aspect ratios for dummies, and file size

[dumbdumber]

Can someone please explain what the difference between DVD 4:3 and DVD 16:9.
How should I be saving my file if it is to be shown on 18" tv screens ?
Or does how I save it depend on something to do with the photographs I have in the slideshow?
Will saving it as 4:3 reduce the overall file size ? Or is there another way to reduce the file size so I can fit more onto a DVD? At the moment I can only fit just over an hour onto a 4.7gb DVD. Any help appreciated for the video editing dummy that I am.

[Trevor Andrew]

Hi

Can you tell me where you are in this big world, so I know if you are using Pal or Ntsc tv system.
I can then refer to the correct frame sizes.

First my comments refer to standard definition not high definition.

Frame size and aspect ratio, I am in the UK and use Pal, this uses 720 x 576 as its frame size.
This is the same for 4:3 or 16:9. aspects.
The pixels 720 x 576 are not square but rectangular.
For widescreen 16:9 they are stretched horizontally to fit the screen. I know it sounds strange……….
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File sizes will not change much when using 4:3 or 16:9, the file size of a video is determined by the “bit rate” ( kbps)
Video Studio defaults to using 8000kbps, this produces a file at 4.3Gb (4.7) for a 60 minute movie.

Using 6000kbps will allow for 90 minutes movie

4000kbps will allow for 120 minutes of movie, this is equivalent to VHS quality.
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Can you say what version of video studio you are using?
Tell us what are your project properties, in particular the aspect ratio, press Alt+Enter.

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Viewing my guide to widescreen may answer some of your questions
http://lata.me.uk/video_studio/16_9/16_9.htm

[Ron P.]

First, the video file size for DVDs is determined by the bit-rate only. You can have large photos, or small photos, and put the same amount of each onto a DVD, provided the same bit-rate is used for both. The bit-rate will also affect the quality of the video. Fast bit-rates are used to obtain better quality, and for fast movement. Slow bit-rates result in lesser quality, and is used for static or very slight motion in video.

Your camera takes the photos at certain frame sizes, called the resolution. Most newer cameras can take very high quality photos, and the resolution or frame sizes will be huge. However video does not use that high or large a resolution. So the program, VS in this case, must resize those photos to fit within the frame size of your project. If you're producing a standard-definition video, the maximum frame size allowed is 720 x 480 for NTSC regions, and 720 x 576 for PAL regions. High-definition videos allow up to 1920 x 1080. However that is still much smaller than most current photos. Applying zoom to your photos in VS, you should allow for twice the frame size of your project to retain as much quality as possible.

Now the Aspect Ratio is nothing more than the frame size's ratio. It involves some math to figure out what the aspect ratio is for your photos and your project. Divide the first number in the ratio by the second number, ie; 4 divided by 3, which equals 1.333. For 16:9, 16 divided by 9 equals 1.777. 16:9 is considered a wide-screen aspect ratio. The video/images will be wider than they are tall, like Landscape for photos. A 4:3 aspect ratio is used for more of a square video, however it's not a true square, as it's still slightly wider than it is tall.

So you would think that 720 x 480 is a 4:3 aspect ratio.. wrong.. 720 / 480 = 1.5. So it's really not a 4:3 ratio, and not quite a 16:9. However the same frame size can be used for either. How? It has to do with the shape of the pixels. Non-square pixels help form the 16:9 ratio for NTSC video at 720 x 480. Trevor has an excellent website with information, one explaining the aspect ratios... http://lata.me.uk/video_studio/16_9/16_9.htm

Wikipedia is always a real good place to learn about a lot of things.. http://en.wikipedia.org/wiki/Aspect_ratio_%28image%29
Here's an online Aspect Ratio Calculator... http://www.wideopendoors.net/design/asp ... lator.html

[dumbdumber]

Thanks for your answer, I'm in Greece.
I'm using Pro x4.

The project properties are:
MPEG files
NTSC drop frame
24bits, 720x480, 29.97fps
DVD NTSC 16:9
Video date rate variable (max 8000kbps)
LPCM audio

So how would I change the bit rate? And would this reduce the quality of the video?

Thanks

[skier-hughes]

Firstly, is your 18" tv screen 4.3 or 16.9?
Secondly, Greece used to use SECAM, but around 1990 they opted to go for PAL, so you should be working in PAL, not NTSC.

Where has your file come from, can you right click on it while it is on the time line and let us have it's properties.

[Ron P.]

The bitrate used by the template, uses the default bitrate of 8000kbps, which is a good bitrate for most videos. To change the bitrate for your video, (Share>Create Video File) you need to select Share>Create Video File>Custom. Then in the next dialog that opens, press the Options button and go to the Compression tab. In the Video Settings section you can change the Video Data Rate, which is the same as the bitrate. I think the default is also showing a variable data rate. I would change that to Constant for slideshows. Variable is used for video that has both fast motion and static. This is also best used when invoking the Two-Pass encoding, which takes longer to render, however allows VS to use the first pass to analyze the content of the video for the extreme differences (fast and static or slow), and then apply different bitrates/data-rates where appropriate.

Now not to further confuse you, but using a variable data-rate with video, can also help in reducing the file size, as the high data-rates are applied only to the parts of the video that have a lot of fast action, like a NASCAR race. I don't think it would have any advantage when your video is a photo slideshow.

Ok, back to the data-rate, the default being 8000kbps, you can drop this down to whatever you want it to be, I don't think I would go any lower than around 6000kbps for a photo slideshow. Lower than that and I think you will notice a difference in quality. There are bitrate calculators found online to help you figure out what bitrate to use to fit more video onto a DVD. Most of the time this is done in the DVD authoring stage, as you also need to take into account the bitrate of the audio being used. DVDs (which are Standard-Def), must meet the International DVD specifications, which allow for a Maximum combined total bitrate of around 10,000kbps or 10Mbps. Actually there's overhead needed for writing DVDs so really you should not exceed 9600kpbs. FWIW, I have a small Canon FS300 camcorder that records SD video in MPEG-2 format, at 9600kpbs, and have had problems when producing DVDs with that bitrate. I must drop it down to around 8000kbps for one of my DVD players to play it properly.

Bitrate Calculator
http://www.videohelp.com/calc.htm

[Trevor Andrew]

Hi

When you install Video Studio you are given the option to choose Pal or Ntsc, or the option to select a country, either will set the default for Video Studio to the correct type.
However this option defaults to NTSC, so if you don’t change it then the program will install using NTSC.

The only way to set the program to use Pal by default is to re-install the program.

However you can change the project properties to use Pal.
Press Alt+Enter then Edit

These are typical Pal settings

PAL (25 fps)
MPEG files
24 bits, 720 x 576, 25 fps
Upper Field First (this should match your video files field order)
(DVD-PAL), 16:9
Video data rate: Constant(6000 kbps) (this will give approx 90 minutes of video)
Audio data rate: 256 kbps
Dolby Digital Audio, 48 KHz, 2/0(L,R)
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I assume you are making a slide show using images , but are you using any video in the project?

Render your project using Share create video File -Same as project settings

[dumbdumber]

I'm sure I chose Greece when I installed, but maybe not..........

It still plays ok though, do I have to change it to PAL? Why if it still plays, are there any other advantages/disadvantages?

I work in a hotel and it will be played on the tv's in the rooms, so I'll have to check what aspect ratio they are. All I know is they are LG flat screens and were bought a few months ago.

The project is mainly a slide show but does have a couple of video clips in it.

Thanks for all your help on this, I understand slightly better now, but am now worried it won't play on the tv's if I have it as NTSC instead of PAL.........

[Trevor Andrew]

Hi

The TV’s are probably widescreen 16:9.

If the video you are using is NTSC then the Project Properties may have automatically changed to match.
Right click one of the video clips and select properties, what are they?

There is no problem in changing the project to Pal, follow my details above.
After creating the video file, start a new project-Share Create Disc – DVD
From the burner module-Add Video.

It doesn’t matter to your computer what type you are using, Pal or Ntsc works.
Some DVD players will not support both types, having said that there are more that do and will have no problems playing both types.

[Trevor Andrew]

Hi

The easiest way to check Video Studio if Pal or Ntsc installed….
Start Video Studio or select File -- New Project.
Press Alt+Enter
Do the project properties show for Pal?

[dumbdumber]

Project properties show NTSC, but I've put the DVD in both DVD players I have at home, one plays fine, the other is really jumpy and not watchable. Will have to check DVD player in hotel tomorrow, if it doesn't play I'll have to take my home DVD player to play them.

At least that's cleared something up for me, now I know it's the DVD player that matters, and not the tv......

Thanks for your help, will make sure I change all future projects to PAL, or uninstall and reinstall Videostudio.

[Ron P.]

At least that's cleared something up for me, now I know it's the DVD player that matters, and not the tv......

Not completely true... You can have a DVD player that will play either, however a TV that will not. In your case, since the TVs in the hotel are all newer, you should be alright.

FYI, the difference is due mainly to the electricity used in various countries. In the United States it is 60hz, where in UK, they use 50hz. So this is relative to how the televisions and other such appliances work. The NTSC is something that this part of the world came up with due to the different electrical current flow. It's really much more in depth, but as of late it seems that those differences are not quite as critical as they once were. Steve (sjj1805) sent me a DVD that he produced some years ago. Steve is located in England, which is PAL, I'm in the U.S.A. which is NTSC. While the DVD would play, my DVD player and TV would only show it in black and white, not color.

[skier-hughes]

Due to differences in the chrominance, luminance, black burst............................ the colour is carried in different ways. Like composite and s-video

[Trevor Andrew]

Hi

I have to say I have had no problems playing any NTSC discs on any DVD player I have owned.

I realise that playing Pal types in the US can be a problem, but don’t understand why?

I create discs to be sold worldwide and am aware to create the correct type for different countries.
So when we sell to the US we send an NTSC disc.
I would find it difficult to create a NTSC type not having the ability to play and check quality.