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Fixed in 2020.1.X

Fixed in 2019.3.X



Found in




Issue ID




Stereo video becomes horizontally stretched when transcoded with "Keep Alpha" enabled



How to reproduce:
1. Open the attached "" project
2. In the Project view, select "testvideo.webm"
3. In the Inspector, play the preview of the video

Expected results: The video plays and shows two images
Actual results: The video shows half of each image and is stretched

Reproducible with: 2019.3.0a9, 2019.3.0f1, 2020.1.0a15
Not reproducible with: 2018.4.35f1, 2018.4.13f1, 2019.2.14f1, 2019.3.0a8

Note: The issue does not reproduce is you disable "Keep Alpha" in the Transcode options

  1. Resolution Note (fix version 2020.1):

    Unity uses a split-alpha layout internally to add transparency support for codecs that don't natively support it such as H.264/H.265. This has the side-effect of doubling the image width which must be undone at display time. Addition of hardware-accelerated video decoding on Windows/UWP has broken this. Fixed the missing width compensation in the new code.

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