BT.601 or 709 : how to find out ?!

[leeperry]

hey guys, I got a question about BT.601/709

so decoding 601 in 709 is not a good idea after all :

If you decode 601 encoded signals with a 709 decoder then the green amplitude is reduced by 15.5% so it looks darker, (which you may be interpreting as more saturated - it isn't, it's just darker) and the red amplitude is increased by about 9% and about 10% green is added to the red, so it looks lighter and is more orange (it really isn't less saturated, it's a different hue.)"

and indeed, the red looks more greenish and less saturated, and the green is darker, which kills some contraste.

what about the opposite ? what's the drawback of decoding 709 in 601 ? how can I find out if that's the case ?

some DVD's are 601, some others are 709 from what ppl say.......so I'm pretty much lost here :devil:
Thanks,

[manono]

Hi-

Run the Vobs through DGIndex (File->Preview) and it will tell you which colorimetry the DVD uses. What you have to do, if anything, at least partly depends on what your encoder expects.

[drmpeg]

http://www.avsforum.com/avs-vb/attachment.php?attachmentid=32137

Ron

[leeperry]

http://www.avsforum.com/avs-vb/attachment.php?attachmentid=32137

Ron

awesome thanks!

Hi-

Run the Vobs through DGIndex (File->Preview) and it will tell you which colorimetry the DVD uses. What you have to do, if anything, at least partly depends on what your encoder expects.

wow, just perfect! any other tool that could do that for MKV/AVI ?! I wonder if it tries to read some MPEG2 flag or if it actually analyzes the stream ?!

[chainring]

wow, just perfect! any other tool that could do that for MKV/AVI ?! I wonder if it tries to read some MPEG2 flag or if it actually analyzes the stream ?!MKV/AVI are just containers and, someone may need to correct me on this, do not determine the colorimetry. Also, if you're using anything MPEG4, I believe it is 601 by default.

So, if you're wanting to convert a normal ole DVD, fire up DGIndex, browse to the VTS's in question. Open them up and do the preview as manono suggested. In the right hand pane that opens up, you'll see the colorimetry listed. It can be more than just 601 or 709. SMPTE 170M is another. Here's a very good post by "kumi" in the DVD Rebuilder forum that can help with ColorMatrix:
http://forum.doom9.org/showpost.php?p=970511&postcount=2

Quite overwhelming, isn't it? If you're looking to do some x264, be prepared for even more fun. It'll keep ya busy.

[leeperry]

ok thanks I'll check it out.

but I got many bluray/hd-dvd MKV rips.......so are they 601 or 709 ? :D

my eyes tell me 709, but well I am teh colorblind ;)

[chainring]

I'm pretty sure the HD stuff is 601, but you'll need to ask someone more experienced than I. Check the AVC/H.264 forum as you'll likely find the answer there.

[leeperry]

so what's supposed to use 709 then ?
i thought it was an enhanced space over 601 specially made for HD ?! :D

thanks ;)

[chainring]

Many regular DVD's use 709. I sometimes see: 601 and SMPTE 170M, but very infrequently.

[KoD]

709 is the standard for any HD material. 709 is also being introduced in dealing with SD material, as well.

[leeperry]

well H264 is BT.709 it seems :
http://www.google.com/search?hl=en&q=h264+bt.709&btnG=Search&lr=

and XviD/DivX would be 601 ?

[foxyshadis]

You might want to run h264_parse over the raw bitstream to see what vui_colorometry tags it has, if any. The default, no-flag-present colorometry of MPEG2 in SD is 709 and for MPEG4 ASP/AVC (and maybe HD MPEG2), is 601, but any video can flag alternate colors. And of course, there's nothing stopping them from having wrong primaries, flagged or unflagged, so it's not totally cut & dry.

[leeperry]

hey thanks for the tip, but I can't seem to locate this app ?!

it's not part of the "mpeg4ip-1.5.0.1.tar.gz" package :(

got any URL pls ? does it work on MKV files ?

thanks!

[foxyshadis]

You have to compile it if you download the source package. Bond would know where to get an up-to-date build, so you might PM him. And it only works on raw demuxed streams, so that's something you'd have to do before using it.

[leeperry]

ahhhhh forget it, I'll judge by eyes :)

red too orange and green too dark > 601 decoded in 709

red too dark and green yellowish > 709 decoded in 601

my SANYO Z3 projector is perfectly calibrated, so it's not too hard to find out......and doesn't take a half hour to find out ;)

[leeperry]

hummmmmm I got a DVDRip avi here that's definitely 709......I guess not everyone does 709>601 conversion for XViD encoding......god bless Haali's Renderer and it's 709/601 option.......just wish it was automatic :D