[MPlayer-users] HD movies, aspect ratio, and scaling

[Reimar Döffinger]

On Sat, Dec 19, 2009 at 01:07:44PM +0100, Tobia Conforto wrote:
> Hi
> I have a couple of questions about a HD movie. I would like to better understand scaling issues.
> 
> The movie clip is WMV3 anamorphic 1440x1080 and my monitor has a 1440x900 resolution with square pixels. I'm using MPlayer OS X Extended rev12 (mplayer r29777)
> 
> The first issue is that ffwmv3 doesn't detect the aspect ratio of the movie clip. I guess that's a bug with FFMpeg.
> 
> So I go ahead and add the -aspect 16:9 option, and this is what happens:
> 
> Movie-Aspect is 1.78:1 - prescaling to correct movie aspect.
> SwScaler: reducing / aligning filtersize 5 -> 4
> SwScaler: reducing / aligning filtersize 5 -> 4
> SwScaler: reducing / aligning filtersize 1 -> 1
> SwScaler: reducing / aligning filtersize 5 -> 4
> [swscaler @ 0x100ff60c0]BICUBIC scaler, from yuv420p to rgb24 using MMX2
> [swscaler @ 0x100ff60c0]using 4-tap MMX scaler for horizontal luminance scaling
> [swscaler @ 0x100ff60c0]using 4-tap MMX scaler for horizontal chrominance scaling
> [swscaler @ 0x100ff60c0]using n-tap MMX scaler for vertical scaling (BGR)
> [swscaler @ 0x100ff60c0]1440x1080 -> 1920x1080
> VO: [corevideo] 1440x1080 => 1920x1080 Packed YUY2  [fs]
> 
> Why is it software-scaling the movie horizontally, up to 1920x1080?

It isn't.
The line
> VO: [corevideo] 1440x1080 => 1920x1080 Packed YUY2  [fs]
tells the overlay is scaling it.
As someone else pointed out the other output is just the screenshot filter
preparing to do its job.

> Can't it just play the 1440x1080 source in a 1440x810 window, using the hardware overlay?

Sure just use -noaspect. Or just don't add -aspect if you don't want it to scale..

> If that's not possible, wouldn't it be more efficient to down-scale vertically to 1440x810?

You can tell it to by using either -vf scale or dsize manually.