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#1 2020-04-07 09:52:06

microcord
Member
Registered: 2017-06-21
Posts: 31

video recording blues

I'm permanently a Linux NooB and a total video ignoramus; but, like many millions, am suddenly expected to communicate by video (ugh). I have a fresh installation of BL Helium, bang up to date. All the software has been installed either via Synaptic (from the default BL repository) or by clicking conky's invitations to install (e.g. "Office | LibreOffice | Install | Install LibreOffice Calc") -- nothing from any dubious source.

Today I installed webcamoid. I run it simply by typing "webcamoid" at the terminal. It seems to work OK: I see my face on the screen. (I don't yet have a potential test partner on Zoom, Jitsi, or similar.)  However, the terminal tells me:

file:///usr/lib/x86_64-linux-gnu/qt5/qml/QtQuick/Controls/TextField.qml:638:5: QML TextInputWithHandles: Binding loop detected for property "text"

(several times), and also:

[swscaler @ 0x7f9e4800d0c0] Warning: data is not aligned! This can lead to a speedloss

By contrast, when I try to record, things slow down as the hard drive makes a remarkable number of accesses; the sound and sluggishness remind me of an ancient 386 machine frantically moving data in and out of its tiny memory. I can, if I'm patient, save a file to the hard drive. But VLC media player won't start to play it (no error message, but the play button stays grey). Webcamoid soon dies, and terminal tells me:

Output #0, mp4, to '/home/peter/Video 2020-04-07 17-49-31.mp4':
    Stream #0:0: Unknown: none (mpeg4)
    Stream #0:1: Unknown: none (aac)
[mp4 @ 0x55d261db1c00] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
[mp4 @ 0x55d261db1c00] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
Killed

(Webcamoid does manage to take photos, save these as [valid] PNG files, and not crash in the process; I suppose I should be grateful for that.)

I'd be very grateful for any tips. (Please assume that you're addressing an idiot.)

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#2 2020-04-07 12:08:50

iMBeCil
WAAAT?
From: Edrychwch o'ch cwmpas
Registered: 2015-09-29
Posts: 767

Re: video recording blues

Welcome to the club, microcord wink I'm also a victim of ignoring video stuff for a along time, and suddenly become in need of communicating over video and recording video materials ...

I have learned a lot, especially about formats and codecs (mostly, I have put a recording of myself as a teaching materials ... and a few screen casts, also as recordings).

As for the terminal errors/warnings you should probably google that stuff; for example:

microcord wrote:
[swscaler @ 0x7f9e4800d0c0] Warning: data is not aligned! This can lead to a speedloss

I googled that, and it seems to be mostly harmless, but you could try to change resolution of the video you are recording. Note: all warnings and errors are probably coming from ffmpeg, as probably all video and audio software is using it under the hood.

BTW, for webcam, I use 'guvcview' (it is in usual debian repos, installable by simple 'sudo apt install', or should be via synaptic) ... it seems to be working nicely, and it can record video (with sound). And I can confirm it works nicely with skype for linux and with certain Cisco web conference software called Webex.

As for the HDD activity ... video recording is a b*tch, space-wise and cpu-wise ... It needs a lot of free space for video-file, and a lot of cpu cycles for encoding the video. For example, with my Logitech 720p web usb camera @ 1280x720, simply showing real time picture on the screen makes CPU 7-8% (without: 4-5%). And while recording video, it goes up to 25-30%. (I have MacBook Pro from 2013/4, Intel(R) Core(TM) i7-4850HQ CPU @ 2.30GHz, with SSD).

Also, 26 seconds of recorded video with above resolution is 43.7 MB on disk.

I hope those numbers will help you to put your computer and requirements into the perspective.

I know this doesn't answer your questions, but I hope it will help you to understand video stuff a little bit more. angel


Postpone all your duties; if you die, you won't have to do them ..

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#3 2020-04-07 13:18:39

microcord
Member
Registered: 2017-06-21
Posts: 31

Re: video recording blues

iMBeCil wrote:

I have learned a lot, especially about formats and codecs

I suppose I'll have to as well. All I know about codecs is that attempts to play new video files on old systems tend to bring messages saying no deal, the codec is missing. I now have to choose among codecs, and their names mean no more to me than do those of crochet stitches or dog breeds.

[swscaler @ 0x7f9e4800d0c0] Warning: data is not aligned! This can lead to a speedloss

Thank you for the links for that one. (Yes, you're right, I should have googled. I'm sorry.) The bottom line is that resolutions in powers of two, e.g. 516×256, are good. Maybe. (Some people seem to disagree.) But it's moot, because unsurprisingly webcamoid doesn't offer any such resolution.

iMBeCil wrote:

BTW, for webcam, I use 'guvcview' [...]

I took a look, and read about it:

Guvcview audio support can be selected from two APIs: portaudio or pulseaudio (if availbale)

All interfaces (ALSA, OSD, JACK, ...) supported by portaudio should be available in guvcview.

"portaudio", "pulseaudio", "ALSA", "OSD", "JACK" -- never heard of any of them.

iMBeCil wrote:

As for the HDD activity ... video recording is a b*tch, space-wise and cpu-wise ... It needs a lot of free space for video-file, and a lot of cpu cycles for encoding the video.

And my little test videos were low-resolution and each about ten seconds long. Hmm, so there really is a reason for a fast machine other than playing games and watching pr0n? Well well, I live and learn. This little machine has 450GB of empty space on its hard drive, but only 4GB RAM. But I'm stuck with it.

Think I'll go to bed and tomorrow morning try installing different software.

Beats me why my employer thinks that our clients will want to see my talking head. (I'm not pretty, and I'm less lucid than when I write.) I was slightly looking forward to using webcamoid because of all the ways it can make me look less boring (see this video, from around the eleven-minute mark).

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#4 2020-04-07 14:10:01

iMBeCil
WAAAT?
From: Edrychwch o'ch cwmpas
Registered: 2015-09-29
Posts: 767

Re: video recording blues

microcord wrote:
[swscaler @ 0x7f9e4800d0c0] Warning: data is not aligned! This can lead to a speedloss

Thank you for the links for that one. (Yes, you're right, I should have googled. I'm sorry.) The bottom line is that resolutions in powers of two, e.g. 516×256, are good. Maybe. (Some people seem to disagree.) But it's moot, because unsurprisingly webcamoid doesn't offer any such resolution.

Well, that's strange ... or not? The guvcview will offer resolutions supported by the hardware, only - i.e. by the web usb cam. It may mean that the webcamoid will do not only capture, but postprocessing as well ... There might lay your problem - webcamoid will not only fill your HDD with video, it will also use your CPU to transcode video to some strange resolution? (I might be completely wrong, perhaps your web usb camera has less-than-a-standard resolutions. Please check it.)

For me, standard workflow is to record something with usb camera native resolution (to free up CPU from additional tasks), and then post-process it with openshot-qt (or directly with ffmpeg for simpler post-processing). Of course, it is completely different for real-time video - different workflow ... guvcview also has a few effects, but I wonder if they are as powerful as webcamoid's ...

I do suggest you try it with guvcview, though.

microcord wrote:

I took a look, and read about it:

Guvcview audio support can be selected from two APIs: portaudio or pulseaudio (if availbale)

All interfaces (ALSA, OSD, JACK, ...) supported by portaudio should be available in guvcview.

"portaudio", "pulseaudio", "ALSA", "OSD", "JACK" -- never heard of any of them.

Don't worry about these ... as long as you hear the sound, it is OK. The guvcview, if started AFTER connecting a web camera, will most probably properly autodetect the audio source.


microcord wrote:

Hmm, so there really is a reason for a fast machine other than playing games and watching pr0n? Well well, I live and learn.

big_smile  big_smile  big_smile Exactly my reaction  big_smile  big_smile I have 16G and SSD, I do a lot of numerical calculation, and only now, when I needed video, I understand why would anyone want home desktop with, say, 32GB memory, huge SSD, huge external HDD (to backup large videos from SSD), and lots of CPUs. Simple transcoding of half an hour recorded video to Youtube format (vp9) takes around 2 to 3 hours @ 1920x1080 resolution ...

microcord wrote:

Beats me why my employer thinks that our clients will want to see my talking head. (I'm not pretty, and I'm less lucid than when I write.) I was slightly looking forward to using webcamoid because of all the ways it can make me look less boring (see this video, from around the eleven-minute mark).

I fully understand about being smarter while writing something - welcome to the club smile ... but if you consider yourself ugly, you can pixelate yourself in guvcview, or combine it with blurring and decreasing brightness smile
Seriously, though, it is only my suggestion to use guvcview ... perhaps, there are some options to adjust in webcamoid which would work for you. At the end, it is up to you to decide which tool is the best for you. (Did you consider using a mobile phone, instead of computer? Perhaps you have a good one which will satisfy all your requirements ...)

Good luck.


Postpone all your duties; if you die, you won't have to do them ..

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#5 2020-04-07 23:58:28

microcord
Member
Registered: 2017-06-21
Posts: 31

Re: video recording blues

iMBeCil wrote:

I have 16G and SSD [...] Simple transcoding of half an hour recorded video to Youtube format (vp9) takes around 2 to 3 hours @ 1920x1080 resolution ...

And on my cheapo computer with 4G and no SSD, perhaps three days? Holy intercoursing..... Well, it's lucky that I also have another (slow) machine that I can be using while the hard drive on this one is thrashing away.

(My own computer purchasing "philosophy" this century has been: Keep using any computer until it freezes or spontaneously reboots on average more than once a day. Then look for the cheapest available replacement, but double whatever's the bog-standard amount of memory. Until this week, this has worked.)

iMBeCil wrote:

Good luck.

Thank you! I'll need all of it.

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#6 2020-04-08 09:07:09

rbh
Member
From: Sweden/Vasterbotten/Rusfors
Registered: 2016-08-11
Posts: 695

Re: video recording blues

microcord wrote:

but, like many millions, am suddenly expected to communicate by video

Comunicate by video is one thing and record video is another.

I just used webcamoid to record a video on an ol IBM Thinkpad T43 with single core Intel Pentium M 1,8 GHz and 1.5 GB RAM. It is possible. Should be possible on your computer too.
But, Guvcview, is a much better alternative when having low resources. Guvcview is also easier to handle. When embarking new paths, it can be good to use simpler tools.

If you want to use a live videochat, there is many alternatives. Zoom is not one of them. Their latest Debian client is for Debian 8! I have filed a suport case a week ago. As unpriviliged free user, it will probabley take a long time before they react on the case. They have also some security problems...

There is some good tools to record computer screen and audio (live video chat). Simple Screen Recorder, is light.

I am not good about multimedia. I throw in a lot off packages, to support record video...


// Regards rbh

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#7 2020-04-08 09:31:34

iMBeCil
WAAAT?
From: Edrychwch o'ch cwmpas
Registered: 2015-09-29
Posts: 767

Re: video recording blues

rbh wrote:

There is some good tools to record computer screen and audio (live video chat). Simple Screen Recorder, is light.

One can also use ffmpeg, see my BL post for example(s) ... TBH, I think SimpleScreenRecorder is simply kind of wrapper around ffmpeg, which allows one to select screen coordinates with mouse ... I prefer direct approach, with ffmpeg (it seems I'm a minimalist smile )


Postpone all your duties; if you die, you won't have to do them ..

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#8 2020-04-08 10:38:07

microcord
Member
Registered: 2017-06-21
Posts: 31

Re: video recording blues

rbh wrote:

Comunicate by video is one thing and record video is another.

There's an expectation that I should at least offer both (A) to communicate "live" by video and (B) to provide (prerecorded) videos.

rbh wrote:

I just used webcamoid to record a video on an ol IBM Thinkpad T43 with single core Intel Pentium M 1,8 GHz and 1.5 GB RAM. It is possible.

I believe you. But which version of webcamoid is it? (The video I linked to above shows 8.1.0; the version normally available in Helium is 7.2.1.)

I'm now trying OBS Studio. I was unenthusiastic about Zoom, but then I read more about it and my little enthusiasm evaporated. So now I'm trying to work out how to get OBS Studio and Jitsi to work together.

(Actually I suspect the whole idea of live videoconferencing is now a waste of time, because my colleagues will be trying to persuade our students to use Zoom. The students may or may not use Zoom in response to requests by half a dozen teachers; it's hard to believe that any would be interested in Jitsi as well, just for one teacher.)

rbh wrote:

But, Guvcview, is a much better alternative when having low resources. Guvcview is also easier to handle. When embarking new paths, it can be good to use simpler tools. [...] Simple Screen Recorder, is light.

iMBeCil wrote:

I think SimpleScreenRecorder is simply kind of wrapper around ffmpeg [...]

Thank you both. I'll keep the names in mind, for when my current attempts fail.

There's a prodigious amount of background noise here. Any recordings I succeed in making will be painful to listen to, at least until I receive the headset that I ordered days ago....

Sorry for wallowing in self-pity here!

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#9 2020-04-08 11:35:08

iMBeCil
WAAAT?
From: Edrychwch o'ch cwmpas
Registered: 2015-09-29
Posts: 767

Re: video recording blues

microcord wrote:

I'm now trying OBS Studio. I was unenthusiastic about Zoom, but then I read more about it and my little enthusiasm evaporated. So now I'm trying to work out how to get OBS Studio and Jitsi to work together.

(Actually I suspect the whole idea of live videoconferencing is now a waste of time, because my colleagues will be trying to persuade our students to use Zoom. The students may or may not use Zoom in response to requests by half a dozen teachers; it's hard to believe that any would be interested in Jitsi as well, just for one teacher.)

Haha, you are doomed  devil
Unless you are a head of an IT, have everything under control and you have hacker audience, you stand no chance of persuading people to use anything than mainstream solutions like Zoom/whatever. At least it is my experience. (If you try, prepare for total collapse, because 90% of people will not know how to setup and use their computers/clients ... the background or behind-the-scene support/setup like log-in servers and similar, when lots of different people are present, is essential here.) I suggest you embrace your fate, as much as you may be unsatisfied with this. And use time for other normal activity, like pr0n and cat videos wink

Second hand experience: my kid(?), University grade lol , some professors teach real-time over Zoom, and my kid says it is perfectly OK, and seems to be satisfied with this.


Postpone all your duties; if you die, you won't have to do them ..

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#10 2020-04-08 13:17:29

rbh
Member
From: Sweden/Vasterbotten/Rusfors
Registered: 2016-08-11
Posts: 695

Re: video recording blues

microcord wrote:

I believe you. But which version of webcamoid is it?

Sorry, I have migrated to Lithium, så it is version 8.5.0+dfsg-2 now. But I have used webcamaoid on a Dell, when it had Helium. A Dell with 2 cores 1.8 GHz cpu and 2 GB RAM....

I'm now trying OBS Studio.

I installed thar for some months ago, still not had the time to configure it. Started the automatic konfiguration, but that does not add video-source... So darn simple in Guvcview. And draws less resources.

I was unenthusiastic about Zoom,

It has some advantages. 2 organisations I'm member of (Friendes of the earth and "Swedish Nature Conservation Society") use it for meetings now. So, I had to install it on my android phone.

(Actually I suspect the whole idea of live videoconferencing is now a waste of time, because my colleagues will be trying to persuade our students to use Zoom. The students may or may not use Zoom in response to requests by half a dozen teachers; it's hard to believe that any would be interested in Jitsi as well, just for one teacher.)

? One has to go with the flock, when communicating... But why do not the school get an " G Suite for Education"  account? Google has now expanded Google Meet. An google Nonprofit account, can now take (temporarily) 250 connections (usualey only 50).

iMBeCil wrote:

I think SimpleScreenRecorder is simply kind of wrapper around ffmpeg [...]

As OBS studio also I think?

There's a prodigious amount of background noise here.

That is no good! But, do you not have a android phone? Often in video metings, I connect both with computer and phone. Use the phone only for sound. When I want to record, it is a little pain. I have so many audiosources on the pc and often get lost and do not get all sound.
Google meet, have built in recording. Some minutes after shuting down the Video-konferens, it is saved in Google Drive. Only the account who start the meeting can start the recording.

Last edited by rbh (2020-04-08 13:18:40)


// Regards rbh

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#11 2020-04-08 13:28:41

rbh
Member
From: Sweden/Vasterbotten/Rusfors
Registered: 2016-08-11
Posts: 695

Re: video recording blues

Jitsi - https://meet.jit.si , seems a good find. Thanks


// Regards rbh

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#12 2020-04-08 23:14:18

microcord
Member
Registered: 2017-06-21
Posts: 31

Re: video recording blues

iMBeCil wrote:

Unless you are a head of an IT, have everything under control and you have hacker audience, you stand no chance of persuading people to use anything than mainstream solutions like Zoom/whatever

This isn't anything to do with the head of IT. There's no time for that. I guess my colleagues decided on Zoom because that was what they'd read about.

If it had been the head of IT, he (always a "he"!) would have called a series of committee meetings, and these eventually would have decided on some "solution" that was proprietary and expensive and required Windows.

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#13 2020-04-09 02:27:33

microcord
Member
Registered: 2017-06-21
Posts: 31

Re: video recording blues

OBS Studio recognizes my computer's built-in (and of course crappy) microphone and camera; or, if I plug in a second camera (with built-in mic), then both my microphones and both my cameras. Nothing to complain about! It's not (yet!) obvious that I have any problem with OBS Studio.

When I try Jitsi Meet with just the computer's built-in camera and mic, Jitsi recognizes the mic; but, unlike OBS Studio (which is running simultaneously), it doesn't show my ugly face. It warns "Failed to access your camera". When I click the downwards icon next to Jitsi's icon showing a crossed-out (i.e. turned off) video camera, it tells me "Preview unavailable". Yet I infer that Jitsi has some level of awareness of my camera(s): when I plug in the second one and do what I've just described, I get not one but two black rectangles each saying "Preview unavailable".

Unfortunately this helpful message thread at jitsi.org "Jitsi Meet - Failed to access your camera/microphone" could be written in Mongolian for all the sense it makes to me. (No offence intended to speakers of Mongolian.)

By contrast, "Failed to access your camera using firefox 69.0.1" does make sense to me. Of course it's about Firefox, whereas (following Jitsi's advice) I'm using Chromium. Anyway, appr.tc (which the page recommends) didn't work, instead telling me:

Error getting user media: Starting video failed
getUserMedia error: Failed to get access to local media. Error name was AbortError. Continuing without sending a stream.

Another recommendation (for Firefox) in that page is "Javascript-Java bridge"
(an add-on for Firefox, supposedly at https://addons.mozilla.org/en-US/firefo … ava-bridge but no longer there). I googled for it and found it for Chromium: https://chrome.google.com/webstore/deta … va-bridge/. It's hardly recommended, but I tried it all the same.

And it half worked! It showed my external camera on Jitsi (a camera pointing downward at documents), but not the computer's built-in camera (pointing at me). Oh well, halfway to success.

I closed Chromium and reopened it (and Jitsi). No change.

Not knowing how to turn the computer's camera off and then back on, I rebooted the computer. After rebooting, as expected, OBS Studio shows output from both cameras. But Jitsi-on-Chromium now shows me output from neither camera (an attempt again shows two "Preview unavailable" rectangles). I'm back to where I was before installing Javascript-Java Bridge.

Yes, Chromium's menu "More tools | Extensions" shows that Javascript-Java Bridge is present and running.

I used that same menu to turn Javascript-Java Bridge off and then back on again. No change.

Now I'm utterly baffled.

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#14 2020-04-09 06:39:31

rbh
Member
From: Sweden/Vasterbotten/Rusfors
Registered: 2016-08-11
Posts: 695

Re: video recording blues

If you are running OBS Studio and Video chat simultaneous. the videometting wont get access to the camera. If you want to record the meeting, you have to record the screen, a window or some part of the screen.


// Regards rbh

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#15 2020-04-09 06:58:38

microcord
Member
Registered: 2017-06-21
Posts: 31

Re: video recording blues

rbh wrote:

If you are running OBS Studio and Video chat simultaneous. the videometting wont get access to the camera. If you want to record the meeting, you have to record the screen, a window or some part of the screen.

You're right. I'm sorry. My attempts at videoconferencing are bringing on premature senility.

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#16 2020-04-10 21:37:40

iMBeCil
WAAAT?
From: Edrychwch o'ch cwmpas
Registered: 2015-09-29
Posts: 767

Re: video recording blues

OK, first offff, I'm drunk. Thats ok though, since it's friday, usual time for my/our beer with my friends - on line this time.

What is outstanding though is that lockdown has forced us to use confrence softwaree, Lo and behold ... jitsi meet seems to be completely excellent. With their server jit.si didi miracle.! I'm impressed.

Note to tommorow myself: establish and cofigure your ownr jits meet server!. The point is that meet.jitsi.si is probably very bussy serving all web conf meetings, it sometimes freezes picture ... otherwise, it seems extremely robust. Also, although there is no special requirements: they recommend Chrome/ium, but it works prefectly OK with firefox. Nothing for client to install ... nor on linux, nor on windows, nor android/OS nor, nor.

So, @microcord: my appologies for bahsing your ideas! If you can provide good linux server with debian, there are jitsi cupplied packages for installin jitsi server with apache/nginx. Not so complicated ... And all this is opensource. Fabulous!

Beware though, server should have certain bandwitdh available ... there are some estimates it is few Mbits/sec per person for decent vido+audio. If one is in teaching business, it shouldn't be a problem. (I intend to try it ... may post a results latre this week.)


Postpone all your duties; if you die, you won't have to do them ..

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#17 2020-04-10 23:03:43

microcord
Member
Registered: 2017-06-21
Posts: 31

Re: video recording blues

iMBeCil wrote:

OK, first offff, I'm drunk. Thats ok though, [...]

I hope that the beer wasn't just efficacious but also tasted good; also, that you're feeling good the morning after!

iMBeCil wrote:

they recommend Chrome/ium, but it works prefectly OK with firefox.

When I use Chromium (version 73.0.3683.75), I can't share my screen. I mean, clicking on "Share your screen" does nothing (no error message; no sign of any response whatever). I googled for this and found that one needs an extension in order to allow Chrome to share the screen. Assuming that this would be true for Chromium as well, I installed "Screen Sharing" (version 1.0.5). This made no difference.

When I use Firefox, I can share my screen (even without installing any plug-in or similar). I get rather irritating messages telling me that I'm not using a recommended browser. (There doesn't seem to be an option for responding "Yes, I understand; please don't tell me again.") As you'll have seen, there's a little menu button right next to the audio on/off button and another right next to the video on/off button; with Firefox (version 68.7.0esr, 64-bit), these little menu buttons don't work.

Yesterday I had a stroke of genius (not): Simultaneously (i) use Chromium for everything except screen sharing; (ii) use Firefox only for screen sharing. (In the Firefox tab for Jitsi, turn off both video and the mike; in the Chromium tab, mute my Firefox alter ego.) Visually, it works; however, there's an echo of my speech (and of the speech of Carl, my helpful partner in Jitsi-testing) after about five seconds. (Presumably some ingredient of my Linux installation imposes this delay in order to avoid a destructive feedback loop.) It doesn't affect Carl, who's happily using the iOS app, and who hears me, and himself, only once. (For me, it's like being the subject in a rather sadistic psychology experiment: "Carl, would you please. [5-second pause] Speak in short bursts. [5-second pause] Because you're driving me nuts.") And therefore it's unworkable.

Using Chromium (or Chrome), are you able to share your screen?

Presumably a great number of people are using Microsoft Edge these days. Strangely, the Jitsi people don't seem to mention it, even though it is (I think) based on Chromium.

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#18 2020-04-11 06:39:12

rbh
Member
From: Sweden/Vasterbotten/Rusfors
Registered: 2016-08-11
Posts: 695

Re: video recording blues

If you get error message, using too old browser, maybe you should consider upgrade BL? In Debian Buster (BL Lithium), Chromium is version 80.0.3987.162-1.

I know that Google only guarantee support for all functions in the last two versions of supported browsers.


// Regards rbh

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#19 2020-04-11 07:41:49

microcord
Member
Registered: 2017-06-21
Posts: 31

Re: video recording blues

rbh wrote:

If you get error message, using too old browser, maybe you should consider upgrade BL?

I actually hadn't thought of that.

Just when I was getting used to my new installation of Helium.... But yes, it seems a good idea. Thank you!

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