Camtasia renders at wrong size?

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  • Updated 7 years ago
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I'm working with Camtasia Studio 7.1.1 (Build 1785).

Using Camtasia, I captured a short screen cast with dimensions 853 (w) x 480 (h).
After importing the .camrec file in Camtasia studio I use "recording dimensions" everywhere.
Then I produce the file:
- Custom production settings
- MP4 / FLV / SWF
- No Controls / MP4 / 853x480 (Editing dimensions)
- the rest all default settings

After production is complete, the Production Results dialog tells me :
- Video Dimensions : 853 x 480
- Total Dimensions : 853 x 480

When placing the movie on our website, a black vertical line appears at the right of the video (video is mainly white and the web page background too). Closer inspection reveals that the MP4 file that was created is not 853 pixels wide but 854 pixels wide. Height is ok at 480 pixels.

The black line is two pixels wide, I assume one pixel is caused by the fact that the video is one pixel too wide. There appears no horizontal offset to the left, it seems that the right most column of pixels of the original is turned black, when I compare to the original.

I verified the dimensions of the avi in the camrec file: 853 x 480.

What is causing the output dimensions to go wrong and the black line to appear in the video and how can I avoid it?

Thanks in advance,

Erik
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ErikT

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Posted 7 years ago

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Dave O'Rourke, Senior Software Engineer

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Erik,

This is a known issue that stems from a limitation of the encoder SDK we're using for the MP4 output. Unfortunately, the SDK we use does not handle odd dimensions, and will always add an extra pixel to the width or height if an odd production width or height is used. This results in an MP4 with a 1 pixel black line on the right or bottom of the video, which is not wanted.

For now, the only workaround is to always use an even width and height when you specify your dimensions.

Sorry for the trouble.
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ErikT

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Thank you David, for your explanation.

If this is a known issue, then why does Camtasia not give a warning for this, when the movie is produced:

if ( height = odd) or (width = odd) then DisplayWarning.

I only noticed this issue when my movie was placed on a web page, with a white background. All movie players I have access too, use a black background, so an extra black line is not really noticed.

Since I did not want to remake my whole movie (including capturing), I looked for work-arounds to overcome this issue.

While doing that I noticed that it appears not to be an odd/even issue, but that dimensions need to be multiples of 4.

For my project, I changed the editing size from 853 x 480 to 856 x 480 (had to uncheck "keep aspect ratio"). The original movie is not resized but centered in the editing area, causing lines at both sides. Callouts had to be moved 1 pixel to the right.
When producing the new movie, I had the production dimension set to 856 x 480 and in the "Flash Options", I have set the background color to "white". Now, the produced MP4 movie is 856 x 480 pixels large and has a white line at each side, which is not noticed on a white background, so for this project, my issue is solved.

I will keep this in mind when capturing new movies.

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