MP4 video sent from Android does not play on iOS

A five second MP4 video clip recorded with Android’s default Camera app has a resolution of 1920x1080 and a size of 15 MB.

If this video is passed to Delta Chat, it is converted to 360x640 of size 1 MB.

So far so good.

Sent to an iPhone or iPad, it does not play. You click on ‘start’, but nothing happens.

Sent back to Delta Chat on Android, it plays perfectly.

Apparently, MP4 is not an ideal format for platform interoperability.

well, please note that ios is, in contrast to android, in early beta stage.
it is pretty probably, that things will evolve and finally work :slight_smile:

Oops, sorry, I forgot to mention, that on iOS side no Delta Chat apps are involved, just the stock email clients.

Anyway, this problem will rise again, when the iOS Delta Chat app becomes public :slightly_smiling_face:.

One more thing: If I transfer the original MP4 video to my iPad, it plays fine.

Obviously, Delta Chat’s conversion process does something strange.

(If I convert the original file to .mov with ffmpeg, the file plays well on iOS and on Android.)

Now, case closed :smile:.

Just out of curiosity:
Can you play it with VLC for iOS?

Might be (I have no VLC installed) and VLC is known for serving a variety of formats.

The file is not wrong per se, because it plays on Android and Linux.

The Linux “file” utility states for the original file

ISO Media, MP4 v2 [ISO 14496-14]

while for the converted file

ISO Media, MP4 Base Media v1 [IS0 14496-12:2003]

This “version 1” might be the problem for iOS, however, another v1 file downloaded from the Internet was playable on the iPad.

I tried to upload the file here, but only pictures are allowed and enforced.

The video was created on a Google Pixel 3a with Android 10.

partly related issue: https://github.com/deltachat/deltachat-ios/issues/117