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 3D01F45FA2 for ; Mon, 22 May 2023 23:36:40 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 2F10868C122; Tue, 23 May 2023 02:36:14 +0300 (EEST) Received: from relay3-d.mail.gandi.net (relay3-d.mail.gandi.net [217.70.183.195]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id B891168C0C1 for ; Tue, 23 May 2023 02:36:05 +0300 (EEST) Received: (Authenticated sender: michael@niedermayer.cc) by mail.gandi.net (Postfix) with ESMTPSA id F3D9360004 for ; Mon, 22 May 2023 23:36:04 +0000 (UTC) From: Michael Niedermayer To: FFmpeg development discussions and patches Date: Tue, 23 May 2023 01:35:59 +0200 Message-Id: <20230522233601.20552-4-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 4/6] avcodec/kbdwin: 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 used about 7 times as many cpu cycles as new Signed-off-by: Michael Niedermayer --- libavcodec/kbdwin.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/libavcodec/kbdwin.c b/libavcodec/kbdwin.c index bf32aeb317..5dff334250 100644 --- a/libavcodec/kbdwin.c +++ b/libavcodec/kbdwin.c @@ -21,8 +21,6 @@ #include "libavutil/attributes.h" #include "kbdwin.h" -#define BESSEL_I0_ITER 50 // default: 50 iterations of Bessel I0 approximation - av_cold void ff_kbd_window_init(float *window, float alpha, int n) { int i, j; @@ -34,9 +32,7 @@ av_cold void ff_kbd_window_init(float *window, float alpha, int n) for (i = 0; i < n; i++) { tmp = i * (n - i) * alpha2; - bessel = 1.0; - for (j = BESSEL_I0_ITER; j > 0; j--) - bessel = bessel * tmp / (j * j) + 1; + bessel = av_bessel_i0(sqrt(tmp) * 2); sum += bessel; local_window[i] = sum; } -- 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".