Signal-desktop: Forwarded mp4 loses file suffix / won't play in app

[jeremymasters]

- [x] I have searched open and closed issues for duplicates

Bug description

Some videos, when forwarded from an android device to a contact B, show up with no suffx in the desktop app, despite showing up with one in the android app

Steps to reproduce

1. Receive mp4 video from User A on iOS device (2.19.3) on Android device (videos show preview and can play successfully on Android device)
2. On Android device, forward video to another contact B (videos show up fine and can play in second conversation)
3. go over to desktop app (that was running the whole time, so not asleep or nor disconnected) and try to view videos in the conversation with A. Videos work fine.
4. go to desktop app conversation with B. :frowning:

Actual result:
Videos do not show preview, cannot play, and when saved, the filename has the suffix "-" without the quotes...so something like signal-blah-blah.-
If I change the suffix to something like mpg, it works fine but loses rotation if it was in portrait and instead plays in landscape.

Expected result:
I can preview videos that were forwarded in that conversation just fine like in the initial conversation ans save them with the proper suffix with no manual intervention.

Screenshots

Platform info

Signal version:
1.1 production release

Operating System:
Win 7

Linked device version:
4.14.10

Link to debug log

https://gist.github.com/d13d7d66420ebe3e28406112e6c57cbf

[scottnonnenberg]

How was the mp4 video generated initially, before being sent by the iOS device? I want to try this scenario out myself.

[jeremymasters]

It was simply recorded via an iPhone and then sent via signal

[scottnonnenberg]

I took a look at this, and the contentType of the attachment in the forward case is video/* which we don't understand. I just submitted a PR to bulletproof ourselves against this.