Best way to downconvert HDV?

Randy Donato · June 15th, 2005, 07:11 PM

Steven is dead on with his remarks. That is a lot of work to get to a conversion from 4:4:4 to 4:2:0 but technically is the very best method. I do not go the uncompressed route... Edius using HQ to make a dvd basicaly goes from 4:2:2 to the DVD 4:2:0 and there is no conversion down to DV spec(4:1:1 NTSC and 4:2:0 PAL) that occurs. Because the resolution of HDV is twice the resolution of DV there is more than enough information to create 4:4:4 though.

Horizontal Vertical NTSC
4:4:4--- Y 720 480
Cb 720 480
Cr 720 480
4:2:2--- Y 720 480
Cb 360 480
Cr 360 480
4:1:1--- Y 720 480
Cb 180 480
Cr 180 480
4:2:0--- Y 720 480
Cb 360 240
Cr 360 240
In case of HDV (1440x1080):

4:2:0--- Y 1440 1080
Cb 720 540
Cr 720 540
If we just divide by 2 the horizontal and vertical resolution of HDV signal then we get the result below:

Y 720 540
Cb 720 540
Cr 720 540

which is where the 4:4:4 can come from.

Jack Zhang · June 16th, 2005, 02:49 PM

I have a tape question, does MPEG IMX or Digibeta support 4:4:4?

June 15th, 2005, 07:11 PM	#31
Randy Donato Regular Crew Join Date: Feb 2005 Location: Houston, Texas Posts: 138	Steven is dead on with his remarks. That is a lot of work to get to a conversion from 4:4:4 to 4:2:0 but technically is the very best method. I do not go the uncompressed route... Edius using HQ to make a dvd basicaly goes from 4:2:2 to the DVD 4:2:0 and there is no conversion down to DV spec(4:1:1 NTSC and 4:2:0 PAL) that occurs. Because the resolution of HDV is twice the resolution of DV there is more than enough information to create 4:4:4 though. Horizontal Vertical NTSC 4:4:4--- Y 720 480 Cb 720 480 Cr 720 480 4:2:2--- Y 720 480 Cb 360 480 Cr 360 480 4:1:1--- Y 720 480 Cb 180 480 Cr 180 480 4:2:0--- Y 720 480 Cb 360 240 Cr 360 240 In case of HDV (1440x1080): 4:2:0--- Y 1440 1080 Cb 720 540 Cr 720 540 If we just divide by 2 the horizontal and vertical resolution of HDV signal then we get the result below: Y 720 540 Cb 720 540 Cr 720 540 which is where the 4:4:4 can come from.

June 16th, 2005, 02:49 PM	#32
Jack Zhang Inner Circle Join Date: May 2005 Location: Burnaby, BC, Canada Posts: 3,053	I have a tape question, does MPEG IMX or Digibeta support 4:4:4?