non-square pixels and pixel aspect ratio

[perf]

Originally Posted by Narflex

This is all handled automatically in V5.1. All you need to specify is the display aspect ratio of your monitor/TV.

Will this also go for the extender? Currently the extender cuts out a 4:3 picture from the center of any 16:9 content, which is terrible for widescreen TVs. (The same files play back correctly using the original Hauppauge software, and the Hauppauge software even has a 16:9 setting, which signals 16:9 output to the TV - at least with SCART.)

/Per

[mayamaniac]

This is what I know of NTSC or DV standards:
Resolution is 720x480. (display aspect ratio, about 4:3 ratio)
Pixel Aspect ratio is 0.9:1 (non-squared, stretched vertically)
Frame rate is 29.97 (interlaced)

When viewing on your computer monitor, which is squared pixels, the image is slightly stretched horizontally or slightly squashed vertically. This is due to the conversion from non-squared-pixels to squared-pixels. The display aspect ratio is just a resolution format ratio, which is commonly refered to as 4:3 ratio. As for frame rate, the actual deinterlaced frame rate is 23.976 frames per second, but extra frames were added or "interlaced" into the video to produce the 29.97 frame rate. Why do they do that? Read about history of NTSC here.

To correct these problems for video playback on the computer software media player, the software decoders not only decode the video compression, which is usually MPEG2, but also deinterlaced the video to remove the extra frames for smooth playback, and correct the display aspect ratio to compensate for the stretching of the non squared pixels.

Our NTSC TV actually does none of that, the pixel on the TV is already non-squared so the video actually looks correct without any stretching done. And it actually shows the video as interlaced, but our eyes are not fast enough to catch the interlaced frames unless we pause and go frame by frame.

NTSC is retarded.

[korben_dallas]

Originally Posted by mayamaniac

This is what I know of NTSC or DV standards:
Resolution is 720x480. (display aspect ratio, about 4:3 ratio)
Pixel Aspect ratio is 0.9:1 (non-squared, stretched vertically)
Frame rate is 29.97 (interlaced)

When viewing on your computer monitor, which is squared pixels, the image is slightly stretched horizontally or slightly squashed vertically. This is due to the conversion from non-squared-pixels to squared-pixels. The display aspect ratio is just a resolution format ratio, which is commonly refered to as 4:3 ratio. As for frame rate, the actual deinterlaced frame rate is 23.976 frames per second, but extra frames were added or "interlaced" into the video to produce the 29.97 frame rate. Why do they do that? Read about history of NTSC here.

To correct these problems for video playback on the computer software media player, the software decoders not only decode the video compression, which is usually MPEG2, but also deinterlaced the video to remove the extra frames for smooth playback, and correct the display aspect ratio to compensate for the stretching of the non squared pixels.

Our NTSC TV actually does none of that, the pixel on the TV is already non-squared so the video actually looks correct without any stretching done. And it actually shows the video as interlaced, but our eyes are not fast enough to catch the interlaced frames unless we pause and go frame by frame.

Very clear explanation, Maya. Thanks for that.

So is the decoder (PureVideo in my case) aware of the display hardware? i.e. does it know when the video is playing on a progressive CRT/FP vs. an interlaced TV? Or is that something the video card handles?

Originally Posted by mayamaniac

NTSC is retarded.

Ah, well, it worked well for half a century.. that's not too retarded. Though it certainly is way outdated now.