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Old 04-10-2012, 22:26
Sideburns57
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We seem to have 2 options for Scart Video Output: RGB or PAL. What is the best and wht is the difference?! Just curious.....
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Old 04-10-2012, 23:15
Andy2
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RGB is by far the best quality, but you can only use it with other equipment that is compatible. Almost all TVs etc will work with PAL, but the quality is much worse and it can look really ugly on an HD TV.
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Old 04-10-2012, 23:39
Sideburns57
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Thank you, Andy2.
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Old 05-10-2012, 00:09
chrisjr
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The image you see on the TV screen is made up of only three colours, Red, Green and Blue (no guesses for what RGB stands for ).

RGB video uses three connections, one for each colour, whereas PAL or as it is also known, Composite, uses just a single connection. So PAL/Composite has to encode the colour components into a single signal that the TV has to decode back to the three colour signals.

However the process is not perfect so if you take a RGB source, encode it to Composite, then decode back to RGB, the result is not an exact copy of the original. Therefore if you want to preserve the quality of the source it is better to use RGB.

There is also a third option found on some kit, S-Video. This uses two connections, again using an encoding scheme to create these two signals from the RGB source. It is often better than Composite but again not quite as good as RGB.
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Old 05-10-2012, 11:22
stanandjan
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Hence an issue that has bothered me for years and yet tests I have made have not been conclusive..
When recording the signal in RGB on DVD or Hard drive.. what is the Quality of Recording that is just more than enough..
I have XQ SP LP and EP..Equally as important got me is.. where in that spectrum of 4 does Composite then fit please.and Vid S for that matter..
I have tried ..over the years..but the variation of content and eye tireness and brain retention makes it hard to be definitive..
I have settled as a cautious old dodderer for the SP mode of quality as that gives me 2 hours on a DVD but i often feel that I am over providing on qualty for me as..These are SD Wildlife recordings in Composite for when i then store on the PC for a 2Meg wmv for Club showings on projector..
I now think that ..Possibly the 1.5 or 1 Meg quality wmv would be more than enough on the PC anyway.. I'm baffled..
Many thanks

Stan
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Old 05-10-2012, 11:45
grahamlthompson
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RGB is the best source, The recording modes aren't really connected except of course the best source deserves the best quality. The different recording modes simply use differing bitrates with the highest quality using the highest bitrate, and as a result produces larger files.
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Old 05-10-2012, 11:50
chrisjr
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RGB, Composite and S-Video are entirely different animals to the recording formats. They are in no way related. Except in so far as the quality of the source determines the quality of the recording.

The digital data that gets recorded onto the disk is essentially RGB it does not change with the format of the video signal you feed into it. Raw digitised video takes up a lot of data capacity so DVD, Blu-Ray and broadcast TV use data compression schemes to reduce the amount of data required.

It is the amount of data compression that varies when you select the recording mode. So in EP mode far higher compression is being applied than in SP so that the same amount of data capacity can accommodate a greater duration of video material.

If you want the best quality possible then select RGB video as your source and the recording option with the shortest maximum recording time. The lower the maximum recording time the higher the quality the recorded signal will be.

Conversion to a different format will lose a little bit of the quality. All the common data compression schemes in use are lossy, ie they throw away bits of the original raw data and once gone it can never be retrieved. If you then convert to another lossy format you just reduce the quality a little bit more. There is actually no real point converting a recording made in EP to SP as you will never get the same quality as if you had recorded directly to SP in the first place.

If you are recording onto a DVD recorder then copying to PC to convert to WMV format your best option is to put the disk in the DVD drive on the PC and rip the video file(s) to the PC and convert them directly. Playing the disk from the DVD recorder into a video capture card attached to the PC will lose a bit of quality. Plus ripping the files from the disk is a lot quicker than copying in real time!

In all this if quality matters then record using the highest quality source available using the highest quality recording option. You can always make the recording "worse" if you need a smaller file size. But you cannot put back quality that wasn't there in the original.
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Old 05-10-2012, 13:34
Sideburns57
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The image you see on the TV screen is made up of only three colours, Red, Green and Blue (no guesses for what RGB stands for ).

RGB video uses three connections, one for each colour, whereas PAL or as it is also known, Composite, uses just a single connection. So PAL/Composite has to encode the colour components into a single signal that the TV has to decode back to the three colour signals.

However the process is not perfect so if you take a RGB source, encode it to Composite, then decode back to RGB, the result is not an exact copy of the original. Therefore if you want to preserve the quality of the source it is better to use RGB.

There is also a third option found on some kit, S-Video. This uses two connections, again using an encoding scheme to create these two signals from the RGB source. It is often better than Composite but again not quite as good as RGB.
Yes, I did know what RGB stood for - I know little else though (as my posts confirm!). Thanks for your advice.
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Old 06-10-2012, 20:25
stanandjan
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The lucid explanations have aided me greatly in my understanding..Thank you all.

Stan
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Old 08-10-2012, 20:12
stanandjan
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I am now one stage further on and a final option baffles me..
When i have trimmed some progs in MM on an Xp machine.. i get the option to save to PC and i have tried wmvs at "2.1 Megs" and also "Hi Quality for PC"..
The latter produces files often only a few Megs different to the "2.1M" quality but says they are 4Megs or thereabouts.
.MY videos usually involve only centrally placed actions of animals with the rst of the scenery quite still..
Is there a way I can decide to save at 2.1 or the HP option please.. to enable me to optimise the quality of the videos..for eventual projection?
On the PC they both seem much of a muchness..

Stan
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