Application crashes when uploading/downloading big files

[abugandar]

Description

When uploading video files above 500MB the application becomes white and freezes. After restart of the app it works but I am unable to upload a big video file. This happens only when dragging and dropping the video file.

Steps to reproduce

• Open the app and start a chat
• drag a video file more than 500 MB (I tried about 750MB)

I upload smaller videos 130 MB in size, it uploads, shows a player and I can play my uploaded file. I expected the same with a big video file. But it crashes.

Log: not sent

Version information

• Platform: desktop

For the desktop app:

• OS: Windows 8.1 32 bit
• Version: 0.10.2

[MTRNord]

What is the output in the console?

[turt2live]

@MTRNord

Edit: Slightly more information

Steps I used:

• Find a suitably large video (1.1gb mp4/h264 in my case)
• Drag it onto a room
• Note that the upload bar freezes at 0B/0B for a while
• Crash screen as shown above after several seconds

[abugandar]

This issue must be fixed

[t3chguy]

@abugandar all issues must be fixed :)

[lampholder]

It might be simpler to whack a max filesize on the UX for starters, though this might be a relatively easy fix to stream upload the file rather than store the whole thing in memory first.

[turt2live]

I'm starting to see this happen on files as little as 100mb. Granted, my riot tab is also a few GB in size.

[Half-Shot]

Basically this is a huge no-no and we should be streaming the file but I guess it's easier to be lazy and do it this way.

[Half-Shot]

Did a little digging tonight when I couldn't upload a file. We would be better off not thumbnailing until after we have uploaded the file, because we block waiting for the video element to become ready before we upload.

EDIT: Seems to crash way before the upload stage, at https://github.com/matrix-org/matrix-react-sdk/blob/master/src/ContentMessages.js#L166

EDIT 2:

Okay so what I think is the problem, and I feel kinda dim for not spotting this sooner is that we create DataURLs for files when we thumbnail them. Now picture that with 100MB, and then a GB. Yeah? Oh dear.

Right, so the easy solution is to do something like URL.createObjectURL(videoFile); and then just be sensible to delete it after use. This creates a blob link rather than a base64 string and means the thumbnailer will appear near instantly and will not try to stream the entire contents of the file into a base 64 string.

[turt2live]

this also applies to download

[SethFalco]

Just want to forward some of my findings and be explicit here that in impacts uploading profile pictures too.

Tested on Ubuntu 18.04, Riot 1.5.3.

• Setting the profile picture to a 3.8 GB MKV file causes a crash.
• Setting the profile picture to a 1.2 GB image file stalls the application. It eventually recovers, but the profile picture does not appear.

For large image files I would expect either a clear file size limit such as 1024 KB or 8 MB, and for the application to not stop responding during the uploading of the image.

---

Later I can confirm the behavior with the latest version of Element, for now, I just ported the information from my previous bug report.

[Yannick7777]

bump as I still get problems uploading files >=1.6GB with the same symptoms as #21094.
This problem only occurs in encrypted rooms..
File uploads fail instantly and return follow generic error: The file 'test' failed to upload.
It seems like only files are affected with a size of exactly 1.6GB or more.
fallocate -l 1.599999G test creates a file which is still able to be uploaded without any problems. A file created with fallocate -l 1.6G test fails instantly tho.

Tested with version 1.11.86 on Linux and Docker