[FFmpeg-devel] overlay filter option/alternative

[James Darnley]

On 2015-12-04 06:29, Ryan Williams wrote:
> EDIT: Fixed errors in syntax.
> 
> TLDR, Would you consider an 'underlay' filter or perhaps an option on the 'overlay' filter that reverses the order of the input labels?
> 
> Consider the following shorthand syntax "[input][a] overlay, [b] overlay, [c] overlay [output]"
> Which expands to "[input][a] overlay [unnamed1]; [b][unnamed1] overlay [unnamed2]; [c][unnamed2] overlay [output]"
> Giving the final layer composition of "c,b,input,a"
> 
> If there was an underlay filter or equivalent the shorthand syntax "[input][a] overlay, [b] underlay, [c] underlay [output]"
> Would expand to "[input][a] overlay [unnamed1]; [b][unnamed1] underlay [unnamed2]; [c][unnamed2] underlay [output]"
> Giving the final layer composition of "input,a,b,c"
> 
> I am aware that I can provide longhand syntax to achieve the same result but I am programmatically apply a varying number of watermarks and would like to avoid a lot of temporary labels.
> If you're open to the idea I'm willing to code it.

If you can make it as an alias to overlay then I reckon it stands a good
chance of being favourably accepted.

If you're right about just switching around arguments then it shouldn't
be too hard.  Look in the overlay filter.  Duplicate the filter and
options definitions.  Change as needed.  Compile and test your new
underlay filter.

Even if people don't like it you still have what you want.


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