Raspberry Pi ZeroW Camera Focus with FFMPEG

I wanted a quick and dirty method to test my camera module installation on my Raspberry Pi ZeroW installation. I don’t have a monitor connected to the Raspberry, and explicitly did not install the desktop version of the operating system. This is especially important because the camera itself may not be properly focused after installation in the case, and the only way to easily focus the camera is with a video stream allowing you to make small adjustments and see them nearly real time.

I’ve used FFMPEG for years as it handles almost any kind of video or audio I can throw at it. I use VLC on my desktop machine for similar reasons.

I did a quick install of ffmpeg on my Pi with the following command, allowing it to install all the requirements, adding up to almost 126 new packages and 56MB that needed to be downloaded and installed.

sudo apt-get install ffmpeg -y

After it finished installing, I was able to run the following command with the address being my desktop computer.

ffmpeg -f video4linux2 -input_format h264 -video_size 1280x720 -framerate 30 -i /dev/video0 -vcodec copy -an -f mpegts udp://

On my desktop computer I ran VLC, under the Media menu, selected Open Network Stream, and opened:


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What I’m doing is to use FFMPEG to pull video from the device and push it using UDP datagrams at my desktop on port 5000. Then VLC opens a port on the local machine at port 5000 to receive the datagrams and it decodes and displays the video. An interesting thing about this method is that I can stop transmitting from the raspberry, then restart it, and VLC will accept the packets since UDP is a connectionless protocol.

What really surprised me was that when I logged in a second time to my Raspberry Pi to view the CPU usage for streaming, it was only running around 12% of the CPU. I was interested in knowing what native formats the camera supported..

ffmpeg -f v4l2 -list_formats all -i /dev/video0
ffmpeg version 4.1.4-1+rpt1~deb10u1 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 8 (Raspbian 8.3.0-6+rpi1)
  configuration: --prefix=/usr --extra-version='1+rpt1~deb10u1' --toolchain=hardened --libdir=/usr/lib/arm-linux-gnueabihf --incdir=/usr/include/arm-linux-gnueabihf --arch=arm --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-omx-rpi --enable-mmal --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  libavutil      56. 22.100 / 56. 22.100
  libavcodec     58. 35.100 / 58. 35.100
  libavformat    58. 20.100 / 58. 20.100
  libavdevice    58.  5.100 / 58.  5.100
  libavfilter     7. 40.101 /  7. 40.101
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  3.100 /  5.  3.100
  libswresample   3.  3.100 /  3.  3.100
  libpostproc    55.  3.100 / 55.  3.100
[video4linux2,v4l2 @ 0x2367e40] Raw       :     yuv420p :     Planar YUV 4:2:0 : {32-3280, 2}x{32-2464, 2}
[video4linux2,v4l2 @ 0x2367e40] Raw       :     yuyv422 :           YUYV 4:2:2 : {32-3280, 2}x{32-2464, 2}
[video4linux2,v4l2 @ 0x2367e40] Raw       :       rgb24 :     24-bit RGB 8-8-8 : {32-3280, 2}x{32-2464, 2}
[video4linux2,v4l2 @ 0x2367e40] Compressed:       mjpeg :            JFIF JPEG : {32-3280, 2}x{32-2464, 2}
[video4linux2,v4l2 @ 0x2367e40] Compressed:        h264 :                H.264 : {32-3280, 2}x{32-2464, 2}
[video4linux2,v4l2 @ 0x2367e40] Compressed:       mjpeg :          Motion-JPEG : {32-3280, 2}x{32-2464, 2}
[video4linux2,v4l2 @ 0x2367e40] Raw       : Unsupported :           YVYU 4:2:2 : {32-3280, 2}x{32-2464, 2}
[video4linux2,v4l2 @ 0x2367e40] Raw       : Unsupported :           VYUY 4:2:2 : {32-3280, 2}x{32-2464, 2}
[video4linux2,v4l2 @ 0x2367e40] Raw       :     uyvy422 :           UYVY 4:2:2 : {32-3280, 2}x{32-2464, 2}
[video4linux2,v4l2 @ 0x2367e40] Raw       :        nv12 :         Y/CbCr 4:2:0 : {32-3280, 2}x{32-2464, 2}
[video4linux2,v4l2 @ 0x2367e40] Raw       :       bgr24 :     24-bit BGR 8-8-8 : {32-3280, 2}x{32-2464, 2}
[video4linux2,v4l2 @ 0x2367e40] Raw       :     yuv420p :     Planar YVU 4:2:0 : {32-3280, 2}x{32-2464, 2}
[video4linux2,v4l2 @ 0x2367e40] Raw       : Unsupported :         Y/CrCb 4:2:0 : {32-3280, 2}x{32-2464, 2}
[video4linux2,v4l2 @ 0x2367e40] Raw       :        bgr0 : 32-bit BGRA/X 8-8-8-8 : {32-3280, 2}x{32-2464, 2}
/dev/video0: Immediate exit requested

That output leads me to believe that the camera module could output either h264 or mjpeg without significant CPU overhead. What it doesn’t do is tell me efficient frame sizes. It seems to say that horizontal and vertical sizes can be anything between 32 to 3280 and 32 to 2464. I know that the specs on the camera say that it will run still frames at the high resolution, but video is significantly less.

Two Video4Linux commands that return interesting and similar results are:

pi@WimPiZeroCamera:~ $ v4l2-ctl --list-formats-ext
        Type: Video Capture

        [0]: 'YU12' (Planar YUV 4:2:0)
                Size: Stepwise 32x32 - 3280x2464 with step 2/2
        [1]: 'YUYV' (YUYV 4:2:2)
                Size: Stepwise 32x32 - 3280x2464 with step 2/2
        [2]: 'RGB3' (24-bit RGB 8-8-8)
                Size: Stepwise 32x32 - 3280x2464 with step 2/2
        [3]: 'JPEG' (JFIF JPEG, compressed)
                Size: Stepwise 32x32 - 3280x2464 with step 2/2
        [4]: 'H264' (H.264, compressed)
                Size: Stepwise 32x32 - 3280x2464 with step 2/2
        [5]: 'MJPG' (Motion-JPEG, compressed)
                Size: Stepwise 32x32 - 3280x2464 with step 2/2
        [6]: 'YVYU' (YVYU 4:2:2)
                Size: Stepwise 32x32 - 3280x2464 with step 2/2
        [7]: 'VYUY' (VYUY 4:2:2)
                Size: Stepwise 32x32 - 3280x2464 with step 2/2
        [8]: 'UYVY' (UYVY 4:2:2)
                Size: Stepwise 32x32 - 3280x2464 with step 2/2
        [9]: 'NV12' (Y/CbCr 4:2:0)
                Size: Stepwise 32x32 - 3280x2464 with step 2/2
        [10]: 'BGR3' (24-bit BGR 8-8-8)
                Size: Stepwise 32x32 - 3280x2464 with step 2/2
        [11]: 'YV12' (Planar YVU 4:2:0)
                Size: Stepwise 32x32 - 3280x2464 with step 2/2
        [12]: 'NV21' (Y/CrCb 4:2:0)
                Size: Stepwise 32x32 - 3280x2464 with step 2/2
        [13]: 'BGR4' (32-bit BGRA/X 8-8-8-8)
                Size: Stepwise 32x32 - 3280x2464 with step 2/2
pi@WimPiZeroCamera:~ $ v4l2-ctl -L

User Controls

                     brightness 0x00980900 (int)    : min=0 max=100 step=1 default=50 value=50 flags=slider
                       contrast 0x00980901 (int)    : min=-100 max=100 step=1 default=0 value=0 flags=slider
                     saturation 0x00980902 (int)    : min=-100 max=100 step=1 default=0 value=0 flags=slider
                    red_balance 0x0098090e (int)    : min=1 max=7999 step=1 default=1000 value=1000 flags=slider
                   blue_balance 0x0098090f (int)    : min=1 max=7999 step=1 default=1000 value=1000 flags=slider
                horizontal_flip 0x00980914 (bool)   : default=0 value=0
                  vertical_flip 0x00980915 (bool)   : default=0 value=0
           power_line_frequency 0x00980918 (menu)   : min=0 max=3 default=1 value=1
                                0: Disabled
                                1: 50 Hz
                                2: 60 Hz
                                3: Auto
                      sharpness 0x0098091b (int)    : min=-100 max=100 step=1 default=0 value=0 flags=slider
                  color_effects 0x0098091f (menu)   : min=0 max=15 default=0 value=0
                                0: None
                                1: Black & White
                                2: Sepia
                                3: Negative
                                4: Emboss
                                5: Sketch
                                6: Sky Blue
                                7: Grass Green
                                8: Skin Whiten
                                9: Vivid
                                10: Aqua
                                11: Art Freeze
                                12: Silhouette
                                13: Solarization
                                14: Antique
                                15: Set Cb/Cr
                         rotate 0x00980922 (int)    : min=0 max=360 step=90 default=0 value=0 flags=modify-layout
             color_effects_cbcr 0x0098092a (int)    : min=0 max=65535 step=1 default=32896 value=32896

Codec Controls

             video_bitrate_mode 0x009909ce (menu)   : min=0 max=1 default=0 value=0 flags=update
                                0: Variable Bitrate
                                1: Constant Bitrate
                  video_bitrate 0x009909cf (int)    : min=25000 max=25000000 step=25000 default=10000000 value=10000000
         repeat_sequence_header 0x009909e2 (bool)   : default=0 value=0
            h264_i_frame_period 0x00990a66 (int)    : min=0 max=2147483647 step=1 default=60 value=60
                     h264_level 0x00990a67 (menu)   : min=0 max=11 default=11 value=11
                                0: 1
                                1: 1b
                                2: 1.1
                                3: 1.2
                                4: 1.3
                                5: 2
                                6: 2.1
                                7: 2.2
                                8: 3
                                9: 3.1
                                10: 3.2
                                11: 4
                   h264_profile 0x00990a6b (menu)   : min=0 max=4 default=4 value=4
                                0: Baseline
                                1: Constrained Baseline
                                2: Main
                                4: High

Camera Controls

                  auto_exposure 0x009a0901 (menu)   : min=0 max=3 default=0 value=0
                                0: Auto Mode
                                1: Manual Mode
         exposure_time_absolute 0x009a0902 (int)    : min=1 max=10000 step=1 default=1000 value=1000
     exposure_dynamic_framerate 0x009a0903 (bool)   : default=0 value=0
             auto_exposure_bias 0x009a0913 (intmenu): min=0 max=24 default=12 value=12
                                0: -4000 (0xfffffffffffff060)
                                1: -3667 (0xfffffffffffff1ad)
                                2: -3333 (0xfffffffffffff2fb)
                                3: -3000 (0xfffffffffffff448)
                                4: -2667 (0xfffffffffffff595)
                                5: -2333 (0xfffffffffffff6e3)
                                6: -2000 (0xfffffffffffff830)
                                7: -1667 (0xfffffffffffff97d)
                                8: -1333 (0xfffffffffffffacb)
                                9: -1000 (0xfffffffffffffc18)
                                10: -667 (0xfffffffffffffd65)
                                11: -333 (0xfffffffffffffeb3)
                                12: 0 (0x0)
                                13: 333 (0x14d)
                                14: 667 (0x29b)
                                15: 1000 (0x3e8)
                                16: 1333 (0x535)
                                17: 1667 (0x683)
                                18: 2000 (0x7d0)
                                19: 2333 (0x91d)
                                20: 2667 (0xa6b)
                                21: 3000 (0xbb8)
                                22: 3333 (0xd05)
                                23: 3667 (0xe53)
                                24: 4000 (0xfa0)
      white_balance_auto_preset 0x009a0914 (menu)   : min=0 max=9 default=1 value=1
                                0: Manual
                                1: Auto
                                2: Incandescent
                                3: Fluorescent
                                4: Fluorescent H
                                5: Horizon
                                6: Daylight
                                7: Flash
                                8: Cloudy
                                9: Shade
            image_stabilization 0x009a0916 (bool)   : default=0 value=0
                iso_sensitivity 0x009a0917 (intmenu): min=0 max=4 default=0 value=0
                                0: 0 (0x0)
                                1: 100000 (0x186a0)
                                2: 200000 (0x30d40)
                                3: 400000 (0x61a80)
                                4: 800000 (0xc3500)
           iso_sensitivity_auto 0x009a0918 (menu)   : min=0 max=1 default=1 value=1
                                0: Manual
                                1: Auto
         exposure_metering_mode 0x009a0919 (menu)   : min=0 max=2 default=0 value=0
                                0: Average
                                1: Center Weighted
                                2: Spot
                     scene_mode 0x009a091a (menu)   : min=0 max=13 default=0 value=0
                                0: None
                                8: Night
                                11: Sports

JPEG Compression Controls

            compression_quality 0x009d0903 (int)    : min=1 max=100 step=1 default=30 value=30



Raspberry PiZeroW Camera Module


When you’ve gotten used to Amazon Prime and free shipping, purchasing inexpensive items from other online retailers where the shipping doubles the cost of the item makes it harder to impulse buy items. An item for $5 that costs $7 in shipping often doesn’t get bought. Even a pair of items that cost $16 together that then cost $7 in shipping cause me to delay the purchase.


Because I was purchasing a Raspberry Pi 4 and Raspberry Pi USB-C Power Supply from Sparkfun, I decided to throw in another Pi ZeroW and case for another $16. I then added the Raspberry Pi Camera module because the case has an optional cover enclosing the camera and I wanted to see how it all worked together. I only wish I’d realized that there was a Noir version, because I’ve always wanted to play with infrared photography.

Having recently streamlined the installation of a Pi Zero, I installed the camera and Pi ZeroW in the case, put the configured micro sd card in place, plugged it into my HDMI monitor just to watch it boot and applied power. I never saw anything on the monitor. The Pi ZeroW only has a single LED, which is generally on, but blinks for micro sd activity. Because I’d closed the case, the LED wasn’t visible, and with no monitor activity I was wondering if I’d gotten a bad board.


I opened the case and powered it on again, this time I knew I was seeing LED activity. I did a quick search of my network for new devices and found the new board was responding on ssh and appeared to be working correctly other than no HDMI output.  I was even able to take a snapshot with the camera using the command:

raspistill -o image.jpg

I decided to test booting the device without the camera installed. That worked fine, and I had HDMI output during the boot process. Now I started to wonder if perhaps the power supply I was using didn’t provide enough power. Perhaps the camera and the HDMI device were mutually exclusive in the amount of power required

A lot of searching on the web resulted in nothing about the power required for the camera affecting the HDMI output. I found that I might be able to reduce the power requirements by 25mA by turning off the HDMI, but that the Pi ZeroW was already the lowest power draw available. https://www.jeffgeerling.com/blogs/jeff-geerling/raspberry-pi-zero-conserve-energy

I found the tvservice command and the -s option with the camera installed was resulting in a different result from without the camera installed.

pi@WimPiZeroCamera:~ $ sudo /usr/bin/tvservice -s
state 0x40000 [NTSC 4:3], 720x480 @ 60.00Hz, interlaced
pi@WimPiZeroW:~ $ sudo /usr/bin/tvservice -s
state 0xa [HDMI CEA (16) RGB lim 16:9], 1920x1080 @ 60.00Hz, progressive

At least recognizing that difference was progress. For some reason under Raspian Buster the camera module is causing the HDMI output to be different. I found options in https://www.raspberrypi.org/documentation/configuration/config-txt/video.md that allow me to force the HDMI output to what I want. I changed /boot/config.txt with the following and now I’ve got both camera and video working properly.

# uncomment to force a specific HDMI mode (this will force [HDMI CEA (16) RGB lim 16:9], 1920x1080 @ 60.00Hz, progressive)

I hope that this helps someone else having problems with both camera and hdmi video output. I don’t know if this was specific to Buster since I never tried it under Jessie or Stretch.

Headless Raspberry Pi Setup

I’ve been using a raspberry pi as a ADSB data feeder for FlightAware and FlightRadar24 for a while and the micro sd card developed a bad sector. That meant I needed to rebuild the installation. I really didn’t want to deal with connecting a keyboard, monitor, and mouse to the Pi for the installation. I found https://core-electronics.com.au/tutorials/raspberry-pi-zerow-headless-wifi-setup.html giving me useful information on how to avoid all that. I’m documenting my steps here for my own memory.

Step 1. Download the most recent version of Raspian Buster Lite from https://www.raspberrypi.org/downloads/raspbian/

Step 2. Download balenaEtcher portable from https://www.balena.io/etcher/

Step 3. Use Etcher to overwrite an SD card with the Raspian image I downloaded earlier.

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Step 4. Eject the flash card and close Etcher, then insert the flash card again, rejecting the option to format the drive.  The flash card is now formatted with multiple partitions, only the first is easily read in windows.

Step 5. create two files on the sd card boot partition. ssh and wpa_supplicant.conf. ssh is an empty file. wpa_supplicant.conf should have the following contents, customized for your WiFi Network:

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev


Step 6. Eject your micro sd card, put it in the Raspberry Pi and power on the raspberry. You’ll need to wait a couple of minutes for the raspberry to finish several steps before you can connect to it over the network. The Raspberry Pi is expanding the native filesystem to fill the available space on the flash card, then rebooting another time with the new filesystem. You’ll need to figure out what IP address the Raspberry retrieved on your network. If you have access to your router, you may be able to see the attached devices and find the new Raspberry that way. I like the NirSoft Wireless Network Watcher to find what’s on my network https://www.nirsoft.net/utils/wireless_network_watcher.html.

Step 7. Connect to the Raspberry Pi with ssh. You’ll be using the default user and password to connect: “pi” and “raspberry”. I used the new Microsoft Windows Terminal in Windows 10 for this example. https://www.microsoft.com/en-us/p/windows-terminal-preview/9n0dx20hk701#activetab=pivot:overviewtab

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The Raspberry is up and running now. There are several steps I recommend to do immediately. Use sudo raspi-config to set the user password, the machine hostname, and the timezone you want the machine to use.

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After waiting for the raspberry to reboot and reconnecting via ssh, updating the software to the latest version is the next step.

sudo apt-get update -y
sudo apt-get upgrade -y
sudo shutdown -r now

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Then I install several tools that I like to have.

sudo apt-get install lighttpd mc mrtg lrzsz nmap dnsutils etherwake snmpd snmp arp-scan shairport-sync -y

My next steps are to get PiAware and FlightRadar up and running.

1970s Rain Jet Sprinkler Install Guide

Recently going through my parents old house documentation we came across this lawn sprinkler installation guide. I especially like the illustrations with Mr. Rain “Chet”.

This was all in a folder labeled Permanent Home Improvements Carrolton Texas. We moved out of this house in 1976. I’m quite happy that so much of my hording of history is purely digital, though it’s not filed as well as my parents paper files.

There was also a full color glossy brochure for Buckner 1972 Lawn and Garden Sprinkler Equipment

TaoTronics Bluetooth Transmitter connected to my Samsung Soundbar

A couple of years ago I bought a discount sound bar to use as my computer speaker. I’ve been really happy with the sound quality. It’s connected via an optical cable to my computer and has a separate subwoofer.

This summer I moved into a new apartment, and during the last month I’ve run into a problem. One of my neighbors seems to be connecting to my soundbar via Bluetooth.

By watching the display I was able to at least learn what brand device was connecting. I still don’t know the exact model name. https://www.taotronics.com/bluetooth-transmitter-reset.html shows how to reset the device itself. Unfortunately my soundbar doesn’t have a way of setting the Bluetooth pairing code, or resetting the handshake with any devices that may want to connect with it, or fully disabling Bluetooth. https://www.samsung.com/us/support/owners/product/2015-soundbar-w-subwoofer-hw-j355

When I first noticed the problem, the sound bar was in a mode that would let Bluetooth turn on the sound bar, which was extremely frustrating when I was nearly asleep and the soundbar would start playing noises for no reason. That caused me to learn how to disable the Bluetooth power on feature of the sound bar.  Now at least it will only switch to Bluetooth when I’m actually using the soundbar for computer output.

The TaoTronics devices seem to be able to connect to multiple devices at the same time. I’m guessing that my neighbor has no idea that they are connecting to a second device at all. Obviously it’s built to make connecting to devices as easy as possible.

If anyone has suggestions on how to reject an already paired device from Bluetooth, I’d love to see it in the comments. I’m willing to use one of my Raspberry Pi devices that supports Bluetooth to see if there’s a way to send an interrupt signal.

Part 4 of ROAV Dash Cam C1 Pro

I’d figured out that a 128 GB micro sd card would yield about 16 hours of video on the ROAV Dashcam which was good enough that I could make most of my daily long drives without overwriting anything.


I had a PNY 128 GB drive that I’d been using in my GoPro so I put it into the ROAV Dashcam. The ROAV requires the card be formatted as FAT32 and not the newer exFAT, but the dashcam was able to do the formatting.

After a couple of months of use, I got a strange error on the ROAV saying that the memry card was corrupted and it needed reformatting. Before I did that, I put the card into my computer and tried to copy all the data off it. I ran into an issue with some files being corrupted, and then found I was not able to reformat the card in the computer, as it was somehow being reported as read only.

Because there is no physical write protect slider on a micro SD card, I fired up diskpart and issued the commands that should clear the write protect status on a drive.

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It appeared to work, but then checking the status after issuing the command attributes clear disk readonly showed that no changes had really happened.

I’d been frustrated trying to figure this out for the past week. Then I came across an article in comp.risks that described exactly this sort of issue.

Micro SD cards silently switching to read-only when they’re “too old”

Mon, 16 Jul 2018 23:38:44 +0200

The 64G Patriot micro SD I had been using in my cell phone from mid 2014
just decided to turn itself into a read-only memory card.  From what I read,
it most likely reached its maximum number of uses, as it happens at least
with some Samsung cards too.  It would be to protect the card from losing
all its data, after its cells were erased "too many times" (limit number
depending on the card, and appearing to be in the order of 10-100k).  And
according to Internet forums, and card reviews on Amazon, it looks like it's
getting more and more common!

A very bad point is that there were no error messages at all.  I added music
files before a trip, but I had none of the new files available later so at
first I thought I didn't do it correctly (even if the transfer was fine, it
could for example have been to my card backup on an hard drive instead of
going to the actual card).  Then, despite the pictures still being taken
correctly by my phone (browsing was OK, able to delete the bad ones...), I
lost all of the new ones when my phone rebooted. So they were only in a
cache memory somewhere, but nowhere on the SD card (not found by deep
recovery tools either).  More fun, the older ones I deleted came back during
the same reboot...

I understand it would be bothering to have an error message at each card
access, but at least I would have known to change the card and would not
have lost 3 days of pictures!  So beware...

I’ve written low level code dealing with flash memory in the past, so I understand that there are only so many rewrite times each sector can handle. I’m also familiar with the differences in file systems between FAT32, exFAT and NTFS. I don’t believe MicroSD cards have any sort of wear leveling algorithms in them that a full fledged SSD has between the flash and the controller. The fact that ROAV puts their constantly changing data two levels deep in the directory structure at least means the data for the root directory isn’t the constantly erased and overwritten sector, but it does mean that the directory structure is getting re-written each time a new file is created. They probably aren’t writing the directory data to a new sector each time, but just overwriting the old location, possibly accelerating the death of the microsd card. because the cluster size on a 128GB Fat32 partition is fairly large, at least 32KB, it holds a lot of directory entries in a single sector.

I had a 200 GB card that I thought I’d replace the failed drive with. The ROAV attempted to format it but reported that it couldn’t. I’m thinking that they simply cannot handle a drive bigger than 128 GB.


Since I had a second 128GB card, I put it into the dashcam. I’ll be interested in seeing how long it takes for it to report as non-functional.


Part 2 of FFMPEG and ROAV Dash Cam C1 Pro

While writing my software to concatenate and speed up the video files from my ROAV Dashcam I ran into an interesting issue with FFMPEG.

The -filter_complex option seems to stop parsing it’s parameters somewhere above 960 characters on the command line. I didn’t narrow down the exact point, or go digging in the FFMPEG source code to find the size. I expect this is an arbitrary buffer size in FFMPEG. I may contribute to the source code since it fails with no explanation, even when generating a report file. Learning the FFMPEG source structure in itself is a large task, meaning that I’ve not found time to do anything beyond find a workaround.

My workaround was to recognize when the command size will get long and fall back to using the -f concat option with a temporary file listing the input files instead of using the complex filtergraph.

The advantage of the complex filtergraph is twofold. It does not require a secondary input file or any cleanup. It can deal with input files that change resolution if necessary.

Here’s an example of the complex filtergraph:

ffmpeg.exe -report -i 2018_0705_101335_006.MP4 -i 2018_0705_101635_007.MP4 -i 2018_0705_101935_008.MP4 -i 2018_0705_102235_009.MP4 -i 2018_0705_102535_010.MP4 -i 2018_0705_102835_011.MP4 -i 2018_0705_103135_012.MP4 -i 2018_0705_103435_013.MP4 -i 2018_0705_103613_014A.MP4 -i 2018_0705_103615_015A.MP4 -i 2018_0705_104449_016A.MP4 -i 2018_0705_104750_017A.MP4 -i 2018_0705_105050_018A.MP4 -i 2018_0705_105350_019A.MP4 -i 2018_0705_105650_020A.MP4 -i 2018_0705_105950_021A.MP4 -i 2018_0705_110250_022A.MP4 -i 2018_0705_110550_023A.MP4 -i 2018_0705_110850_024A.MP4 -i 2018_0705_143415_025.MP4 -i 2018_0705_143716_026.MP4 -i 2018_0705_144016_027.MP4 -i 2018_0705_144316_028.MP4 -i 2018_0705_144616_029.MP4 -i 2018_0705_144916_030.MP4 -i 2018_0705_145216_031.MP4 -i 2018_0705_145516_032.MP4 -i 2018_0705_145816_033.MP4 -i 2018_0705_150116_034.MP4 -i 2018_0705_150416_035.MP4 -i 2018_0705_150716_036.MP4 -i 2018_0705_151016_037.MP4 -i 2018_0705_151316_038.MP4 -i 2018_0705_151616_039.MP4 -i 2018_0705_151916_040.MP4 -i 2018_0705_152216_041.MP4 -i 2018_0705_152516_042.MP4 -i 2018_0705_152816_043.MP4 -i 2018_0705_153116_044.MP4 -i 2018_0705_153416_045.MP4 -i 2018_0705_153716_046.MP4 -i 2018_0705_154016_047.MP4 -i 2018_0705_154316_048.MP4 -i 2018_0705_154616_049.MP4 -i 2018_0705_154916_050.MP4 -i 2018_0705_155216_051.MP4 -i 2018_0705_155516_052.MP4 -i 2018_0705_155816_053.MP4 -i 2018_0705_160116_054.MP4 -i 2018_0705_160416_055.MP4 -i 2018_0705_160716_056.MP4 -i 2018_0705_161016_057.MP4 -i 2018_0705_161316_058.MP4 -i 2018_0705_161616_059.MP4 -i 2018_0705_161916_060.MP4 -i 2018_0705_162216_061.MP4 -i 2018_0705_162516_062.MP4 -i 2018_0705_162816_063.MP4 -i 2018_0705_163116_064.MP4 -i 2018_0705_163416_065.MP4 -i 2018_0705_163716_066.MP4 -i 2018_0705_164016_067.MP4 -i 2018_0705_164316_068.MP4 -i 2018_0705_164616_069.MP4 -i 2018_0705_164916_070.MP4 -i 2018_0705_165215_071.MP4 -i 2018_0705_165516_072.MP4 -i 2018_0705_165815_073.MP4 -i 2018_0705_170115_074.MP4 -i 2018_0705_170415_075.MP4 -i 2018_0705_170715_076.MP4 -i 2018_0705_171015_077.MP4 -i 2018_0705_171315_078.MP4 -i 2018_0705_171615_079.MP4 -i 2018_0705_171915_080.MP4 -i 2018_0705_172216_081.MP4 -i 2018_0705_172515_082.MP4 -i 2018_0705_172815_083.MP4 -i 2018_0705_173115_084.MP4 -i 2018_0705_173415_085.MP4 -i 2018_0705_173715_086.MP4 -i 2018_0705_174015_087.MP4 -i 2018_0705_174315_088.MP4 -i 2018_0705_174615_089.MP4 -i 2018_0705_174915_090.MP4 -i 2018_0705_175215_091.MP4 -i 2018_0705_175515_092.MP4 -i 2018_0705_175815_093.MP4 -i 2018_0705_180115_094.MP4 -i 2018_0705_180415_095.MP4 -i 2018_0705_180715_096.MP4 -i 2018_0705_181015_097.MP4 -i 2018_0705_181315_098.MP4 -i 2018_0705_181615_099.MP4 -i 2018_0705_181915_100.MP4 -i 2018_0705_182215_101.MP4 -i 2018_0705_182515_102.MP4 -i 2018_0705_182815_103.MP4 -i 2018_0705_183115_104.MP4 -i 2018_0705_183415_105.MP4 -i 2018_0705_183715_106.MP4 -i 2018_0705_184015_107.MP4 -i 2018_0705_184315_108.MP4 -i 2018_0705_184615_109.MP4 -i 2018_0705_184915_110.MP4 -i 2018_0705_185215_111.MP4 -i 2018_0705_185515_112.MP4 -i 2018_0705_185815_113.MP4 -i 2018_0705_190115_114.MP4 -i 2018_0705_190415_115.MP4 -filter_complex [0:v][1:v][2:v][3:v][4:v][5:v][6:v][7:v][8:v][9:v][10:v][11:v][12:v][13:v][14:v][15:v][16:v][17:v][18:v][19:v][20:v][21:v][22:v][23:v][24:v][25:v][26:v][27:v][28:v][29:v][30:v][31:v][32:v][33:v][34:v][35:v][36:v][37:v][38:v][39:v][40:v][41:v][42:v][43:v][44:v][45:v][46:v][47:v][48:v][49:v][50:v][51:v][52:v][53:v][54:v][55:v][56:v][57:v][58:v][59:v][60:v][61:v][62:v][63:v][64:v][65:v][66:v][67:v][68:v][69:v][70:v][71:v][72:v][73:v][74:v][75:v][76:v][77:v][78:v][79:v][80:v][81:v][82:v][83:v][84:v][85:v][86:v][87:v][88:v][89:v][90:v][91:v][92:v][93:v][94:v][95:v][96:v][97:v][98:v][99:v][100:v][101:v][102:v][103:v][104:v][105:v][106:v][107:v][108:v][109:v]concat=n=110:v=1[v];[v]setpts=(1/60)*PTS,drawtext=fontfile=C\\:/WINDOWS/Fonts/consola.ttf:fontcolor=white:fontsize=80:y=main_h-text_h-50:x=50:text=WimsWorld[o] -map [o] -c:v libx265 -crf 23 -preset veryfast -movflags +faststart -bf 2 -g 15 -pix_fmt yuv420p -y “Output.mp4”

Here’s an example of the command where all the input files are defined in the temporary file:

ffmpeg.exe -report -f concat -safe 0 -i C:\Users\Wim\AppData\Local\Temp\Wim4BD3.tmp -vf setpts=(1/60)*PTS,drawtext=fontfile=C\\:/WINDOWS/Fonts/consola.ttf:fontcolor=white:fontsize=80:y=main_h-text_h-50:x=50:text=WimsWorld -an -c:v libx265 -crf 23 -preset veryfast -movflags +faststart -bf 2 -g 15 -pix_fmt yuv420p -y “Output.mp4”


FFMPEG and ROAV Dash Cam C1 Pro

I recently purchased a dedicated dashcam on sale to replace my GoPro setup for trip videos. This gives me a new need to understand a new file format.


The Roav Dashcam stores sequential mp4 files. When configuring the camera it’s possible to set the loop time, which is the duration of each mp4. There’s also an option to watermark the files. I have it turned on, and the only thing I’ve noticed is the ROAV logo, timestamp, and speed in the bottom right. It does not appear to have a way of adjusting the size of the text.

My initial recordings were set to run at 1080p 60 fps. I wanted to concatenate multiple files, add some text of my own, and speed up the video. This was my first experience using the -filter_complex option of FFMPEG. Here’s what I came up with to put together three files, speed the output up by a factor of 60, and add some text. I’m dropping the audio completely. The ROAV can record audio inside the car, but I configured it not to, as I don’t want to hear what I was listening to on the radio or what I might be saying if I make a phone call..

ffmpeg.exe -hide_banner -i 2018_0512_130537_050A.MP4 -i 2018_0512_131537_051A.MP4 -i 2018_0512_132537_052A.MP4 -filter_complex "[0:v] [1:v] [2:v] concat=n=3:v=1 [v];[v]setpts=0.01666*PTS,drawtext=fontfile=C\\:/WINDOWS/Fonts/consola.ttf:fontcolor=white:fontsize=80:y=main_h-text_h-50:x=50:text=WimsWorld[o]" -map "[o]" -c:v libx265 -crf 23 -preset veryfast -movflags +faststart -bf 2 -g 15 -pix_fmt yuv420p  FirstMixSpeed60Concat.mp4

This first video was recorded at 1080p60. The camera can record at 1440p30 which I will be trying soon to see if things like license plates are more legible. The setpts factor that I’m currently using was 1/60, so that 1 minute of real time was compressed to 1 second of video, and just dropping the extra frames. I expect to need to change the setpts factor to 1/30 because of the decreased frame rate at the higher resolution.

SD Card Holder

I’d been traveling with several microSD cards for both GoPro and Drone usage for the past year when I finally got around to buying this inexpensive plastic card to organize them.


Before buying it, I had read several reviews, and worried that cheap plastic might either make it brittle, or let the flash cards fall out of the enclosure. For $6.95 it was worth a try.

What I really found out was that I should have been using it for at least a year before I got it. The fact that I can carry 10 micro SD cards and they are all in order is a complete boon for organization.

20170922_185055016_iOSBefore using this, I’d often have two identical looking SD cards in my hands and forget which one was full and which one was empty. I’d also take a card out of my device and set it down, and nearly lose it.  Now I take a card out of my camera and immediately put it into this holder. I fill this holder from one end with empty cards and from the other with full cards and never have to remember which cards have something on them any more.

It’s essentially the same size as a credit card, but is quite a bit thicker. I wouldn’t carry it in my wallet, nor would I use the hole for a key ring, but having it in a pocket in my drone bag keeps all the memory cards in one place in a known order.

VLAN Tagging for CenturyLink

I’ve dealt with CenturyLink provided WiFi access points in two locations I’ve lived recently, and not been happy with their performance. My 5 year old Netgear WNDR3800 seemed to provide better speed with both 5GHz and 2.4GHz than the Actiontec C1900A provided by CenturyLink, which only supported 2.4GHz.

Unfortunately it was not as simple as learning the PPoE credentials that the Actiontec was using and putting those details into the Netgear. Centurylink in their infinite wisdom decided that the network packets need to be tagged to run on VLAN 201.

One solution would be to go out and buy a new WiFi router that supports VLAN Tagging. The newer Netgear Nighthawk routers support tagging, following the details at this support page.

The Netgear AC1900 router (also referred to as R7000) would do what I want, but would also cost close to $150.

Instead I spent $33 on a Netgear GS105Ev2 switch and spent a little time configuring its VLANs and am mostly happy with the result. My only disappointment is that this switch doesn’t seem to support SNMP for traffic monitoring.


I have this configured so that Port1 connects to the Centurylink Fiber Termination Box, Port2 connects to my WNDR3800 WAN Port, and Port3 is connected to one of the LAN ports on the WNDR3800.

Port1 is configured to send Tagged Packets on VLAN 201.
Port2 is configured to send Untagged Packets on VLAN 201.
Ports 3-5 are configured to sent Untagged Packets on VLAN 1, the default for this switch.

The steps to get this working, starting with existing setup of Actiontec connected to Fiber Termination box.

  1. Connect GS105Ev2 Port3 to available LAN port on Actiontec and make sure link connection LEDs appear.
  2. Find what IP address the GS105Ev2 acquired on local network using a network scanning tool. I used  NirSoft Wireless Network Watcher and found that my switch was on Going to gave me a login to the new switch with the default password of “password”. gs105ev2-login
  3. You should get a switch information page similar to this.gs105ev2-login-successful
  4. Select the menu item VLAN, then 802.1Q and the radio button Enable. You should get a warning message that it’s about to erase all current VLAN settings. Hit OK.gs105ev2-vlan1
  5. Go under Advanced, VLAN Configuration, there’s a text box on the right that says VLAN ID. Enter 201 and push the Add button above it. gs105ev2-vlan2Now we have a new VLAN with no Port Members assigned.gs105ev2-vlan3
  6. Go to Port PVID on the left menu. Select Port 1. Type 201 in the text box. Hit Apply.gs105ev2-vlan4Select Port 2. Type 201. Hit Apply.gs105ev2-vlan5
  7. Now we go to the VLAN Membership setting. With the VLAN ID dropdown showing 1, click Port 1 and Port 2 through the available options until neither T nor U is showing, leaving Ports 3, 4, and 5 showing U. Then click Apply.gs105ev2-vlan6
  8. Now drop down to select VLAN 201. Click so that Port 1 is T, Port 2 is U, Ports 3, 4, and 5 are blank, and Apply.gs105ev2-vlan7
  9. If you look at the VLAN Configuration, you’ll now see that ports 1 and 2 are assigned to 201, while 3, 4, and 5 are assigned to 1.gs105ev2-vlan8
  10. At this point the GS105Ev2 has been configured as much as it needs to be. I had already configured my WNDR3800 to connect to the ISP using PPoE and given it the correct credentials.
  11. Power off Actiontec and put it in a closet. Connect Fiber Termination device to port 1 on GS105Ev2. Connect WNDR3800 WAN to port 2 on GS105Ev2. Optionally connect port 3 on GS105Ev2 to a lan port on WNDR3800, as it will only gain you one extra gigabit port compared to the four built into the WNDR3800.

Thanks to this post for the same information that I’ve presented here. I’d attempted to do this before with an existing GS108Tv2 switch I had sitting around. What I’d forgotten to do was make the port going to the WNDR3800 send Untagged packets. I’d been properly sending tagged packets to the fiber, but the WNDR3800 didn’t know what to do with the tagged packets. After confirming it worked with the GS108Tv2 I ordered the cheaper 5 port switch just to have something else to play with. My only disappointment with the 5 port switch is that it doesn’t seem to support SNMP to monitor the traffic going over the network.