Discussion:
[CinCV] capture video from webcam
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Raffaele Morelli
2011-10-07 07:15:10 UTC
Permalink
Hi,
I am trying to capture video from my webcam, the device is there and audio
monitor works (/dev/oss) but I can't get any useful image from the webcam.

Sometimes I see a green screen, someother a dots or lines... I am using
"quicktime for linux" and tried motion jpeg, mpeg4 and so on for video
formats but nothing.

Any idea? suggestion?
Regards

-raffaele
--
*L'unica speranza di catarsi, ammesso che ne esista una, resta affidata
all'istinto di ribellione, alla rivolta non isterilita in progetti, alla
protesta violenta e viscerale.*
Einar Rünkaru
2011-10-07 09:03:41 UTC
Permalink
Hi.

On Fri, Oct 7, 2011 at 10:15 AM, Raffaele Morelli
Post by Raffaele Morelli
Hi,
I am trying to capture video from my webcam, the device is there and audio
monitor works (/dev/oss) but I can't get any useful image from the webcam.
Sometimes I see a green screen, someother a dots or lines... I am using
"quicktime for linux" and tried motion jpeg, mpeg4 and so on for video
formats but nothing.
Any idea? suggestion?
Regards
-raffaele
Webcam capture is buggy and it works only with certain parameters. You
have to find out yours.

I got video from v4l2 driver only with resolution 600x800.

Better find some other video capture program.

Einar
Edouard Chalaron
2011-10-07 09:31:34 UTC
Permalink
Post by Einar Rünkaru
I got video from v4l2 driver only with resolution 600x800.
Better find some other video capture program.
Einar
?????
I am very surprised ...
I am capturing 1600x1200 pixels frames from /dev/video1 @ 12 fps

I think gnome meeting can stream to /dev/video0.
I do it from Coriander though but I can't see any difference.
Basically if you stream to /dev/video0 you make cinelerra listen to /dev/video1, see records settings

Cheers
E
Einar Rünkaru
2011-10-07 11:54:55 UTC
Permalink
Post by Edouard Chalaron
Post by Einar Rünkaru
I got video from v4l2 driver only with resolution 600x800.
Better find some other video capture program.
Einar
?????
I am very surprised ...
I think gnome meeting can stream to /dev/video0.
I do it from Coriander though but I can't see any difference.
Basically if you stream to /dev/video0 you make cinelerra listen to /dev/video1, see records settings
As I said video capture works with certain parameters. These
parameters depend on your hardware and system setup.

I am seriously thinking about removing all capture features from
Cinelerra in the future. How mutch people use it (were able to find
working settings)? For what purpose tehy use it?

Einar
Raffaele Morelli
2011-10-07 12:09:04 UTC
Permalink
Post by Edouard Chalaron
Post by Edouard Chalaron
Post by Einar Rünkaru
I got video from v4l2 driver only with resolution 600x800.
Better find some other video capture program.
Einar
?????
I am very surprised ...
I think gnome meeting can stream to /dev/video0.
I do it from Coriander though but I can't see any difference.
Basically if you stream to /dev/video0 you make cinelerra listen to
/dev/video1, see records settings
As I said video capture works with certain parameters. These
parameters depend on your hardware and system setup.
I am seriously thinking about removing all capture features from
Cinelerra in the future. How mutch people use it (were able to find
working settings)? For what purpose tehy use it?
Einar
I think capture features are useful... I am not a video expert and don't own
a cam but I've used screencapture for a couple of video tutorial for my
friends using linux, now I am trying to record music & video of myself while
playing guitar and using ardour, jack, etc etc... so, I would not say
capture features aren't useful.

about working settings, I must say I can't capture anything but green
frames... audio it's ok, but no video, no matter how I tried with sizes &
video codecs, maybe capture features needs to be improved a little.

my 0.02€

regards
raffaele
Edouard Chalaron
2011-10-07 20:52:26 UTC
Permalink
Post by Einar Rünkaru
Post by Einar Rünkaru
Better find some other video capture program
Can you point something better ?
Post by Einar Rünkaru
I am seriously thinking about removing all capture features
from
Cinelerra in the future. How mutch people use it (were able
to find
working settings)? For what purpose tehy use it?
??????? Gosh Einar, I am sorry but you may want to look a little bit further than the lens of your ipod camera....

Cinelerra would become some sort of Kino just designed for camcorders and highy compressed videos. Why don't just remove importing file sequences, RGB float etc since you are willing to shoot yourself in the foot ?

The use of it ? controlling imports or scans (like I do) with a vectorscope
I am starting a hack of the invert plugin to work on scanned negative films. This is what it can be used for.

Unfortunately I am not a developper, just an end user. However it happens that someone here I know is technical director for Peter Jackson, I sent him a 16 bit/pixel frame of my scans on 16mm negs, comment was "just as good as our Arri scanner, what soft did you use to import" .. Do you really want to remove that ?

Why not fixing ffmpeg integration instead like you pointed out a couple of days ago? or hacking some RED camera support that sounds more useful.

If you are not busy enough, why not considering rewriting proper denoisers? for say there is no temporal denoiser for full RGB frames. Does not it sound more important than removing something that works even for few people?

If you want to denoise a quicktime the cinelerra denoisers are just useless, you need to export through a yuv4mpeg stream etc.

How about Feior plugins ? OpenCV ?? convolution ?


Times to consider my options with openshot or blender, or Lumiera if it comes to life. I am starting to wonder if the CV version is not turning like the original.

E
slightly bitter
Raffaella Traniello
2011-10-08 11:59:12 UTC
Permalink
Ciao Edouard!
Post by Edouard Chalaron
??????? Gosh Einar, I am sorry but you may want to look a little bit
further than the lens of your ipod camera.... Cinelerra would become
some sort of Kino just designed for camcorders and highy compressed
videos. Why don't just remove importing file sequences, RGB float etc
since you are willing to shoot yourself in the foot ?
Calm down. :-)

Capture functions in Cinelerra are pretty unstable. In particular they
seem to depend on hardware. For some people they work perfectly (a
minority it seems) for others they are really unusable.

To have a very buggy feature is not good, so we are brainstorming on
possible solutions. Fix the feature if it is useful (that's an expensive
solution), remove it if it is un-used (cheaper solution).
Post by Edouard Chalaron
How much people use it (were able to find working settings)? For
what purpose they use it?
controlling imports or scans (like I do) with a vectorscope I am
starting a hack of the invert plugin to work on scanned negative
films. This is what it can be used for.
It is very useful also to know Cinelerra does a good job.


There is no need to remind you we are all volunteers helping each other
making CinelerraCV the best NLE ever. You know it already. :-)

Thanks for believing so much in Cinelerra. :-)

Ciao!
Raffaella
Einar Rünkaru
2011-10-09 11:34:11 UTC
Permalink
Post by Edouard Chalaron
Post by Einar Rünkaru
Post by Einar Rünkaru
Better find some other video capture program
Can you point something better ?
Everyone has to find out personally. It depends on hardware and requrements.
Post by Edouard Chalaron
Post by Einar Rünkaru
I am seriously thinking about removing all capture features
from
Cinelerra in the future. How mutch people use it (were able
to find
working settings)? For what purpose tehy use it?
??????? Gosh Einar, I am sorry but you may want to look a little bit further than the lens of your ipod camera....
I have no iPod, iPhone or iPad. I have only iRon.

The look of futher shows two problems.

a) v4l1 support is already dropped from linux kernel, probably after
next upgrade of your system it stops working
b) there is no developer power to support capture in Cinelerra.

You are lucky, because capture in Cinelerra works for your current
configuration. I wanted to know how many lucky persons are there in
the world. So far I counted two - you and me. And one, who thinks it
is useful. There is a lot of complaints from other that capture does
not work.

Capture is very loosely related to the rest cinelerra - it reads from
device and stores information to disk. It uses gui subsystem of
Cinelerra to communicate with user, encoding subsystem to store video
on disk. Capture needs different optimizations from a program than
NLE. I think that dropping capture support enables to concentrate more
on enchancements in editing.

So my recommendation is to find a suitable and supported capture
program for your device and requirements. Or avoid any upgrades - it
is a working solution, I have tried.

I try to not touch capture areas in next two years.

Einar
Herman Robak
2011-10-09 19:58:08 UTC
Permalink
P=C3=A5 Fri, 07 Oct 2011 22:52:26 +0200, skrev Edouard Chalaron <e.chala=
The use of it ? controlling imports or scans(like I do) with a vectors=
cope
I am starting a hack of the invert plugin to work onscanned negative f=
ilms. This is what it can be used for.

What kind of camera/scanner do you scan the film with?
I'm kinda curious as to how it is done, and what hardware
is needed. (I could get hold of an Arri and some footage)

What is your workflow, exactly?

-- =

Herman Robak
E Chalaron
2011-10-12 04:30:32 UTC
Permalink
Hi Hermann

The scan is done on each frame in 1624x1234 max via coriander and V4L
fed into Cinelerra.
The camera is a Stingray from AVT

I need coriander as an intermediate for the external triggering : 1
frame -> trigger -> one scan -> TIFF sequence or MOV file

At the moment we are hacking the invert plugin to be able to have an
optimal inversion on C41 negs scanned on white light.

You can have a look at a first attempt with an average corrective
profile done by a command line an a TIFF sequence.
50 ASA 16 mm, daylight film (smae camera, same light, same day, same
processing batch). Nothing fancy just family stuff.

http://vimeo.com/28967231

Hopefully we will be able to have a specific corrective profile for each
particular scene.
Dev is done by incorporating magick ++

Cheers
E

Edouard Chalaron
2011-10-08 22:35:25 UTC
Permalink
Post by Edouard Chalaron
Post by Edouard Chalaron
??????? Gosh Einar, I am sorry but you may want to
look a little bit
Post by Edouard Chalaron
further than the lens of your ipod camera....
Cinelerra would become
Post by Edouard Chalaron
some sort of Kino just designed for camcorders and
highy compressed
Post by Edouard Chalaron
videos. Why don't just remove importing file
sequences, RGB float etc
Post by Edouard Chalaron
since you are willing to shoot yourself in the foot ?
Calm down. :-)
Well, I am sorry if my rant was felt like an attack, but it is difficult to remain calm. It looks like it is one man decision and not even the possibility to discuss the consequences.
Post by Edouard Chalaron
Capture functions in Cinelerra are pretty unstable. In
particular they
seem to depend on hardware. For some people they work
perfectly (a
minority it seems) for others they are really unusable.
Already the /dev/v4l works wonder and yet it has been decided to remove the support for it... or am I wrong ? I use it everyday without a single problem, moreover it is interfaced with an external soft. I do import all different format and so far 0% error. So is unstable or not used properly ?
Not being on top of Linux dev I just wonder if people are really trying.
Post by Edouard Chalaron
To have a very buggy feature is not good, so we are
brainstorming on
possible solutions. Fix he feature if it is useful (that's
an expensive
solution), remove it if it is un-used (cheaper solution).
To me it appears not so buggy.... so what am I doing wrong ? :-)
Post by Edouard Chalaron
Post by Edouard Chalaron
How much people use it (were able to find working
settings)? For
Post by Edouard Chalaron
what purpose they use it?
controlling imports or scans (like I do) with a
vectorscope I am
Post by Edouard Chalaron
starting a hack of the invert plugin to work on
scanned negative
Post by Edouard Chalaron
films. This is what it can be used for.
It is very useful also to know Cinelerra does a good job.
What it does is (among others) to help to calibrate a white light for film scan :
before recording select a broad range and assign the live video plugin and a videoscope, may be an histogram too for good measures.
Start recording listening on /dev/video1 if your camera is streaming on /dev/video0

Look athe compositor and the videoscope, see what you have, muck around with the histogram to get what you want. Or keep data as a reference for your lighting calibration purpose.

I think for people scanning films or working on grabbing frames for animation purpose it is a fantastic tool.
Moreover, once you start your recording you can choose almost whatever format you want.
OpenEXR does not seem to work I must admit. but TIFF file sequence and quicktime RGB uncompressed is top notch.

Cinelerra can go much further than video clips with titles and sequences etc ... it has also some great possibilities of grading and calibration despite some lack of tools.

I was talking of Openshot... well no I won't for now... I am just afraid Cinelerra is going to turn like that. I tried it yesterday and it is nowhere close to Cinelerra.
Post by Edouard Chalaron
There is no need to remind you we are all volunteers
helping each other
making CinelerraCV the best NLE ever. You know it already.
:-)
I know that. I'll try to provide with what I can but that won't be development from me. I am not a coder. Clearly..

However I am willing to get this plugin for negative films to work (by patching "invert" or creating a new one). I have someone to work on it this week. I hope we will get to the bottom of the story and forward the patch to you guys soon.
If that works : one would be able to calibrate a color scanner for negative films and actually control on the fly.
Post by Edouard Chalaron
Thanks for believing so much in Cinelerra. :-)
I trust in the obvious, there has been so much effort put into that that the idea of seeing it amputated from a major feature freaks the mickey out of me.

Since we are here : Cinelerra is like italian motorbikes, nothing beats them as long as you know how to use them !
Cheers
E
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