Why are we still using 'PAL' and 'NTSC' for video recording? - Page 1
Forum section: electronics / general

author: KedasProbe
author_rank: Frequent Contributor
timestamp: May 10, 2015, 09:23:55 am
content: I did buy a new (released 2015) DSRL camera and it can also record video up to 1080p60.When I looked in the settings I had to change it from PAL to NTSC to get 60Hz recordings instead of 50Hz.Does someone know if there is any other difference between 1080p50 and 1080p60 except for the fps?(I assume the colour space is exactly the same)It would have made more sense to me to see 1080p50 and 1080p60 in the same selection list.('1080p24' is always in the list)I keep it on 1080p60 since I don't see the point for recording at 1080p50, maybe size but then you should probably better go for 1080i50 instead.Is it just nostalgia or habit that we don't let go of these two acronyms?BTW I still have a working 32" CRT in storage (accepts PAL and NTSC), and I think the price for it is rising

author: steve30
author_rank: Frequent Contributor
timestamp: May 11, 2015, 07:59:45 am
content: I've also wondered this. I don't know for sure, but I'd guess it is just habit; because people are familiar with NTSC being 60Hz and PAL being 50Hz.Do PAL and NTSC actually require certain refresh rates? For example, is there any reason why you couldn't use NTSC colour with 50Hz video and PAL colour with 60Hz video?

author: tom66
author_rank: Super Contributor
timestamp: May 11, 2015, 08:25:02 am
content: Quote from: steve30 on May 11, 2015, 07:59:45 amSee PAL-M (60Hz PAL) for an example.As typically defined NTSC and PAL must be transmitted at the correct frame rate or the TV/decoder may not be able to interpret it correctly.

author: babysitter
author_rank: Frequent Contributor
timestamp: May 11, 2015, 08:56:59 am
content: Color is transmitted using a Subcarrier whose frequency is at the high side of the video bandwidth, and needs to have a certain ratio to the vertical sync frequency which is locked to the frame rate. The classic PAL used ~4.43 MHz which has not the right ratio for 60 Hz, NTSC uses iirc a 3.58 MHz-ish Subcarrier. At PAL-M, they use PAL color encoding with a different subcarrier frequeny that matches 60 Hz.Also, at NTSC-setting of modern equipment they might turn on something that adds a error signal that lets colors get wrong

author: SteveyG
author_rank: Unknown
timestamp: May 11, 2015, 09:19:28 am
content: Quote from: steve30 on May 11, 2015, 07:59:45 amI have a feeling my camera has shutter speeds that are a multiple of the frame rate so that you don't get banding on video, but I'm not sure.

author: george graves
author_rank: Super Contributor
timestamp: May 11, 2015, 09:25:19 am
content: Well, I could ask the same question like this. Why are uC offten powered by 3.3 volts and 5 volts? Why not 2.048 and 4.069 volts? Seems it would make Vref easier!Quote from: KedasProbe on May 10, 2015, 09:23:55 amStay as far away from interlaced video as you can. It's a PITA. I think they only reason 1080i was in the HDTV spec was that some manufactures weren't ready for 1080p at 30 FPS. (at the time of the rool out of equipment, almost every one could support 1080p at 24 FPS - so I suspect there was some bottle neck in a processing chips somewhere that people were using - just a guess)A good editing program will allow you to mix and match media on the time line, and you choose the output. Not the consumer stuff like Dave1 uses(although I haven't looked at consumer stuff in years - maybe it kinda does now), you need to work with Vegas Pro, or Premiere, or Avid - they may be others, but it makes life much easier.

author: funkyant
author_rank: Unknown
timestamp: May 11, 2015, 02:37:11 pm
content: Quote from: babysitter on May 11, 2015, 08:56:59 amThis was with analog video. Who uses that nowadays? IMO PAL and NTSC should be banished and there should be a standard. And preferably one that displays well on most PC refresh rates.

author: tom66
author_rank: Super Contributor
timestamp: May 11, 2015, 03:41:06 pm
content: PAL/NTSC is absurdly simple to implement given the vast array of ICs on the market that can work with it. Plus, it only needs one 75 ohm coax cable. Few other signalling standards can beat the simplicity of it when you just need video. (e.g. for a CCTV system.)

author: technix
author_rank: Super Contributor
timestamp: May 11, 2015, 03:42:43 pm
content: Quote from: funkyant on May 11, 2015, 02:37:11 pmNew standards are like 1080p60 or 720i50 but you still need to consider downward compatibility interfacing those dinosaurs.

author: helius
author_rank: Super Contributor
timestamp: May 11, 2015, 03:50:48 pm
content: Quote from: tom66 on May 11, 2015, 03:41:06 pmThe same way 3G-SDI only needs one 75 ohm coax cable?

author: funkyant
author_rank: Unknown
timestamp: May 11, 2015, 03:56:54 pm
content: SDI can run over coax, and people who insist on using gear off The Ark can use a converter - just like they needed a decoder in Oz when analog TV transmission was shut down.They are all low definition standards. Why do the remnants of this need to be carried on into High Definition digital standards? I don't get it.

author: m100
author_rank: Regular Contributor
timestamp: May 11, 2015, 03:58:03 pm
content: Quote from: funkyant on May 11, 2015, 02:37:11 pmNever Twice (the) Same Colour should have been banished decades ago. First time I went to the USA I was shocked that humans in the street looked just the same as in EuropeBut could I get a decent picture on the TV in my hotel room? Not a hope in hell of achieving that.

author: electr_peter
author_rank: Unknown
timestamp: May 11, 2015, 04:33:45 pm
content: Mostly legacy reasons and the fact that analog signal be advantageous in some cases.Analog TV signals are very good for low latency transmissions (RC copters and similar) because little of encoding/decoding is done.PAL/NTSC transmits "raw" data with no tricks and black magic (which are computationally expensive and adds lag), so it is very robust against interference. It makes OSD or primitive video generation easy.PAL/NTSC does not require to have your own coal plant to run very fast decoding engine (which is becoming harder each year).Personally, I am happy if video is at least BW and is focused. Digital/analog is just a technology difference which does not guarantee best quality by itself. On the contrary, digital video allows broadcasters to be cheap and transmit extra crappy compressed video signal.

author: funkyant
author_rank: Unknown
timestamp: May 11, 2015, 05:23:02 pm
content: Quote from: electr_peter on May 11, 2015, 04:33:45 pmYou are correct on all points there (especially the last point), but why does a purely digital HD signal, still need to be designated as PAL or NTSC?

author: tom66
author_rank: Super Contributor
timestamp: May 11, 2015, 05:45:47 pm
content: Quote from: helius on May 11, 2015, 03:50:48 pmI did say "few", not none. SDI is probably the only one I could think of. Are there any others? HDBaseT needs 8 pairs, HDMI needs 21 pins, etc...

author: i4004
author_rank: Regular Contributor
timestamp: May 11, 2015, 05:49:38 pm
content: Quote from: funkyant on May 11, 2015, 05:23:02 pmwell, it doesn't need to be designated, as said this is used for historical reasons.analog and digital formats don't have that much in common. digital sd formats have numbers of scanlines and fps so that analog fits in nicely, but hd digital formats...no, there are no real simillarities, be it luma or chroma encoding.kedasprobeQuoteit's easier for the customer to differentiate what he needs as a format for his living room if you give him "pal" and "ntsc".ieit wasin the days you only had dvds and crt tvs that may or may not support pal60,etc.today it's kinda moot as most new tvs support anything digital.if you have the right codec and container.electr_peterQuotei always saw BW as an abomination and totally inhuman experience.crappy compression part, i agree. just look at the many yt videos and sometimes even broadcasts of that overcompressed modern codec crap.essentially good analog pal transmission beats mpeg2)and newer codecs), but the fact is that it was never that easy to get perfect analog reception.teh fact is also that most people wouldn't be able to see that difference. and one more fact: hd beats analog pal's sd.(offcourse, unless you upload that hd to yt..then all bets are off)

author: rolycat
author_rank: Super Contributor
timestamp: May 11, 2015, 06:50:46 pm
content: Quote from: tom66 on May 11, 2015, 05:45:47 pmAnd consumers are not allowed to use SDI - it hasn't been fettered with encrypted DRM bullshit.

author: hamster_nz
author_rank: Super Contributor
timestamp: May 11, 2015, 09:18:04 pm
content: Quote from: rolycat on May 11, 2015, 06:50:46 pmAnd most consumers couldn't make SDI work anyway - it is a purely one way system, so can't query the display/sink and then auto-configure...

author: ivan747
author_rank: Super Contributor
timestamp: May 13, 2015, 03:46:05 am
content: Quote from: i4004 on May 11, 2015, 05:49:38 pmI have heard many many audio people (partially) saying vinyl records and analog media are better than digital but it's the first time I hear someone (partially) saying that analog TV is better than digital TV.

author: SeanB
author_rank: Super Contributor
timestamp: May 13, 2015, 04:46:27 am
content: Good analogue video, mostly either studio shots, or direct from a film scanner, is very good quality. Even a first generation copy using a broadcast quality video recorder will introduce very little degradation ( mostly noise) in it. The digital signal however has had lossy compression done on it to get the bandwidth down to something that will fit in 8MHz of spectrum, often with other streams, so the loss is severe. Thus there is often visible degradation, so it is going to show visible macroblocks, and will also break into bigger blocks with fast motion.Easiest thing is to look at the analogue recording of something like an award ceremony, where there are a lot of camera's with flash, which make a single white frame in the video. Analogue is unaffected by this, while the digital signal will have significant errors before ( strange, but that is an artefact of bidirectional coding) and a long recovery time afterwards with often having moving white blocks on screen. If the data rate has been lowered by the encoder ( other data streams with it and the data rate is getting to the limits) this can break the data stream totally for a few seconds. As well fast motion ( in car camera on a GP race) will show up the grass as basically a static green block, as it cannot do the fast moving areas properly.

author: helius
author_rank: Super Contributor
timestamp: May 13, 2015, 05:48:27 am
content: When digital video equipment first became available in the early '90s, the difference with analog was stunning.Digital displays revealed noise and optical defects that were blurred away by the limited bandwidth of analog video.This uncompressed digital signal requires very high bandwidth, though; 270 MHz for standard definition and 3 GHz for HD, from 45x to 500x the bandwidth of analog broadcast video. So this superior digital video is never actually sent over the air or cable plant; only an inferior compressed signal is used.

author: miguelvp
author_rank: Super Contributor
timestamp: May 13, 2015, 06:18:24 am
content: I remember around 15 years ago when I got Dish Network I was less than impressed with the quality.The problem I noticed was a severe color banding in some smooth color gradients like if they were using a 16 bit DACs for all three color channels, like 5 bits for red and blue and 6 bits for green.But I'm sure now they probably are better, not sure because I just don't watch TV anymore, but when I watch movies via Hulu, Amazon or Netflix on the TV I don't see that banding anymore but maybe it is because I don't pay attention that much.The banding as I recall was more noticeable on scenes that had smoke or fog, or any primary color ramps like from dark red to bright red over a large section of the scene. Of course DVDs and Blue Ray Discs didn't have those artifacts but they are not going to transmit all that data over the air/satellite.But I would assume that by now, they probably have at least the equivalent of 8 bits per color at full 1080p. I recall as well when I switched to FIOS about 10 years ago I was still seeing that banding.On my last move, in 2009, I dropped cable all together so I have no idea how digital TV looks like, funny thing is that my current internet provider demands local channels cable so I do have it, but we don't watch it at all, not even sure if that even works or how it looks, I guess I could try to check it out just to see if the quality has improved and as far as I'm aware I never did watch over the air digital TV since they made the move, then again I haven't watched over the air analog TV either for a long long time.

author: dexters_lab
author_rank: Unknown
timestamp: May 13, 2015, 08:03:19 am
content: Quote from: KedasProbe on May 10, 2015, 09:23:55 amyea it's annoying... there is settings in the GoPro Hero cameras for PAL/NTSC too and all it really does is change what frame rates you can pick in the menus

author: ivan747
author_rank: Super Contributor
timestamp: May 13, 2015, 01:58:00 pm
content: Quote from: helius on May 13, 2015, 05:48:27 amThen why did we switch to digital TV when we could have just revised NTSC and PAL to become high definition analog?

author: technix
author_rank: Super Contributor
timestamp: May 13, 2015, 03:52:54 pm
content: Quote from: ivan747 on May 13, 2015, 01:58:00 pmTo transmit high definition analog down radio spectrum requires a lot of bandwidth - we are essentially transmitting unencoded uncompressed video feed here - and ITU cannot allocate any and there are a lot of new applications of the radio spectrum.Transmitting it digitally allow us to not only reduce the amount of information transmitted (since compression can be used, the crappy compression is a brain burp in standardizing bodies, there is nothing preventing us from transmitting lossless H264 or ProRes 4:4:4) but also multiplex different streams (or "channels") into one transmission stream. This allow every "channel" to effectively consume way less radio spectrum bandwidth than analog SD (let alone HD)

author: funkyant
author_rank: Unknown
timestamp: May 13, 2015, 04:00:16 pm
content: I can't say I'm sold on this line of reasoning. Digital has error correction built in and has superior transmission capabilities with regards to RF noise rejection.One reason why digital terrestrial transmission is not always as good as it could be, is that each broadcaster wants to cram as much content into their allocated bandwidth as possible, and they are forever "optimizing" their codecs. If they just broadcast one HD channel they might actually come close to real HD.But we digress very far from the original discussion of, 'Why is PAL and NTSC still relevant to HD digital video"?

author: m100
author_rank: Regular Contributor
timestamp: May 13, 2015, 06:17:54 pm
content: Quote from: ivan747 on May 13, 2015, 01:58:00 pmThere are significant power savings at the transmitter end by switching to digital and the ability to fit far more channels in the same bandwidth.For instance one UK transmitter region transmitted at 870kW on analogue. It is just 174kW for DVB-T for the same effective service area.There were five TV channels each at 870kW, and there are about 80 TV channels and thirty radio channels across six 174kW multiplexes each occupying the same 8MHz slot as the analogue channels, In addition to these six SD multiplexes using DVB-T, two multiplexes using DVB-T2 have capacity for five HDTV channels per multiplexSo that is just five analogue channels using 40MHz of spectrum, or 80 SD TV, 30 Radio and 10 HDTV channels using 64MHz of spectrum.I'd hazard a guess that the Euro version of DVB-T and DVB-T2, the former in use for nearly 17 years now in the UK could have been used worldwide...except it wasn't invented by the Americans.