i captured video of new app running on iphone 6 using quicktime player , lightning cable. afterwards created app preview project in imovie, exported , upload itunes connect.
apple requires developers upload app previews in different resolutions dependent on screen size, namely:
- iphone 5(s): 1080 x 1920 or 640 x 1136
- iphone 6: 750 x 1334 (what have)
- iphone 6+: 1080 x 1920
obviously, 1080 x 1920 killing 2 birds 1 stone. know upscaling isn't perfect solution, it's meeting needs. since don't own 6+, recording session won't trick.
unfortunately, itunes connect extremely picky accept. here's tried, no avail:
- handbrake, imovie, quicktime not support upscaling
- mpeg streamclip
ffmpeg -i input.mp4 -acodec copy -vf scale=1080:1920 output.mp4
strangely enough, itunes connect keeps complaining wrong resolution when try upload output.mp4 of ffmpeg.
finally, ffmpeg -i input.mp4 -acodec copy -crf 12 -vf scale=1080:1920,setsar=1:1 output.mp4 did trick!
turns out ffmpeg tries smart aspect ratio, actual size 1079x1920 aspect ratio of 2000:2001.
setsar=1:1forces aspect ratio of 1:1 , hence, right resolution-crf 12desired quality results in same file size original file created imovie, should safe bet bit rate-wise
