Editing in SE then exporting to Mac - Pixel ratio difference

edmellnik

Toasting since 1990
I just finished editing a SD piece in Speededit on my Tricaster 860.
Exporting to my Mac I see the file still shows 720 x 480 but the people look thinner.

Could this have something to do with Mac showing video as SQuare pixels and windows machines .9?

Ed
 

Shabazzy

LightWave Fan Boi
Hi Ed,

By the sounds of it, the video was shot in SD 16:9 and as you're probably aware, an SD 720 x 480 NTSC resolution video is of a 4:3 resolution. Video shot in the SD 16:9 (or 4:3) screen aspect ratio means that the pixel ratio is not a square 1:1 ratio. Video shot in this resolution was really intended for TV broadcasts and not computer screens which do use a 1:1 pixel ratio.

You have two options to display video shot in this non square pixel aspect ratio onto computer screens:

Option 1: It's all in the video player

Some software based video players have a setting to convert the video into a computer friendly pixel aspect. Speaking from my own experience, I use a Windows PC running a video player called VLC, this has an option in the 'View' menu for changing the video's aspect ratio (View>Aspect Ratio). This is a fine solution so long as everyone who plays your video uses the same playback software or has the same capability.

Option 2: It's all in the editor

The alternative is to ensure that the video plays back in the correct 16:9 aspect ratio (for playback on computer screens either locally or online and not through a DVD player/broadcast or similar) regardless of software based video player used. It is therefore important to set up your SE project resolution correctly in the first instance.

The process

Before beginning a new project, open your old finished edit and select everything on the timeline. Click copy or cut to place the edit in the clipboard.

Start a new SE project and you should get a window appear that allows you to 'open a recent project' on the left or 'start a new project' on the right.

At the bottom of the list on the right is an option named 'Custom...' click it and a project settings window will appear. From here do the following:

  1. Choose your desired resolution from the 'Preset Name' drop down list (in this case NTSC 480i 16:9)
  2. Select the 'Aspect Ratio' dropdown list and choose 'Ignore Aspect Ratio (assume square pixels)'
  3. Click the 'Progressive' radio dial
  4. Click 'OK'

The window will disappear and you can begin editing. Make sure the Timebar is at the start of the project and click the 'Paste' button located at the top of the editor. Your finalised edit should appear on the timeline.

Save your project with a new name.

Go to render and select your chosen 'Format' and then click the 'Customize' button. A new window will open up allowing you to tweak the render settings. All you are interested in here is the 'Use Project Settings' check box. Make sure it's ticked.

Click 'OK'

Then in the 'Render' window click the 'Render' button to render out your project.

When the render is done, you'll see that the rendered video will have black bars at the top and the bottom of the video but the SD video will look correct in any computer based video playback software. They will all be reproducing an SD 4:3 TV screen in their respective video playback window.

Again, this is assuming that the video was shot in SD 16:9.

Let us know if this solution helped and how you got on.

Shabazzy
 

edmellnik

Toasting since 1990
Thanks for your time... but no it is a 4 x 3 SD project with sd video.
I was talking about the difference between Mac square pixels and windows .9 rectangular pixels.
But thanks anyway.
Ed
 

SBowie

'the write stuff'
Staff member
I was talking about the difference between Mac square pixels and windows .9 rectangular pixels.
Square pixels are square pixels, wherever they are found, and that's as true in Microsoft Windows as elsewhere (such as in OS X). The software in use either 'knows' about non-square pixels and displays them correctly, or it doesn't; or, alternatively, it may be capable of conforming its display to different aspect ratios, but has to be manually configured to do so. So, for example, the display windows in apps in the 'TV Paint' family typically allow you to selectively display an image at 1:1 (square) or using the project's pixel aspect ratio.

Some file formats retain the image aspect ratio (which is not quite the same thing as pixel aspect, as you doubtless know) in the file header, others do not. Either way, some apps pay attention to the aspect information when available, others do not, or may or may not provide for a little manual intervention. Some software assumes that SD resolution files (e.g., 720x480 or 720x486) are 4:3, and adjust PAR to match, while treating everything else as square pixel. Some also respect the SD 16:9 flag, which may or may not be included in the file. There are a lot of variations, depending on the specific software.

To answer your question with any more certainty, we'd need to know what application you are using to view the file on the Mac, Ed; and it might be helpful to know what file format you exported from SE.
 

Shabazzy

LightWave Fan Boi
Following on, the .9 pixel aspect that you thought relates to windows machines actually relates to NTSC video which stores this information within the video file itself.

The machine/device/software app that plays back this NTSC video file needs to conform it's output display to the information stored in it. How this is done it explained in option 1 of my first response and in Steve's explaination.
 
Top Bottom