diff options
| author | Paul B Mahol <onemda@gmail.com> | 2015-12-28 23:45:34 +0100 |
|---|---|---|
| committer | Paul B Mahol <onemda@gmail.com> | 2015-12-29 12:11:33 +0100 |
| commit | efa666e0da5e5fd2ded2e7dce4191bf04ac35952 (patch) | |
| tree | 85bbdcdbdcd1a0798481166113867a9ddc6684a1 | |
| parent | e30e5c83aed79f1ecde064c36b952aee4fc7827b (diff) | |
| download | ffmpeg-efa666e0da5e5fd2ded2e7dce4191bf04ac35952.tar.gz | |
avfilter/avf_showspectrum: properly calculate w factor
It is used in calculating loudness of each frequency bin.
Signed-off-by: Paul B Mahol <onemda@gmail.com>
| -rw-r--r-- | libavfilter/avf_showspectrum.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/libavfilter/avf_showspectrum.c b/libavfilter/avf_showspectrum.c index fa994574a6..187213575d 100644 --- a/libavfilter/avf_showspectrum.c +++ b/libavfilter/avf_showspectrum.c @@ -60,6 +60,7 @@ typedef struct { FFTSample **rdft_data; ///< bins holder for each (displayed) channels float *window_func_lut; ///< Window function LUT int win_func; + double win_scale; float overlap; float *combine_buffer; ///< color combining buffer (3 * h items) } ShowSpectrumContext; @@ -231,6 +232,11 @@ static int config_output(AVFilterLink *outlink) return AVERROR(ENOMEM); ff_generate_window_func(s->window_func_lut, win_size, s->win_func, &s->overlap); + for (s->win_scale = 0, i = 0; i < win_size; i++) { + s->win_scale += s->window_func_lut[i] * s->window_func_lut[i]; + } + s->win_scale = 1. / (sqrt(s->win_scale) * 32768.); + /* prepare the initial picref buffer (black frame) */ av_frame_free(&s->outpicref); s->outpicref = outpicref = @@ -315,7 +321,7 @@ static int plot_spectrum_column(AVFilterLink *inlink, AVFrame *insamples) * height (or half the RDFT window size) */ const int nb_freq = 1 << (s->rdft_bits - 1); const int win_size = nb_freq << 1; - const double w = 1. / (sqrt(nb_freq) * 32768.); + const double w = s->win_scale; int h = s->orientation == VERTICAL ? s->channel_height : s->channel_width; int ch, plane, n, x, y; |