[FFmpeg-devel] [PATCH] lavfi/alphaextract: switch to filter_frame API

[Stefano Sabatini]

On date Friday 2012-12-07 02:49:37 +0100, Clément Bœsch encoded:
> On Fri, Dec 07, 2012 at 12:06:08AM +0100, Stefano Sabatini wrote:
> > ---
> >  libavfilter/vf_alphaextract.c |   26 ++++++++++++++++----------
> >  1 file changed, 16 insertions(+), 10 deletions(-)
> > 
> > diff --git a/libavfilter/vf_alphaextract.c b/libavfilter/vf_alphaextract.c
> > index 35402f6..766cc8c 100644
> > --- a/libavfilter/vf_alphaextract.c
> > +++ b/libavfilter/vf_alphaextract.c
> > @@ -29,6 +29,7 @@
> >  #include "avfilter.h"
> >  #include "drawutils.h"
> >  #include "formats.h"
> > +#include "internal.h"
> >  #include "video.h"
> >  
> >  enum { Y, U, V, A };
> > @@ -59,16 +60,21 @@ static int config_input(AVFilterLink *inlink)
> >      return 0;
> >  }
> >  
> > -static int draw_slice(AVFilterLink *inlink, int y0, int h, int slice_dir)
> > +static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *cur_buf)
> >  {
> >      AlphaExtractContext *extract = inlink->dst->priv;
> > -    AVFilterBufferRef *cur_buf = inlink->cur_buf;
> > -    AVFilterBufferRef *out_buf = inlink->dst->outputs[0]->out_buf;
> > +    AVFilterLink *outlink = inlink->dst->outputs[0];
> > +    AVFilterBufferRef *out_buf =
> > +        ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
> > +
> > +    if (!out_buf)
> > +        return AVERROR(ENOMEM);
> 
> I think you need to unref cur_buf this time.

Reworked.
 
> > +    avfilter_copy_buffer_ref_props(out_buf, cur_buf);
> >  
> >      if (extract->is_packed_rgb) {
> >          int x, y;
> >          uint8_t *pin, *pout;
> > -        for (y = y0; y < (y0 + h); y++) {
> > +        for (y = 0; y < inlink->h; y++) {
> >              pin = cur_buf->data[0] + y * cur_buf->linesize[0] + extract->rgba_map[A];
> >              pout = out_buf->data[0] + y * out_buf->linesize[0];
> >              for (x = 0; x < out_buf->video->w; x++) {
> > @@ -79,19 +85,19 @@ static int draw_slice(AVFilterLink *inlink, int y0, int h, int slice_dir)
> >          }
> >      } else if (cur_buf->linesize[A] == out_buf->linesize[Y]) {
> >          const int linesize = cur_buf->linesize[A];
> > -        memcpy(out_buf->data[Y] + y0 * linesize,
> > -               cur_buf->data[A] + y0 * linesize,
> > -               linesize * h);
> > +        memcpy(out_buf->data[Y], cur_buf->data[A], linesize * inlink->h);
> 

> This code looks better than the previous one. Though there is something
> that bugs me, but that's because I don't know the internals enough: can't
> the padding between width and linesize be uninitialized data? It will work
> but valgrind might complain. Also, second concern, and it's also somehow
> unrelated to this patch but: if that padding is very large (like after a
> crop filter), won't this be slower than a loop?

Fixed in a different commit.

> 
> >      } else {
> >          const int linesize = FFMIN(out_buf->linesize[Y], cur_buf->linesize[A]);
> >          int y;
> > -        for (y = y0; y < (y0 + h); y++) {
> > +        for (y = 0; y < inlink->h; y++) {
> >              memcpy(out_buf->data[Y] + y * out_buf->linesize[Y],
> >                     cur_buf->data[A] + y * cur_buf->linesize[A],
> >                     linesize);
> 
> ...looks like it should be merged with this better code.
> 
> >          }
> >      }
> > -    return ff_draw_slice(inlink->dst->outputs[0], y0, h, slice_dir);
> > +
> > +    avfilter_unref_bufferp(&cur_buf);
> 
> avfilter_unref_buffer(cur_buf) should be enough but well.
> 
> > +    return ff_filter_frame(outlink, out_buf);
> >  }
> >  
> >  static const AVFilterPad alphaextract_inputs[] = {
> > @@ -99,7 +105,7 @@ static const AVFilterPad alphaextract_inputs[] = {
> >          .name         = "default",
> >          .type         = AVMEDIA_TYPE_VIDEO,
> >          .config_props = config_input,
> > -        .draw_slice   = draw_slice,
> > +        .filter_frame = filter_frame,
> >          .min_perms    = AV_PERM_READ,
> >      },
> >      { NULL }
> 
> LGTM otherwise, thanks!

Updated.
-- 
FFmpeg = Faithless and Faithful Magnificient Ponderous Eretic Glue
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