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TOPIC: Exporting videos with alpha channel

Exporting videos with alpha channel 2 weeks, 6 days ago #214196

  • tittybiter
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Hi Everyone! Let me be brief:

I have searched the forum and found that in the past, several people have asked about exporting with an alpha channel. The only suggestion people got back is export as a series of PNGs with transparency, and then using another program to make those PNGs into an animation. I have two questions

- Is this still the case or does lightwork now support exporting video formats with an alpha channel?
- What program might you use to put a series of PNGs with transparency into a video?

I downloaded Lightworks thinking it would do everything I needed, but if someone can recommend a program by which I can put in PNGs and output a video with transparency, I will be very happy. If Lightworks can now export with an alpha channel, I will also be very happy.

Right now I can't even seem to get a PNG with an alpha channel to work properly in the editor (unless I use chromakeying), it comes up as black instead of transparent. Have I missed something obvious?

Thanks for your help and support.
Last Edit: 2 weeks, 6 days ago by tittybiter.

Re: Exporting videos with alpha channel 2 weeks, 6 days ago #214198

  • hugly
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Hello,

Currently Lightworks does not support export of video formats with alpha channel, but import, even with the free version.

With the Free version of Lightworks export is limted to the h.264 YUV 4:2:0 video codec anyway, which doesn't support an alpha channel by design. With the Pro version, you can export e.g. PNG image sequences with transparency.

To make transparency visible in the timeline you have to create a composite by connecting a background with Blend, DVE or similar effects. Transparency over nothing makes not much sense in most cases.

When searching the internet you'll find free software which support export of video formats with alpha channel. Which one to use, depends on your needs. If you need a very powerful package, have a look into Blender, it has a steep learning curve though.
It's better to travel well than to arrive...

Re: Exporting videos with alpha channel 2 weeks, 6 days ago #214199

  • schrauber
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If you only want to use the transparent video as a kind of intermediate format for reimporting into Lightworks, maybe there are other ways to achieve the same goal? (maybe even faster and more elegant solutions? depending on what you need)
Mainly automatically translated
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Software: Lightworks 2020.1 & 14.5; || Windows 10, 64 Bit
Hardware: Intel i5-4440 (3,1 GHz); || shared RAM: 8 GB; || Intel HD Graphics 4600 (can use max. 2 GB of shared RAM)

Re: Exporting videos with alpha channel 2 weeks, 6 days ago #214214

  • tittybiter
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Thanks for your responses!


Hugly: I've had a look at blender for other projects and I thought it was overkill for such a simple project. Maybe I was wrong and exporting with an alpha channel requires very specialist technology. You'd be surprised how long I've spent looking for software that can do this. It appears I may need to update my iOS and get adobe premiere pro.

It's a shame that lightworks has this flaw (even in the premium version) but I suppose it's not really designed to cope with modern web demands.

Schrauber: The transparent video is the end step; it's for a website with an irregularly sized/shaped video animation.

Re: Exporting videos with alpha channel 2 weeks, 6 days ago #214216

  • hugly
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I wouldn't call that a flaw, just a missing feature.

Feel free to invest some money to get the job done, but personally, I would identify the colour of the background of the webpage and use a matte effect in Lightworks with that colour as background for the composite. That works even with the free version.
It's better to travel well than to arrive...
Last Edit: 2 weeks, 6 days ago by hugly.

Re: Exporting videos with alpha channel 2 weeks, 6 days ago #214218

  • tittybiter
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Videos are rendered differently in each browser so the technique you described would not work across browsers (it wouldn't even work the same in chrome mobile vs. chrome desktop). Also, as I said, the idea is to make an irregularly shaped video playing over a background, not a single colour.

We can call it a missing feature if you prefer but it's a shame that it's been missing since around 2015 when people on the forum first started asking for it.

Re: Exporting videos with alpha channel 2 weeks, 6 days ago #214219

  • hugly
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I'm not with Editshare, but since the video pipeline fully supports alpha channel, it shouldn't be rocket science to implement a video format which support it, e.g. Cineform 12-bit RGBA 4:4:4:4.

For the time being, converting a PNG image sequence and merging the sound with FFmpeg is quite simple and doesn't take long.
It's better to travel well than to arrive...

Re: Exporting videos with alpha channel 2 weeks, 6 days ago #214221

  • briandrys
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I can move this thread into feature requests, since I can only find one other thread requesting this in there.
Last Edit: 2 weeks, 6 days ago by briandrys.
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