Alpha channeled transparent video from sdcard

Is there a way to be playback video with alpha channel from sd card on Android? I know if the video is part of the unity project and transcode is clicked, it works. What does this transcode do, how could I replicate it?

 

Transcoding means unpacking the video to a raw format and encoding it again with a diffrent codec and/or settings. Imported videos should allow use of transparency: https://docs.unity3d.com/Manual/VideoTransparency.html

For playback you'll probably want the VideoPlayer class: https://docs.unity3d.com/ScriptReference/Video.VideoPlayer.html

 

Yes I can play the transcoded transparent videos with no problem (if the are added to unity first). But I want to support alpha channel on videos, that were not added to the unity project initially (downloaded later for example). Can I somehow manually run the transcode method on a video that is not part of unity?

 

ffmpeg through command line.

 

I have tried ffmpeg, with the options described here: https://forum.unity.com/threads/settings-for-importing-a-video-with-an-alpha-channel.457657/
ffmpeg -i my_clip_with_alpha.xyz -vcodec vp8 -pix_fmt yuva420p -metadata:s:v:0 alpha_mode="1" my_vp8_clip_with_alpha.webm

But when I tried to play it back on Android, there was no transparency.

 

What are you using to play it?

 

https://docs.unity3d.com/Manual/VideoTransparency.html
"One notable exception is Android. This platform’s native VP8 support does not include transparency support, which means transcoding must be enabled so Unity uses its internal alpha representation."

 

I am using android, but I want to playback videos that are not initially part of the unity project, but downloaded later.

 

Enable transcoding, then.

 

But the problem is that I want to play a video that is not part of the project ( videos downloaded later on). Clicking transform on them in not an option.

 

Is it still not possible to play transparent video on Android on fly? I mean without importing video in project before build. Just by downloading in app from some URL, etc.
The only solution I've found so far is to prepare a special version of video before using it. For example, make video frame with double width and render mask beside video picture. Like this - https://stackoverflow.com/questions/27319821/video-with-transparency-on-android
Are there any ways to just play video with alpha channel on Android?