[FFmpeg-devel] [PATCH 1/3] avfilter/showwaves: add "center" mode.

[Stefano Sabatini]

On date Tuesday 2014-08-19 14:47:02 +0200, Clément Bœsch encoded:
> From: Clément Bœsch <clement at stupeflix.com>
> 
> ---
>  doc/filters.texi            |  3 +++
>  libavfilter/avf_showwaves.c | 24 +++++++++++++++++++-----
>  2 files changed, 22 insertions(+), 5 deletions(-)
> 
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 0ca1d6f..828f2b4 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -10813,6 +10813,9 @@ Draw a vertical line for each sample.
>  
>  @item p2p
>  Draw a point for each sample and a line between them.
> +
> + at item center
> +Draw a centered vertical line for each sample.
>  @end table
>  
>  Default value is @code{point}.
> diff --git a/libavfilter/avf_showwaves.c b/libavfilter/avf_showwaves.c
> index e025663..e4911cc 100644
> --- a/libavfilter/avf_showwaves.c
> +++ b/libavfilter/avf_showwaves.c
> @@ -36,6 +36,7 @@ enum ShowWavesMode {
>      MODE_POINT,
>      MODE_LINE,
>      MODE_P2P,

> +    MODE_CENTER,

Nit: what about CENTERED_LINE, then you can use cl or cline as abbreviation.

>      MODE_NB,
>  };
>  
> @@ -62,6 +63,7 @@ static const AVOption showwaves_options[] = {
>          { "point", "draw a point for each sample", 0, AV_OPT_TYPE_CONST, {.i64=MODE_POINT}, .flags=FLAGS, .unit="mode"},
>          { "line",  "draw a line for each sample",  0, AV_OPT_TYPE_CONST, {.i64=MODE_LINE},  .flags=FLAGS, .unit="mode"},
>          { "p2p", "draw a line between samples", 0, AV_OPT_TYPE_CONST, {.i64=MODE_P2P}, .flags=FLAGS, .unit="mode"},
> +        { "center","draw a centered line for each sample", 0, AV_OPT_TYPE_CONST, {.i64=MODE_CENTER}, .flags=FLAGS, .unit="mode"},
>      { "n",    "set how many samples to show in the same point", OFFSET(n), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, FLAGS },
>      { "rate", "set video rate", OFFSET(rate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, 0, FLAGS },
>      { "r",    "set video rate", OFFSET(rate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, 0, FLAGS },
> @@ -206,26 +208,30 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
>                  memset(outpicref->data[0] + j * linesize, 0, outlink->w);
>          }
>          for (j = 0; j < nb_channels; j++) {
> -            h = showwaves->h/2 - av_rescale(*p++, showwaves->h/2, MAX_INT16);
> +            int start, end;
>              switch (showwaves->mode) {
>              case MODE_POINT:
> +                h = showwaves->h/2 - av_rescale(*p++, showwaves->h/2, MAX_INT16);
>                  if (h >= 0 && h < outlink->h)
>                      *(outpicref->data[0] + showwaves->buf_idx + h * linesize) += x;
>                  break;
>  
>              case MODE_LINE:
> -            {
> -                int start = showwaves->h/2, end = av_clip(h, 0, outlink->h-1);
> +                h     = showwaves->h/2 - av_rescale(*p++, showwaves->h/2, MAX_INT16);
> +                start = showwaves->h/2;
> +                end   = av_clip(h, 0, outlink->h-1);
>                  if (start > end) FFSWAP(int16_t, start, end);
>                  for (k = start; k < end; k++)
>                      *(outpicref->data[0] + showwaves->buf_idx + k * linesize) += x;
>                  break;
> -            }
> +
>              case MODE_P2P:
> +                h = showwaves->h/2 - av_rescale(*p++, showwaves->h/2, MAX_INT16);
>                  if (h >= 0 && h < outlink->h) {
>                      *(outpicref->data[0] + showwaves->buf_idx + h * linesize) += x;
>                      if (showwaves->buf_idy[j] && h != showwaves->buf_idy[j]) {
> -                        int start = showwaves->buf_idy[j], end = av_clip(h, 0, outlink->h-1);
> +                        start = showwaves->buf_idy[j];
> +                        end = av_clip(h, 0, outlink->h-1);
>                          if (start > end)
>                              FFSWAP(int16_t, start, end);
>                          for (k = start + 1; k < end; k++)
> @@ -233,6 +239,14 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
>                      }
>                  }
>                  break;
> +
> +            case MODE_CENTER:
> +                h     = av_rescale(abs(*p++), showwaves->h, UINT16_MAX);
> +                start = (showwaves->h - h) / 2;
> +                end   = start + h;
> +                for (k = start; k < end; k++)
> +                    *(outpicref->data[0] + showwaves->buf_idx + k * linesize) += x;
> +                break;
>              }
>              /* store current y coordinate for this channel */
>              showwaves->buf_idy[j] = h;

LGTM otherwise, thanks.
-- 
FFmpeg = Friendly Fierce Moronic Peaceless Extroverse Gigant