A poster in the DMN Vegas forum noticed a problem with the displaying aspect ratio with HDV 1080i video when using the new HDV 1080i project properties preset. I believe that the PAR of the HDV 1080i project template should be 1.000 by default. Here is my workaround explanation.
1. In project properties, when using the HDV 1080i setting, set the pixel aspect ratio to 1.000. Now the preview window will display the video at the correct aspect ratio in a 4:3 letterboxed display.
2. In project properties, use the HD 1080 setting. The display area itself will be 16:9 aspect ratio, thus maximizing preview space for video.
3. Set project properties to HDV 1080i with PAR=1.333 (default). Now you have to set each clip PAR (right click clip in timeline, select "properties" and go to "media" tab) to 1.777. This will also display a letterboxed preview as in case #1.
Be sure to remember to use the "HDV 1080i" output template when rendering your project. That will give it the proper 16:9 SAR (screen aspect ratio).
Now, the BIG question is WHY is this going on? After a few minutes of tinkering I think I have Vegas's logic worked on this one.
Since computer monitors can ONLY display square pixels, either the horizontal or vertical pixels must be remapped to display 16:9 video. In the case of video the horizontal pixels are generally remapped. The PAR is the "instruction" that tell Vegas how to scale the horizontal pixels for remapping.
Here's how Vegas is doing this, by my calculations anyway. It is remapping the horizontal pixels by dividing the CLIP PAR by the PROJECT PROPERTIES PAR to calculate the final preview window aspect ratio. Let's call this final value the scaling factor. Let's check some cases to verify this.
Let's try default first, or the problem that you are having with the Vegas HDV template. Project is 1.333 PAR and Clip is 1.333 PAR. Dividing 1.333/1.333 give 1.000 scaling factor. NO remapping occurs so the 1440x1080 video stream displays (incorrectly) at an aspect ratio of 1440/1080, which is 4/3. Remember pixels in the preview window are always square.
Now let's look at case #1. Project properties PAR=1.000 and Clip PAR=1.333. Divinding Clip PAR/Project PAR, gives 1.333/1.000=1.333 scaling factor. This instructs Vegas to remap the horizontal pixels of the preview window by a factor of 1.333. So if for example you are displaying at full resolution, 1440x1.333=1920 and the video is displayed 1920x1080, which using square pixels is 16:9 SAR. This scaling or remapping occurs for all preview window sizes on the fly of course (and it also happens in playback software such as WMP or WinDVD).
How about setting the Project PAR to 1.333 and the Clip PAR to 1.000? this will give 1.000/1.333=3/4 scaling factor or a really squashed preview window! It will further REDUCE horizontal pixels making the situation worse.
How about leaving the HDV template PAR at 1.333 and "fixing" the clip PAR? Well, in order to get the correct 1.333 final scaling factor we'll need to set the clip PAR to 1.777 since 1.777/1.333=1.333 or the correct scaling factor.
Finally, when you set the Project Properties to HD 1080, the "expected" resolution of the media is 1920x1080, using square pixels. Since the resolution of the display (1920x1080 or some multiple) matches the media (after scaling, remember the HDV clips have PAR 1.333 set in their header) the preview windows will display the clips WITHOUT LETTERBOXING.
In the above cases where we were working with 1440x1080 resolution in the project properties Vegas added letterboxing since the unscaled resolution is actually 4:3, it basically "rescales" the video to fit the preview window dimensions.
Another way to look at it is to realize that Vegas will generate preview window aspect ratio based on the resolution in the Project Properties AND THEN use a horizontal scaling factor computed by dividing the Clip PAR by the Project Properties PAR (Clip PAR/Project Properties PAR).
Understanding these types of concepts in general ways can be a powerful tool for avoiding hang-ups in your workflow, it takes the guessing out of setting things up as you want them. For more information like this have a look at the book I co-authored with Spot, "HDV: What You Need To Know" over at the VASST Site.
I hope this helps!
Mark
1. In project properties, when using the HDV 1080i setting, set the pixel aspect ratio to 1.000. Now the preview window will display the video at the correct aspect ratio in a 4:3 letterboxed display.
2. In project properties, use the HD 1080 setting. The display area itself will be 16:9 aspect ratio, thus maximizing preview space for video.
3. Set project properties to HDV 1080i with PAR=1.333 (default). Now you have to set each clip PAR (right click clip in timeline, select "properties" and go to "media" tab) to 1.777. This will also display a letterboxed preview as in case #1.
Be sure to remember to use the "HDV 1080i" output template when rendering your project. That will give it the proper 16:9 SAR (screen aspect ratio).
Now, the BIG question is WHY is this going on? After a few minutes of tinkering I think I have Vegas's logic worked on this one.
Since computer monitors can ONLY display square pixels, either the horizontal or vertical pixels must be remapped to display 16:9 video. In the case of video the horizontal pixels are generally remapped. The PAR is the "instruction" that tell Vegas how to scale the horizontal pixels for remapping.
Here's how Vegas is doing this, by my calculations anyway. It is remapping the horizontal pixels by dividing the CLIP PAR by the PROJECT PROPERTIES PAR to calculate the final preview window aspect ratio. Let's call this final value the scaling factor. Let's check some cases to verify this.
Let's try default first, or the problem that you are having with the Vegas HDV template. Project is 1.333 PAR and Clip is 1.333 PAR. Dividing 1.333/1.333 give 1.000 scaling factor. NO remapping occurs so the 1440x1080 video stream displays (incorrectly) at an aspect ratio of 1440/1080, which is 4/3. Remember pixels in the preview window are always square.
Now let's look at case #1. Project properties PAR=1.000 and Clip PAR=1.333. Divinding Clip PAR/Project PAR, gives 1.333/1.000=1.333 scaling factor. This instructs Vegas to remap the horizontal pixels of the preview window by a factor of 1.333. So if for example you are displaying at full resolution, 1440x1.333=1920 and the video is displayed 1920x1080, which using square pixels is 16:9 SAR. This scaling or remapping occurs for all preview window sizes on the fly of course (and it also happens in playback software such as WMP or WinDVD).
How about setting the Project PAR to 1.333 and the Clip PAR to 1.000? this will give 1.000/1.333=3/4 scaling factor or a really squashed preview window! It will further REDUCE horizontal pixels making the situation worse.
How about leaving the HDV template PAR at 1.333 and "fixing" the clip PAR? Well, in order to get the correct 1.333 final scaling factor we'll need to set the clip PAR to 1.777 since 1.777/1.333=1.333 or the correct scaling factor.
Finally, when you set the Project Properties to HD 1080, the "expected" resolution of the media is 1920x1080, using square pixels. Since the resolution of the display (1920x1080 or some multiple) matches the media (after scaling, remember the HDV clips have PAR 1.333 set in their header) the preview windows will display the clips WITHOUT LETTERBOXING.
In the above cases where we were working with 1440x1080 resolution in the project properties Vegas added letterboxing since the unscaled resolution is actually 4:3, it basically "rescales" the video to fit the preview window dimensions.
Another way to look at it is to realize that Vegas will generate preview window aspect ratio based on the resolution in the Project Properties AND THEN use a horizontal scaling factor computed by dividing the Clip PAR by the Project Properties PAR (Clip PAR/Project Properties PAR).
Understanding these types of concepts in general ways can be a powerful tool for avoiding hang-ups in your workflow, it takes the guessing out of setting things up as you want them. For more information like this have a look at the book I co-authored with Spot, "HDV: What You Need To Know" over at the VASST Site.
I hope this helps!
Mark