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[79.124.17.100]) by mx.google.com with ESMTP id i10si14390089ejd.170.2022.02.03.10.47.14; Thu, 03 Feb 2022 10:47:14 -0800 (PST) Received-SPF: pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) client-ip=79.124.17.100; Authentication-Results: mx.google.com; dkim=neutral (body hash did not verify) header.i=@gmail.com header.s=20210112 header.b=lPLoK4dy; spf=pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) smtp.mailfrom=ffmpeg-devel-bounces@ffmpeg.org; dmarc=fail (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 16E3768B1C1; Thu, 3 Feb 2022 20:45:47 +0200 (EET) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org Received: from mail-qt1-f173.google.com (mail-qt1-f173.google.com [209.85.160.173]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id D58AA68B0E8 for ; Thu, 3 Feb 2022 20:45:40 +0200 (EET) Received: by mail-qt1-f173.google.com with SMTP id b5so3614783qtq.11 for ; Thu, 03 Feb 2022 10:45:40 -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=mTUaY35F2RxD50O0GlBvVMsr0cRTZ8FkCrrqhCbjJZ8=; b=lPLoK4dyboqSKUrLN5uGSMPK9p/avDZQy2uDRSXixlR08BOZbhpo5DIWtnMr+XK0GZ hzo5l6JIiK9RafS9TusISNw7imbIskBAzWIJ0PXGqU6lXPP10WmwKqEGsSpwAqIk42nA 5Nnyg83jAdeiMQKTlZRmwdS0rMvadfstJLqNDdalHZpxb91TU62yqKqXBoBko3mKBuO/ OvoZAXOHeYCVf+RtziHil8u4Eo7n45zI1cckjuPzS2yRMlD+MKmpAGt/FT/KJ5WLI/V2 OP9igSUTIiYszunoOV7VlhewW4lVnTPPMnmR+6TK0Sx9qx3xGQh6dOsufakC+1FHai+a t+Jg== 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=mTUaY35F2RxD50O0GlBvVMsr0cRTZ8FkCrrqhCbjJZ8=; b=Cwv49JX1J93aSkHoneH0d9n3ejN22KyuS0iH6oEUyTQwLDqVNiONX6eb8MityOAmkn zX4ZBrN38k5AgiTKyo8KzZVh/vblz7w0EPAXgjtxLTC91YuCbHSY9OM0dfu2maG9mBbj L/91B+Vi5fki7mQffZuHSGd363eu02GpvpNOiO/2EHof261bmzNGLMLQWeMGAZ63sr+f 3lHuSRRJ7EvB+8Bxl8EUrDJHQd/TC8LwYYnRJ3alAZmBWZmgQnttXu8iCmDjttX0S66B Qj5Ns+rC7y3c+SDHYltKEM7TpY6a1r8Ex2PwAE2vE8EMRWiyaOEQohhPTHossmjKz9Rn ijEA== X-Gm-Message-State: AOAM531DpNBSFwrE9bWsdV7qDye4/aw45W4fzZ9GYFIRKNSJaASq60cH 7nt4ZCVcD35/GI3pjx3n6LkBrnkwh9VPJQ== X-Received: by 2002:a05:622a:20a:: with SMTP id b10mr27432850qtx.291.1643913939093; Thu, 03 Feb 2022 10:45:39 -0800 (PST) Received: from localhost.localdomain ([151.200.235.219]) by smtp.gmail.com with ESMTPSA id f16sm5947887qtk.8.2022.02.03.10.45.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Feb 2022 10:45:38 -0800 (PST) From: Scott Theisen To: ffmpeg-devel@ffmpeg.org Date: Thu, 3 Feb 2022 13:44:49 -0500 Message-Id: <20220203184450.5491-13-scott.the.elm@gmail.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220203184450.5491-1-scott.the.elm@gmail.com> References: <20220201212056.29712-1-scott.the.elm@gmail.com> <20220203184450.5491-1-scott.the.elm@gmail.com> MIME-Version: 1.0 Subject: [FFmpeg-devel] [PATCH v2 12/13] cbs_mpeg2.c: improve readability of start code search (part 2) 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 Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" X-TUID: qKQq+s7WHpXZ If the last four bytes form a valid start code, the loop would run another time. Since (start == buf_end), start_code is invalidated so the loop terminates. However, calling avpriv_find_start_code() with p == end, it will immediately return due to the zero size buffer. Thus the history is not needed. --- libavcodec/cbs_mpeg2.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/libavcodec/cbs_mpeg2.c b/libavcodec/cbs_mpeg2.c index f2efedde5d..bf95fb7546 100644 --- a/libavcodec/cbs_mpeg2.c +++ b/libavcodec/cbs_mpeg2.c @@ -168,8 +168,9 @@ static int cbs_mpeg2_split_fragment(CodedBitstreamContext *ctx, // the next unit will be treated as the last unit. start_code = 0; } - - end = avpriv_find_start_code(start, buf_end, &start_code, 0); + else { + end = avpriv_find_start_code(start, buf_end, &start_code, 1); + } 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