[Al-Mo]

Hello Everyone,

Now, I have read a lot about the difference between Progressive and Interlaced scanning, yet, I can't seem to fully understand some details.

Now, what I have come understand is that, for some technological difficulties, old TV's could not display a full single frame using all the supported 300, or whatever number of horizontal lines available. So, they had to divide them into two groups of lines. Odd lines, or upper group of lines, and even or lower group of lines.

So, what's basically going to happen is that each frame will have only one group of lines to display the data within it. And, if we, say, have two consecutive frames; for the first frame we will only see the data provided by the odd or upper group of lines, and the rest of the lines, (the even group) will be lost data of this very single frame because there's a technological issue that forces the even group of lines not to illuminate and transmit data at this particular instance. And for the second frame, the even group of lines will now start transmitting data, and the odd group will turn off.

Now, why do we see a sequence full pictures that do not lack any data despite the fact that 50% of each frame gets rid off?

I had an asnwer that was satisfying, but, I found it to be wrong. The speed of switching frames and alternating the two groups of lines is extremely fast that it creates an illusion to the human eye which allows you to watch the video smoothly without noticing any lost data.

If that's true, then why do you see a full set of lines when you pause an interlaced video and check a single frame and zoom in to see the scan lines? Why do you see the upper and the lower groups of lines both functioning completely without any sign of lost data? Instead, you can see two overlapping frames. The upper odd group represents a frame, and the even lower group represents another. How do they both exist in the same instance if that was a technological impossibility in the frist place?

[Al-Mo]

Another question:

I can undestand that TV's can use interlaced scanning, or progressive scanning as a method of VIEWING.

But, what does it mean to have a camera that RECORDS using interlaced or progressive technology?

[Al-Mo]

The answer:

What is deinterlacing? The best method to deinterlace movies

[choddo2006]

Originally Posted by Al-Mo

Hello Everyone,

Now, I have read a lot about the difference between Progressive and Interlaced scanning, yet, I can't seem to fully understand some details.

Now, what I have come understand is that, for some technological difficulties, old TV's could not display a full single frame using all the supported 300, or whatever number of horizontal lines available. So, they had to divide them into two groups of lines. Odd lines, or upper group of lines, and even or lower group of lines.

So, what's basically going to happen is that each frame will have only one group of lines to display the data within it. And, if we, say, have two consecutive frames; for the first frame we will only see the data provided by the odd or upper group of lines, and the rest of the lines, (the even group) will be lost data of this very single frame because there's a technological issue that forces the even group of lines not to illuminate and transmit data at this particular instance. And for the second frame, the even group of lines will now start transmitting data, and the odd group will turn off.

Now, why do we see a sequence full pictures that do not lack any data despite the fact that 50% of each frame gets rid off?

I had an asnwer that was satisfying, but, I found it to be wrong. The speed of switching frames and alternating the two groups of lines is extremely fast that it creates an illusion to the human eye which allows you to watch the video smoothly without noticing any lost data.

If that's true, then why do you see a full set of lines when you pause an interlaced video and check a single frame and zoom in to see the scan lines? Why do you see the upper and the lower groups of lines both functioning completely without any sign of lost data? Instead, you can see two overlapping frames. The upper odd group represents a frame, and the even lower group represents another. How do they both exist in the same instance if that was a technological impossibility in the frist place?

I guess you've got your answer clear enough now? But it's pretty simple - old CRT TVS didn't show both sets of lines. LCD and plasma TVs have to show an entire frame so they guess the content of the missing lines.

The camera question - most cameras can record in either mode. If they're only producing content for interlaced broadcast, they create interlaced content to save bandwidth and storage (there's some maths that goes on to avoid line twitter and so on) requirements in the broadcast chain