[MPlayer-users] Aspect Ratio in vfilters

[Alexander Roalter]

RC wrote:
> On Tue, 13 Mar 2007 10:59:34 +0100
> Alexander Roalter <alex at roalter.it> wrote:
> 
>> But I don't know how to get the desired aspect ratio from the video in
>>
>> the filters, since they seem to operate entirely on the image before 
>> stretching and resizing. Any way to do that?
> 
> IIRC, you're probably looking for d_width/d_height.

Thank you, that helped a lot. Got it finally working now, this is how 
I've done it (in case anyone is interested):

diff vf_cropdetect.c old vs. new:
20a21
 >       float aspect;
54a56,59
 >       if (d_height == 0)
 >               vf->priv->aspect = 1;
 >       else
 >               vf->priv->aspect = (float)d_width/(float)d_height;
59a65,66
 >       float ratio;
 >       float stretch;
129,133c136,151
<
<     mp_msg(MSGT_VFILTER, MSGL_INFO, MSGTR_MPCODECS_CropArea,
<       vf->priv->x1,vf->priv->x2,
<       vf->priv->y1,vf->priv->y2,
<       w,h,x,y);
---
 >       ratio = (((float)(vf->priv->x2 - vf->priv->x1 + 1))/
 >               ((float)(vf->priv->y2 - vf->priv->y1 + 1)));
 >       if ((mpi->height == 0) || (mpi->width == 0))
 >               stretch = 1;
 >       else
 >               stretch = vf->priv->aspect / ((float)mpi->width/ 
(float)mpi->height);
 >
 >         mp_msg(MSGT_VFILTER, MSGL_INFO, MSGTR_MPCODECS_CropArea,
 >       vf->priv->x1,vf->priv->x2,
 >       vf->priv->y1,vf->priv->y2, ratio * stretch,
 >       w,h,x,y);
 >
 > //    mp_msg(MSGT_VFILTER, MSGL_INFO, MSGTR_MPCODECS_CropArea,
 > //    vf->priv->x1,vf->priv->x2,
 > //    vf->priv->y1,vf->priv->y2,
 > //    w,h,x,y);

And in help/help_mp-en.h (and it should be done in any other language...)

1654a1654
< #define MSGTR_MPCODECS_CropArea "[CROP] Crop area: X: %d..%d  Y: 
%d..%d  (-vf crop=%d:%d:%d:%d).\n"
 > #define MSGTR_MPCODECS_CropArea "[CROP] Crop area: X: %d..%d  Y: 
%d..%d R:%0.2f:1 (-vf crop=%d:%d:%d:%d).\n"


Maybe someone can use it to some avail. I wouldn't miss it.

cheers,
Alex