OpenIMP

OpenIMP is an open implementation of Ingenic's libimp video API. It runs against the stock ISP, sensor, FrameSource, and AVPU kernel drivers.

Architecture

There is one encoder implementation for T31, T40, and the T41 bring-up:

• src/t40/openimp_p2_encoder.c owns the public encoder lifecycle.
• src/t40/codec-t40.c owns the shared AVPU codec backend.
• src/al_avpu.c, src/device_pool.c, src/fifo.c, and src/hw_encoder.c provide the common hardware path.
• src/t31/, src/framesource/framesource_tseries.c, src/isp/isp_tseries.c, src/kernel_interface.c, and src/dma_alloc.c are the T31 stock-driver ABI seam.
• src/t40/openimp_p1.c and src/t40/openimp_p2_dma.c are the corresponding T4 stock-driver seam, with explicit T40/T41 ABI branches.

T31 does not carry a separate scheduler, rate-control graph, or codec implementation. Platform conditionals are restricted to real ABI differences such as public structure sizes, ioctl layouts, device behavior, and cache maintenance.

Audio processing belongs to libaudioProcess-neo. Logging and system support libraries belong to ingenic-system-libs-neo. OpenIMP's normal builds do not export audio APIs or build replacement libsysutils/libalog libraries.

Build

# T31 (default)
./build-for-device.sh
# or
make t31

# T40/T40XP
./build-for-device.sh T40
# or
make t40

# T41/T41NQ
./build-for-device.sh T41
# or
make t41

Outputs:

• build/t31/libimp.so
• build/t40/libimp.so
• build/t41/libimp.so

Both build scripts reject a produced library that depends on an OEM libimp.so. The T31 build additionally rejects accidental audio exports and records RVD import coverage in build/t31/.

Current status

• T40: decoder-clean, resolution-independent H.264 streaming through the stock T40XP ISP and AVPU drivers.
• T31: the shared T40-derived encoder ran for more than 1,000 hardware frames on a stock-driver GC2053 camera. Main 1920x1080 H.264 and AAC probed and decoded without H.264 errors during the device smoke cycle. The T31 FrameSource seam now preserves the kernel DQBUF completion timestamp in the OEM frameInfo.timeStamp slot at offset 0x20; the shared encoder copies that capture timestamp into each public pack instead of substituting encoder-start wall time. A 30-second live decode completed 721 frames with zero duplicate/non-monotonic DTS warnings, compared with 11 warnings in the prior 12-second checkpoint.
• Capture ownership is an explicit platform policy: T31 returns a frame after AVPU completion, while T40 returns it immediately after submission. This preserves full-rate capture on both stock-driver ABIs.
• T41: active bring-up. The T41 build covers every RVD/RAD IMP import and the stock-driver pipeline reaches live dual-channel FrameSource capture and the native T41 AVPU command-slot submission. H.264 output is not yet valid: the remaining blocker is conversion of the inherited T40 command payload into T41's 4 KiB command/status layout.
• Sensor configuration and tuning remain owned by the stock ISP driver, so the userspace encoder is sensor-independent.

See docs/T40_STATUS.md and docs/T41_STATUS.md for the detailed runtime gates.