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 C4E9740BF4 for ; Sat, 5 Feb 2022 06:36:38 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 29E0368B245; Sat, 5 Feb 2022 08:36:36 +0200 (EET) Received: from mail-qk1-f171.google.com (mail-qk1-f171.google.com [209.85.222.171]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id DFBD268B249 for ; Sat, 5 Feb 2022 08:36:29 +0200 (EET) Received: by mail-qk1-f171.google.com with SMTP id o10so6631140qkg.0 for ; Fri, 04 Feb 2022 22:36:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=BuLT9bY1lE5p5mlJ1W7KdqYJtANcbOtql1B6COyiD7s=; b=PcOm1Z4JmNQ57AitV2kDaYoYClcHiR0V6oQRkEHXFlu02UEf8/GVjiEJ4UNLiC74ph 8w2WS5Pk7J9xLkMggwYQqDOXwk/txn2PgxJ29jLawL/253YRTc8izIg8FrwvG6Tt/bYe 44BVePdMMsxtbDntW49pM93tIKUs6+D1kSzWbxlCzhNJAs5ZTQK1l1kgBEYZFj9hIobi HoKS8k/0gdM4iMQIP8uHglbp6lds8N3fHM7CeO431uOf8gtnR4gz6sOytrqT49Q60ops bfdvtGpcsvWMtNrONhcssHgRgCi/GV1e3sNt7fv/Z2RiWCCZEFviYV+OuQPK5Ycmlkug XsyQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=BuLT9bY1lE5p5mlJ1W7KdqYJtANcbOtql1B6COyiD7s=; b=vNQ3R/BTsLyE7PVkAd0vK7W+1+hEuAGTzJ4N6VabLf+9fSQ3R51FvLLJ/BDg3m9gV3 YbwD8jR9ruvNG2kB48uZpYswNwP226VPD81rSwoVUz5Ey7IbhTZiBe/YcfHda5qoIOQk 6/g+mVVyrErj7lHZtGKWHRsyyMw4tip1ReokGojPznwVcn+Or9Qv2FjGCKIUpmJQJJHE y5rK0MCfTFkAhl56M40q07OM6p7g0NJGIlXQ7V0VIocnMX6bnpx38WHDclRhaCu2eJdi jcnEdHVE0SK7mavPhuI4mGtsuJ2h7cYz2dcyBL2lC7Lt4VHMZ/pThoVM//3AXJGmhhRD aylg== X-Gm-Message-State: AOAM533CYXU6OQg3aJkxECzCsoquv/QixDgMBakK/CRb4/R0gBHEXvtP LOvPJ+NnM3XoLxi0zTuC0UgM4n/KG56Jmw== X-Google-Smtp-Source: ABdhPJzQ8AlJbLOPnpr8uK8FopqtZFcd7OKWrdn9ionyZyQHrQ3grfO4Qxhfn3LEYft34v+RUMe8CQ== X-Received: by 2002:a37:9a09:: with SMTP id c9mr1310141qke.251.1644042988243; Fri, 04 Feb 2022 22:36:28 -0800 (PST) Received: from localhost.localdomain ([151.200.235.219]) by smtp.gmail.com with ESMTPSA id c20sm2500594qtb.58.2022.02.04.22.36.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Feb 2022 22:36:27 -0800 (PST) From: Scott Theisen To: ffmpeg-devel@ffmpeg.org Date: Sat, 5 Feb 2022 01:36:03 -0500 Message-Id: <20220205063603.28156-1-scott.the.elm@gmail.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: References: MIME-Version: 1.0 Subject: [FFmpeg-devel] [PATCH] cbs_mpeg2_split_fragment(): cache the buffer end 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 Cc: Scott Theisen 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: It is constant, so instead of recalculating it every time, only calculate it once. Also add a few clarifying comments. --- libavcodec/cbs_mpeg2.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/libavcodec/cbs_mpeg2.c b/libavcodec/cbs_mpeg2.c index dfea12ef1b..d3204b885a 100644 --- a/libavcodec/cbs_mpeg2.c +++ b/libavcodec/cbs_mpeg2.c @@ -144,12 +144,12 @@ static int cbs_mpeg2_split_fragment(CodedBitstreamContext *ctx, CodedBitstreamFragment *frag, int header) { - const uint8_t *start; + const uint8_t *start = frag->data; + const uint8_t * const buf_end = frag->data + frag->data_size; uint32_t start_code = -1; int err; - start = avpriv_find_start_code(frag->data, frag->data + frag->data_size, - &start_code); + start = avpriv_find_start_code(start, buf_end, &start_code); if (start_code >> 8 != 0x000001) { // No start code found. return AVERROR_INVALIDDATA; @@ -165,10 +165,9 @@ static int cbs_mpeg2_split_fragment(CodedBitstreamContext *ctx, // start code in any way (as e.g. happens when there is a // Sequence End unit at the very end of a packet). start_code = UINT32_MAX; - end = avpriv_find_start_code(start--, frag->data + frag->data_size, - &start_code); - - // start points to the byte containing the start_code_identifier + end = avpriv_find_start_code(start, buf_end, &start_code); + start--; + // decrement so start points to the byte containing the start_code_identifier // (may be the last byte of fragment->data); end points to the byte // following the byte containing the start code identifier (or to // the end of fragment->data). @@ -178,6 +177,7 @@ static int cbs_mpeg2_split_fragment(CodedBitstreamContext *ctx, unit_size = (end - 4) - start; } else { // We didn't find a start code, so this is the final unit. + // There is no start code to remove from end, hence not (end - 4). unit_size = end - start; } -- 2.32.0 _______________________________________________ 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".