 800000000 0 0 50000 N 38300000.vpu_g1 clk_hantro
vpu_pll_ref_sel 0 0 0 24000000 0 0 50000 Y deviceless no_connection_id
vpu_pll 0 0 0 700000000 0 0 50000 Y deviceless no_connection_id
vpu_pll_bypass 0 0 0 700000000 0 0 50000 Y deviceless no_connection_id
vpu_pll_out 0 0 0 700000000 0 0 50000 N deviceless no_connection_id
vpu_g2 0 0 0 700000000 0 0 50000 N deviceless no_connection_id
vpu_g2_root_clk 0 0 0 700000000 0 0 50000 N 38310000.vpu_g2 clk_hantro