Comment by cogman10 | Hacker News Reader

Comment by cogman10 | Hacker News Reader

Parent Full thread

From what I've read, Netflix has been investing quite a bit towards automatically detecting these sorts of issues and rejecting video that's been poorly handled by the studios. AFAIK, they reject interlaced content.

From a compression standpoint, netflix wants everything to be progressive. Interlaced media (funnily) requires a lot more bandwidth to transmit with modern codecs. I say funnily because interlacing was a technique to save bandwidth for analog transmissions. It gives the illusion of a higher framerate. Unfortunately, modern video codecs work by tracking object movement from one frame to the next. Interlacing really messes that up requiring more bits spent for the same amount of quality.

Some of the older codecs have interlacing built into the standard (mpeg2 and h264). Newer ones have banned it all together (VP9, AV1) due to the codec complexity it introduces for very little benefit.

https://netflixtechblog.com/high-quality-video-encoding-at-s...

> It gives the illusion of a higher framerate.

I mean, it doesn't really give the illusion of it. It is higher frame rate when recorded from a camera[1], as most TV was. The fields are independent moments in time (and you can very clearly see this in freeze-frames of interlaced motion, that's part of what combing is).

What it gives the illusion of is greater vertical resolution.

[1] video game systems that used interlacing, like the n64, playstation, and up until the hdmi era, did not usually do this afaik, opting to instead drop the frame rate to 30fps with 2 fields per frame, so they really were in many ways the worst of all worlds.

> up until the HDMI era

I think that's wrong: didn't PS2-era consoles use interlacing to get higher resolution? You're definitely right for PS1 and earlier though.

I think what parent is saying is that camera-captured interlaced video was displaying scanlines from different images in each field, whereas game consoles using interlacing displayed the even/odd lines of the same image in two fields.

Thus parent's argument is that we can consider camera-captured interlaced video to be 60 (or 50 for PAL) fps despite being interlaced, but games using interlacing were 30 fps. It makes sense to me.

It was a choice of the game. There were definitely truly 60FPS interlaced games during the PS2 generation.

> video game systems that used interlacing, like the n64, playstation, and up until the hdmi era, did not usually do this afaik, opting to instead drop the frame rate to 30fps with 2 fields per frame, so they really were in many ways the worst of all worlds.

480i Nintendo consoles (N64, GCN, WII) all had many 60FPS games. The 30FPS limit was almost always because of the relatively underpowered hardware. Some N64 games even ran at 20FPS!

I wouldn't call the Wii a 480i console; it can run in 480p, 480i, or 240p, depending on system settings and the game itself (I don't think 240p is used much outside of a hidden mode in virtual console, but I could be wrong). I think the gamecube can too, but it requires the digital out port, and I think that was rarely used. N64 is 480i or 240p depending on the game.

Reply on news.ycombinator.com