diff options
| -rw-r--r-- | doc/filters.texi | 6 | ||||
| -rw-r--r-- | libavfilter/avf_showspectrum.c | 13 |
2 files changed, 17 insertions, 2 deletions
diff --git a/doc/filters.texi b/doc/filters.texi index aa05b3f4fa..30a52c4fdb 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -20872,6 +20872,12 @@ Draw time and frequency axes and legends. Default is enabled. @item rotation Set color rotation, must be in [-1.0, 1.0] range. Default value is @code{0}. + +@item start +Set start frequency from which to display spectrogram. Default is @code{0}. + +@item stop +Set stop frequency to which to display spectrogram. Default is @code{0}. @end table @subsection Examples diff --git a/libavfilter/avf_showspectrum.c b/libavfilter/avf_showspectrum.c index b39c084a4b..bbe42ba7c7 100644 --- a/libavfilter/avf_showspectrum.c +++ b/libavfilter/avf_showspectrum.c @@ -1128,6 +1128,8 @@ static const AVOption showspectrumpic_options[] = { { "gain", "set scale gain", OFFSET(gain), AV_OPT_TYPE_FLOAT, {.dbl = 1}, 0, 128, FLAGS }, { "legend", "draw legend", OFFSET(legend), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, FLAGS }, { "rotation", "color rotation", OFFSET(rotation), AV_OPT_TYPE_FLOAT, {.dbl = 0}, -1, 1, FLAGS }, + { "start", "start frequency", OFFSET(start), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT32_MAX, FLAGS }, + { "stop", "stop frequency", OFFSET(stop), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT32_MAX, FLAGS }, { NULL } }; @@ -1240,6 +1242,11 @@ static int showspectrumpic_request_frame(AVFilterLink *outlink) drawtext(s->outpicref, 2, outlink->h - 10, "CREATED BY LIBAVFILTER", 0); drawtext(s->outpicref, outlink->w - 2 - strlen(text) * 10, outlink->h - 10, text, 0); + if (s->stop) { + char *text = av_asprintf("Zoom: %d Hz - %d Hz", s->start, s->stop); + drawtext(s->outpicref, outlink->w - 2 - strlen(text) * 10, 3, text, 0); + av_freep(&text); + } av_freep(&text); @@ -1283,7 +1290,8 @@ static int showspectrumpic_request_frame(AVFilterLink *outlink) dst[x] = 200; } for (y = 0; y < h; y += 40) { - float hertz = y * (inlink->sample_rate / 2) / (float)(1 << (int)ceil(log2(h))); + float range = s->stop ? s->stop - s->start : inlink->sample_rate / 2; + float hertz = s->start + y * range / (float)(1 << (int)ceil(log2(h))); char *units; if (hertz == 0) @@ -1348,7 +1356,8 @@ static int showspectrumpic_request_frame(AVFilterLink *outlink) dst[x] = 200; } for (x = 0; x < w - 79; x += 80) { - float hertz = x * (inlink->sample_rate / 2) / (float)(1 << (int)ceil(log2(w))); + float range = s->stop ? s->stop - s->start : inlink->sample_rate / 2; + float hertz = s->start + x * range / (float)(1 << (int)ceil(log2(w))); char *units; if (hertz == 0) |