fix: Fix flip vertical video image for received video

[karasusan]

Fix a bug in this PR.

• 971

[aet]

the default behavior for VideoStreamTrack changed too. Now i'm supposed to pass CopyTextureHelper.VerticalFlipCopy, is it on purpose?

[karasusan]

@aet The previous PR changes the flag false. It looks passing true is right. https://github.com/Unity-Technologies/com.unity.webrtc/pull/971/files#diff-f4a6f4c4bccd5c3f082e2ee65fc6785d7c1af35098d1d68374a1ae2955ba7f25R182

[MaximKurbanov]

@aet The previous PR changes the flag false. It looks passing true is right. https://github.com/Unity-Technologies/com.unity.webrtc/pull/971/files#diff-f4a6f4c4bccd5c3f082e2ee65fc6785d7c1af35098d1d68374a1ae2955ba7f25R182

I also changed the Sender, now the Sender sends the image without flip. And upon receipt, a flip is not required. If we put flip, we will get a vertically flipped image. If you receive a normal image from a camera(webcamera) without flip, then you also do not need to flip it when sending. Else if you received a fliped image from a camera, then you need to flip it to normal and send it. So the receiver doesn't need flip.

972

[aet]

@MaximKurbanov Hum, I don't use any of the webcam stuff but just receiving external video tracks and rendering to textures and sending them forward (includes the received video track), in both scenarios the default behavior changed? I think the intent of the new CopyTexture parameter is good, to give flexibility to rare cases like the smart glasses you were using.

The default should be something that works for majority of the users, being backwards compatible is a plus. I'm ok explicitly adding the flip flags on my tracks, but seems like extra step for majority of the users.

[aet]

Sorry, I was talking about public VideoStreamTrack(Texture texture, bool needFlip = true) changing into VideoStreamTrack(Texture texture, CopyTexture copyTexture = null) that is a different case from NeedReceivedVideoFlipVertically

[MaximKurbanov]

The default should be something that works for majority of the users, being backwards compatible is a plus. I'm ok explicitly adding the flip flags on my tracks, but seems like extra step for majority of the users.

I agree with you.

[MaximKurbanov]

My recommendation for optimization is to set NeedReceivedVideoFlipVertically to false. And use "copyTexture: Graphics.Blit" in the VideoStreamTrack constructor.

[karasusan]

@MaximKurbanov I agree with you about suggestion of the performance improvement. However, it is needed to support browser and unity at the same time.