Re: [FFmpeg-devel] [PATCH] swscale: set sane alpha blending defaults

2015-08-30 Thread Ivan Kalvachev
On 8/30/15, wm4 wrote: > On Sun, 30 Aug 2015 18:09:05 + (UTC) > Carl Eugen Hoyos wrote: > >> wm4 googlemail.com> writes: >> >> > Change the default to blend with black, which >> > gives generally expected results. >> >> Given that this introduces a speed regression, is >> rarely needed and i

Re: [FFmpeg-devel] [PATCH] swscale: set sane alpha blending defaults

2015-08-30 Thread Carl Eugen Hoyos
wm4 googlemail.com> writes: > > And "black" may be sensible for prores, in all > > other cases, it is either suboptimal or bad. > > Such as? Name all the counter examples you know. I'm curious. I already told you: laraShadow_dl.flv > But side from that, blending with _any_ color is > still m

Re: [FFmpeg-devel] [PATCH] swscale: set sane alpha blending defaults

2015-08-30 Thread Hendrik Leppkes
On Sun, Aug 30, 2015 at 8:22 PM, wm4 wrote: > On Sun, 30 Aug 2015 18:09:05 + (UTC) > Carl Eugen Hoyos wrote: > >> wm4 googlemail.com> writes: >> >> > Change the default to blend with black, which >> > gives generally expected results. >> >> Given that this introduces a speed regression, is >

Re: [FFmpeg-devel] [PATCH] swscale: set sane alpha blending defaults

2015-08-30 Thread wm4
On Sun, 30 Aug 2015 18:09:05 + (UTC) Carl Eugen Hoyos wrote: > wm4 googlemail.com> writes: > > > Change the default to blend with black, which > > gives generally expected results. > > Given that this introduces a speed regression, is > rarely needed and it is immediately visible that >

Re: [FFmpeg-devel] [PATCH] swscale: set sane alpha blending defaults

2015-08-30 Thread wm4
On Sun, 30 Aug 2015 18:09:05 + (UTC) Carl Eugen Hoyos wrote: > wm4 googlemail.com> writes: > > > Change the default to blend with black, which > > gives generally expected results. > > Given that this introduces a speed regression, is > rarely needed and it is immediately visible that >

Re: [FFmpeg-devel] [PATCH] swscale: set sane alpha blending defaults

2015-08-30 Thread Carl Eugen Hoyos
wm4 googlemail.com> writes: > Change the default to blend with black, which > gives generally expected results. Given that this introduces a speed regression, is rarely needed and it is immediately visible that the function is needed, I don't think this is a sensible change. Note that contr

[FFmpeg-devel] [PATCH] swscale: set sane alpha blending defaults

2015-08-30 Thread wm4
The old default for alpha -> non-alpha conversion was discarding the alpha channel without. This meant that parts of the image which were not meant to be visible became visible. This was a problem for video which actually contained and used alpha. It can affect PNGs with an alpha channel as well -