Rainbows on interlace combing?

[helge79]

Dear experts,

It seems to me that there are rainbows on the interlace combing in these frames:

http://img363.imageshack.us/img363/9760/jiuge2ww1.png

http://img363.imageshack.us/img363/4450/jiuge1nx4.png

Is it just my eyes, or you can see them, too?

If they are really there, does it mean I should apply a rainbow reduction filter before deinterlacing? Any recommendations about choosing the filter? The DVD is an NTSC video recording...

Thanks for your advice! http://img174.imageshack.us/img174/311/bowfr8.gif

[wonkey_monkey]

Not rainbows, but a loss of colour information - it looks to me like it was encoded as progressive instead of interlaced. My first thought would be to vertically blur the colour channels (after deinterlacing). Not sure how to do that though!

David

[Guest]

How did you make the screen captures? It has all the hallmarks of improper chroma upconversion of YV12, i.e., upconverting interlace sampled video as progressive. E.g., you open an interlace sampled YV12 clip in VirtualDub. You'll see video just like your shots.

[helge79]

How did you make the screen captures?
I've run DGIndex on the source, then loaded the d2v-file to VirtualDub with mpeg2source() and took the captures. Could anything go wrong with that?

[Guest]

I've run DGIndex on the source, then loaded the d2v-file to VirtualDub with mpeg2source() and took the captures. Could anything go wrong with that? Yes, exactly what I suggested. VirtualDub upsamples to RGB for display and filtering but always does so progressively.

Put this at the end of your script and see what happens:

ConvertToRGB(interlaced=true)

Note that if you are going to encode to a YV12 format without filtering in VirtualDub, then you can omit the conversion and then not use Full Processing mode in VirtualDub. Your YV12 will pass through without conversions.

[helge79]

Thank you! I just want to deinterlace the video (most likely, with TDeint) and encode it as progressive AVI. I won't be using VirtualDub filters, but I will be using AviSynth filters.

Does "upsamples to RGB for display" mean that I can actually disregard the problem, and this bizarre appearance of combing on my captures will not affect the actual deinterlacing by TDeint?

Please do let me know. I guess I am slightly confused at this point... :confused:

[Leak]

Does "upsamples to RGB for display" mean that I can actually disregard the problem, and this bizarre appearance of combing on my captures will not affect the actual deinterlacing by TDeint?
Yes. The problem comes from VirtualDub trying to display interlaced video progressively; so if it's not getting displayed (or filtered) by VirtualDub (i.e. fast recompress) the problem won't crop up - unless your encoder has a similar problem, but I digress...

np: Christ - Balaam (Blue Shift Emissions)

[helge79]

Thank you for confirming this, Leak!.. http://img174.imageshack.us/img174/311/bowfr8.gif