align.padding_bottom should plus two to make height as 2 aligned.

Submitted by Jian Li

Link to original bug (#726678)

Description

I found in gst_ffmpegviddec_decide_allocation(), align.padding_bottom is added 1 extra pixel padding to match libav buffer allocation sizes, this will make the padding_bottom to odd number. But when calculate each planes offset in fill_planes(), it will GST_ROUND_UP_2 (height) for I420 format.

This makes the calculated height by height + align.padding_top + align.padding_bottom not match with the plane offset.

It will cause problem for showing video with v4l2 output, as the height is not match with the real video height, cause v4l2 calculate u/v offset incorrect, then cause video color is wrong.

So shall align.padding_bottom add 2 extra pixel to make the height an even number?

Patch is attached.

Version: 1.2.3