OpenCV "no support for memory mapping"--any workarounds?
Hi all, Trying to run an OpenCV python script on a Raspberry Pi 4 with 7.3 and 4G of ram with a single 2K webcam. I'm getting this when I try to set the camera to shoot at 2K resolution (1920px x 1080px): capture is open... [ WARN:0@2.098] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.115] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.115] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.115] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.115] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.115] global cap_v4l.cpp:847 requestBuffers VIDEOIO(V4L2:/dev/video0): Insufficient buffer memory [ WARN:0@2.131] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.131] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.131] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.131] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.131] global cap_v4l.cpp:847 requestBuffers VIDEOIO(V4L2:/dev/video0): Insufficient buffer memory [ WARN:0@2.154] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.154] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.154] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.154] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.154] global cap_v4l.cpp:847 requestBuffers VIDEOIO(V4L2:/dev/video0): Insufficient buffer memory FPS: 30.303, Height: 480.0, Width: 640.0, Exp: auto, Gain: auto, AutoExp: -1.0, Frames: 3 Requested 1920 x 1080 and got 640 x 480. I had a similar issue before with an amd64 stick: https://marc.info/?l=openbsd-ports&m=162862043308236&w=2 This is OpenCV installed from packages: jross@allsky:/home/jross $ pkg_info opencv Information for inst:opencv-4.7.0 It would seem then that this problem isn't going away any time soon but if someone has a workaround I'd love to hear it. I had hoped to use the RPi4 to drive 5 of these 2K webcams to make an allsky camera. I have an amd64 with 16G of ram that I'll try next just in case there's a big difference between amd64 and arm64. Jeff dmesg: jross@allsky:/home/jross $ dmesg OpenBSD 7.3 (GENERIC.MP) #2080: Sat Mar 25 14:20:25 MDT 2023 dera...@arm64.openbsd.org:/usr/src/sys/arch/arm64/compile/GENERIC.MP real mem = 4124950528 (3933MB) avail mem = 3963645952 (3780MB) random: good seed from bootblocks mainbus0 at root: Raspberry Pi 4 Model B Rev 1.5 cpu0 at mainbus0 mpidr 0: ARM Cortex-A72 r0p3 cpu0: 48KB 64b/line 3-way L1 PIPT I-cache, 32KB 64b/line 2-way L1 D-cache cpu0: 1024KB 64b/line 16-way L2 cache cpu0: CRC32,ASID16 cpu1 at mainbus0 mpidr 1: ARM Cortex-A72 r0p3 cpu1: 48KB 64b/line 3-way L1 PIPT I-cache, 32KB 64b/line 2-way L1 D-cache cpu1: 1024KB 64b/line 16-way L2 cache cpu1: CRC32,ASID16 cpu2 at mainbus0 mpidr 2: ARM Cortex-A72 r0p3 cpu2: 48KB 64b/line 3-way L1 PIPT I-cache, 32KB 64b/line 2-way L1 D-cache cpu2: 1024KB 64b/line 16-way L2 cache cpu2: CRC32,ASID16 cpu3 at mainbus0 mpidr 3: ARM Cortex-A72 r0p3 cpu3: 48KB 64b/line 3-way L1 PIPT I-cache, 32KB 64b/line 2-way L1 D-cache cpu3: 1024KB 64b/line 16-way L2 cache cpu3: CRC32,ASID16 efi0 at mainbus0: UEFI 2.8 efi0: Das U-Boot rev 0x20211000 smbios0 at efi0: SMBIOS 3.0 smbios0: vendor U-Boot version "2021.10" date 10/01/2021 smbios0: Unknown Unknown Product apm0 at mainbus0 "system" at mainbus0 not configured "axi" at mainbus0 not configured simplebus0 at mainbus0: "soc" bcmclock0 at simplebus0 bcmmbox0 at simplebus0 bcmgpio0 at simplebus0 bcmaux0 at simplebus0 ampintc0 at simplebus0 nirq 256, ncpu 4 ipi: 0, 1, 2: "interrupt-controller" bcmtmon0 at simplebus0 bcmdmac0 at simplebus0: DMA0 DMA2 DMA4 DMA5 DMA6 DMA7 DMA8 DMA9 DMA10 "timer" at simplebus0 not configured pluart0 at simplebus0: rev 2, 16 byte fifo pluart0: console "local_intc" at simplebus0 not configured bcmdog0 at simplebus0 bcmirng0 at simplebus0 "firmware" at simplebus0 not configured "power" at simplebus0 not configured "mailbox" at simplebus0 not configured sdhc0 at simplebus0 sdhc0: SDHC 3.0, 250 MHz base clock sdmmc0 at sdhc0: 4-bit, sd high-speed, mmc high-speed "gpiomem" at simplebus0 not configured "fb" at simplebus0 not configured "vcsm" at simplebus0 not configured "clocks" at mainbus0 not configured "phy" at mainbus0 not configured "clk-27M" at mainbus0 not configured "clk-108M" at mainbus0 not configured simplebus1 at mainbus0: "emmc2bus"
Re: OpenCV "no support for memory mapping"--any workarounds?
This is the message printed by CvCaptureCAM_V4L::requestBuffers when the ioctl fails with EINVAL. For uvideo the backend to this is uvideo_reqbufs() in /sys/dev/USB/uvideo.c - this has several cases which return EINVAL. Did you get any kernel messages (dmesg, /var/log/messages) while it was reporting these "no support for memory mapping" errors? If not, you can differentiate between some of these EINVAL by building a kernel with "#define UVIDEO_DEBUG" added to uvideo.c (before the #ifdef UVIDEO_DEBUG), which might give some clues about what your Python code is doing that didn't work with openbsd's v4l2 implementation. But...if my quick calculations are right, reading and processing at that resolution in colour is about 6MByte per frame, so 5 channels at say 8fps would be in the region of ~240MByte/s (~2Gbit/s). Even if you can get the code working with openbsd, I really think you are going to struggle to read that from USB and run image processing on the data on a Pi 4 running openbsd (also openbsd's USB layer is not known for being particularly reliable). I think this task is better suited to running under Linux. -- Sent from a phone, apologies for poor formatting. On 11 July 2023 22:12:37 Jeff Ross wrote: Hi all, Trying to run an OpenCV python script on a Raspberry Pi 4 with 7.3 and 4G of ram with a single 2K webcam. I'm getting this when I try to set the camera to shoot at 2K resolution (1920px x 1080px): capture is open... [ WARN:0@2.098] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.115] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.115] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.115] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.115] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.115] global cap_v4l.cpp:847 requestBuffers VIDEOIO(V4L2:/dev/video0): Insufficient buffer memory [ WARN:0@2.131] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.131] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.131] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.131] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.131] global cap_v4l.cpp:847 requestBuffers VIDEOIO(V4L2:/dev/video0): Insufficient buffer memory [ WARN:0@2.154] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.154] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.154] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.154] global cap_v4l.cpp:868 requestBuffers VIDEOIO(V4L2:/dev/video0): no support for memory mapping [ WARN:0@2.154] global cap_v4l.cpp:847 requestBuffers VIDEOIO(V4L2:/dev/video0): Insufficient buffer memory FPS: 30.303, Height: 480.0, Width: 640.0, Exp: auto, Gain: auto, AutoExp: -1.0, Frames: 3 Requested 1920 x 1080 and got 640 x 480. I had a similar issue before with an amd64 stick: https://marc.info/?l=openbsd-ports&m=162862043308236&w=2 This is OpenCV installed from packages: jross@allsky:/home/jross $ pkg_info opencv Information for inst:opencv-4.7.0 It would seem then that this problem isn't going away any time soon but if someone has a workaround I'd love to hear it. I had hoped to use the RPi4 to drive 5 of these 2K webcams to make an allsky camera. I have an amd64 with 16G of ram that I'll try next just in case there's a big difference between amd64 and arm64. Jeff dmesg: jross@allsky:/home/jross $ dmesg OpenBSD 7.3 (GENERIC.MP) #2080: Sat Mar 25 14:20:25 MDT 2023 dera...@arm64.openbsd.org:/usr/src/sys/arch/arm64/compile/GENERIC.MP real mem = 4124950528 (3933MB) avail mem = 3963645952 (3780MB) random: good seed from bootblocks mainbus0 at root: Raspberry Pi 4 Model B Rev 1.5 cpu0 at mainbus0 mpidr 0: ARM Cortex-A72 r0p3 cpu0: 48KB 64b/line 3-way L1 PIPT I-cache, 32KB 64b/line 2-way L1 D-cache cpu0: 1024KB 64b/line 16-way L2 cache cpu0: CRC32,ASID16 cpu1 at mainbus0 mpidr 1: ARM Cortex-A72 r0p3 cpu1: 48KB 64b/line 3-way L1 PIPT I-cache, 32KB 64b/line 2-way L1 D-cache cpu1: 1024KB 64b/line 16-way L2 cache cpu1: CRC32,ASID16 cpu2 at mainbus0 mpidr 2: ARM Cortex-A72 r0p3 cpu2: 48KB 64b/line 3-way L1 PIPT I-cache, 32KB 64b/line 2-way L1 D-cache cpu2: 1024KB 64b/line 16-way L2 cache cpu2: CRC32,ASID16 cpu3 at mainbus0 mpidr 3: ARM Cortex-A72 r0p3 cpu3: 48KB 64b/line 3-way L1 PIPT I-cache, 32KB 64b/line 2-way L1 D-cache cpu3: 1024KB 64b/line 16-way L2 cache cpu3: CRC32,ASID16 efi0 at mainbus0: UEFI 2.8 e
Re: OpenCV "no support for memory mapping"--any workarounds?
On 7/11/23 11:55 PM, Stuart Henderson wrote: This is the message printed by CvCaptureCAM_V4L::requestBuffers when the ioctl fails with EINVAL. For uvideo the backend to this is uvideo_reqbufs() in /sys/dev/USB/uvideo.c - this has several cases which return EINVAL. Did you get any kernel messages (dmesg, /var/log/messages) while it was reporting these "no support for memory mapping" errors? If not, you can differentiate between some of these EINVAL by building a kernel with "#define UVIDEO_DEBUG" added to uvideo.c (before the #ifdef UVIDEO_DEBUG), which might give some clues about what your Python code is doing that didn't work with openbsd's v4l2 implementation. But...if my quick calculations are right, reading and processing at that resolution in colour is about 6MByte per frame, so 5 channels at say 8fps would be in the region of ~240MByte/s (~2Gbit/s). Even if you can get the code working with openbsd, I really think you are going to struggle to read that from USB and run image processing on the data on a Pi 4 running openbsd (also openbsd's USB layer is not known for being particularly reliable). I think this task is better suited to running under Linux. -- Sent from a phone, apologies for poor formatting. On 11 July 2023 22:12:37 Jeff Ross wrote: Hi all, Trying to run an OpenCV python script on a Raspberry Pi 4 with 7.3 and 4G of ram with a single 2K webcam. Thanks as always Stuart. I'll be stacking 20-30 half second exposures for the all sky cameras but I didn't know about the USB layer reliability issue. The amd64 rig will be a better fit for this project. Jeff
