Panasonic and Cedocida dv codecs-one question

[SerbianBoss]

If we have 2 dv codecs in computer Panasonic and Cedocida (also we have program like Vcswap to swap between codecs), and if we capture with Panasonic our dv avi file will be in RGB24 colorspace. But if we change to Cedocida that file which we captured now became YUY2 or YV12(if we chose in cedocida decoder option).

So, if we capture with panasonic we have rgb24, and if we change to cedocida we have yuy2 or yv12. Can we use this method to change colorspace? I mean does its real yuy2 or yv12?

[jagabo]

Inside the DV AVI file the video is always encoded as YUV with 4:2:0 subsampling on PAL systems, 4:1:1 subsampling on NTSC systems. If I remember correctly you are using an ADVC 100. DV capture is basically a transfer of the already compressed DV data from the ADVC 100 to the computer. The capture process doesn't involve any codecs, except to decompress and display the video on-screen while capturing.

The difference with the two codecs is how the video is passed to another program after decompression. Cedocida gives the option to force its output to YUY2, YV12, or RGB. I'm not sure what the Panasonic DV codec outputs, I no longer have it installed so I can't test it. But most codecs will negotiate the uncompressed video format with the program that's using them. The program will first ask for the video in the highest quality format it supports. If the codec can't supply that it asks for another, less desirable format, etc.

[vhelp]

- December 17, 2006 - 9:58pm - REVISED -

Evening.

Hi SerbianBoss,

I feel your pain and frustration with Color spaces, DV, and other Codecs.
They do present their many challenges.

If we have 2 dv codecs in computer Panasonic and Cedocida (also we have
program like Vcswap to swap between codecs), and if we capture with Panasonic
our dv avi file will be in RGB24 colorspace..

Yes, but not exactly.

Unless you mean, "..we use the Panasonic DV codec as the decoder for the captured
dv avi file, the dv codec will decode the captured dv avi into RGB24 color space.."


PART 1:

..But if we change to Cedocida that file which we captured now became
YUY2 or YV12(if we chose in cedocida decoder option).

Well, not exactly. You see, you are missing something, that no one told
you about. You see, before you go around changing this with DV codecs, you
have to be aware that prior to making any changes to the way Cedocida will
Decode the dv avi and then serve it in a particular color space, you fist
have to be in Cedocida's setup/configuration mode, make the changes, and
then exit out. So far, I only know of one way to do this. And, to do this,
you have to be in an video editor, like VirtualDub or VirtualDubMod and go
into:

** Video\Compression\Cedocida

and make the proper changes. Then, you [OK] out of the setup, and exit
VirtualDub (or other video editor) and re-open your DV avi file with the
new Cedocida set up for color space you require for your Frameserve or
MPEG Encoder or both.

Ahh, but there's a catch. You have to watch out for when you uninstall
Cedocida or re-install a new/different DV codec. Either way, sometimes
Cedocida gets removed and is no longer viewable inside VirtualDub.

The solution to this slight issue, is to re-install Cedocida. But, ahh,
another catch.. you will most probably have to re-configure Cedocida to
whatever setting you desire. The last setting change you may have done
earlier might have been removed.

So, the wise move would be to always check/review Cedocida's setting/
configuration and make sure that the settings you see, are what you
need for your next Frameserve and/or MPEG Encoding project.


PART 2:

..But if we change to Cedocida that file which we captured now became
YUY2 or YV12(if we chose in cedocida decoder option).

.
.

So, if we capture with panasonic we have rgb24, and if we change to cedocida we have yuy2 or yv12. Can we use this method to change colorspace? I mean does its real yuy2 or yv12?

Ok. By now, you have a better understanding of what is required to setup
Cedocida for each DV avi Frameserve and/or MPEG Encoding project.

Now, we need to make sure we have our YUV color space properly selected
and understood by the Frameserver mechanism, AVIsynth.

Depending on your DirectX/DirectShow driver version on your OS pc, you
may experience different outcomes. I know I have. And, I'm still running
WIN98 gold (first edition) with all my Video work.

PAL video..
If you are capturing pal video with a dv capture device.. ie, ADVC-110
then your probable solution would be to configure the DV codec to decode
the captured dv avi straight to YV12. Now, I'm not too sure on this, but
your ADVC-110 color space sampling might be in the same YV12 layout that
AVIsynth will (or can) require, and further, your MPEG Encoder might be
in this same format. Lucky you, if this be true. Thus, this is the
route you want for your captured ADVC-110 dv avi to any one of these
processes..

First, be sure that your script includes this method to open certain DV
avi sources to work properly with Cedocida:

** AVISource( x )

Then your path becomes:

** ADVC-110 [YV12] -> Cedocida [YV12] -> HCenc
** ADVC-110 [YV12] -> Cedocida [YV12] -> AVIsynth [YV12] -> HCenc
** ADVC-110 [YV12] -> Cedocida [YV12] -> VirtualDub [fast recompres] -> HCenc

The whole point of all this run-around nonsense, is so that you don't
have to fiddle with additional filtering processes. Because, the
more you fiddle (in the middle) the more probable that you will be
swaying your color levels because of the conversion and rounding
errors associated with this. So, try and keep your DV in as straight
and clean a path as possible.

Note 1:
in Cedocida's configuration setup, make sure the following are observed:

Output section
[ ] RGB
[ ] YUY2
[x] YV12

Note 2:
The purpose of AVISource ( X ) , where X = "\path:\filename.avi"
is so that the dv codec, Cedocida will be properly handled through
the AVIfile handles that AVIsynth uses. When I used any other method,
AVIsynth's function, info() would always output YUY2, every
time. And, it was after many trial n error runs, that I found this
found this out. So, you (and others reading this) might find this info
useful in other areas of video processing.

Note 3: -- BUG warning..

** AVISource( filename.avi ) and DirectShowSource( filename.avi )

Also, a special note on VirtualDub [FastRecompress] <-and-> AVIsynth processing.
If you goal is to work inside VirtualDub and then frameserve it into
AVIsynth, but to keep the source's color space (ie, DV AVI YV12) there
is a BUG in AVIsynth's handling of VirtualDub's *.vdr (renaming to .avi
has no effiect) frameserver, and AVIsynth will always report RGB24.

I don't know if this is isolated with the Cedocida DV codec, or DV codecs
or any of the opening of avi sources comming in from VirtualDub. I've
only tested it with Cedocida DV codec.

So, this may have been your troubles in many of your *other* attempts
in those other threads/topics. I don't know if anyone is aware of
this BUG. But, I'm brining it out, today.


NTSC video..
Because ntsc is YUV411 color space, the probable recommendation is to use
whatever DV codec's internal upsampling conversion it performs. This does
not apply to you, so you are lucky.

As for NTSC, forget about it. Actually, for us poor faulks, ours is
probably best suited for either RGB24 or YUY2. Either way, we are
screwed. Well, its not so bad, really. I'm exagerating a little.


PART 3:

So, if we capture with panasonic we have rgb24, and if we change to cedocida we have yuy2 or yv12. Can we use this method to change colorspace? I mean does its real yuy2 or yv12?

YUY2 prefered pre-processing..
Ok. If you've reached this part of this article, then you've moved in
to other territory of processing.

So, you want to take advantage of the YUY2 filter/plugin's available
for AVIsynth ?? Ok. You may want to reconsider other filters if at
all possible, unless the video requires certain filters that are not
available in YV12 format. In this case, you have no choice but to go
with YUY2 and the conversion there-of. These are compremises that you
make on a day-to-day bases. Anyway.

If your goal is to take advantage of the YUY2 filter/plugin's and your
final choice is MPEG Encoder for CCE, then your prefered options are
probably like this:

** ADVC-110 [YV12] -> Cedocida [YUY2] -> CCE
** ADVC-110 [YV12] -> Cedocida [YUY2] -> AVIsynth [YUY2] -> CCE

- Here is a slight warning..

If you want to use HCenc, cause of all the great talk about it, and you
go through the above processes, then please be aware that *adding* yet
another color sampling conversion will sway the color levels further.
Some may feel that it is unoticable, while others may see it. But, it
is a compremise, still. I leave that up to you to decide. Thus, if you
do go with HCenc anyways, then expect the path to now be the following:

** ADVC-110 [YV12] -> Cedocida [YUY2] -> (YUY2->YV12) -> HCenc
** ADVC-110 [YV12] -> Cedocida [YUY2] -> AVIsynth [YUY2] -> (YUY2->YV12) -> HCenc

And, in conclusion..

This is just my opinion. Any time you have a PAL source, try and stay within
the straight and clean path to YV12, to get to MPEG-2.YV12.

And, Any time you have an NTSC source, the probable prefered route is to
use either RGB or YUY2, to get to MPEG-2.YV12.

And, one last thing..

Oh, and by the way, your posts (questions) are not boring. Its just that
sometimes we may not have the answer just yet.

-vhelp 4175

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