[RTL8735B / AmebaPro2] Technical Inquiry: 256MB DDR3 Support, VOE Heap Limits, Platform Lifecycle & SDK Closed-Source Components

Hardware
1

Hi Ameba IoT Team / Realtek FAE,

We are finalizing the hardware specifications for a mass-production 1080p camera product based on the RTL8735B (AmebaPro2) platform. Our target application requires running a 1080p30 main RTSP stream concurrently with JPEG snapshots and motion detection sub-channels.

During testing on the 128MB DDR2 EVB, we encountered VOE heap overflow errors when enabling 1080P alongside 4 encoding channels, forcing us to downscale the main stream to 720P for system stability. Therefore, 256MB RAM is a mandatory prerequisite for our 1080P mass production.

SDK Investigation Findings (config.cmake)

In the official SDK (project/realtek_amebapro2_v0_example/GCC-RELEASE/config.cmake), only 64MB and 128MB DDR options are defined:

CMake

if(DDR STREQUAL "128M")
    SAU_INIT_END5 = 0x77DFFFFF      DDR_SIZE = 128
elseif(DDR STREQUAL "64M")
    SAU_INIT_END5 = 0x73DFFFFF      DDR_SIZE = 64
endif()

(Extrapolating the SAU address map, 256MB should mathematically correspond to SAU_INIT_END5 = 0x7FDFFFFF with DDR base at 0x70000000 and 2MB reserved for TrustZone, but this remains unverified.)

Technical Inquiries for Realtek FAE

Section 1: 256MB DDR3 Support & VOE Memory Boundaries (Key Blocker)

  • [Q1 / C-1] 256MB Part Number & Datasheet: Does the RTL8735B officially support 256MB DDR3? If supported, what is the exact commercial part number (e.g., is “RTL8735BDM-VA9-CG” valid?) and datasheet?

  • [Q2 / C-2] DDR Controller Initialization: Beyond updating SAU_INIT_END5 and DDR_SIZE, are additional DDR controller timing, row/column address width, or PHY initialization changes required? Are these parameters configured in boot.bin, ROM code, or customizable in SDK source code?

  • [Q3 / C-3] CRITICAL BLOCKER - VOE / libvideo Memory Limit: Can the precompiled libvideo / VOE engine dynamically utilize physical memory beyond 128MB? Does libvideo contain any hardcoded address boundary or heap size assumptions that limit its operation above 128MB?

    If VOE cannot allocate memory above 128MB, 256MB will not solve our multi-stream heap overflow issue, requiring an immediate architecture pivot.

  • [Q4 / C-4] 256MB Reference Designs: Are there official reference designs, EVBs, or mass-production customer cases utilizing 256MB RAM on RTL8735B?

  • [Q5 / C-5] Supply Chain & Lead Time: What is the current mass-production availability, Minimum Order Quantity (MOQ), and typical lead time for the 256MB SoC variant?

Section 2: Platform Lifecycle, Certification & Interfaces

  • [Q6 / C-6] Product EOL Commitment: What is Realtek’s official longevity / EOL (End-of-Life) commitment period (in years) for the RTL8735B / RTL8735C product family?

  • [Q7 / C-7] Full Datasheet Access: Can we obtain the complete NDA datasheet (including the full Pin Mux matrix and FEPHY electrical parameters)?

  • [Q8 / C-8] ONVIF Compliance Reference Cases: Are there existing customer products built on AmebaPro2 that have successfully passed ONVIF Profile T or Profile G certification?

  • [Q9 / C-9] SDIO Performance & Bus Contention: For continuous 7x24 SD card recording (~250 KB/s write throughput) running simultaneously with RTSP video streaming, has bus contention been evaluated? Does the hardware support SDIO High-Speed mode?

  • [Q10 / C-10] SDK Closed-Source Component Inventory: Besides libvideo, libwlan, and USB CDC-ECM, what other pre-compiled binary libraries (.a / .bin) exist in the Standard SDK? Please provide a full list to assist our long-term maintenance and risk assessment.

Thank you for your technical support. We look forward to your feedback to finalize our hardware design freeze.