Composite Out at DVinfo.net

Trevor Allin · June 29th, 2006, 11:37 AM

Hi

Can anyone tell me for sure the following?

(1) Does the composite out truly provide uncompressed video?

(2) Can you get BOTH standard definition and High definition out of these connectors?

Many thanks

Trevor

Antony Michael Wilson · June 29th, 2006, 11:44 AM

The analogue outputs will give you uncompressed video live off the camera (but obviously not on tape playback) as they by-pass the HDV encoder. Of course, the signal has had a digital to analogue conversion.

The composite output will give you SD only (of course) but you don't really want to use composite for image capture do you? CVBS is not great by definition.

Component will give you HD or SD for sure. This is what you should be using for image capture to an external device if you want uncompressed images live off the camera. You have to set the outputs for HD or SD in the relevant menu.

Tim Dashwood · June 29th, 2006, 12:27 PM

Using the live anolog component output while shooting will yield an "uncompressed" result as described in JVC literature. Unfortunately, "uncompressed" is a subjective term used in this way, especially since the term is usually used to describe digital video files, and not an analog signal.

It is true that when the camera is in "camera mode" the analog output bypasses the Mpeg2 encoder, therefore sparing you from Mpeg2 compression artifacts and yielding 4:2:2 colour instead of HDV's 4:2:0. The other benefit is that the output is "double-clocked," so you will be able to capture 720P60 when in 720P30 mode, 720P50 when in 720P25 mode, and 720P48 when in 720P24 mode. This allows for "over-cranked" slow motion. There is a little more info about these frame rates on cineform's blogspot.

However, even with 720P60 and 4:2:2 colour, the processing is 8-bit and you have introduced a D-A converter. So, I guess if you capture using a Wafian, Kona or Decklink in 8-bit, 4:2:2, uncompressed codec, then I guess you could say that the output-to-capture workflow is uncompressed, even though 8-bit signal processors and D-A have been introduced between the CCD and output of the camera.

These methods do not work when playing back from a recorded HDV tape, since 4:2:0 and Mpeg2 compression are already inherent in the signal.

Jack Walker · June 29th, 2006, 01:17 PM

The Wafian HR-1 Seems to run about $15,000 to $17,000.

Has anyone tried to put together a portable recording setup that can come in under $3000.

Perhaps a Decklink card a rackmount motherboard and drives all mounted in a shockresistant rackmount case (like musicians use and Wafian sells for their unit).

Or perhaps one of those small computer boxes that network junkies take to WiFi parties?

Are there samples and plans out there?

Trevor Allin · June 29th, 2006, 03:44 PM

Thanks everyone.

Jack, I wait with baited breath to see if there are any answers to your question!

Trevor

June 29th, 2006, 11:37 AM	#1
Trevor Allin Regular Crew Join Date: Sep 2005 Posts: 152	Composite Out Hi Can anyone tell me for sure the following? (1) Does the composite out truly provide uncompressed video? (2) Can you get BOTH standard definition and High definition out of these connectors? Many thanks Trevor

June 29th, 2006, 12:27 PM	#3
Tim Dashwood Wrangler Join Date: Aug 2005 Location: Toronto, ON, Canada Posts: 3,637	Using the live anolog component output while shooting will yield an "uncompressed" result as described in JVC literature. Unfortunately, "uncompressed" is a subjective term used in this way, especially since the term is usually used to describe digital video files, and not an analog signal. It is true that when the camera is in "camera mode" the analog output bypasses the Mpeg2 encoder, therefore sparing you from Mpeg2 compression artifacts and yielding 4:2:2 colour instead of HDV's 4:2:0. The other benefit is that the output is "double-clocked," so you will be able to capture 720P60 when in 720P30 mode, 720P50 when in 720P25 mode, and 720P48 when in 720P24 mode. This allows for "over-cranked" slow motion. There is a little more info about these frame rates on cineform's blogspot. However, even with 720P60 and 4:2:2 colour, the processing is 8-bit and you have introduced a D-A converter. So, I guess if you capture using a Wafian, Kona or Decklink in 8-bit, 4:2:2, uncompressed codec, then I guess you could say that the output-to-capture workflow is uncompressed, even though 8-bit signal processors and D-A have been introduced between the CCD and output of the camera. These methods do not work when playing back from a recorded HDV tape, since 4:2:0 and Mpeg2 compression are already inherent in the signal. __________________ Tim Dashwood

June 29th, 2006, 11:44 AM	#2
Antony Michael Wilson Major Player Join Date: Sep 2005 Location: London, UK Posts: 343	The analogue outputs will give you uncompressed video live off the camera (but obviously not on tape playback) as they by-pass the HDV encoder. Of course, the signal has had a digital to analogue conversion. The composite output will give you SD only (of course) but you don't really want to use composite for image capture do you? CVBS is not great by definition. Component will give you HD or SD for sure. This is what you should be using for image capture to an external device if you want uncompressed images live off the camera. You have to set the outputs for HD or SD in the relevant menu.

June 29th, 2006, 01:17 PM	#4
Jack Walker Trustee Join Date: Jun 2006 Location: Burbank Posts: 1,811	The Wafian HR-1 Seems to run about $15,000 to $17,000. Has anyone tried to put together a portable recording setup that can come in under $3000. Perhaps a Decklink card a rackmount motherboard and drives all mounted in a shockresistant rackmount case (like musicians use and Wafian sells for their unit). Or perhaps one of those small computer boxes that network junkies take to WiFi parties? Are there samples and plans out there?

June 29th, 2006, 03:44 PM	#5
Trevor Allin Regular Crew Join Date: Sep 2005 Posts: 152	Thanks everyone. Jack, I wait with baited breath to see if there are any answers to your question! Trevor