[FFmpeg-devel] [PATCH] lowres=3 support in mpegvideo decoder

Michael Niedermayer michaelni
Fri Jan 15 22:34:44 CET 2010


On Fri, Jan 15, 2010 at 09:16:43PM +0300, Anatoliy Nenashev wrote:
> Hi!
> Here goes a patch for lowres=3 support in MPEG video decoder.

does this have some practical use?


>  mpegvideo.c |   29 ++++++++++++++++-------------
>  1 file changed, 16 insertions(+), 13 deletions(-)
> bae3f45f531d15f5236ec407d10ef1107604fd56  mpeg_lowres.patch
> diff --git a/libavcodec/mpegvideo.c b/libavcodec/mpegvideo.c
> index ea96cbe..81d814b 100644
> --- a/libavcodec/mpegvideo.c
> +++ b/libavcodec/mpegvideo.c
> @@ -1416,6 +1416,7 @@ static inline int hpel_motion_lowres(MpegEncContext *s,
>                                    int motion_x, int motion_y)
>  {
>      const int lowres= s->avctx->lowres;
> +    const int op_index = (lowres < 3) ? lowres : 2;

FFMIN


>      const int s_mask= (2<<lowres)-1;
>      int emu=0;
>      int sx, sy;
> @@ -1440,11 +1441,11 @@ static inline int hpel_motion_lowres(MpegEncContext *s,
>          emu=1;
>      }
>  
> -    sx <<= 2 - lowres;
> -    sy <<= 2 - lowres;
> +    sx = ( sx << (3 - lowres) ) >> 1;
> +    sy = ( sy << (3 - lowres) ) >> 1;

that can be done simpler



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