No analog-digital passthrough on HC-1?

Christian de Godzinsky · October 4th, 2006, 04:21 AM

Hi,

I fully understand Sonys logic here. It makes sense to leave this feature out. Not many would have had use for it anyhow. And HC1 is a pure digital unit, even if it has analog outputs - a necessity still for some years to come.

External analog video input is commonplace in Cam's having a CCD. A CCD outputs the signal in the analog domain, and thus requires an A/D-converter to convert the signal into digital. This A/D converter's input can be easily switched to another analog source, such as external analog video, using a cheap video multiplexer. Thus implemeting this feature costs nothing.

The CMOS sensor used in HC1 has an integrated AD-converter directly on the sensor chip. The CMOS output is already in the digital domain. So there is no need for an external AD-converter elsewhere in the HC1. Adding one just to digitize external analog video would not have been clever, just adding to the cost and complecxity of the camera.

This is the logic why there is no analog video input in HC1. It would have been possible to design the CMOS chip in such a way that there would have been also an external input for analog video. But, hey, it is an image sensor chip in the first place. Please remember that the CMOS chip is scanned using completely different frequencies and line counts than PAL/NTSC. Digitizing a PAL/NTSC video using the same AD-converter would have been very difficult if not impossible.

So, in order to digitize analog video, you have to use other equipment. Not a big problem since such devices exist and does not cost very much. You can also use your older camcorder for that. Probably you want to keep it anyhow for playing bakc DV-cassettes without wearing the HC1 unnecessarily.

Best regards,

Christian

David Jasany · November 22nd, 2006, 06:50 AM

Since the HC3 doesn't have analog pass through, does this mean the camera cannot be used for digital to analog conversion for video editing external monitor preview? Thanks.

Douglas Spotted Eagle · November 22nd, 2006, 09:47 AM

It can be used for digital to analog preview for monitoring, but cannot be used for Analog input to digital output, for digitizing VHS tape, or other external, analog sources.

David Jasany · November 22nd, 2006, 10:11 AM

Thanks DSE, I'm glad to know the HC3 supports this function. In shopping for a new camera I'm really uncertain how I know if a MiniDV camcorder supports the digital to analog preview ability. It seems like there's no way of knowing from the features and specs of the camera. Maybe I'm worrying about nothing and most if not all camcorders operate in this manner.

Douglas Spotted Eagle · November 22nd, 2006, 10:43 AM

To my knowledge, all of the DV camcorders (in the US, different in some non-US regions) support ieee1394 pass through to analog, but not all DV camcorders allow for analog input, 1394 output.

Christian de Godzinsky · January 20th, 2007, 02:15 AM

Hi,

I had the opportunity to have a look at the HC1's schematic and block diagram. It seems that the video A/D converters are EXTERNAL from the CMOS imager chip. I was wrong in my earlier assumption that these were ON-chip. SO, it would have been possible for Sony to make an analog pass through with just some minor effort. Seems to more be a political decision. HC1 is regarded as a full digital cam, the analog outputs are a must because the majority of monitors used today have analog inputs...

Christian

David Delaney · January 20th, 2007, 08:37 AM

My buddy sold me his PV852 and I haven't regreted it. It has the ana-dig passthrough. Maybe look for some similar cameras in a lower price range.

Mauritius Seeger · January 23rd, 2007, 09:37 PM

Quote:

Originally Posted by Christian de Godzinsky

Hi,

I had the opportunity to have a look at the HC1's schematic and block diagram. It seems that the video A/D converters are EXTERNAL from the CMOS imager chip. I was wrong in my earlier assumption that these were ON-chip. SO, it would have been possible for Sony to make an analog pass through with just some minor effort. Seems to more be a political decision. HC1 is regarded as a full digital cam, the analog outputs are a must because the majority of monitors used today have analog inputs...

Christian

also i think the video input is a very different kind of signal to the one originating at the CMOS. at the very least this would require extra circutry to deal with PAL/ NTSC systems. also i believe that all the DV camcorders with analogue input use some type of TBC or simmilar. also not something you need for reading out from a CCD / CMOS.

i still think an A/D capability would have been immensly usefull for me, but i can see that for the most part people have stopped using analog sources. the whole input / ouput is very limited on the HC1. no digital display output. no input other than firewire. to be honest i would have even expected sony to include an HD component to digital (i.e.HDV) conversion. it is an HD camera after all - how else are you supposed to record an analog HD signal?

Jeff DeMaagd · January 24th, 2007, 12:20 AM

Quote:

Originally Posted by Mauritius Seeger

i still think an A/D capability would have been immensly usefull for me, but i can see that for the most part people have stopped using analog sources. the whole input / ouput is very limited on the HC1. no digital display output. no input other than firewire. to be honest i would have even expected sony to include an HD component to digital (i.e.HDV) conversion. it is an HD camera after all - how else are you supposed to record an analog HD signal?

How many analog HD sources do you have? There are component input add-in cards for computers. Based on the prices for those, putting that feature in the camcorder would make it a lot less attractive for most buyers.

Christian de Godzinsky · January 24th, 2007, 08:42 AM

Hi,

You can record a DIGITAL HD signal with the HC1, for example using Vegas and export to HDCAM... Ok, you have to get the analog HD signal first in into Vegas, and there HC1 has no role :)

Mauritius, you are right that the analog video is completely a different signal than what comes out of the HC1'S CMOS sensor. However, the A/D bandwith would be enought to sample a composite DV signal directly with color subcarriers etc. I just would have required some digital post processing. This circuitry would have been required as an additional part just for this A/D function - and for nothing else.

I am not sure if any camcorder analog inputs have timebase correction? Most decks have it - though. Anyhow - all this would have added to the complexity in the already quite crammed HC1.

Most of us still probably have an DV cam with this A/D capability. I have one and have no intentions of getting rid of it, i prefer NOT to use my HC1 for unnecessary playback of just plain old DV cassettes...

Regards,

Christian

October 4th, 2006, 04:21 AM	#16
Christian de Godzinsky Regular Crew Join Date: Dec 2005 Location: Helsinki/Finland Posts: 131	Why no analog input in HC1?? Hi, I fully understand Sonys logic here. It makes sense to leave this feature out. Not many would have had use for it anyhow. And HC1 is a pure digital unit, even if it has analog outputs - a necessity still for some years to come. External analog video input is commonplace in Cam's having a CCD. A CCD outputs the signal in the analog domain, and thus requires an A/D-converter to convert the signal into digital. This A/D converter's input can be easily switched to another analog source, such as external analog video, using a cheap video multiplexer. Thus implemeting this feature costs nothing. The CMOS sensor used in HC1 has an integrated AD-converter directly on the sensor chip. The CMOS output is already in the digital domain. So there is no need for an external AD-converter elsewhere in the HC1. Adding one just to digitize external analog video would not have been clever, just adding to the cost and complecxity of the camera. This is the logic why there is no analog video input in HC1. It would have been possible to design the CMOS chip in such a way that there would have been also an external input for analog video. But, hey, it is an image sensor chip in the first place. Please remember that the CMOS chip is scanned using completely different frequencies and line counts than PAL/NTSC. Digitizing a PAL/NTSC video using the same AD-converter would have been very difficult if not impossible. So, in order to digitize analog video, you have to use other equipment. Not a big problem since such devices exist and does not cost very much. You can also use your older camcorder for that. Probably you want to keep it anyhow for playing bakc DV-cassettes without wearing the HC1 unnecessarily. Best regards, Christian __________________ The future does not exist - we must invent it !

November 22nd, 2006, 09:47 AM	#18
Douglas Spotted Eagle VASST Join Date: Jan 2004 Location: Stockton, UT Posts: 5,648	It can be used for digital to analog preview for monitoring, but cannot be used for Analog input to digital output, for digitizing VHS tape, or other external, analog sources. __________________ Douglas Spotted Eagle/Spot Author, producer, composer Certified Sony Vegas Trainer http://www.vasst.com

November 22nd, 2006, 10:43 AM	#20
Douglas Spotted Eagle VASST Join Date: Jan 2004 Location: Stockton, UT Posts: 5,648	To my knowledge, all of the DV camcorders (in the US, different in some non-US regions) support ieee1394 pass through to analog, but not all DV camcorders allow for analog input, 1394 output. __________________ Douglas Spotted Eagle/Spot Author, producer, composer Certified Sony Vegas Trainer http://www.vasst.com

January 20th, 2007, 02:15 AM	#21
Christian de Godzinsky Regular Crew Join Date: Dec 2005 Location: Helsinki/Finland Posts: 131	Hi, I had the opportunity to have a look at the HC1's schematic and block diagram. It seems that the video A/D converters are EXTERNAL from the CMOS imager chip. I was wrong in my earlier assumption that these were ON-chip. SO, it would have been possible for Sony to make an analog pass through with just some minor effort. Seems to more be a political decision. HC1 is regarded as a full digital cam, the analog outputs are a must because the majority of monitors used today have analog inputs... Christian __________________ The future does not exist - we must invent it !

January 24th, 2007, 08:42 AM	#25
Christian de Godzinsky Regular Crew Join Date: Dec 2005 Location: Helsinki/Finland Posts: 131	Hi, You can record a DIGITAL HD signal with the HC1, for example using Vegas and export to HDCAM... Ok, you have to get the analog HD signal first in into Vegas, and there HC1 has no role :) Mauritius, you are right that the analog video is completely a different signal than what comes out of the HC1'S CMOS sensor. However, the A/D bandwith would be enought to sample a composite DV signal directly with color subcarriers etc. I just would have required some digital post processing. This circuitry would have been required as an additional part just for this A/D function - and for nothing else. I am not sure if any camcorder analog inputs have timebase correction? Most decks have it - though. Anyhow - all this would have added to the complexity in the already quite crammed HC1. Most of us still probably have an DV cam with this A/D capability. I have one and have no intentions of getting rid of it, i prefer NOT to use my HC1 for unnecessary playback of just plain old DV cassettes... Regards, Christian __________________ The future does not exist - we must invent it !

November 22nd, 2006, 06:50 AM	#17
David Jasany Major Player Join Date: Jun 2004 Location: North Carolina Posts: 313	Since the HC3 doesn't have analog pass through, does this mean the camera cannot be used for digital to analog conversion for video editing external monitor preview? Thanks.

November 22nd, 2006, 10:11 AM	#19
David Jasany Major Player Join Date: Jun 2004 Location: North Carolina Posts: 313	Thanks DSE, I'm glad to know the HC3 supports this function. In shopping for a new camera I'm really uncertain how I know if a MiniDV camcorder supports the digital to analog preview ability. It seems like there's no way of knowing from the features and specs of the camera. Maybe I'm worrying about nothing and most if not all camcorders operate in this manner.

January 20th, 2007, 08:37 AM	#22
David Delaney Trustee Join Date: Feb 2006 Location: Niagara Ontario Canada Posts: 1,121	My buddy sold me his PV852 and I haven't regreted it. It has the ana-dig passthrough. Maybe look for some similar cameras in a lower price range.