Superwhites

Graham Hickling · September 8th, 2009, 10:17 AM

The AVCHD files that my HF10 produces contain superwhites - i.e. highlight details above 100 IRE.

I'd be interested to hear how others are handling this - particularly ways to transcode to intermediate formats without those superwhites being clipped during transcoding.

One suggestion I've seen is uses TMPGEnc, with a reduced-luminance or reduced-contrast filter applied to the source AVCHD footage.

Stuart Robinson · September 8th, 2009, 11:02 AM

I'm not sure using a brightness or contrast filter when creating your intermediaries is a good idea, because information lost there can't be recovered in your NLE. What intermediary format and colour space are you using? CineForm NEO Scene will retain all levels, which I then correct in Vegas.

Graham Hickling · September 8th, 2009, 02:00 PM

I'm converting from AVCHD to Cineform using HDLink, from the latest ProspectHD4.

The resulting CFHD avis have the superwhites clipped off (to my surprise, since that isn't the case with CFHDs originating from my HDV footage).

I posted about this on the Cineform forum last night, to see if this is consistent with what others are finding, but no responses so far.

Stuart Robinson · September 8th, 2009, 02:40 PM

I'll keep an eye on your CineForm thread.

If it helps at all, putting an AVCHD file side-by-side with the same file converted to CineForm via HDLink in NEO on the same timeline, I can see a change of levels - the CineForm levels being fractionally higher (the mean shifts by about two points) but the luminance values extend well above 100 IRE, so I'm not seeing any hard clipping at that point.

Out of interest, do you have the ITU.Bt.709 colour space enabled in the VfW CODEC?

Graham Hickling · September 8th, 2009, 07:24 PM

Thanks for the response. I have 709 enabled for both encode and decode. I have 'Video systems RGB' disabled for both. Does that sound right?

Graham Hickling · September 9th, 2009, 09:13 AM

Hmmmm ..... this seems to be a CS3 vs. CS4 thing. When I pull my transcoded CFHD-avi into a CS4 timeline, the superwhites are there and the YC waveform is essentially identical to the original AVCHD footage.

But when I pull the same CFHD-avi into CS3 everything above 100IRE is gone!

Since this isnt a problem with the HF10, I'll quit this thread and carry on in the Cineform forum: http://www.dvinfo.net/forum/cineform...d-footage.html

September 8th, 2009, 10:17 AM	#1
Graham Hickling Trustee Join Date: May 2004 Location: Knoxville, Tennessee Posts: 1,669	Superwhites - workflow suggestions? The AVCHD files that my HF10 produces contain superwhites - i.e. highlight details above 100 IRE. I'd be interested to hear how others are handling this - particularly ways to transcode to intermediate formats without those superwhites being clipped during transcoding. One suggestion I've seen is uses TMPGEnc, with a reduced-luminance or reduced-contrast filter applied to the source AVCHD footage.

September 8th, 2009, 11:02 AM	#2
Stuart Robinson Regular Crew Join Date: Aug 2009 Location: Chester, UK Posts: 48	I'm not sure using a brightness or contrast filter when creating your intermediaries is a good idea, because information lost there can't be recovered in your NLE. What intermediary format and colour space are you using? CineForm NEO Scene will retain all levels, which I then correct in Vegas.

September 8th, 2009, 02:00 PM	#3
Graham Hickling Trustee Join Date: May 2004 Location: Knoxville, Tennessee Posts: 1,669	I'm converting from AVCHD to Cineform using HDLink, from the latest ProspectHD4. The resulting CFHD avis have the superwhites clipped off (to my surprise, since that isn't the case with CFHDs originating from my HDV footage). I posted about this on the Cineform forum last night, to see if this is consistent with what others are finding, but no responses so far.

September 8th, 2009, 02:40 PM	#4
Stuart Robinson Regular Crew Join Date: Aug 2009 Location: Chester, UK Posts: 48	I'll keep an eye on your CineForm thread. If it helps at all, putting an AVCHD file side-by-side with the same file converted to CineForm via HDLink in NEO on the same timeline, I can see a change of levels - the CineForm levels being fractionally higher (the mean shifts by about two points) but the luminance values extend well above 100 IRE, so I'm not seeing any hard clipping at that point. Out of interest, do you have the ITU.Bt.709 colour space enabled in the VfW CODEC?

September 8th, 2009, 07:24 PM	#5
Graham Hickling Trustee Join Date: May 2004 Location: Knoxville, Tennessee Posts: 1,669	Thanks for the response. I have 709 enabled for both encode and decode. I have 'Video systems RGB' disabled for both. Does that sound right?

September 9th, 2009, 09:13 AM	#6
Graham Hickling Trustee Join Date: May 2004 Location: Knoxville, Tennessee Posts: 1,669	Hmmmm ..... this seems to be a CS3 vs. CS4 thing. When I pull my transcoded CFHD-avi into a CS4 timeline, the superwhites are there and the YC waveform is essentially identical to the original AVCHD footage. But when I pull the same CFHD-avi into CS3 everything above 100IRE is gone! Since this isnt a problem with the HF10, I'll quit this thread and carry on in the Cineform forum: http://www.dvinfo.net/forum/cineform...d-footage.html