Media Encoder is changing my dimension by a pixel

[skywalkr92]

Hello! I am trying to export a FbAd (1200x625 dimension) from after effects. I have done this before and not changed any of my settings, so the problem is baffling me! Well I have setup my composition with these settings. 

However, when I export it to Media Encoder it changes the dimensions to these. As you can see the source is reading the document correctly but the output is being changed.

Match Source does not seem to want to work and when I try to manually change the dimensions it will adjust to 1200x626 but not what I am looking for 1200x625.

Thank you for your help all!

-Alex

[Szalam]

H.264 can't render to an odd pixel number. It has to be even.

[Rick Gerard]

You have a misunderstanding of video compression. If you want a compressed file, especially an intraframe (MPEG H.264) for distribution and you are going to play that file with a media player the frame size must be an even number of pixels and better yet, evenly divisible by 4. Odd numbers are not allowed because the compression software works on groups of pixels that contain at least 4 pixels. There is no workaround except to render to a lossless format that does not care what the frame size is.

You also don't want to send odd pixel sized artwork to the web because there is a very high likelihood that the image will soften more than an even-numbered pixel image will when it is scaled with a style sheet. You cannot center an image on a web page and have the pixels line up if it is an odd number of pixels high or wide. The entire image will be resampled and the quality will degrade.

So there is no fix for that frame size. In almost every case you are much better off designing your projects for standard frame sizes. The only notable exception is digital signage displays that have odd sizes and use custom players. Every standard media player will default to one of the standard aspect ratios. There is no way to force them to display anything else. None of them respond well to a frame size that has an odd number of lines or rows.

[Starbreaker]

@Rick Gerard I am working on a digital sign and the pixel dimensions it needs is 775x160. Is there a way to deliver an mp4 at these dimensions? Thanks you for your help. 

[Rick Gerard]

You have to make the comp an even number of pixels if you are using compression. MP4 is just a container. What codec are using. H.264 is a MPEG format. All MPEG files must be an even number of pixels. 

[Shuhai22071843pqvn]

Hi Rick,

I want to know if there are any spec can explaination "(MPEG H.264) for distribution and you are going to play that file with a media player the frame size must be an even number of pixels and better yet, evenly divisible by 4"?

I am fixing some bugs in the open source project that are caused by the odd width or height of the H264 frame. I try to find something in H264 specification in link[1], but I don't find anything helpful. Could you provide a strong reference specification for me?

[1]https://www.itu.int/rec/T-REC-H.264 

Thanks,

Shuhai