I'm about to make an animation to be displayed on a TV screen, so I thought
I'd use Pov-Ray's field rendering feature.

If I understand correctly, it stores alternate lines of the animation in two
consecutive TGA files (doubling the lines to retain the image height).

So a program is obviously needed which will extract the lines from each pair
of TGA files and interlace them into a series of single frames which would
then be stored in an AVI file. The interlaced AVI file could then be loaded
into a video editing package just like any other piece of captured video.

As this is the only way to produce an interlaced AVI from Pov-Ray, surely
such a tool must already exist, but I can't find it.

There are a couple of tools on the Pov-Ray site but they don't mention
processing interleaved sequences of TGA files, and anyway the links are no
longer valid.

Can anyone suggest a tool to do this?

Thanks

Colin

Post a reply to this message

Hmm I don't know a tool like this but I got a question.

What encoder do you want to use?
The mpeg1/2 encoders I know take complete frames in 25 fps and calculate 
the needed 50 fps fields out of them.

Just trace your animation with complete images and 25 fps the encoder 
does the rest.
(Rendering half-frames with 50 fps would take the same time. Hmm but 
when thinking about it would give the smoother animation...)

Maybe that helps

Sebastian H.

Post a reply to this message

> So a program is obviously needed which will extract the lines from each
pair
> of TGA files and interlace them into a series of single frames which would
> then be stored in an AVI file. The interlaced AVI file could then be
loaded
> into a video editing package just like any other piece of captured video.

Adobe Premiere does this, but it's sort of hidden in the menus. You have to
import the frames as a single clip, which it does automatically if you try
to import the first frame. Then put them on the timeline, and if you right
click on it there, there's some option somewhere that will combine every
pair of frames. I think it's in the video options submenu, maybe look for
something about 'fields', I think you have to check the correct box or radio
button somewhere.

I've done it before. If you can't figure it out from this, I can go in and
figure it out again. I posted the answer a long time ago around here... at
least a month though.

- Slime
[ http://www.slimeland.com/ ]
[ http://www.slimeland.com/images/ ]

Post a reply to this message

"Sebastian H." <seb### [at] webde> wrote in message
news:3CB### [at] webde...
> (Rendering half-frames with 50 fps would take the same time. Hmm but
> when thinking about it would give the smoother animation...)

Exactly! :)

That's why I'm doing field rendering - half the processing time too.

Colin

Post a reply to this message

Thanks, I'll investigate this.

Colin

"Slime" <noo### [at] hotmailcom> wrote in message
news:3cbe1494@news.povray.org...
> > So a program is obviously needed which will extract the lines from each
> pair
> > of TGA files and interlace them into a series of single frames which
would
> > then be stored in an AVI file. The interlaced AVI file could then be
> loaded
> > into a video editing package just like any other piece of captured
video.
>
> Adobe Premiere does this, but it's sort of hidden in the menus. You have
to
> import the frames as a single clip, which it does automatically if you try
> to import the first frame. Then put them on the timeline, and if you right
> click on it there, there's some option somewhere that will combine every
> pair of frames. I think it's in the video options submenu, maybe look for
> something about 'fields', I think you have to check the correct box or
radio
> button somewhere.
>
> I've done it before. If you can't figure it out from this, I can go in and
> figure it out again. I posted the answer a long time ago around here... at
> least a month though.
>
> - Slime
> [ http://www.slimeland.com/ ]
> [ http://www.slimeland.com/images/ ]
>
>

Post a reply to this message

> Adobe Premiere does this, but it's sort of hidden in the menus. You have
> to import the frames as a single clip, which it does automatically if you
try
> to import the first frame. Then put them on the timeline, and if you right
> click on it there, there's some option somewhere that will combine every
> pair of frames. I think it's in the video options submenu, maybe look for
> something about 'fields', I think you have to check the correct box or
radio
> button somewhere.

Unfortunately this doesn't do what is required. This option causes the odd
lines from frame 1 to be interleaved with the even lines of frame 2 making a
new output frame. Then the even lines from frame 1 are interleaved with the
odd lines of frame 2 to make a second output frame. Thus you end up with all
of the lines of all frames being used and the same total number of new
frames.

What is actually required to create an interlaced movie from a POV field
rendered sequence is for the odd lines of frame 1 to be interleaved with the
even lines of frame 2 to make a new output frame. Then the odd lines of
frame 3 are interleaved with the even lines of frame 4 to make a second
output frame. Thus half of the lines of each frame are ignored and you end
up with half the number of frames you started with (i.e. if your POV
sequence contains 200 images these need to be interleaved to create a 100
frame animation).

So it looks like there isn't a tool to perform this sort of interleaving.
I'm very surprised - you NEED such a tool to produce field rendered
animations from POV !!!

It looks like I'll have to get my hands dirty and write a program to do
this. :(

Colin



"PovRAY" <cbd### [at] my-dejacom> wrote in message
news:3cc2e4e3@news.povray.org...
> Thanks, I'll investigate this.
>
> Colin
>
> "Slime" <noo### [at] hotmailcom> wrote in message
> news:3cbe1494@news.povray.org...
> > > So a program is obviously needed which will extract the lines from
each
> > pair
> > > of TGA files and interlace them into a series of single frames which
> would
> > > then be stored in an AVI file. The interlaced AVI file could then be
> > loaded
> > > into a video editing package just like any other piece of captured
> video.
> >
> > Adobe Premiere does this, but it's sort of hidden in the menus. You have
> to
> > import the frames as a single clip, which it does automatically if you
try
> > to import the first frame. Then put them on the timeline, and if you
right
> > click on it there, there's some option somewhere that will combine every
> > pair of frames. I think it's in the video options submenu, maybe look
for
> > something about 'fields', I think you have to check the correct box or
> radio
> > button somewhere.
> >
> > I've done it before. If you can't figure it out from this, I can go in
and
> > figure it out again. I posted the answer a long time ago around here...
at
> > least a month though.
> >
> > - Slime
> > [ http://www.slimeland.com/ ]
> > [ http://www.slimeland.com/images/ ]
> >
> >
>
>

Post a reply to this message

> Unfortunately this doesn't do what is required. This option causes the odd
> lines from frame 1 to be interleaved with the even lines of frame 2 making
a
> new output frame. Then the even lines from frame 1 are interleaved with
the
> odd lines of frame 2 to make a second output frame. Thus you end up with
all
> of the lines of all frames being used and the same total number of new
> frames.


I remember coming across this problem, and I overcame it. It was a nuisance,
and I really can't remember how I did it, but in the end I closely examined
it and it was exactly right, so I know it's possible. It's probably some
other checkbox hidden somewhere.

- Slime
[ http://www.slimeland.com/ ]
[ http://www.slimeland.com/images/ ]

Post a reply to this message

On Thu, 2 May 2002 23:10:46 +0100, "PovRAY" <cbd### [at] my-dejacom>
wrote:

<snip>
>
>
>So it looks like there isn't a tool to perform this sort of interleaving.
>I'm very surprised - you NEED such a tool to produce field rendered
>animations from POV !!!
>
>
>
I've never been convinced that POV's field rendering is of any use
whatsoever with regard to targetting animations for interlaced devices
such as TV/Video.

I've done a few small field-rendered animations using 3ds max that
look super silky smooth when played on my TV. I did a test recently to
see how 3ds max does it.

Basically, using PAL output as an example, which is odd fields first
and 25 frames per second (also 50 fields per second),  3ds max renders
a frame with the odd lines drawn for the animation at time t seconds
and the even lines drawn for the animation at t + 0.02 seconds (i.e. t
+ half a frame). The only exception to this is the final frame where
both odd and even lines as drawn for the animation at time t.

If POV did field renderings like this animations would not need any
post processing to get the frames correctly interlaced - maybe this is
a bug with the exisitng method or, if any users actually have a use
for the current field rendering behaviour, there should be an
additional setting added to POV's field rendering options?

Cheers,

Scott

Post a reply to this message

> If POV did field renderings like this animations would not need any
> post processing to get the frames correctly interlaced - maybe this is
> a bug with the exisitng method or, if any users actually have a use
> for the current field rendering behaviour, there should be an
> additional setting added to POV's field rendering options?

the current beahvior works as designed because what you suggest requires two
scene representations to be in memory at the same time.  This is simply not
possible without reparsing, and I take it the last thing you want is to let
POV-Ray reparse the scene for every line, do you?  The solution is to use a
program that does the conversion as described by teh other posters.  Adobe
Premiere is one such program but I am sure a similar option is available in
every reasonable video editing program if one just looks for it.

    Thorsten

Post a reply to this message

On Fri, 3 May 2002 12:59:09 +0200, "Thorsten Froehlich"
<tho### [at] trfde> wrote:

>
>the current beahvior works as designed because what you suggest requires two
>scene representations to be in memory at the same time.  This is simply not
>possible without reparsing, and I take it the last thing you want is to let
>POV-Ray reparse the scene for every line, do you?  The solution is to use a
>program that does the conversion as described by teh other posters.  Adobe
>Premiere is one such program but I am sure a similar option is available in
>every reasonable video editing program if one just looks for it.
>
>    Thorsten
>

Hi Thorsten,

You would need to reparse for every line!!?
Surely you would parse once to do all the odd lines at time t and then
re-parse to do all the even lines at time t + halfframe?
This seems to be what 3ds max does. It first renders all the odd lines
and then all the even lines before moving on to the next frame.
Admittedly this requires two parses per frame (you could think of it
as one parse per field) The benefit of this is that you get better
temporal resolution (I hope that makes sense!) at the expense of
vertical resolution. The output on TV made my jaw drop at how smooth
movement was as compared to a non interlaced (progressive scan)
animation.

Who knows, I'm a C++ developer myself so maybe I might do a patch when
the 3.5 source come out. I've been lurking for a few years and would
like to give something back to the POV community so if anyone thinks
this would be useful then let me know.

Cheers,

Scott

Post a reply to this message

> Surely you would parse once to do all the odd lines at time t and then
> re-parse to do all the even lines at time t + halfframe?
> This seems to be what 3ds max does. It first renders all the odd lines
> and then all the even lines before moving on to the next frame.

But this is exactly what POV-Ray does!  The only difference is that it does
not merge two half frames into one image for you.  As pointed out, video
editors are able to do this, so I fail to see the problem.

    Thorsten

Post a reply to this message

On Fri, 3 May 2002 13:31:57 +0200, "Thorsten Froehlich"
<tho### [at] trfde> wrote:

>
>But this is exactly what POV-Ray does!  The only difference is that it does
>not merge two half frames into one image for you.  As pointed out, video
>editors are able to do this, so I fail to see the problem.
>
>    Thorsten
>

Hmm, the output images I've seen of POV and 3ds for similar animations
with field rendering turned on are definitely not the same.

I'll post some images to povray.binaries.images to show what I mean.

Cheers,

Scott

Post a reply to this message

On Fri, 03 May 2002 13:05:09 +0100, Scott Moore <sdm### [at] zoomcouk>
wrote:

>
>Hmm, the output images I've seen of POV and 3ds for similar animations
>with field rendering turned on are definitely not the same.
>
>I'll post some images to povray.binaries.images to show what I mean.
>
>Cheers,
>
>Scott
On second thoughts, I won't post some images - I see where you're
coming from. <thinking out loud> If you want a 100 frame interlaced
animation you need to produce 200 images using POV with field
rendering turned on and then use another tool to interlace them into
the final 100 frames. Hmm, 3ds max is doing this final step for you.
</thinking out loud>

What I'm saying is that maybe POV could be modified to do this for
you? So if you want a 100 frame interlaced animation POV will output
100 correctly interlaced frames.

Ah well, just a thought anyway.

Bye,

Scott

Post a reply to this message

In article <vnv4du0p2ditk649ustosq2er9jueubqbm@4ax.com> , Scott Moore 
<sdm### [at] zoomcouk>  wrote:

> On second thoughts, I won't post some images - I see where you're
> coming from. <thinking out loud> If you want a 100 frame interlaced
> animation you need to produce 200 images using POV with field
> rendering turned on and then use another tool to interlace them into
> the final 100 frames. Hmm, 3ds max is doing this final step for you.

You are not the first person to be confused about this.  I suppose I small
note about this littel but important difference should be added to the
documentation...


    Thorsten


____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

Post a reply to this message

Reading through some of the posts here I can see that there is quite a bit
of confusion about how POV implements its field rendering. If you have a
look back at my earlier posting it describes how the lines and fields are
output by POV. Yes, like 3DS or other programs it needs to parse the scene
twice for each frame because in an animation the position of objects will
have changed between the two fields.

The problem is that in POV the two fields are output to two separate files
which is quite bizzare. And each field/file has alternate lines which are
redundant. Thorsten says he believes that "Premiere" and other editing
programs must have a feature that can interleave the POV file/fields and
that he therefore can't see the problem - I'm not so sure that such features
exist which can interleave POV fields correctly. As I expalined earlier the
"interleave frames" feature on Premiere doesn't do what is required to merge
POV field-pair files into single properly interleaved frames (actually it
goes part of the way but you would then need to delete alternate frames in
Premiere because the alternate frames are comprised of the redundant lines
from the POV output targa files). I may be wrong but I can't see that an
editing program would need a feature which performed the kind of interlacing
which the POV files require.

What POV ought to do when field rendering is switched on, is to create a new
numbered targa file only for fields 1, 3, 5, etc and to write the "odd"
field lines into the file; and then for fields 2, 4, 6 etc it should RE-OPEN
the previous file and write the "even" lines between the previously written
odd lines. Then you would end up with half the number of files and each file
would contain a complete and properly interleaved frame.

I can't see why POV should not do field-rendering this way, it would remove
a lot of the hassle of trying to merge the exiting output files. I know that
POV needs to calculate the redundant lines in memory if anti-aliasing is
switched on, but there's nothing to stop it only outputting the alternate
"used" lines to file.

I have just about finished a program which will do this interlacing, but it
really shouldn't be necessary.

Incidentally, I'm not to keen on the terms "odd" and "even" when refering to
fields as they are ambiguous, depending on whether you start counting from
line 1 or 0. When someone mentions the "odd" field you really can't be sure
which they mean. Unfortunately POV uses this terminology and appears to
start at line 0. I wish they would use "upper" or "lower" field instead as
this is unambiguous.

Colin


"Thorsten Froehlich" <tho### [at] trfde> wrote in message
news:3cd2db83@news.povray.org...
> In article <vnv4du0p2ditk649ustosq2er9jueubqbm@4ax.com> , Scott Moore
> <sdm### [at] zoomcouk>  wrote:
>
> > On second thoughts, I won't post some images - I see where you're
> > coming from. <thinking out loud> If you want a 100 frame interlaced
> > animation you need to produce 200 images using POV with field
> > rendering turned on and then use another tool to interlace them into
> > the final 100 frames. Hmm, 3ds max is doing this final step for you.
>
> You are not the first person to be confused about this.  I suppose I small
> note about this littel but important difference should be added to the
> documentation...
>
>
>     Thorsten
>
>
> ____________________________________________________
> Thorsten Froehlich, Duisburg, Germany
> e-mail: tho### [at] trfde
>
> Visit POV-Ray on the web: http://mac.povray.org

Post a reply to this message

In article <3cd30b70@news.povray.org> , "PovRAY" <cbd### [at] my-dejacom> wrote:

> Thorsten says he believes that "Premiere" and other editing
> programs must have a feature that can interleave the POV file/fields and
> that he therefore can't see the problem - I'm not so sure that such features
> exist which can interleave POV fields correctly.

As for Adobe Premiere I know it has it.  And I believe other programs on other
platforms have it as well.

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

Post a reply to this message

> What POV ought to do when field rendering ....
> RE-OPEN the previous file and write the "even" lines
> between the previously written odd lines. Then you
> would end up with half the number of files and each file
> would contain a complete and properly interleaved frame.

I agree, that this would be an improvement.

> I'm not to keen on the terms "odd" and "even" when refering
> to fields as ...... I wish they would use "upper" or "lower"
> field instead as this is unambiguous.

I agree with this, too.

Regards,
Hugo

Post a reply to this message

In article <3cd3ce88$1@news.povray.org> , "Hugo" <hua### [at] post3teledk> wrote:

>> I'm not to keen on the terms "odd" and "even" when refering
>> to fields as ...... I wish they would use "upper" or "lower"
>> field instead as this is unambiguous.
>
> I agree with this, too.

The terms "odd" and "even" are the correct technical terms which are used in
all technical literature and all (professional) software.  In fact I have
never seen "upper" or "lower" been used before anywhere, and they don't really
make sense either when dealing with something that is counted...

    Thorsten


A few references:

* Bt848/848A/849A Single-Chip Video Capture for PCI Data Sheet
  Brooktree Corporation

* AD724 RGB to NTSC/PAL Encoder Data Sheet
  Analog Devices, Inc.

* LM1881 Video Sync Separator Data Sheet
  National Semiconductor Corporation

* QuickTime 5 API Reference
  Apple Computer, Inc.

* Media Composer 1000 User Manual
  Avid Technology, Inc.



____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

Post a reply to this message

"Thorsten Froehlich" <tho### [at] trfde> wrote in message
news:3cd3a44c@news.povray.org...
> In article <3cd30b70@news.povray.org> , "PovRAY" <cbd### [at] my-dejacom>
wrote:
>
> > Thorsten says he believes that "Premiere" and other editing
> > programs must have a feature that can interleave the POV file/fields and
> > that he therefore can't see the problem - I'm not so sure that such
features
> > exist which can interleave POV fields correctly.
>
> As for Adobe Premiere I know it has it.  And I believe other programs on
other
> platforms have it as well.

I'd be grateful if you can tell me where the feature is in Premiere, because
I can't find anything which does this.

The closest is "interlace fields" but as I said earlier this interlaces both
fields of all frames, so you would then have to manually delete alternate
alternate frames and close up all of the gaps which is very laborious.

Post a reply to this message

"Thorsten Froehlich" <tho### [at] trfde> wrote in message
> The terms "odd" and "even" are the correct technical terms which are used
in
> all technical literature and all (professional) software.  In fact I have
> never seen "upper" or "lower" been used before anywhere, and they don't
really
> make sense either when dealing with something that is counted...

I am very surprised that you have never seen "upper" or lower" used
anywhere.

Premiere has a project setting for "upper or lower field first" which it is
very important to get right.. Also a quick search on the web will throw up
numerous technical pages which refer to "upper" and lower"  fields, such as
this on google which includes technical pages from the Adobe site:

http://www.google.com/search?hl=en&q=upper+lower+field+video

There's also a good explanation of why "odd" and "even" are ambiguous on the
oft-linked-to Lurkers Guide to Video. There's a small section entitled
"Thoroughly Ambiguous: Avoid The Terms Even and Odd" half way down this
page:

http://www.lurkertech.com/lg/dominance.html

I accept that many specs assume that the reader appreciates that line
numbering starts from 1, but this is not universal.

> "upper" or "lower" ... don't really make sense either when dealing with
something
> that is counted...

But that is the problem. It depends what number you start counting the lines
from - 0 or 1. If you start from 0 then the top line is part of the even
field, but if you start from 1 it is part of the odd field. Some specs may
say that line numbers (or field numbers) start from 1, but there are a lot
of sources including Pov-Ray which start numbering from 0. Consequently if a
program only tells you that its output has the odd frame temporally before
the even field you don't know for certain whether the field containing the
top line is the earlier or later - and you need to know this. Once you have
imported this clip into Premiere you don't have to count lines, but you must
know whether the field which includes the top line (the upper field) is
temporally earlier than the other (lower) field otherwise your finished
project may playback on interlaced devices with jitter.

Colin







Never? The project settings of Premiere require you to set "upper" or
"lower" field first.



>
>     Thorsten
>
>
> A few references:
>
> * Bt848/848A/849A Single-Chip Video Capture for PCI Data Sheet
>   Brooktree Corporation
>
> * AD724 RGB to NTSC/PAL Encoder Data Sheet
>   Analog Devices, Inc.
>
> * LM1881 Video Sync Separator Data Sheet
>   National Semiconductor Corporation
>
> * QuickTime 5 API Reference
>   Apple Computer, Inc.
>
> * Media Composer 1000 User Manual
>   Avid Technology, Inc.
>
>
>
> ____________________________________________________
> Thorsten Froehlich, Duisburg, Germany
> e-mail: tho### [at] trfde
>
> Visit POV-Ray on the web: http://mac.povray.org

Post a reply to this message

In article <3cd6d677@news.povray.org> , "PovRAY" <cbd### [at] my-dejacom> wrote:

> I'd be grateful if you can tell me where the feature is in Premiere, because
> I can't find anything which does this.
>
> The closest is "interlace fields" but as I said earlier this interlaces both
> fields of all frames, so you would then have to manually delete alternate
> alternate frames and close up all of the gaps which is very laborious.

Nope, you can use that.  Instructions can be found in this thread:

<http://news.povray.org/povray.beta-test/19628/127824/>

    Thorsten

____________________________________________________
Thorsten Froehlich
e-mail: mac### [at] povrayorg

I am a member of the POV-Ray Team.
Visit POV-Ray on the web: http://mac.povray.org

Post a reply to this message

> Instructions can be found in this thread:
>
> <http://news.povray.org/povray.beta-test/19628/127824/>

Aha! The Rate Stretch tool. That sounds like it would do the trick. You'd
have to be careful that it removed the *redundant* frames though. I'll give
it a try.

Thanks Thorsten  :)

Colin

Post a reply to this message

*There* it is! I've been looking for that.

Yeah, the rate stretch tool seems like sort of a hack, but if it works, it
works. I'll trust my past self on this one. =)

- Slime
[ http://www.slimeland.com/ ]
[ http://www.slimeland.com/images/ ]

Post a reply to this message

> I'm about to make an animation to be displayed on a TV screen, so I
thought
> I'd use Pov-Ray's field rendering feature.


Great idea. I respond at the high level of the thread for convenience. I
hope you will excuse me.

Well. Like you have said: to compute interlaced files (i.e. with odd and
even fields), you must compute twice as the images as needed.

Then, you must import in Adobe Premiere and find the "good" button. In fact,
the last time I have done that; I was not able to do this in one part: I've
exported with Abode and re-imported [and forgotten the manipulation!]. But
you know: Premiere is sometimes like an asshole (sorry, but it's true).

I'm making a program (ask directly by mail) to solve this problem. You just
have to give it the root name of files and it generates a AVI non-compressed
file for Premiere. To gain space on disk, it can delete BMP files after
treatment - I will post the source in C when ready and fully tested (in a
couple days).

It's only for BMP 24bits/color uncompressed (this IS the Povray output) to
an UNCOMPRESSED AVI file. When you have the file in Adobe, you can output it
with the correct codec (AVI, DIVX, MPEG,...).

William.

Post a reply to this message