720/30p – 720/60p – 1080/30p Best for SD down convert?

[Dave Raizman]

I’m just finishing up a project I shot 1080p24 on an ex1 that looked just beautiful in fcp. I got a Matrox MXO for doing color correction and was surprised to see that some of the richness and smoothness of the image was lost. It wasn’t too bad but just not as nice. I have my fcp sequence setting set to prores 422 because I read that would preserve the most image quality.

But my real shock came when I exported the file through compressor for DVD. Even using the best quality settings it just looks so much worse. I realize there’s going to be some degradation of the image because of the mpeg2 compression. I also seem to have lost a lot of the filmic quality of the original footage in the compression too.

I’m trying to follow this discussion thread and not completely getting it. Are people saying the shooting in 720p60 results in the best quality SD down converts?

Thanks,
Dave

[Craig Seeman]

[Dave Raizman] “I got a Matrox MXO for doing color correction and was surprised to see that some of the richness and smoothness of the image was lost.”

MXO is for monitoring and color correction. It doesn’t change your source video. You calibrate your viewing monitor and it shows ACTUALLY what your source looks like. If you don’t like what the source actually looks like you Color Correct. MXO set up properly shows you “reality.”

[Dave Raizman]

By “reality” do you mean that my source footage in actuality won’t look as good as it looks in fcp or do you mean that I may not have the mxo properly calibrated? If it’s properly calibrated should my footage look about the same as it does in fcp?

thanks,
Dave

[John Sharaf]

With an 8 bit master (even if imported to 10 bit Pro Res) any color correction deteriorates the image. This is why eventually all high end production that has not already migrated to 10 bit mastering (HDCAM -SR, AVC-I, etc.) will do so. In 8 bit formats like DVCPRO100, HD XDCAM, HDCAM, etc. the best you can do is get it right when you shoot it (both exposure and paint).

JS

[Dave Raizman]

Are you saying there is no benefit to using the prores422 50Mbps sequence rendering setting?

Dave Raizman
Springboard Media
springboardhd.com
802-223-7625

[Rafael Amador]

Hi Denis,

A. 1080p/30p (so the zoom resizing has more to work with): To have a bit of room for resizing is great.

Too have too much complicates your rendering. 720 for SD is perfect.

B. 720/30p (so there are fewer compression artifacts from the 35mbs compression ??)

720 will be always more efficient than 1080. Less pixels to compress with the same amount of data allowed.

C. 720/60p (so the 16 gop encoding gives an I frame about every 1/4 second instead of every 1/2 second, thus helping the mpeg encoder ??)

This doesn’t means nothing. In the end every GOP have the same number of frames. You still having an I frame every 15 frames.
Shoting p60 or p50 makes only sense when you can play your images with that time-base.
p60 is obviously 1/2 efficient than p30. You use the same data for two frames instead that for one.

My only question in this case is if you want your movie interlaced or progressive.
If interlaced go to 1080i30.
if progressive, 720p30.
rafael

http://www.nagavideo.com

[Craig Seeman]

[Dave Raizman] “By “reality” do you mean that my source footage in actuality won’t look as good as it looks in fcp or do you mean that I may not have the mxo properly calibrated? If it’s properly calibrated should my footage look about the same as it does in fcp?”

Calibrate Broadcast monitor. What you see in Broadcast monitor (HDTV) will be how your video will look on TV.

FCP to uncalibrated computer monitor is not accurate at all. Even FCP to calibrated computer monitor will not look the same as calibrated Broadcast monitor.

Computer monitors and TV monitors look display color differently. MXO can make any monitor (computer or HDTV) look like a calibrated Broadcast monitor. Even HDTV uncalibrated is not accurate.

MXO is used to Calibrate a monitor so your video is ACCURATELY represented. Once you know how your video actually looks on calibrated monitor you can THEN color correct.

If your doing video for web you may yet need to do a different calibration. Macs and Windows have different gamma defaults. Computer monitors don’t handle color the way a Broadcast monitor does.

[Craig Seeman]

But if you’re shooting fast action (sports) 720p60 will give you better temporal resolution and 60 units of progressive motion a second should keep same temporal resolution going to standard def 60 units interlace.

p30 has only 30 units of temporal motion a second and your standard def is likely to be 60 units interlace for standard def broadcast.

in other words 60 progressive frames to 60 interlace fields holds same temporal resolution.
30 progressive frames to 60 interlace fields will have less temporal resolution.

For me
1080i60 or 720p60 for sports.
1080p30 for less action
720p30 will give you more bits but obviously less spatial resolution. Also overcrank in same time base. I’ve used this for Digital Signage advertising.
1080p24 and 720p24 gives you easiest convert to PAL (speed change) and NTSC (pull down)
720p24 gives you overcrank in same time base.