progressive scan in theory at DVinfo.net

Riley Harmon · March 19th, 2004, 10:51 PM

Ok, here's my question. The Sony TRV900 and VX2000 both have 'progressive scan ccds' in their specs. So the camera itself must add some interlacing to the video, or add as it's recorded, right? So.....In theory....when you de-interlace with footage from these cameras, isn't that just like reverting back to the pure image before the interlace was added. So...in theory....when you de-interlace footage from these cameras, you should not encounter as many "jaggies" as you normally would?

Matthew Groff · March 19th, 2004, 11:57 PM

I don't believe this to be true. As I've seen noted elsewhere, there is a class action lawsuit over Sony's designation of "progressive scan" on some models. I believe that the slow shutter speed feature seems like progressive scan, but IIRC it's just a line doubled frame. If they were true progressive scan CCDs, they would allow for progressive capture and lay down to tape. Those models are capturing a run-of-the-mill interlaced frame. Anyone with more tech info care to confirm?

mg

Riley Harmon · March 20th, 2004, 04:07 AM

well lets say it was a true progressive scan ccd, like some of the JVC models have and like the old optura pi....would the theory be true?

Guy Bruner · March 20th, 2004, 06:42 AM

There is a technical document that has been referenced before on this forum that says CCDs are progressive scan devices. It goes on to say, after the CCD captures 481 lines, circuitry in the camcorder combines lines in buffers then outputs them as interlaced signals. Don't know if that answers your question or not.

Chris Hurd · March 20th, 2004, 12:40 PM

The motion is captured progressively but is laid to tape as interlace. Otherwise it wouldn't be DV. The progressive motion signature is preserved in this process. In normal interlace recording, the two fields are recorded at different points in time, 1/60th of a second apart. In progressive, the two fields are recorded at the exact same time. It's still going to tape as interlaced (it wouldn't be recordable if it weren't), but there is no time difference between the two fields. Therefore the video frames are 1/30th of a second apart for a more pronounced motion judder, as opposed to the smoother 1/60th of a second apart of normal interlace. Hope this helps,

March 19th, 2004, 10:51 PM	#1
Riley Harmon Major Player Join Date: Jul 2003 Location: Oklahoma Posts: 424	in theory Ok, here's my question. The Sony TRV900 and VX2000 both have 'progressive scan ccds' in their specs. So the camera itself must add some interlacing to the video, or add as it's recorded, right? So.....In theory....when you de-interlace with footage from these cameras, isn't that just like reverting back to the pure image before the interlace was added. So...in theory....when you de-interlace footage from these cameras, you should not encounter as many "jaggies" as you normally would?

March 20th, 2004, 12:40 PM	#5
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,366 Images: 513	The motion is captured progressively but is laid to tape as interlace. Otherwise it wouldn't be DV. The progressive motion signature is preserved in this process. In normal interlace recording, the two fields are recorded at different points in time, 1/60th of a second apart. In progressive, the two fields are recorded at the exact same time. It's still going to tape as interlaced (it wouldn't be recordable if it weren't), but there is no time difference between the two fields. Therefore the video frames are 1/30th of a second apart for a more pronounced motion judder, as opposed to the smoother 1/60th of a second apart of normal interlace. Hope this helps, __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!

March 19th, 2004, 11:57 PM	#2
Matthew Groff Regular Crew Join Date: Mar 2003 Location: New York, NY Posts: 132	I don't believe this to be true. As I've seen noted elsewhere, there is a class action lawsuit over Sony's designation of "progressive scan" on some models. I believe that the slow shutter speed feature seems like progressive scan, but IIRC it's just a line doubled frame. If they were true progressive scan CCDs, they would allow for progressive capture and lay down to tape. Those models are capturing a run-of-the-mill interlaced frame. Anyone with more tech info care to confirm? mg

March 20th, 2004, 04:07 AM	#3
Riley Harmon Major Player Join Date: Jul 2003 Location: Oklahoma Posts: 424	well lets say it was a true progressive scan ccd, like some of the JVC models have and like the old optura pi....would the theory be true?

March 20th, 2004, 06:42 AM	#4
Guy Bruner Major Player Join Date: Nov 2003 Location: Ashford, AL Posts: 937	There is a technical document that has been referenced before on this forum that says CCDs are progressive scan devices. It goes on to say, after the CCD captures 481 lines, circuitry in the camcorder combines lines in buffers then outputs them as interlaced signals. Don't know if that answers your question or not.