[FFmpeg-devel] [PATCH] lavfi/showspectrum: add sliding mode.

[Clément Bœsch]

On Mon, Oct 22, 2012 at 12:15:33AM +0200, Stefano Sabatini wrote:
> On date Sunday 2012-10-21 21:02:18 +0200, Clément Bœsch encoded:
> > ---
> >  doc/filters.texi               |  3 +++
> >  libavfilter/avf_showspectrum.c | 17 +++++++++++++----
> >  2 files changed, 16 insertions(+), 4 deletions(-)
> > 
> > diff --git a/doc/filters.texi b/doc/filters.texi
> > index 916655a..72bf0a1 100644
> > --- a/doc/filters.texi
> > +++ b/doc/filters.texi
> > @@ -4675,6 +4675,9 @@ spectrum.
> >  
> >  The filter accepts the following named parameters:
> >  @table @option
> > + at item sliding
> > +Specify if the spectrum should slide along the window. Default value is
> > + at code{0}.
> 
> I prefer "slide" for consistency with other similar options
> (e.g. "stitch"), also shorter.
> 

Renamed, but kept sliding internally since the code makes more sense that
way IMO.

> >  @item size, s
> >  Specify the video size for the output. Default value is @code{640x480}.
> >  @end table
> > diff --git a/libavfilter/avf_showspectrum.c b/libavfilter/avf_showspectrum.c
> > index 641c27f..55bf260 100644
> > --- a/libavfilter/avf_showspectrum.c
> > +++ b/libavfilter/avf_showspectrum.c
> > @@ -37,6 +37,7 @@ typedef struct {
> >      int w, h;
> >      AVFilterBufferRef *outpicref;
> >      int req_fullfilled;
> > +    int sliding;                ///< 1 if sliding mode, 0 otherwise
> >      int xpos;                   ///< x position (current column)
> >      RDFTContext *rdft;          ///< Real Discrete Fourier Transform context
> >      int rdft_bits;              ///< number of bits (RDFT window size = 1<<rdft_bits)
> > @@ -52,6 +53,7 @@ typedef struct {
> >  static const AVOption showspectrum_options[] = {
> >      { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "640x480"}, 0, 0, FLAGS },
> >      { "s",    "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "640x480"}, 0, 0, FLAGS },
> > +    { "sliding", "set sliding mode", OFFSET(sliding), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, FLAGS },
> >      { NULL },
> >  };
> >  
> > @@ -247,16 +249,23 @@ static int plot_spectrum_column(AVFilterLink *inlink, AVFilterBufferRef *insampl
> >  
> >          for (y = 0; y < outlink->h; y++) {
> >              // FIXME: bin[0] contains first and last bins
> > -            const int pos = showspectrum->xpos * 3 + (outlink->h - y - 1) * outpicref->linesize[0];
> > +            uint8_t *p = outpicref->data[0] + (outlink->h - y - 1) * outpicref->linesize[0];
> >              const double w = 1. / sqrt(nb_freq);
> >              int a =                           sqrt(w * MAGNITUDE(RE(0), IM(0)));
> >              int b = nb_display_channels > 1 ? sqrt(w * MAGNITUDE(RE(1), IM(1))) : a;
> >  
> 
> > +            if (!showspectrum->sliding) {
> > +                p += showspectrum->xpos * 3;
> > +            } else {
> > +                memmove(p, p + 3, (outlink->w - 1) * 3);
> > +                p += (outlink->w - 1) * 3;
> > +            }
> 
> Nit+: avoid negative logic when avoidable
> 

Sure whatever, toggled

> > +
> >              a = FFMIN(a, 255);
> >              b = FFMIN(b, 255);
> > -            outpicref->data[0][pos]   = a;
> > -            outpicref->data[0][pos+1] = b;
> > -            outpicref->data[0][pos+2] = (a + b) / 2;
> > +            p[0] = a;
> > +            p[1] = b;
> > +            p[2] = (a + b) / 2;
> >          }
> >          outpicref->pts = insamples->pts +
> >              av_rescale_q(showspectrum->consumed,
> 
> LGTM, also bump micro so people/programs know when the feature was
> added, thanks.

lavfi micro bumped, and applied.

-- 
Clément B.
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