HM100 HDMI capture pre- or post-compression? at DVinfo.net

Trip Gould · July 26th, 2009, 02:59 AM

Quick question. Is it possible to capture live from the HDMI stream on the HM100? If so, at what point in the compression scheme does that feed come from? What sort of bitrate and colorspace would you be getting? Just curious. Thanks.

Tim Dashwood · July 26th, 2009, 04:17 AM

I do it all the time with the Blackmagic Intensity Pro. The live output image has not been compressed yet and is still 4:2:2. The bitrate you record on your computer is completely up to you. Uncompressed would be the highest but you will need a striped array to do it.

Joe Carney · July 26th, 2009, 04:34 AM

thanks Tim, is it 8 or 10 bit?

Tim Dashwood · July 26th, 2009, 05:13 AM

Well that's up to interpretation since there is no clear indication in the manual. The HM100 manual recommends the use of Category 2 cables (which would be required for 1080p) which leads me to assume that the camera output conforms to the HDMI 1.3 spec (even though I cannot find reference to this specifically in the manual.) HDMI 1.3 supports 8-bit, 10-bit, 12-bit and 16-bit. HDMI 1.2 only supported 8-bit.
If we go into the connection settings menu there is an option for "AUTO" or "RGB" and the "HDMI ENHANCE SETTING" which the manual describes "for setting the color range of HDMI signals." It suggests "OFF" for "conventional" monitors and "ON" for PC monitors. This leads me to believe that this option is actually JVC's implementation of x.v.Color mode, which would would theoretically mean the higher bit rates are possible.

With that said I have not done detail testing in this area and have restricted myself to short 8-bit captures because of my simple RAID limitations. In fact I usually use ProRes422 as the codec.

I have all new DSC charts so I will do some detailed testing in this area shortly.

Trip Gould · July 26th, 2009, 04:59 PM

So, how does that compare to coming off of the component connection on the HD200? I believe that is also pre-compression, but is it 8-bit or 10-bit and is it 4:2:2? That would make up for the lesser codec and bitrate on the HD200, would it not? And what is the most cost effective way to get that signal off of the cam (component to HDMI converter and then into BM or similar?). How about the firewire signal on the HD200? I think I've also read that is pre-compression or at least different compression than HDV. Where does that fall in the spectrum?

Thanks.

Anmol Mishra · September 17th, 2012, 03:39 AM

Hi Tim. Just wondering if you did any test ?
x.v.color still uses 8-bit BTW except it uses the range from 1-254

Quote:

Originally Posted by Tim Dashwood

Well that's up to interpretation since there is no clear indication in the manual. The HM100 manual recommends the use of Category 2 cables (which would be required for 1080p) which leads me to assume that the camera output conforms to the HDMI 1.3 spec (even though I cannot find reference to this specifically in the manual.) HDMI 1.3 supports 8-bit, 10-bit, 12-bit and 16-bit. HDMI 1.2 only supported 8-bit.
If we go into the connection settings menu there is an option for "AUTO" or "RGB" and the "HDMI ENHANCE SETTING" which the manual describes "for setting the color range of HDMI signals." It suggests "OFF" for "conventional" monitors and "ON" for PC monitors. This leads me to believe that this option is actually JVC's implementation of x.v.Color mode, which would would theoretically mean the higher bit rates are possible.

With that said I have not done detail testing in this area and have restricted myself to short 8-bit captures because of my simple RAID limitations. In fact I usually use ProRes422 as the codec.

I have all new DSC charts so I will do some detailed testing in this area shortly.

July 26th, 2009, 02:59 AM	#1
Trip Gould Regular Crew Join Date: Jan 2009 Location: Pasadena, CA Posts: 40	HM100 HDMI capture pre- or post-compression? Quick question. Is it possible to capture live from the HDMI stream on the HM100? If so, at what point in the compression scheme does that feed come from? What sort of bitrate and colorspace would you be getting? Just curious. Thanks.

July 26th, 2009, 04:17 AM	#2
Tim Dashwood Wrangler Join Date: Aug 2005 Location: Toronto, ON, Canada Posts: 3,637	I do it all the time with the Blackmagic Intensity Pro. The live output image has not been compressed yet and is still 4:2:2. The bitrate you record on your computer is completely up to you. Uncompressed would be the highest but you will need a striped array to do it. __________________ Tim Dashwood

July 26th, 2009, 04:34 AM	#3
Joe Carney Inner Circle Join Date: Jul 2002 Location: Centreville Va Posts: 1,828	thanks Tim, is it 8 or 10 bit? __________________ Boycott Guinness, bring back the pint!!!

July 26th, 2009, 05:13 AM	#4
Tim Dashwood Wrangler Join Date: Aug 2005 Location: Toronto, ON, Canada Posts: 3,637	Well that's up to interpretation since there is no clear indication in the manual. The HM100 manual recommends the use of Category 2 cables (which would be required for 1080p) which leads me to assume that the camera output conforms to the HDMI 1.3 spec (even though I cannot find reference to this specifically in the manual.) HDMI 1.3 supports 8-bit, 10-bit, 12-bit and 16-bit. HDMI 1.2 only supported 8-bit. If we go into the connection settings menu there is an option for "AUTO" or "RGB" and the "HDMI ENHANCE SETTING" which the manual describes "for setting the color range of HDMI signals." It suggests "OFF" for "conventional" monitors and "ON" for PC monitors. This leads me to believe that this option is actually JVC's implementation of x.v.Color mode, which would would theoretically mean the higher bit rates are possible. With that said I have not done detail testing in this area and have restricted myself to short 8-bit captures because of my simple RAID limitations. In fact I usually use ProRes422 as the codec. I have all new DSC charts so I will do some detailed testing in this area shortly. __________________ Tim Dashwood

July 26th, 2009, 04:59 PM	#5
Trip Gould Regular Crew Join Date: Jan 2009 Location: Pasadena, CA Posts: 40	So, how does that compare to coming off of the component connection on the HD200? I believe that is also pre-compression, but is it 8-bit or 10-bit and is it 4:2:2? That would make up for the lesser codec and bitrate on the HD200, would it not? And what is the most cost effective way to get that signal off of the cam (component to HDMI converter and then into BM or similar?). How about the firewire signal on the HD200? I think I've also read that is pre-compression or at least different compression than HDV. Where does that fall in the spectrum? Thanks.