From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id 8439740587 for ; Mon, 22 May 2023 23:36:31 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 2521068C11A; Tue, 23 May 2023 02:36:13 +0300 (EEST) Received: from relay9-d.mail.gandi.net (relay9-d.mail.gandi.net [217.70.183.199]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id CE40868C0B9 for ; Tue, 23 May 2023 02:36:04 +0300 (EEST) Received: (Authenticated sender: michael@niedermayer.cc) by mail.gandi.net (Postfix) with ESMTPSA id 185A1FF804 for ; Mon, 22 May 2023 23:36:03 +0000 (UTC) From: Michael Niedermayer To: FFmpeg development discussions and patches Date: Tue, 23 May 2023 01:35:58 +0200 Message-Id: <20230522233601.20552-3-michael@niedermayer.cc> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20230522233601.20552-1-michael@niedermayer.cc> References: <20230522233601.20552-1-michael@niedermayer.cc> Subject: [FFmpeg-devel] [PATCH 3/6] avfilter/window_func: Use av_bessel_i0() X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: Old code needed about 6 times as long as new with defaults in afftfilt Signed-off-by: Michael Niedermayer --- libavfilter/window_func.h | 20 +++++--------------- 1 file changed, 5 insertions(+), 15 deletions(-) diff --git a/libavfilter/window_func.h b/libavfilter/window_func.h index 02b5def9dd..13236d8593 100644 --- a/libavfilter/window_func.h +++ b/libavfilter/window_func.h @@ -25,6 +25,7 @@ #include #include "libavutil/avassert.h" #include "libavutil/common.h" +#include "libavutil/timer.h" enum WindowFunc { WFUNC_RECT, WFUNC_HANNING, WFUNC_HAMMING, WFUNC_BLACKMAN, WFUNC_BARTLETT, WFUNC_WELCH, WFUNC_FLATTOP, @@ -59,19 +60,6 @@ enum WindowFunc { WFUNC_RECT, WFUNC_HANNING, WFUNC_HAMMING, WFUNC_BLACKMAN, { "bohman", "Bohman", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BOHMAN}, 0, 0, flag, "win_func" }, \ { "kaiser", "Kaiser", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_KAISER}, 0, 0, flag, "win_func" } -static inline double get_i0(double x) -{ - double y = 1.0, prev = 1.0, i = 1.0; - - while (fabs(prev) > 1e-20) { - double summand = prev * x * x / (4 * i * i); - y += summand; - prev = summand; - i++; - } - - return y; -} static inline void generate_window_func(float *lut, int N, int win_func, float *overlap) @@ -232,13 +220,15 @@ static inline void generate_window_func(float *lut, int N, int win_func, *overlap = 0.75; break; case WFUNC_KAISER: + { + double scale = 1.0 / av_bessel_i0(12.); for (n = 0; n < N; n++) { double x = 2.0 / (double)(N - 1); - - lut[n] = get_i0(12. * sqrt(1. - SQR(n * x - 1.))) / get_i0(12.); + lut[n] = av_bessel_i0(12. * sqrt(1. - SQR(n * x - 1.))) * scale; } *overlap = 0.75; break; + } default: av_assert0(0); } -- 2.17.1 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".