FFMPEG (libx264) "height not divisible by 2"

I am trying to encode a .mp4 video from a set of frames using FFMPEG using the libx264 codec.

This is the command I am running:

/usr/local/bin/ffmpeg -r 24 -i frame_%05d.jpg -vcodec libx264 -y -an video.mp4

I sometimes get the following error:

[libx264 @ 0xa3b85a0] height not divisible by 2 (520x369)

After searching around a bit it seems that the issue has something to do with the scaling algorithm and can be fixed by adding a -vf argument.

However, in my case I don't want to do any scaling. Ideally, I want to keep the dimensions exactly the same as the frames. Any advice? Is there some sort of aspect ratio that h264 enforces?

The answer to the original question should not scale the video but instead fix the height not divisible by 2 error. This can be achieve using this filter:

-vf "pad=ceil(iw/2)*2:ceil(ih/2)*2"

Full command:

ffmpeg -i frame_%05d.jpg -vcodec libx264 \
 -vf "pad=ceil(iw/2)*2:ceil(ih/2)*2" -r 24 \
 -y -an video.mp4 

Basically, .h264 needs even dimensions so this filter will:

1. Divide the original height and width by 2
2. Round it up to the nearest pixel
3. Multiply it by 2 again, thus making it an even number
4. Add black padding pixels up to this number

You can change the color of the padding by adding filter parameter :color=white. See the documentation of pad.