Go to advanced search

by Eichhorn18
Tue Mar 31, 2020 7:12 am
Forum: Advanced users
Topic: .h264 video framerate constant or not?
Replies: 9
Views: 267

Re: .h264 video framerate constant or not?

Do you get drops if you record to the SD card? I can't be sure what I'm seeing 'is' frame dropping. I'm trying to back analyze this problem not having access to the original equipment (owing to the current epidemic). The origianl file that I have turned out is a .h264 file which gets converted to f...
by Eichhorn18
Fri Mar 27, 2020 1:51 pm
Forum: Advanced users
Topic: .h264 video framerate constant or not?
Replies: 9
Views: 267

Re: .h264 video framerate constant or not?

Not really. You can count the number of encoded frames in the stream, but there is no other information in the stream indicating when the frame was captured (that's what the timestamps do). I understand. Given what you've said then, if the know recording time of my video was 20 minutes exactly (con...
by Eichhorn18
Fri Mar 27, 2020 1:14 pm
Forum: Advanced users
Topic: .h264 video framerate constant or not?
Replies: 9
Views: 267

Re: .h264 video framerate constant or not?

The framerate should be constant as long as you have fast enough storage and no data integrity errors. With raspivid you can capture the timestamps of each frame as well by using the -pts <filename> option. You can then use mkvmerge (and probably others) to merge together the two files into a conta...
by Eichhorn18
Fri Mar 27, 2020 10:16 am
Forum: Advanced users
Topic: .h264 video framerate constant or not?
Replies: 9
Views: 267

.h264 video framerate constant or not?

Hello, I am wondering if anyone can shed light on how the .h264 video record works for the Raspberry Pi. I have recorded some video using the python bindings picamera library, and have recorded a 20 minute video in .h264 format. I specify the framerate for the camera to 30. Does anyone know if the f...
by Eichhorn18
Thu Nov 29, 2018 1:59 pm
Forum: Troubleshooting
Topic: rc.local , auto run .sh script at boot in Stretch Desktop
Replies: 6
Views: 1078

Re: rc.local , auto run .sh script at boot in Stretch Desktop

The first and most obvious question is: What makes you think it is not working? I.e., what are the symptoms? The python script should capture photos and save them to the network mount. So the symptom is that the photos are not appearing on the network folder. The python script works fine otherwise ...
by Eichhorn18
Thu Nov 29, 2018 1:19 pm
Forum: Troubleshooting
Topic: rc.local , auto run .sh script at boot in Stretch Desktop
Replies: 6
Views: 1078

Re: rc.local , auto run .sh script at boot in Stretch Desktop

If you want to stay with the rc.local method, then add am "&" to the end of the line, so that the script executes in the background. The other variant is to set up a systemd service (type simple), which is the preferred variant. Thanks for your reply. So I do have the & at the end of the line for r...
by Eichhorn18
Thu Nov 29, 2018 12:10 pm
Forum: Troubleshooting
Topic: rc.local , auto run .sh script at boot in Stretch Desktop
Replies: 6
Views: 1078

rc.local , auto run .sh script at boot in Stretch Desktop

Hi, I am running Stretch Desktop on the Pi 3B. I am trying to run a .sh script at startup to do the following commands, including running a python script: #!/bin/bash sudo mount -a python3 /home/.../python_script.py The above mounts a network drive for which most of the commands to do that mount are...
by Eichhorn18
Tue Sep 11, 2018 1:29 pm
Forum: Camera board
Topic: picamera - capture causing GPU to be in race condition
Replies: 0
Views: 412

picamera - capture causing GPU to be in race condition

Hi, I seem to have put my raspberry pi into race conditions within the CPU or GPU. I am using picamera python library to capture photos. I've posted some other topics on this but not specific to this issue. I am capturing at resolutions 3264 x 2464 and have identified this issue with .JPEG, .YUV, an...
by Eichhorn18
Mon Sep 10, 2018 11:52 am
Forum: Camera board
Topic: YUV capture - is compression occuring?
Replies: 7
Views: 1186

Re: YUV capture - is compression occuring?

Converting to RGB takes processing time and extra memory bandwidth. Whether you wish to do that on the Pi or offline is up to you. So the answer is yes, even though you said the sensor captures in 10bit/pixel bayer data, the next step is to process into YUV? Ah, the use case - always useful to know...
by Eichhorn18
Mon Sep 10, 2018 10:45 am
Forum: Camera board
Topic: YUV capture - is compression occuring?
Replies: 7
Views: 1186

Re: YUV capture - is compression occuring?

Nothing captures 3 x 3264 x 2464. There is 1 x 3264 x 2464 coming from the sensor with pixels being coloured based on a Bayer colour filter. The ISP then interpolates to create the full colour image, but writes a YUV 4:2:0 image out. Conversion to RGB is based on that YUV4:2:0 image. Which format Y...
by Eichhorn18
Mon Sep 10, 2018 9:46 am
Forum: Camera board
Topic: YUV capture - is compression occuring?
Replies: 7
Views: 1186

Re: YUV capture - is compression occuring?

That's fine. YUV has colour channels only downsampled colours from the bayer pattern(only 4x4 bayer pixels create one colour yuv pixel), while RGB interpolates these YUV colours to get a colour value for each pixel. Y -> 3264 x 2464 = 8042496 U -> 3264 x 2464 /4 = 2010624 V -> 3264 x 2464 /4 = 2010...
by Eichhorn18
Mon Sep 10, 2018 8:38 am
Forum: Camera board
Topic: YUV capture - is compression occuring?
Replies: 7
Views: 1186

YUV capture - is compression occuring?

Hello, This question is about YUV capture using the camera v2.1. I have read that the sensor captures YUV natively, meaning it should be the raw data (neglecting bayer filtering). I understand the difference is format between YUV and RGB data. I have captured two images with the same resolution inpu...
by Eichhorn18
Fri Aug 31, 2018 3:05 pm
Forum: General discussion
Topic: RPi 3B+ gigabit ethernet bad download speeds.
Replies: 193
Views: 82035

Re: RPi 3B+ gigabit ethernet bad download speeds.

Well, from RAM you get 30 Mbyte/s. That is 240 Mbit/s which is approaching the expected max rate of ethernet on a RPi 3B+. It's true that is pretty decent. I wonder why the big difference (approximately 50%) for an internet connection that is supposed to give 800 Mbits/s on gigabit ethernet compute...
by Eichhorn18
Fri Aug 31, 2018 11:46 am
Forum: General discussion
Topic: RPi 3B+ gigabit ethernet bad download speeds.
Replies: 193
Views: 82035

Re: RPi 3B+ gigabit ethernet bad download speeds.

Copied from where on the 3B+? How fast can that place source data continuously? Copied from the SD card. I realize that in itself is an unfortunate bottleneck. I have also written files that are stored in RAM, directly to a network mounted folder on a windows machine using CIFS. The transfer speed ...
by Eichhorn18
Thu Aug 30, 2018 2:57 pm
Forum: General discussion
Topic: RPi 3B+ gigabit ethernet bad download speeds.
Replies: 193
Views: 82035

Re: RPi 3B+ gigabit ethernet bad download speeds.

So I'm trying to transfer files through my local network, and scp from my windows machine is showing a max transfer speed of 11.5 MB/s. What is required to check if flow control is turned on/off? I'm running an enterprise network through switches and some managed hubs. [email protected]:~ $ sudo ethto...
by Eichhorn18
Thu Aug 30, 2018 12:50 pm
Forum: Camera board
Topic: Camera preview works, but capture produces an all black .jpeg
Replies: 26
Views: 3362

Re: Camera preview works, but capture produces an all black .jpeg

A small update on this malfunction. I have identified that this problem can occur if the FFC camera cable is bent like a piece of paper, then unbent. I have identified some breakages in the cables that are not visible to the eye. Note to anyone trying to route these FFC cables, particularly if you a...
by Eichhorn18
Thu Aug 30, 2018 12:44 pm
Forum: Camera board
Topic: .PNG and .JPEG photo capture performance - GPU overclocking
Replies: 12
Views: 2403

Re: .PNG and .JPEG photo capture performance - GPU overclocking

...you may find it faster to do it on the ARM cores than asking the GPU to do it (250MHz processor vs 1.4GHz processor). That also allows the GPU to move on to capturing the next still for you. Can you please explain how this could be achieved? I'm not aware of a way to direct a process from python...
by Eichhorn18
Wed Aug 29, 2018 12:45 pm
Forum: Camera board
Topic: .PNG and .JPEG photo capture performance - GPU overclocking
Replies: 12
Views: 2403

Re: .PNG and .JPEG photo capture performance - GPU overclocking

Do you need colour? Or more specifically do you need RGB? 23MB per frame is giving you nearly zero compression as the raw RGB at 24MB. What I really need is a .bmp with colour but capturing directly to a bmp takes too long. I capture as RGB into an array and then post-process it offline of the rasp...
by Eichhorn18
Wed Aug 29, 2018 12:35 pm
Forum: General discussion
Topic: RPi 3B+ gigabit ethernet bad download speeds.
Replies: 193
Views: 82035

Re: RPi 3B+ gigabit ethernet bad download speeds.

CIFS is a dialect of the SMB protocol that Samba implements. We're fairly certain that has been resolved now anyway. It was stalling a single TCP connection rather than a speed issue. https://github.com/raspberrypi/linux/issues/2449 https://github.com/raspberrypi/linux/issues/2482 Yours sounds like...
by Eichhorn18
Wed Aug 29, 2018 9:06 am
Forum: General discussion
Topic: RPi 3B+ gigabit ethernet bad download speeds.
Replies: 193
Views: 82035

Re: RPi 3B+ gigabit ethernet bad download speeds.

There is a suspected issue with Samba (and perhaps other network sharing mechanisms) that we haven't got to the bottom of yet, that may be unrelated. The speedtest-cli result look exactly like flow control is not working effectively. Is there any known issues with cifs as an alternative to samba? J...
by Eichhorn18
Wed Aug 29, 2018 8:30 am
Forum: Networking and servers
Topic: How does mount.cifs transfer data from RAM
Replies: 3
Views: 585

Re: How does mount.cifs transfer data from RAM

ghans wrote:
Tue Aug 28, 2018 10:40 am
A good keyword for Google is "Linux VFS".

ghans
Thank you. This has illustrated my relatively recent adoption of linux. :roll:
by Eichhorn18
Wed Aug 29, 2018 8:28 am
Forum: Camera board
Topic: .PNG and .JPEG photo capture performance - GPU overclocking
Replies: 12
Views: 2403

Re: .PNG and .JPEG photo capture performance - GPU overclocking

Are you using a raspberry pi camera? It would be my guess that the camera is noisier than the distortion added by compressing to a 100% JPEG. If you capture images only for a limited period of time, you might consider buffering them to a ramdisk which writes much faster than an SD card. Yes I am us...
by Eichhorn18
Tue Aug 28, 2018 10:11 am
Forum: Networking and servers
Topic: How does mount.cifs transfer data from RAM
Replies: 3
Views: 585

How does mount.cifs transfer data from RAM

Hi there, This question relates to how linux works, but I have not had success finding the answer through search engines. I have a raspberry pi 3B that I have mounted a window network drive using mount.cifs. The mount point is a folder I created on the Desktop of the raspberry pi. My question relate...
by Eichhorn18
Mon Aug 27, 2018 12:26 pm
Forum: Camera board
Topic: .PNG and .JPEG photo capture performance - GPU overclocking
Replies: 12
Views: 2403

Re: .PNG and .JPEG photo capture performance - GPU overclocking

Two differences: 1) There is no hardware acceleration for PNG, whilst there is for JPEG. 2) PNG encodes an RGB image. JPEG encodes a YUV image. The camera always produces YUV, so therefore is a conversion from YUV to RGB required, and again this is done in software. Basically there is no easy way t...
by Eichhorn18
Tue Aug 21, 2018 3:55 pm
Forum: Camera board
Topic: .PNG and .JPEG photo capture performance - GPU overclocking
Replies: 12
Views: 2403

.PNG and .JPEG photo capture performance - GPU overclocking

Hi, I have been trying to capture high quality images from the picamera rapidly for a while now. I have been using the picamera python library. I recently did a comparison between some of the photo formats that can be taken. JPEG images with quality=100 (minimum compression), captures images at a ra...

Go to advanced search