Understanding/controlling MLT melt slideshow?

Question

Consider the following bash script (on Ubuntu 18.04, melt 6.6.0), which uses melt to make a slideshow and play it locally in a window (SDL consumer), m

Answer 1

Ok, so, I spent some time looking into the commands for melt and turns out there is actually a pretty effective way of altering a bunch of images (if the number of arguments is too long or there are too many characters for your terminal to handle).

What you want to do is to use -serialise .melt which will store your commands (you can also create this file manually). Then to execute that file, use melt .melt along with any other options you have for your video file.

Example Format:

melt -serialise .melt

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Example

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Create the melt file (with Melt CLI)

melt image1.png out=50 image2.png out=75 -mix 25 -mixer luma image3.png out=75 -mix 25 -mixer luma image3.png out=75 -mix 25 -mixer luma image4.png out=75 -mix 25 -mixer luma <...> -serialise test.melt

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.melt file format

test.melt

image1.png out=50 image2.png out=75 -mix 25 -mixer luma image3.png out=75 -mix 25 -mixer luma image3.png out=75 -mix 25 -mixer luma image4.png out=75 -mix 25 -mixer luma <...>

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Run

melt test.melt -profile atsc_1080p_60 -consumer avformat:output.mp4 vcodec=libx264 an=1

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Additional Notes

There should be an extra return character at the end of the melt file. If there isn't, Exceeded maximum line length (2048) while reading a melt file. will be outputted

Notice that -serialise .melt will not be in the .melt file

Melt will actually take some time to load the melt file before the encoding process begins