Color matrix issue

[andiandi13]

Hi

I see that VirtualDub2 hasn't been update since 2020, but it has some issues I would like to report to improve it.

This one really annoys me, sometimes, it seems to depend on the source, Vdub changes the color matrix of the video when "No change" is selected in decode format. or example I have a MKV remux of a blu-ray which has all 3 BT .709 tags like it's supposed to have, but the output video is in BT 470 and color are obviously changed visually.

I have not this issue if I select "Rec 709" instead of "No change" in decode format.

I guess all other software base the BT either on the tag or the resolution, or both, but Vdub have a strange behavior.

Since it's an important issue, it'd be nice to have a small update that fixes it

Thank you

[shekh]

Hi
If you switch from "No change" to "709" and there is visible difference it means "709" is not recognized by the decoder, you should also see "Actual format" changing in the same window.
Hard to suggest why it is not recognized. Is the decoder used is "Caching input driver"? (This is written in top line in decode format window).

[andiandi13]

Hi If you switch from "No change" to "709" and there is visible difference it means "709" is not recognized by the decoder, you should also see "Actual format" changing in the same window. Hard to suggest why it is not recognized. Is the decoder used is "Caching input driver"? (This is written in top line in decode format window).

Yes "Decoder : Caching input driver"
So it's not supposed to decode video with this ?

[shekh]

It's ok with the decoder, it should detect matrix tags. Maybe link some sample file to check?

[andiandi13]

It's ok with the decoder, it should detect matrix tags. Maybe link some sample file to check?

Yes here is a sample of that video

sample

[andiandi13]

It's ok with the decoder, it should detect matrix tags. Maybe link some sample file to check?

Sorry the video above is not a good sample. Actually, I realized that for this one the issue was because I opened it through an .avs filter, so color matrix was likely badly decoded.

However, I have another sample, which has no color matrix tag in it, and that's the main issue : VirtualDub2 will not choose a color matrix related to the resolution for those video (so BT 709 for HD and BT 601 for SD) but will always put BT 601 / BT 470 System B/G. That's so risky. I made some encoding and realized this much latter.

Download sample