Capture from DV-CAM Colorspace confusion (YV12 RGB24)

[carlaron]

Hi,

I am digitizing old 8mm/Hi8 and D8 Videos. I am using an old Sony Cam to transfer/digitize the tapes.

I am using DVCapture (old tool from Mainconcept) similar to WinDV to save the stream as type2

When I open the file with avisynth and info() it tells me that the colorspace is RGB24.

Now my question: I thought old video material is always YV12, why does avisynth tell me it is rgb24?
where was the conversion? does this result in any quality loss through "capture"/saving the stream from the camera?

Thanks for any insight.

[poisondeathray]

Probably your VFW DV decoder is outputting RGB24

I think old mainconcept DV decoders did this or had an option to configure the output

If it doesn't try a different decoder e.g. cedocida, or FFMS2

[carlaron]

Does this cost a lot of quality?

WinDV also outputs rgb24

How do I check which dv Codec is used? (winxp)

[poisondeathray]

Originally Posted by carlaron

Does this cost a lot of quality?

WinDV also outputs rgb24

How do I check which dv Codec is used? (winxp)

Yes, RGB output will cause quality loss. The conversion to RGB by your decoder will clip superbrights/darks, and have rounding losses

In vdub, load your AVI directly, look at file=>file information it should tell you which VFW DV decoder is currently being used

[carlaron]

thanks for the input!

i just checked one file on a different laptop (internal dv decoder (dvsd))

any way to figure which codec is used by winDV or MainConcept DVrecorder?

why don't they just transfer the data stream? is that due to using type2 avi?

[poisondeathray]

Not sure about mainconcept dvrecorder, but windv just copies the data stream from the tape

The damage isn't done by windv, it's done by your decoder .

There are no video quality differences between type 1 or type 2

[carlaron]

well, this is strange now... (or probably i am just not getting it) xD

i record with winDV on an old XP machine; then i copy over network to new/fast machine; using avisynth and info() it tells me when opening in virtualDub that it is rgb24...

(probably having panasonicDV on that machine)

[poisondeathray]

panasonic is known to convert to rgb

when I said open in vdub directly and check file=>file information, I mean directly, not through an avs script

[IanB]

For VFW install Cedocide and configure it to output YUY2 or YV12

[carlaron]

Originally Posted by poisondeathray

panasonic is known to convert to rgb

when I said open in vdub directly and check file=>file information, I mean directly, not through an avs script

did so to check; but through avs script gets me the same result...



mei will try when I get back home; i am on business trip for a 10 days

[poisondeathray]

Originally Posted by carlaron

did so to check; but through avs script gets me the same result...

Yes, I know...The point was to identify the decoder. It will usually say which decoder. If it says panasonic and RGB24, then you have your answer

avisynth frameserves uncompressed data, so it will never identify the decoder if you feed an avs script, just the pixel format

The solution was mentioned above, change your decoder e.g. cedocida (you might have to uninstall your current decoder or use vcswap to manage the VFW codecs)

[carlaron]

that is what i did.

i opended the file directly and it said "internal"; that is why i was confused.

[fvisagie]

Originally Posted by carlaron

i opended the file directly and it said "internal"; that is why i was confused.

Turn off VirtualDub > Options > Preferences > AVI > Prefer internal video decoders over installed third-party codecs (MJPEG and DV). Then File > File Information will tell you what external decoder is being used.

Another possibility: what media file filter do you use to input into Avisynth? With YV12 DV input, using DirectShowSource() with default parameters would always produce RGB24 output on my system with Avisynth 2.5.8 (I haven't yet checked what happens with 2.6.0).

Cheers,
Francois

[TheSkiller]

It has been mentioned already, I as well highly recommend installing Cedocida DV Codec. It outputs whatever you want (there's a config window).
Usually, you would want YV12 or YUY2 with MPEG2 chroma placement (DV stores with it's own chroma placement, something one should not forget about).