From patchwork Mon Jan 20 19:20:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Rheinhardt X-Patchwork-Id: 17441 Return-Path: X-Original-To: patchwork@ffaux-bg.ffmpeg.org Delivered-To: patchwork@ffaux-bg.ffmpeg.org Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by ffaux.localdomain (Postfix) with ESMTP id D4F5F44A8BA for ; Mon, 20 Jan 2020 21:21:20 +0200 (EET) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id D159468AB72; Mon, 20 Jan 2020 21:21:20 +0200 (EET) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org Received: from mail-wm1-f67.google.com (mail-wm1-f67.google.com [209.85.128.67]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 0F83868826C for ; Mon, 20 Jan 2020 21:21:14 +0200 (EET) Received: by mail-wm1-f67.google.com with SMTP id p17so497590wmb.0 for ; Mon, 20 Jan 2020 11:21:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=DSCtKrYnFnkuk+mw5cyYpqEXDZJwWSIp5Md64mBFThc=; b=asjWyrOwoyTEGJeOjAlrbNDxiRaIJgYqGAytLzSXwxKCoiPjdnSL8dyxrkrpIGwVK/ rpA5GB5SQ8ElB1WZShZaQyJjPpeV8vjk+7OLJ+juRpiTTEtpE98b0FngcALRapYlZmq9 7K9fBdgMWKexW+0LOsbwc0TG5WZzbqHg+4inDlqc8qfcfRgKGvRDhteBfelslFa1XkbA oL/TDTSGDK3tUE3ugQQDrTna2qJ4Nh/GycQHM+xKvqGVSBewU4uN9YF/cEl/nrHwx4HE VAx+jJ7C2+X4pBswToJA+zlrVXiqt+ArJjF5hVO0hVkcEQLzjFuVuucEZdvCVMnws4xB Kwow== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=DSCtKrYnFnkuk+mw5cyYpqEXDZJwWSIp5Md64mBFThc=; b=qf3SK9/RvOJzZrQ5Oyb6Qx8JdWWxAEY+MMfTNIcV474aPcLzv6qzLt6aHabpjhNupS OJu7yxI9+9HrjsQDS8SrgwQ+QzQ1DnbwFV9pQWCgdleZ7iGMdmYUDcm8/nXEliWnpKbu D2bo2tO6OI02d7/c05zxFvCa8/TQPwDbpqNL+Hf+285P2KKKiEuZSRceBFr8zz0bNh53 E2S/eWxCQ+eO3G2CBS/LztS7XizknYkH5a+gL65B4yPmBSkttaVQPZsAho+SUCGMPTbb 7JGpDUCRxp5NKJOR6mhyIdyjtvP6LIyB85Aixxg0rF60r9E59eMW9HkEwO+7E34Ds9rS NgbA== X-Gm-Message-State: APjAAAWwY5HWJ+fwyvkVBvun0CBsehW2m/C9NYzzGFqA7UTHJ+WRDZJA VYk7GtD6A935VIZPb8t47XjziTQ6 X-Google-Smtp-Source: APXvYqx2OsArY7SJK1I58Ur65byurd/+V0HuoBH0Ah2BACuLM/6YTpW44tf+/uqgweFMt3t/QFWepA== X-Received: by 2002:a7b:cc82:: with SMTP id p2mr331914wma.159.1579548073468; Mon, 20 Jan 2020 11:21:13 -0800 (PST) Received: from sblaptop.fritz.box (ipbcc08bbf.dynamic.kabel-deutschland.de. [188.192.139.191]) by smtp.gmail.com with ESMTPSA id l3sm45002633wrt.29.2020.01.20.11.21.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Jan 2020 11:21:13 -0800 (PST) From: Andreas Rheinhardt To: ffmpeg-devel@ffmpeg.org Date: Mon, 20 Jan 2020 20:20:43 +0100 Message-Id: <20200120192043.4288-2-andreas.rheinhardt@gmail.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200120192043.4288-1-andreas.rheinhardt@gmail.com> References: <20200120192043.4288-1-andreas.rheinhardt@gmail.com> MIME-Version: 1.0 Subject: [FFmpeg-devel] [PATCH 2/2] avcodec/adxdec: Remove unnecessary left-shift X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.20 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 Cc: Andreas Rheinhardt Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Replace "(a * (1 << shift) * b + c) >> shift" by "a * b + (c >> shift)". It is equivalent to the old code because a is in the range of uint16_t, shift is 12 and b is effectively a signed 4-bit number, so that no overflow/truncation of high bits happens during the multiplication (overflow would be undefined anyway). Signed-off-by: Andreas Rheinhardt --- libavcodec/adxdec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/adxdec.c b/libavcodec/adxdec.c index 178ea99dcf..40ed8e5ba7 100644 --- a/libavcodec/adxdec.c +++ b/libavcodec/adxdec.c @@ -81,7 +81,7 @@ static int adx_decode(ADXContext *c, int16_t *out, int offset, s2 = prev->s2; for (i = 0; i < BLOCK_SAMPLES; i++) { d = get_sbits(&gb, 4); - s0 = ((d * (1 << COEFF_BITS)) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS; + s0 = d * scale + ((c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS); s2 = s1; s1 = av_clip_int16(s0); *out++ = s1;