[MPlayer-dev-eng] Re: New remove-logo filter

[Martin Atkins]

Trent Piepho wrote:
> 
> Just make the entire filter depend on configure finding libpng, which it
> already looks for.  Once you support png, there really isn't any point to
> supporting another format.  The advantage of png is that you can use a
> compressed bitmap instead of an uncompressed greyscale image, and you could
> use png images as well for the alpha-blending filter.  In fact, you could use
> the SAME png images for both filters.

Indeed. vf_deblendlogo (currently also under discussion on the list) 
already ignores completely opaque pixels with the intention that they'd 
be handled by a blurring delogo filter instead. If this new filter 
looked for completely opaque pixels in the template and did the blur 
there exactly the same template could be used for both.

There's already PNG-loading code that will require little modification 
in the deblendlogo filter. However, that entire filter is disabled if 
libpng isn't linked, which might be seen as a major drawback by some. A 
simple, generic image loading API for mplayer which supports all 
available image loaders would help fix this, but would be extra bloat in 
itself I suppose.

In fact, if both filters are going to share the same template loading 
code and operate on the same template, it could be argued that they'd be 
better merged into one all-encompassing delogo filter which just takes a 
template and does the right thing for both transparent and [near-]opaque 
elements. Having both together might make for a bit of an unweildy 
filter as regards code readability, though. I dunno.

All the best,
Martin Atkins