avfilter/avf_showspectrum: improve dB scale description

This commit is contained in:
Paul B Mahol 2016-08-07 20:19:34 +02:00
parent f0adb99d06
commit 571f33de0a
1 changed files with 12 additions and 0 deletions

View File

@ -1181,6 +1181,18 @@ static int showspectrumpic_request_frame(AVFilterLink *outlink)
memset(s->outpicref->data[1]+(s->start_y + h * (ch + 1) - y - 1) * s->outpicref->linesize[1] + s->w + s->start_x + 20, av_clip_uint8(out[1]), 10);
memset(s->outpicref->data[2]+(s->start_y + h * (ch + 1) - y - 1) * s->outpicref->linesize[2] + s->w + s->start_x + 20, av_clip_uint8(out[2]), 10);
}
for (y = 0; ch == 0 && y < h; y += h / 10) {
float value = 120.0 * log10(1. - y / (float)h);
char *text;
if (value < -120)
break;
text = av_asprintf("%.0f dB", value);
if (!text)
continue;
drawtext(s->outpicref, s->w + s->start_x + 35, s->start_y + y - 5, text, 0);
}
}
}