From 80dacbedbacfaaed5eeef96a2216921bd84d572c Mon Sep 17 00:00:00 2001 From: Paul B Mahol Date: Sat, 13 Jul 2019 15:43:17 +0200 Subject: [PATCH] avfilter/af_aiir: calculate group delay too --- doc/filters.texi | 2 +- libavfilter/af_aiir.c | 33 ++++++++++++++++++++++++++++++--- 2 files changed, 31 insertions(+), 4 deletions(-) diff --git a/doc/filters.texi b/doc/filters.texi index c92ed8de07..3108ad349e 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -1397,7 +1397,7 @@ How much to use filtered signal in output. Default is 1. Range is between 0 and 1. @item response -Show IR frequency response, magnitude and phase in additional video stream. +Show IR frequency response, magnitude(magenta), phase(green) and group delay(yellow) in additional video stream. By default it is disabled. @item channel diff --git a/libavfilter/af_aiir.c b/libavfilter/af_aiir.c index b23aa3c868..ffe2606da6 100644 --- a/libavfilter/af_aiir.c +++ b/libavfilter/af_aiir.c @@ -721,8 +721,9 @@ static void draw_line(AVFrame *out, int x0, int y0, int x1, int y1, uint32_t col static void draw_response(AVFilterContext *ctx, AVFrame *out) { AudioIIRContext *s = ctx->priv; - float *mag, *phase, min = FLT_MAX, max = FLT_MIN; - int prev_ymag = -1, prev_yphase = -1; + float *mag, *phase, *delay, min = FLT_MAX, max = FLT_MIN; + float min_delay = FLT_MAX, max_delay = FLT_MIN; + int prev_ymag = -1, prev_yphase = -1, prev_ydelay = -1; char text[32]; int ch, i, x; @@ -730,7 +731,8 @@ static void draw_response(AVFilterContext *ctx, AVFrame *out) phase = av_malloc_array(s->w, sizeof(*phase)); mag = av_malloc_array(s->w, sizeof(*mag)); - if (!mag || !phase) + delay = av_malloc_array(s->w, sizeof(*delay)); + if (!mag || !phase || !delay) goto end; ch = av_clip(s->ir_channel, 0, s->channels - 1); @@ -795,23 +797,39 @@ static void draw_response(AVFilterContext *ctx, AVFrame *out) max = fmaxf(max, mag[i]); } + for (i = 0; i < s->w - 1; i++) { + float dw = M_PI / (s->w - 1); + + delay[i] = -(phase[i + 1] - phase[i]) / dw; + min_delay = fminf(min_delay, delay[i]); + max_delay = fmaxf(max_delay, delay[i]); + } + + delay[i] = delay[i - 1]; + for (i = 0; i < s->w; i++) { int ymag = mag[i] / max * (s->h - 1); + int ydelay = (delay[i] - min_delay) / (max_delay - min_delay) * (s->h - 1); int yphase = (0.5 * (1. + phase[i] / M_PI)) * (s->h - 1); ymag = s->h - 1 - av_clip(ymag, 0, s->h - 1); yphase = s->h - 1 - av_clip(yphase, 0, s->h - 1); + ydelay = s->h - 1 - av_clip(ydelay, 0, s->h - 1); if (prev_ymag < 0) prev_ymag = ymag; if (prev_yphase < 0) prev_yphase = yphase; + if (prev_ydelay < 0) + prev_ydelay = ydelay; draw_line(out, i, ymag, FFMAX(i - 1, 0), prev_ymag, 0xFFFF00FF); draw_line(out, i, yphase, FFMAX(i - 1, 0), prev_yphase, 0xFF00FF00); + draw_line(out, i, ydelay, FFMAX(i - 1, 0), prev_ydelay, 0xFF00FFFF); prev_ymag = ymag; prev_yphase = yphase; + prev_ydelay = ydelay; } if (s->w > 400 && s->h > 100) { @@ -822,9 +840,18 @@ static void draw_response(AVFilterContext *ctx, AVFrame *out) drawtext(out, 2, 12, "Min Magnitude:", 0xDDDDDDDD); snprintf(text, sizeof(text), "%.2f", min); drawtext(out, 15 * 8 + 2, 12, text, 0xDDDDDDDD); + + drawtext(out, 2, 22, "Max Delay:", 0xDDDDDDDD); + snprintf(text, sizeof(text), "%.2f", max_delay); + drawtext(out, 11 * 8 + 2, 22, text, 0xDDDDDDDD); + + drawtext(out, 2, 32, "Min Delay:", 0xDDDDDDDD); + snprintf(text, sizeof(text), "%.2f", min_delay); + drawtext(out, 11 * 8 + 2, 32, text, 0xDDDDDDDD); } end: + av_free(delay); av_free(phase); av_free(mag); }