[FFmpeg-devel] [PATCH] swscale: support internal scaler cascades

[Michael Niedermayer]

On Fri, Oct 10, 2014 at 11:30:43PM +0200, Clément Bœsch wrote:
> On Wed, Oct 08, 2014 at 02:11:06AM +0200, Michael Niedermayer wrote:
> > Fixes Ticket3170
> > 
> > Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> > ---
> >  libswscale/swscale.c          |   13 ++++++++++
> >  libswscale/swscale_internal.h |    6 +++++
> >  libswscale/utils.c            |   54 ++++++++++++++++++++++++++++++++---------
> >  3 files changed, 62 insertions(+), 11 deletions(-)
> > 
> > diff --git a/libswscale/swscale.c b/libswscale/swscale.c
> > index e54d448..409e7db 100644
> > --- a/libswscale/swscale.c
> > +++ b/libswscale/swscale.c
> > @@ -27,6 +27,7 @@
> >  #include "libavutil/avutil.h"
> >  #include "libavutil/bswap.h"
> >  #include "libavutil/cpu.h"
> > +#include "libavutil/imgutils.h"
> >  #include "libavutil/intreadwrite.h"
> >  #include "libavutil/mathematics.h"
> >  #include "libavutil/pixdesc.h"
> > @@ -899,6 +900,18 @@ int attribute_align_arg sws_scale(struct SwsContext *c,
> >          av_log(c, AV_LOG_ERROR, "One of the input parameters to sws_scale() is NULL, please check the calling code\n");
> >          return 0;
> >      }
> > +    if (c->cascaded_context[0] && srcSliceY == 0 && srcSliceH == c->cascaded_context[0]->srcH) {
> > +        ret = sws_scale(c->cascaded_context[0],
> > +                        srcSlice, srcStride, srcSliceY, srcSliceH,
> > +                        c->cascaded_tmp, c->cascaded_tmpStride);
> > +        if (ret < 0)
> > +            return ret;
> > +        ret = sws_scale(c->cascaded_context[1],
> > +                        c->cascaded_tmp, c->cascaded_tmpStride, 0, c->cascaded_context[0]->dstH,
> > +                        dst, dstStride);
> > +        return ret;
> > +    }
> > +
> >      memcpy(src2, srcSlice, sizeof(src2));
> >      memcpy(dst2, dst, sizeof(dst2));
> >  
> > diff --git a/libswscale/swscale_internal.h b/libswscale/swscale_internal.h
> > index 1e53690..d072bbc 100644
> > --- a/libswscale/swscale_internal.h
> > +++ b/libswscale/swscale_internal.h
> > @@ -61,6 +61,8 @@
> >  #   define APCK_SIZE 16
> >  #endif
> >  
> > +#define AVERROR_USE_CASCADE -12345
> > +
> 
> Please do not use "AV" prefix for non exposed API.
> 
> [...]
> 
> >  struct SwsContext;
> >  
> >  typedef enum SwsDither {
> > @@ -301,6 +303,10 @@ typedef struct SwsContext {
> >      int sliceDir;                 ///< Direction that slices are fed to the scaler (1 = top-to-bottom, -1 = bottom-to-top).
> >      double param[2];              ///< Input parameters for scaling algorithms that need them.
> >  
> > +    struct SwsContext *cascaded_context[2];
> > +    int cascaded_tmpStride[4];
> > +    uint8_t *cascaded_tmp[4];
> > +
> 
> I think it would be appropriate to add a comment about what issue these
> fields are addressing.

fixed


> 
> [...]
> 
> No opinion on the rest of the patch, but thank you for fixing that issue.
> 

> I'm assuming it's now able to rescale from 4k to 1x1?

of course

and patch applied

thanks

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Democracy is the form of government in which you can choose your dictator
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