[SOLVED] I found a camera. I wonder if I can make it work

hazel · 06-10-2022, 11:22 AM

It's little more than a toy, I can see that now. I was trying today to do something with it that would actually be useful. I think I have the beginning of a fungus infection in one of my fingernails (a recurrence of an old problem if true) and I thought I could take a picture of it for my doctor. It's quite difficult to see a general practitioner in the UK right now so it could be useful to have a picture to send in instead of making an appointment. But I couldn't get a picture that was worth anything.

With guvcview, I get a display window with a fixed picture in it, the same as vlc shows. No sign of moving video. The title bar says 7 or 8 fps. If that is frames per second, then it is certainly rubbish because I read that you need at least 20 for video.

Of course my little laptop has a camera too which I've never used. Maybe now that my curiosity is piqued, I could try with that one and see if I get better results. But if you're right about it being a system problem, the laptop will be worse because it has much less memory and only one processor core.

SW64 · 06-10-2022, 12:19 PM

Quote:

Originally Posted by hazel

I was trying today to do something with it that would actually be useful. I think I have the beginning of a fungus infection in one of my fingernails (a recurrence of an old problem if true) and I thought I could take a picture of it for my doctor. It's quite difficult to see a general practitioner in the UK right now so it could be useful to have a picture to send in instead of making an appointment. But I couldn't get a picture that was worth anything.

A smartphone or a tablet with a builtin camera would be better suit for that. The lenses in these smartphones/tablets tend to do a much better job of focusing on close-up objects than the older generation of webcams would.

Quote:

With guvcview, I get a display window with a fixed picture in it, the same as vlc shows. No sign of moving video. The title bar says 7 or 8 fps. If that is frames per second, then it is certainly rubbish because I read that you need at least 20 for video.

It depends on where the videos are going. If it's to be used in a quality video production then yes, 8fps is rubbish. 20 fps is more ideal. 29.97/30fps or faster are the best. 12 to 15 fps, one could get away with that. But 8 fps or less, I'm wondering if that's just the preview's frame rate. I'm wondering if you do a video capture, will you find that the resulting videos will have a proper frame rate?

I am unable to come up with an explanation why guvcview and vlc are giving you the same preview feed. You should have a working live feed by now.

Quote:

Of course my little laptop has a camera too which I've never used. Maybe now that my curiosity is piqued, I could try with that one and see if I get better results. But if you're right about it being a system problem, the laptop will be worse because it has much less memory and only one processor core.

Maybe it was a good thing that you've found an older generation webcam that was a better match for your laptop. Any thing with capturing videos do required some degree of processing power and transferring bandwidth. Do give your laptop's builtin webcam a try.

cwizardone · 06-10-2022, 03:08 PM

Quote:

Originally Posted by SW64

A smartphone or a tablet with a builtin camera would be better suit for that. The lenses in these smartphones/tablets tend to do a much better job of focusing on close-up objects than the older generation of webcams would...........

Absolutely!
The resolution of images I've seen taken with a smart phone is very impressive, especially those taken with an iPhone. Some of these phones have two or three lenses for various purposes. Mine has one lens, but the results are far superior to my "old" digital camera and it does have a "close up" option.
Seem odd calling a digital camera "old."

amikoyan · 06-10-2022, 03:31 PM

Quote:

Originally Posted by hazel

In Harrow (and probably in other middle-class London districts) there is a long standing convention that if you do not want something but think it might still be usable by others, you put it out by the front gate for anyone passing by to take. I've acquired a lot of stuff that way, both clothes and tech. My present monitor I bought second-hand but all the previous ones were foundlings.

This camera was placed on top of a dustbin together with an envelope containing a tiny multilingual leaflet and a cdrom with Wndows and Mac drivers. The owner could have taken it to the local tip and dropped it on the waste electronics heap but she saved herself the trouble.

So you quite literally found it...

Both my laptops are second hand and work fine, so I am a big fan of recycling/reusing technology.
The built in camera on my 12 year old Thinkpad takes serviceable photos and video, so the one on your laptop might be ok. I put tape over mine after watching a film about Edward Snowden and then reading this: https://www.theguardian.com/commenti...rophone-spying
Perhaps I am being paranoid...

hazel · 06-11-2022, 05:14 AM

I have a lot to report! This morning I installed vlc on my laptop, littleboy. This runs AntiX with apt as package manager, so a whole slew of dependencies came over with it. The built-in camera (/dev/video0) gave me quite decent live video at once and I was able to get a snap of my finger. Then I plugged in the eyeball, which became /dev/video1. It also gave live video on this machine but of poorer quality than the native camera. I was able to improve the focus a bit though.

I conclude that the failure of live video on bigboy is due to a software problem rather than a problem with the webcam, probably a missing dependency of some kind. I shall have to use apt to list the dependencies Debian/AntiX use in their build and then see what I need to install in Slackware. Grunt work but probably not needing a lot of insight.

Thanks to everyone so far. I was never interested in video but I could become so.

amikoyan · 06-11-2022, 05:48 AM

Quote:

Originally Posted by hazel

Thanks to everyone so far. I was never interested in video but I could become so.

Is it video per se that you're interested in? Or the opportunity to sink your teeth into a nice juicy problem to solve? It sounds like you are enjoying the challenge of getting your 'little eyeball' to work at least as much as any pictures it produces.

Enjoy your adventure.

hazel · 06-11-2022, 05:59 AM

Quote:

Originally Posted by amikoyan

Is it video per se that you're interested in? Or the opportunity to sink your teeth into a nice juicy problem to solve? It sounds like you are enjoying the challenge of getting your 'little eyeball' to work at least as much as any pictures it produces.

You have a point there! I was never a visual person. I live through my ears rather than my eyes; for example I think in words and never in pictures. On the other hand, I don't record or play back music either and usually prefer to work in silence.

amikoyan · 06-11-2022, 06:57 AM

I have changed as I have got older; I now think more in pictures, especially for routine or mundane tasks (literally a series of mind images - open garage door, take out lawnmower,close garage door etc...). I have to run through a series of pictures in my mind.

This is necessary these days or else I leave the garage door open, or go out in public unshaven! I don't remember having to do this in the past though.

For more complex or analytical tasks I still think in words. Keeping my mind busy with something helps I think.

SW64 · 06-11-2022, 11:35 AM

Glad you got the second webcam up and running! Hope you get your finger fixed.

Basically, from start to end, working with videos is done in four stages; capturing, editing, exporting, and distributing. Depending on your level of interest and how far you wish to take this to, you may eventually need or want a video editor to put your videos together.

On the GUI side of video editors, Openshot would be a good start. Flowblade is another good one. Kdenlive is meant for advanced users but it is easy enough to use if one know the basics of video editing.

On the CLI side, one can put together videos via ffmpeg (even though ffmpeg is not a video editor). Here's a section taken from this link: https://trac.ffmpeg.org/wiki/Concatenate

Code:

Instructions

Create a file mylist.txt with all the files you want to have concatenated in the following form (lines starting with a # are ignored):

# this is a comment
file '/path/to/file1.wav'
file '/path/to/file2.wav'
file '/path/to/file3.wav'

Note that these can be either relative or absolute paths. Then you can stream copy or re-encode your files:

ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.wav

The -safe 0 above is not required if the paths are relative.

For this example to work, all of the video clips must be of the same format specification. This should work if you only work with one of your webcam sources from the same program (such as guvcview).

This is too useful to not mention. Here's the same list example but with the inputs and outputs added in. The numbers are in total seconds and arbitrary for this example. (You can use hh:mm:ss.ff too. 'inpoint 01:01:01.15' is one hour, one minute, one and a half second in a 30fps video.) This will allow you to concatenate only a certain section of each video clip rather than the whole video clip. I also removed the absolute paths and changed the extension from wav to mkv.

Code:

file 'file1.mkv'
inpoint 5
outpoint 15
file 'file2.mkv'
outpoint 240
file 'file3.mkv'
inpoint 120

For distributing, when you export a finished video, H.264/AAC/MP4 is still a good format to export (or convert) into. You might run into minor and easily resolved H.264 copyright issues on some Linux distros. This format will let you distribute and playback your exported videos on a wide range of devices.

That's working with videos in a nutshell, lol. At least, my version of it. Have fun!

hazel · 06-20-2022, 06:10 AM

Today I copied a video created on Littleboy over to Bigboy. It was filmed in vlc using the built-in camera but I know that the "eyeball" can create moving video on this machine too. Bigboy treated the import as a still image, just like the videos recorded locally.

Then I did the reverse: copied one of the vlc files created with the eyeball in Bigboy over to Littleboy. Bigboy won't display it properly but Littleboy does! The sequence shows normal movement in Littleboy's vlc window, though the picture quality is poor.

I conclude that whatever is causing this problem on Bigboy is tied up with the display, not the recording. So I tried running mesa's glxgear program. And -- surprise, surprise! -- no visible movement! Also when I maximised the window, I got terrible tearing, which remained after resizing it. When I ran glxgears from a terminal, I got this:

Code:

Running synchronized to the vertical refresh.  The framerate should be
approximately the same as the monitor refresh rate.
310 frames in 5.0 seconds = 61.921 FPS
301 frames in 5.0 seconds = 60.024 FPS
301 frames in 5.0 seconds = 60.016 FPS

So, we've nearly solved it! Can anyone tell me what I need to do to X to get this to work?

hazel · 06-22-2022, 12:40 AM

Proof!!

Today I booted into Slackware 14 and tested glxgears. I got normal rotation.

Code:

303 frames in 5.0 seconds = 60.569 FPS
300 frames in 5.0 seconds = 59.998 FPS
304 frames in 5.0 seconds = 60.794 FPS
301 frames in 5.0 seconds = 60.001 FPS
300 frames in 5.0 seconds = 59.993 FPS

So I installed guvcview with its dependencies and tested out the camera. Result: moving video!

Conclusion: on any system where glxgears works, video works. If glxgears doesn't show any movement, video can be recorded but not shown.

But why??? I want to know why? Here's something that works on Slackware-14 but not on Slackware-15. Is that what they call a regression?

SW64 · 06-22-2022, 10:54 AM

If that was on Bigboy, it seems that Slackware 15's mesa no longer support your computer's graphic or monitor by default. Hopefully you can turn it back on. When you say no movement, you get the gears but they are "frozen"? Or are you seeing something like a super slow frame rate on your monitor? Like a really slow slideshow? Maybe your Bigboy is software rendering and a poor one at that. You did mentioned tearing in your earlier post. Maybe Slackware 15's mesa has not recognized your monitor properly.

14.0 is mesa-8.0.4-x86_64-1.txz.
14.1 is mesa-9.1.7-x86_64-1.txz.
14.2 is mesa-11.2.2-x86_64-1.txz.
15.0 is mesa-21.3.5-x86_64-2.txz.
As of today, 15.0 current is mesa-21.3.8-x86_64-1.txz.

https://docs.mesa3d.org/faq.html See 3.1.

I am not familiar with X or mesa so I need to step out at this point. It might be a good idea to start a new thread on this new issue since it doesn't have much to do with running the webcams themselves anymore. If you do decide to start a new thread on this, I suggest posting a link back to this thread for context and maybe the results of the 'inxi --gpu --cpu' and 'inxi --version' on your Bigboy, too.