From patchwork Sat Aug 1 13:47:03 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Rheinhardt X-Patchwork-Id: 21432 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 CF63C44AA8D for ; Sat, 1 Aug 2020 16:49:42 +0300 (EEST) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id B70EA68BA7B; Sat, 1 Aug 2020 16:49:42 +0300 (EEST) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org Received: from mail-ej1-f68.google.com (mail-ej1-f68.google.com [209.85.218.68]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id EF6AD68BA8F for ; Sat, 1 Aug 2020 16:49:40 +0300 (EEST) Received: by mail-ej1-f68.google.com with SMTP id kq25so21199002ejb.3 for ; Sat, 01 Aug 2020 06:49:40 -0700 (PDT) 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=eTk0csESgyIumtWV7QBbHvenJ/uaAO0zbsdS1uqiO5A=; b=LCmuEWvorLNdkc0ERh8dQDvshdFQkkdBqfdnPhhmG9phRTqFdK96u6jdQbHJbqVsWT e3O4qm1TwPNdFko0fyxJ8ADCgG9UzGVnWQEG3gb6m0Py0l8kTZhBzYEvR0drIeTLE9Ez TxXZy08B+Eu4GtFT5G4WL8XC8iqpv0yNI7pTPZNzN+eTVtVtnvGUL+5hXeMuUWW4fgID w+H2VbTgTPolziWAbcOfpLEdzZlApw3X14ouP9gLNHuc+GtTF0eqCD4Hlo8VSSlURlgI ERcKnT2AWHFhTPT27d+CAaP0bOjsW9OI+le4DlC6PytX3hUK3lYrVbztERpP63HEw6PC KnIg== 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=eTk0csESgyIumtWV7QBbHvenJ/uaAO0zbsdS1uqiO5A=; b=ujAD2tQTOaQQmmZSrZh1VYSNsuNlXghRZEBqTS/c/CDKChH2tp0MyAokejwRWzYpbl L9eEPA0MasqFF3RVB3nPWXlv4MOTFKlBYv8E8kr3DfWLFmd5gTZeuOH80LqT4WjBJAwo v9vFlqOgTocYbAh3zXsJphMKpF7HIIXXA5rYEeQvAO+Gn/qI9FOXT3PmDk4/IvpsW66Z QahxeH/a/Ff8O+sHl6D//bDryqvfFdJx/JO+xlv5EmSTFeGEWnRPLR8IBN0aGSbhp36K gxMFlZx4XQWdoBfITVKsNnyN5i85wMu4HhYj5GOGiniHiiDyZ69R+XyrCqyA/USyixqR azDA== X-Gm-Message-State: AOAM532SBfX3JbQcf4IK21kzXqVzfLSzsQxn8cT4wcOH5Gw/Mp0rf4OU XnzoZzwaykRqgoFqjtryV/5RlMSy X-Google-Smtp-Source: ABdhPJw7J2EZfKBBtFaJbbZv1YWzc8iYHqZ0DQWxGqGE1Wdbs1PSIF8lglLnUn6NAAih6HM8ckPn+g== X-Received: by 2002:a17:906:68da:: with SMTP id y26mr8525789ejr.250.1596289779777; Sat, 01 Aug 2020 06:49:39 -0700 (PDT) Received: from sblaptop.fritz.box (ipbcc10296.dynamic.kabel-deutschland.de. [188.193.2.150]) by smtp.gmail.com with ESMTPSA id b24sm12178501edn.33.2020.08.01.06.49.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 01 Aug 2020 06:49:39 -0700 (PDT) From: Andreas Rheinhardt To: ffmpeg-devel@ffmpeg.org Date: Sat, 1 Aug 2020 15:47:03 +0200 Message-Id: <20200801134704.3647-12-andreas.rheinhardt@gmail.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200731112241.8948-1-andreas.rheinhardt@gmail.com> References: <20200731112241.8948-1-andreas.rheinhardt@gmail.com> MIME-Version: 1.0 Subject: [FFmpeg-devel] [PATCH 20/21] avcodec/smacker: Use unsigned for prediction values 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" Up until now, the Smacker decoder has pretended that the prediction values are signed in code like 'pred[0] += (unsigned)sign_extend(val, 16)' (the cast has been added to this code later to fix undefined behaviour). This has been even done in case the PCM format is u8. Yet in case of 8/16 bit samples, only the lower 8/16 bit of the predicition values are ever used, so one can just as well just use unsigned and remove the sign extensions. This is what this commit does. For GCC 9 the time for one call to smka_decode_frame() for the sample from ticket #2425 decreased from 1709043 to 1693619 decicycles; for Clang 9 it went up from 1355273 to 1369089 decicycles. Signed-off-by: Andreas Rheinhardt --- libavcodec/smacker.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/libavcodec/smacker.c b/libavcodec/smacker.c index e588b03820..d2b1c68162 100644 --- a/libavcodec/smacker.c +++ b/libavcodec/smacker.c @@ -595,11 +595,10 @@ static int smka_decode_frame(AVCodecContext *avctx, void *data, int16_t *samples; uint8_t *samples8; uint8_t values[4]; - int val; int i, res, ret; int unp_size; int bits, stereo; - int pred[2] = {0, 0}; + unsigned pred[2], val; if (buf_size <= 4) { av_log(avctx, AV_LOG_ERROR, "packet is too small\n"); @@ -668,7 +667,7 @@ static int smka_decode_frame(AVCodecContext *avctx, void *data, /* this codec relies on wraparound instead of clipping audio */ if(bits) { //decode 16-bit data for(i = stereo; i >= 0; i--) - pred[i] = sign_extend(av_bswap16(get_bits(&gb, 16)), 16); + pred[i] = av_bswap16(get_bits(&gb, 16)); for(i = 0; i <= stereo; i++) *samples++ = pred[i]; for(; i < unp_size / 2; i++) { @@ -687,7 +686,7 @@ static int smka_decode_frame(AVCodecContext *avctx, void *data, else res = values[3]; val |= res << 8; - pred[1] += (unsigned)sign_extend(val, 16); + pred[1] += val; *samples++ = pred[1]; } else { if(vlc[0].table) @@ -700,7 +699,7 @@ static int smka_decode_frame(AVCodecContext *avctx, void *data, else res = values[1]; val |= res << 8; - pred[0] += (unsigned)sign_extend(val, 16); + pred[0] += val; *samples++ = pred[0]; } } @@ -719,14 +718,14 @@ static int smka_decode_frame(AVCodecContext *avctx, void *data, res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3); else res = values[1]; - pred[1] += sign_extend(res, 8); + pred[1] += res; *samples8++ = pred[1]; } else { if(vlc[0].table) res = get_vlc2(&gb, vlc[0].table, SMKTREE_BITS, 3); else res = values[0]; - pred[0] += sign_extend(res, 8); + pred[0] += res; *samples8++ = pred[0]; } }