Discussion:
[CinCVS] Beginner Configuration and Project setting
(too old to reply)
Terje J. Hanssen
2008-01-27 14:42:17 UTC
Permalink
I'm a beginner on Cinelerra, though I have camcorded video during 15
years, mostly Hi8 and now HDV the latest year. I also made a few analog
LE small scale project for my own purpose. Now I've started to prepare
myself on using Cinelerra by reading documentation, and unavoidable some
questions arise.

Trying to apply the Cinelerra Tutorial - Getting Started by Rob Fisher,
the section "Setting Project Options" uses Quicktime (.mov) format. I
will however work with the following three recorded types of PAL video
formats, in different projects in order as follows:

1) DV (converted from Hi8 S-Video)
2) DV Wide (down converted from HDV 1080i in camcorder)
3) HDV 1080i (later)

Here I use the "idvid" tool (part of tovid) to identify my three types
of test files, which then output the following (extracted) output:

1) idvid dv03.dv
File: dv03.dv
Width: 720 pixels
Hight: 576 pixels
Aspect ratio: 1.33:1
Frames: 896
Duration: 00:00:35 hours/mins/secs
Framerate: 25.000 frames per second
Video format: dvsd
Video bitrate: 28800000 bits per second

2) idvid dv02.dv
File: dv02.dv
Width: 720 pixels
Height: 576 pixels
Aspect ratio: 1.77:1
Frames: 14912
Duration: 00:09:56 hours/mins/secs
Framerate: 25.000 frames per second
Video format: dvsd
Video bitrate: 28800000 bits per second

3) idvid hdv01_01.m2t
File: hdv01_01.m2t
Width: 1440 pixels
Height: 1080 pixels
Aspect ratio: 1.77:1
Frames: 175
Duration: 00:00:07 hours/mins/secs
Framerate: 25.000 frames per second
Video format: MPEG2
Video bitrate: 25000000 bits per second


I have some questions regarding useful Cinelerra configuration:

According to the above idvid output, I will expect Cinelerra's Program
window menu Setting>Format should be set as follows:

Frame rate: 25.000
Width: 720 (1440 for HDV)
Height:576 (1080 for HDV)
W Ratio: 1.000 ?
H Ratio: 1.000 ?
Color model: RGBA-8bit ?
Aspect Ratio: 4 : 3 (= 1.33:1 for DV)
16 : 9 (= 1.77:1 for DV Wide and HDV)?
Interlace mode: Bottom field first?

Are the above settings correct, or should something be changed and
possibly why?

What are really "W Ratio" and "H Ratio" vs "Aspect Ratio"?
What about color model to select, RGBA vs i.e YUVA or other?


The pixel number ratio Width/Height=720/576=1.25 for DV and DV Wide, and
1440/1080=1.33 for HDV

The rectangulary pixel Width/Height ratio calculated from the Aspect
ratios should then be
1.33/1.25=1.064 for DV
1.77/1.25=1.416 for DV Wide
1.77/1.33=1.330 for HDV


So to the Program window "Resize track" as mentioned in the same Tutorial:

Size: 720 x 576 (for DV and DV Wide)?
1920 x 1080 (for HDV as 1440x1080 is lacking)?
Scale: 1.000 x 1.000 (for all)?

Can someone explain what the scale here really does and if it should be
changed of some reason?


At last I wonder, is there some of this or other related configurations
that preferably should be set in Preferences?


-------------------
Terje J. Hanssen
Herman Robak
2008-01-27 15:52:36 UTC
Permalink
On Sun, 27 Jan 2008 15:42:17 +0100, Terje J. Hanssen <***@monet.no>=
=

wrote:

...lots of settings...
Are the above settings correct, or should something be changed and =
possibly why?
What are really "W Ratio" and "H Ratio" vs "Aspect Ratio"?
What about color model to select, RGBA vs i.e YUVA or other?
YUVA.
The pixel number ratio Width/Height=3D720/576=3D1.25 for DV and DV Wid=
e, and =
1440/1080=3D1.33 for HDV
The rectangulary pixel Width/Height ratio calculated from the Aspect =
ratios should then be
1.33/1.25=3D1.064 for DV
1.77/1.25=3D1.416 for DV Wide
1.77/1.33=3D1.330 for HDV
I can't provide solid advice from the top of my head, as the full
story is actually more complex than most people realise...

But I will seize the opportunity to complain about a couple of
things that make things harder and less logical in Cinelerra:

Having aspect ratio as a _project setting_ (Format), and only that,
is not the best idea. Pixel aspect ratio is a property of the input
video (source material), and you may have sources with different
aspect ratios. Cinelerra provides no clean way to deal with that.
Besides, if you want to render several versions with different
aspect ratios, the Render dialog has no notion of aspect ratio at
all.

Interlacing is probably not relevant to preview at all (unlike
aspect ratio) since most users will be editing on a computer
with only progressive scan screens. So having the field order
as a Format (Project only) setting is rather awkward. What if
you have input video with one field order and output (Render)
with another? Or if you have sources with different field
orders? Clearly, field ordering is a _resource_ and _render_
property, and is IMHO quite misplaced in the Format dialog.
But I'm afraid per-resource handling of interlacing will be
too deep for Cinelerra 2.x...


Sorry for not really helping. If it is any consolation,
you are not the only one who thinks it is tricky and awkward.

-- =

Herman Robak
Herman Robak
2008-01-27 17:29:58 UTC
Permalink
Post by Herman Robak
...lots of settings...
Post by Terje J. Hanssen
Are the above settings correct, or should something be changed and
possibly why?
What are really "W Ratio" and "H Ratio" vs "Aspect Ratio"?
w/h ratio _seems_ like pixel aspect ratio. But I have not quite
figured out if that works the way it should.

When I feed the pixel aspect ratio for PAL into it (1.094/1.0)
it changes the X (width) from 720 to 787, which would be the
correct _display width_. (Well, almost. See below.*)

But what Cinelerra then does is to squash the 720 pixels of the
source video so that the new 787 pixel wide canvas fits within
a 4:3 box, with black bars on the sides. That's the opposite of
what I wanted. Is it me or Cinelerra who is dumb here?


*) The 720x576 PAL DV image is actually a little wider than 4:3
http://lipas.uwasa.fi/~f76998/video/conversion/
http://www.bbc.co.uk/commissioning/tvbranding/picturesize.shtml
--
Herman Robak
Herman Robak
2008-01-27 17:49:02 UTC
Permalink
Post by Herman Robak
w/h ratio _seems_ like pixel aspect ratio. But I have not quite
figured out if that works the way it should.
When I feed the pixel aspect ratio for PAL into it (1.094/1.0)
it changes the X (width) from 720 to 787, which would be the
correct _display width_. (Well, almost. See below.*)
But what Cinelerra then does is to squash the 720 pixels of the
source video so that the new 787 pixel wide canvas fits within
a 4:3 box, with black bars on the sides. That's the opposite of
what I wanted. Is it me or Cinelerra who is dumb here?
Another setting which puzzles me is the "scale" input boxes in
the "Resize Track" dialog from the track context menu. It does not
scale the track. It just changes the canvas size, as far as I can
tell. It would be really useful if it _did_ scale the track.
--
Herman Robak
Herman Robak
2008-01-28 14:57:28 UTC
Permalink
Post by Herman Robak
Post by Herman Robak
On Sun, 27 Jan 2008 15:42:17 +0100, Terje J. Hanssen
Post by Terje J. Hanssen
What are really "W Ratio" and "H Ratio" vs "Aspect Ratio"?
w/h ratio _seems_ like pixel aspect ratio. But I have not quite
figured out if that works the way it should.
When I feed the pixel aspect ratio for PAL into it (1.094/1.0)
it changes the X (width) from 720 to 787, which would be the
correct _display width_.
But what Cinelerra then does is to squash the 720 pixels of the
source video so that the new 787 pixel wide canvas fits within
a 4:3 box, with black bars on the sides. That's the opposite of
what I wanted. Is it me or Cinelerra who is dumb here?
I think it is me who is "dumb", because I may have misunderstood
the B/W values' intent. Jugding by their behaviour, they look like
convenience inputs that you can use to change the current width and
height by a certain factor.

Usecase: The current resolution is 640x480, and for some reason
you want it to be 1.33 times wider. You don't have to calculate
what 640x1.33 is; you type 1.33 into the "W" input instead, and
Cinelerra calculates it for you.

Do you consider this "helper" feature useful and necessary?
--
Herman Robak
Terje J. Hanssen
2008-01-27 19:49:39 UTC
Permalink
On Sun, 27 Jan 2008 16:52:36 +0100, Herman Robak <[EMAIL PROTECTED]>
On Sun, 27 Jan 2008 15:42:17 +0100, Terje J. Hanssen <[EMAIL
...lots of settings...
Are the above settings correct, or should something be changed
and possibly why?
What are really "W Ratio" and "H Ratio" vs "Aspect Ratio"?
w/h ratio _seems_ like pixel aspect ratio. But I have not quite
figured out if that works the way it should.
When I feed the pixel aspect ratio for PAL into it (1.094/1.0)
it changes the X (width) from 720 to 787, which would be the
correct _display width_. (Well, almost. See below.*)
But what Cinelerra then does is to squash the 720 pixels of the
source video so that the new 787 pixel wide canvas fits within
a 4:3 box, with black bars on the sides. That's the opposite of
what I wanted. Is it me or Cinelerra who is dumb here?
*) The 720x576 PAL DV image is actually a little wider than 4:3
http://lipas.uwasa.fi/~f76998/video/conversion/
<http://lipas.uwasa.fi/%7Ef76998/video/conversion/>
http://www.bbc.co.uk/commissioning/tvbranding/picturesize.shtml
Another Set Format menu selection is the Presets submenu:


-> selecting PAL here fills in the preset attributes DV Video
(corresponds mine for SD DV above)
Frame rate: 25.000
Width: 720
Height: 576
W Ratio: 1.000
H Ratio: 1.000
Color model: RGBA-8 Bit
Aspect Ratio: 4.000 : 3.000
Interlace mode: Bottom field first


-> selecting 1080i here fills in the preset attributes for HDV(?) or
full HD Video
Frame rate: 29.9700
Width: 1920
Height: 1080
W Ratio: 2.6667
H Ratio: 1.8750
Color model: RGBA-8 Bit
Aspect Ratio: 16.0000 : 9.0000
Interlace mode: Bottom field first

My first comment is:
This frame rate is for NTSC, not for PAL. Two better options in my
opinion would here be two selections instead: 1080i/60 (for NTSC) and
1080i/50 (for PAL) respectively. A reasonable suggestion?

Second, I notice the Width=1920, and wonder if this yelds for full
1080iHD video only and not for HDV with width=1440?

Third, I notice the changed values W.Ratio=2.6667 and H.Ratio=1.8750
Again, what are and what do these W and H ratios .......?

And fourth, which values here for the anamorphic DV Wide not covered
among the presets?


----------------
Terje J. Hanssen
Terje J. Hanssen
2008-01-27 21:00:03 UTC
Permalink
Are the above settings correct, or should something be changed and possibly why?
What are really "W Ratio" and "H Ratio" vs "Aspect Ratio"?
What about color model to select, RGBA vs i.e YUVA or other?
YUVA.
According to the Cinelerra wiki (manual)
http://cvs.cinelerra.org/docs/wiki/doku.php?id=english_manual:cinelerra_cv_en_4#video_attributes

YUVA-8888
This allocates an alpha channel to the 8 bit YUV colormodel for
transparency. When using compressed footage, YUV colormodels are usually
faster than RGB colormodels. They also destroy fewer colors than RGB
colormodels. If footage stored as JPEG or MPEG is processed many times
in RGB, the colors will fade whereas they will not fade if processed in YUV.

RGB-Float
This allocates a 32 bit float for the R, G, and B channels and no alpha.
This is used for high dynamic range processing with no transparency.
Years of working with high dynamic range footage have shown floating
point RGB to be the best format for high dynamic range. RGB float does
not destroy information when used with YUV source footage and also
supports brightness above 100%. Be aware that some effects, like
Histogram, still clip above 100% when in floating point.

Some effects, like fade, work around the need for alpha channels while
other effects, like chromakey, require an alpha channel to do anything,
so it is a good idea to try the effect without alpha channels to see if
it works before settling on an alpha channel and slowing it down.


What is really "high dynamic range processing" as mentioned above?

----------------
Terje J. Hanssen
Herman Robak
2008-01-27 22:56:34 UTC
Permalink
Post by Terje J. Hanssen
RGB-Float
This allocates a 32 bit float for the R, G, and B channels and no alpha.
This is used for high dynamic range processing with no transparency.
Years of working with high dynamic range footage have shown floating
point RGB to be the best format for high dynamic range. RGB float does
not destroy information when used with YUV source footage and also
supports brightness above 100%. Be aware that some effects, like
Histogram, still clip above 100% when in floating point.
...
Post by Terje J. Hanssen
What is really "high dynamic range processing" as mentioned above?
Using colour spaces and image formats that have a wider tonal range
than the usual 8 bits per channel. Until recently, a 0-255 brightness
scale was fine enough for most video cameras. But film has always had
a much better tonal resolution than that. Therefore the so-called
"digital intermediates" used for editing movies originated on film
use more bits per colour (like Cineon or DPX, supported by CinePaint).

Some high-end video cameras also support larger dynamic ranges, which
offer extra exposure lattitude, and better data for the colourists
and graders to work on in post-production.

Newer applications of HDR exist in computer graphics. Even though
there are no displays, film or screen, which can reproduce the
tremendous tonal range of an OpenEXR image, the actual brightness
of e.g. the Sun is useful for the generation of synthetic images.
One application of HDR is "image based lighting", described in
great detail by Paul Devebec: http://www.debevec.org/


http://en.wikipedia.org/wiki/High_dynamic_range_imaging
http://en.wikipedia.org/wiki/CinePaint
http://en.wikipedia.org/wiki/Cineon
http://en.wikipedia.org/wiki/DPX

http://en.wikipedia.org/wiki/OpenEXR
--
Herman Robak
Terje J. Hanssen
2008-01-27 23:11:07 UTC
Permalink
On Sun, 27 Jan 2008 15:42:17 +0100, Terje J. Hanssen <[EMAIL
...lots of settings...
Are the above settings correct, or should something be changed
and possibly why?
What are really "W Ratio" and "H Ratio" vs "Aspect Ratio"?
w/h ratio _seems_ like pixel aspect ratio. But I have not quite
figured out if that works the way it should.
.......and more
-> selecting PAL here fills in the preset attributes DV Video (corresponds mine for SD DV above)
Frame rate: 25.000
Width: 720
Height: 576
W Ratio: 1.000
H Ratio: 1.000
Color model: RGBA-8 Bit
Aspect Ratio: 4.000 : 3.000 Interlace mode: Bottom field first
-> selecting 1080i here fills in the preset attributes for HDV(?) or full HD Video
Frame rate: 29.9700
Width: 1920
Height: 1080
W Ratio: 2.6667
H Ratio: 1.8750
Color model: RGBA-8 Bit
Aspect Ratio: 16.0000 : 9.0000 Interlace mode: Bottom field first
......
Third, I notice the changed values W.Ratio=2.6667 and H.Ratio=1.8750
Again, what are and what do these W and H ratios .......?
Playing with number ratios, look at this:

Width of 1080_HD_video/DV=1920/720 =2.6667=W_Ratio_for_1080_HD_video
Height of 1080_HD_video/DV=1080/576=1.8750=H_Ratio_for_1080_HD_video

Mere chanches or some reasonable explanation for these coincidences?

----------------
Terje J. Hanssen
Terje J. Hanssen
2008-01-29 12:20:29 UTC
Permalink
On Sun, 27 Jan 2008 18:29:58 +0100, Herman Robak <[EMAIL PROTECTED]>
On Sun, 27 Jan 2008 15:42:17 +0100, Terje J. Hanssen <[EMAIL
What are really "W Ratio" and "H Ratio" vs "Aspect Ratio"?
w/h ratio _seems_ like pixel aspect ratio. But I have not quite
figured out if that works the way it should.
When I feed the pixel aspect ratio for PAL into it (1.094/1.0)
it changes the X (width) from 720 to 787, which would be the
correct _display width_.
But what Cinelerra then does is to squash the 720 pixels of the
source video so that the new 787 pixel wide canvas fits within
a 4:3 box, with black bars on the sides. That's the opposite of
what I wanted. Is it me or Cinelerra who is dumb here?
I think it is me who is "dumb", because I may have misunderstood
the B/W values' intent. Jugding by their behaviour, they look like
convenience inputs that you can use to change the current width and
height by a certain factor.
Usecase: The current resolution is 640x480, and for some reason
you want it to be 1.33 times wider. You don't have to calculate
what 640x1.33 is; you type 1.33 into the "W" input instead, and
Cinelerra calculates it for you.
Do you consider this "helper" feature useful and necessary?
Herman,
I'm still confused and not sure about the intention and working set of
the B/W values.
And nn case some of our comments have been crossposted, I'll sum up the
essentials from my two last posts on this subject part:

-> selecting Set Format>Presets to 1080i results in the following video
attributes:
Frame rate: 29.9700
Width: 1920
Height: 1080
W Ratio: 2.6667
H Ratio: 1.8750

As full HD video 1920x1080 resolution already is set here, the W and H
values as I understand it cannot be any multiply (x) for these
resolutions values (?)

Playing with number ratios, also have at this calculations:

Width of 1080_HD_video/DV=1920/720 =2.6667=W_Ratio_for_1080_HD_video
Height of 1080_HD_video/DV=1080/576=1.8750=H_Ratio_for_1080_HD_video

Mere chanches or some reasonable explanation for these coincidences?

----------------
Terje J. Hanssen
Herman Robak
2008-01-29 13:32:32 UTC
Permalink
On Tue, 29 Jan 2008 13:20:29 +0100, Terje J. Hanssen <***@monet.no>=
=
Post by Terje J. Hanssen
Post by Herman Robak
I think it is me who is "dumb", because I may have misunderstood
the B/W values' intent. Jugding by their behaviour, they look like
convenience inputs that you can use to change the current width and
height by a certain factor.
Note: I _think_ that I was _dumb_. I don't really have a clue,
and my guess is as good as yours.
Post by Terje J. Hanssen
Post by Herman Robak
Usecase: The current resolution is 640x480, and for some reason
you want it to be 1.33 times wider. You don't have to calculate
what 640x1.33 is; you type 1.33 into the "W" input instead, and
Cinelerra calculates it for you.
Do you consider this "helper" feature useful and necessary?
Here I am asking all of you readers if this feature should be
removed, since users either get confused by it or just ignore it.

I would much rather have a pixel aspect ratio setting than a
convenience feature to recalculate image dimensions. I can use
a calculator if I need that, since it's not that often.
Post by Terje J. Hanssen
Herman,
I'm still confused and not sure about the intention and working set of=
=
Post by Terje J. Hanssen
the B/W values.
I can't blame you :-(
Post by Terje J. Hanssen
And nn case some of our comments have been crossposted, I'll sum up th=
e =
Post by Terje J. Hanssen
-> selecting Set Format>Presets to 1080i results in the following vide=
o =
Post by Terje J. Hanssen
Frame rate: 29.9700
Width: 1920
Height: 1080
W Ratio: 2.6667
H Ratio: 1.8750
As full HD video 1920x1080 resolution already is set here, the W and H=
=
Post by Terje J. Hanssen
values as I understand it cannot be any multiply (x) for these =
resolutions values (?)
Width of 1080_HD_video/DV=3D1920/720 =3D2.6667=3DW_Ratio_for_1080_HD_v=
ideo
Post by Terje J. Hanssen
Height of 1080_HD_video/DV=3D1080/576=3D1.8750=3DH_Ratio_for_1080_HD_v=
ideo
Post by Terje J. Hanssen
Mere chanches or some reasonable explanation for these coincidences?
The best way to answer that is to examine the source code which perfor=
ms
those calculations. Otherwise, I suggest you ignore the B and W values.=

I've always done, and other people I just asked have ignored them, too.

-- =

Herman Robak

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