Mixing HD (709) and SD (601) clips

Bill Ravens · February 23rd, 2008, 05:08 PM

Hold On!!!!

Jon, I may owe you a HUGE THANK YOU. I've been playing with these corrections. Seems as tho', if I ignore the vegas wfm and use the vectorscope to set the correction factors in the Channel Blender, I'm making some progress. Indeed, I've been assuming that the Levels FX resets the chroma as well as the luma, because the WFM shows the colors shifting. BUT, if I IGNORE the WFM reference lines and use the vectorscope, things are looking up.

Only question now is, what are the right factors to go from REC601 to REC709 and back? Shouldn't Vegas do this for me? hehehehe

Steven Thomas · March 26th, 2008, 10:15 PM

Just a sanity check using Sony Vegas 8.0B (8bit mode) with the Sony EX1 and JVC HD100 footage.
I believe both of these codecs are 709 color space.

Going to blu-ray HD is straight forward, no level correction such as (vegas RGB to Studio) is needed. Footage burned direct from the timeline to blu-ray looks great.

Now, I'm using Procoder 3 to convert to SD.
I'm frameserving using Debugmode Framserver to Procoder 3 without going to an intermediate.

In Procoder 3 I'm using a DVD compliant template, but also using the 709 HD to 601 SD filter.

I believe the DVD looks good, but maybe a tad washed.

Going to DVD , If I drop the Vegas SMPTE NTSC color bars on the timeline with JVC HD100 footage 1280x720 HDV (709) and frameserve it out to Procoder 3 DVD compliant template using the 709 HD to 601 SD colorspace filter, will the Vegas SMPTE NTSC color bars survive the export and conversion?

I need to try this.
I'm just wondering what happens to the Vegas SMPTE NTSC color bars when they run through the procoder 709 to 601 conversion?

Bill Ravens · March 27th, 2008, 07:52 AM

Steve..

The vegas color bars are 601. you can drop the studio to computer RGB FX on the bars, which will fix the max/min levels, but not the colors. Your best procedure would be to record 5 secs of the multi format colorbar pattern in your JVC and export/import that into vegas to carry along. This will give you proper 709 colorbars for HD material.

Glenn Chan · March 27th, 2008, 11:07 AM

Quote:

I'm just wondering what happens to the Vegas SMPTE NTSC color bars when they run through the procoder 709 to 601 conversion?

I think you should actually do it and test it out to see what happens. It's not clear to me what the "709 HD to 601 SD filter" does as that can refer to one or a combination of three things. 709 and 601 differ in the luma coefficients, primaries (SD typically uses either SMPTE C primaries or EBU), and the transfer functions. "Correcting" for the luma coefficients may be inappropriate in your situation (a well-designed/engineered system will handle these conversions for you). Handling the other two items will cause the converted color bars to be wrong.

2- The way to test is this:
Make an 8-bit Vegas project. Throw the color bars on.
Render to the main concept MPEG2 encoder.

Render your color bars through Procoder.

Both files should match. Bring them into Vegas and check. If they don't match, then your process going through Procoder is probably wrong. You might toggle the 709 HD to 601 SD filter, and check to see if Procoder expects to see computer RGB levels.

3- You can generate (mostly) correct color bars with Vegas' color bars generator for both HD and SD.

*The I and Q patches (or -I -Q; can't remember) won't line up, but those patches aren't useful nowadays.
**You can also generate incorrect bars if you aren't careful about levels conversion (which you have to manually handle).

Steven Thomas · March 27th, 2008, 01:06 PM

Thank you Bill and Glenn. I'll try these experiments and get back.

I really enjoy using Vegas. I've used it for years and have been satisified with the results. Every since I stepped into the HD / HDV world it has thrown me with the levels and color space differences.

Glenn, I've read your excellent articles regarding these issues. This has been of great help for many.

Recently, I've been asked by a client to work out a DVD promo of a concert we shot with HD100 cameras.

I'm questioning if things are lined up correctly. The highlights seem to blow out on the DVD more than what's viewed on the timeline.

The 709 to 601 procoder 3 filter look like it does correct the colors (I need to confirm this), and appears to be needed when encoding the HD100 footage to a DVD compliant frameserving from Vegas 8.0B. I need to verify this with the color bar test you mentioned.

Also, it would be interesting to just render out the vegas NTSC color bars direct from Vegas, maybe add the "Studio RGB to Computer RGB" as suggested by Bill to correct levels, then frameserve to Procoder 3 and make a file NOT using the 709 to 601 color correction.

Next, render out another Vegas NTSC SMPTE color bar the same way, but this time in Procoder 3, select the 709 to 601 correction. Burn them both to the same DVD and compare. This will be interesting to see which bar will be correct. I would believe the bar without the 709 to 601 will be correct, since the NTSC SMPTE bars should be 601 in the first place.

I guess what I'm asking is:
Using Sony Vegas 8.0B (8 bit mode) & frameserving (bypassing an intermediate) directly to Procoder 3, what magic button settings do I need to click to ensure a correct transfer for levels and color to Procoder's DVD compliant.

I would think, but correct me if I'm wrong on using the following steps for a DVD compliant:

1. Level correction: In Vegas, when I'm finished, I need to drop the "Studio RGB to Computer RGB" level correction when rendering and framserving direct to Procoder 3.

2. Color correction: In Procoder 3, I need to select the DVD Compliant template and ALSO select the 709 HD to 601 SD filter.

Glenn, Bill, are my thoughts correct?

Why in the heck do these programs not correct for this themselves???? !!
They should be able to determine the correct levels and color space conversions based on your source and rendering formats!

hmmm... I'm starting to see why Bill jumped ship... LOL ;)
I can't man. I'm to dang use to Vegas!

Bill Ravens · March 27th, 2008, 01:16 PM

well, I didn't exactly flush my license down the toilet, much as I've felt like doing exactly that. I quite like edius, but, I'm waiting to see if Sony does anything at NAB. I'm pretty tired of forking out $150 every year to see the kind of fubar software vegas has become. There's a lot of things vegas can do that edius can't do. But, it's all moot if I have to make excuses to a DP when I can't get vegas to output the right colors and levels.

March 27th, 2008, 01:06 PM	#20
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	Thank you Bill and Glenn. I'll try these experiments and get back. I really enjoy using Vegas. I've used it for years and have been satisified with the results. Every since I stepped into the HD / HDV world it has thrown me with the levels and color space differences. Glenn, I've read your excellent articles regarding these issues. This has been of great help for many. Recently, I've been asked by a client to work out a DVD promo of a concert we shot with HD100 cameras. I'm questioning if things are lined up correctly. The highlights seem to blow out on the DVD more than what's viewed on the timeline. The 709 to 601 procoder 3 filter look like it does correct the colors (I need to confirm this), and appears to be needed when encoding the HD100 footage to a DVD compliant frameserving from Vegas 8.0B. I need to verify this with the color bar test you mentioned. Also, it would be interesting to just render out the vegas NTSC color bars direct from Vegas, maybe add the "Studio RGB to Computer RGB" as suggested by Bill to correct levels, then frameserve to Procoder 3 and make a file NOT using the 709 to 601 color correction. Next, render out another Vegas NTSC SMPTE color bar the same way, but this time in Procoder 3, select the 709 to 601 correction. Burn them both to the same DVD and compare. This will be interesting to see which bar will be correct. I would believe the bar without the 709 to 601 will be correct, since the NTSC SMPTE bars should be 601 in the first place. I guess what I'm asking is: Using Sony Vegas 8.0B (8 bit mode) & frameserving (bypassing an intermediate) directly to Procoder 3, what magic button settings do I need to click to ensure a correct transfer for levels and color to Procoder's DVD compliant. I would think, but correct me if I'm wrong on using the following steps for a DVD compliant: 1. Level correction: In Vegas, when I'm finished, I need to drop the "Studio RGB to Computer RGB" level correction when rendering and framserving direct to Procoder 3. 2. Color correction: In Procoder 3, I need to select the DVD Compliant template and ALSO select the 709 HD to 601 SD filter. Glenn, Bill, are my thoughts correct? Why in the heck do these programs not correct for this themselves???? !! They should be able to determine the correct levels and color space conversions based on your source and rendering formats! hmmm... I'm starting to see why Bill jumped ship... LOL ;) I can't man. I'm to dang use to Vegas! Last edited by Steven Thomas; March 27th, 2008 at 04:51 PM.

February 23rd, 2008, 05:08 PM	#16
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	Hold On!!!! Jon, I may owe you a HUGE THANK YOU. I've been playing with these corrections. Seems as tho', if I ignore the vegas wfm and use the vectorscope to set the correction factors in the Channel Blender, I'm making some progress. Indeed, I've been assuming that the Levels FX resets the chroma as well as the luma, because the WFM shows the colors shifting. BUT, if I IGNORE the WFM reference lines and use the vectorscope, things are looking up. Only question now is, what are the right factors to go from REC601 to REC709 and back? Shouldn't Vegas do this for me? hehehehe

March 26th, 2008, 10:15 PM	#17
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	Just a sanity check using Sony Vegas 8.0B (8bit mode) with the Sony EX1 and JVC HD100 footage. I believe both of these codecs are 709 color space. Going to blu-ray HD is straight forward, no level correction such as (vegas RGB to Studio) is needed. Footage burned direct from the timeline to blu-ray looks great. Now, I'm using Procoder 3 to convert to SD. I'm frameserving using Debugmode Framserver to Procoder 3 without going to an intermediate. In Procoder 3 I'm using a DVD compliant template, but also using the 709 HD to 601 SD filter. I believe the DVD looks good, but maybe a tad washed. Going to DVD , If I drop the Vegas SMPTE NTSC color bars on the timeline with JVC HD100 footage 1280x720 HDV (709) and frameserve it out to Procoder 3 DVD compliant template using the 709 HD to 601 SD colorspace filter, will the Vegas SMPTE NTSC color bars survive the export and conversion? I need to try this. I'm just wondering what happens to the Vegas SMPTE NTSC color bars when they run through the procoder 709 to 601 conversion?

March 27th, 2008, 07:52 AM	#18
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	Steve.. The vegas color bars are 601. you can drop the studio to computer RGB FX on the bars, which will fix the max/min levels, but not the colors. Your best procedure would be to record 5 secs of the multi format colorbar pattern in your JVC and export/import that into vegas to carry along. This will give you proper 709 colorbars for HD material.

March 27th, 2008, 01:16 PM	#21
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	well, I didn't exactly flush my license down the toilet, much as I've felt like doing exactly that. I quite like edius, but, I'm waiting to see if Sony does anything at NAB. I'm pretty tired of forking out $150 every year to see the kind of fubar software vegas has become. There's a lot of things vegas can do that edius can't do. But, it's all moot if I have to make excuses to a DP when I can't get vegas to output the right colors and levels.