dv to dvd colorspace question

[Todd7]

I have been reading so much on colorspace that I am now totally confused. I understand that converting colorspace degrades quality so you don't want to do it more than you have to. I want to take dv clips transferred by firewire from my minidv camcorder and put it to dvd. I do not need to do editing other than splicing the clips together.

I understand ntsc minidv has colorspace of YUV. I understand dvd compliant mpeg2 has YV12 colorspace. So there will be at least one conversion of colorspace from YUV to YV12.

I know that avisynth will work on YUV without having to convert it to RGB. But when I do 'avisource("dv.avi").Info()' it tells me the colorspace is RGB. I am using the panasonic dv codec, which I believe only does RGB colorspace.

Should I use a different codec that works in YUV or YV12 colorspace? If so which one does?

Or if I run avisynth directly into my mpeg2 encoder will it bypass the codec and be feeding yuv to the encoder?

Or am I just getting too hung up on the colorspace thing and it doesn't really have a noticeable effect on quality?

Thanks in advance.

[bb]

DV uses YUV colourspace indeed, two different variants, depending on whether it's PAL or NTSC.

If you want to stay in the YUV colourspace, you must either install a codec which supports YUV output, e.g. Canopus or MainConcept - Panasonic supports RGB output only. Or you open the DV through Microsoft's DirectShow filter by using the DirectShowSource command in AviSynth.

AviSynth will not "bypass" a codec. If you use AviSource, then the registered VfW DV coced will decode the video; if you use DirectShowSource, then a DirectShow filter will decode the video (typically the one by Microsoft, which is installed on every Windows OS).

Coulourspace conversions usually have a minor impact on quality, but there are issues regarding interlacing, and of course unneeded conversions consume processing time.

bb

[Todd7]

Thank you very much, that seems to be what I am looking for. Now the info shows it as YUY2.

[bb]

NTSC DV is YUV 4:1:1 (every fourth luma sample has a colour sample), whereas PAL DV is YUV 4:2:0 (half-luma sampling rate in both, horizontal and vertical directions).

YUY2 should be YUV 4:2:2, and YV12 is a planar format used by MPEG compression, which corresponds to both DV formats.

For an extensive overview about YUV formats see http://www.fourcc.org

bb