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 5DD2E40155 for ; Thu, 3 Nov 2022 13:01:44 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id BE6D668BF69; Thu, 3 Nov 2022 15:01:42 +0200 (EET) Received: from mail-il1-f169.google.com (mail-il1-f169.google.com [209.85.166.169]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id F359268BF5A for ; Thu, 3 Nov 2022 15:01:35 +0200 (EET) Received: by mail-il1-f169.google.com with SMTP id h18so970744ilq.9 for ; Thu, 03 Nov 2022 06:01:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:content-language :references:to:subject:user-agent:mime-version:date:message-id:from :to:cc:subject:date:message-id:reply-to; bh=dxjp+YKM+jFNuxJgvxBg1IYP7yJf20bFb/4mWKsaUMI=; b=bR5zOeGmK7+376OTz3N4bV/81ZTURznC6JntWwq/TB49ydAv69wPhGm6kCjtBRIvE1 VORjffC8/t7NX9Cs7KbHMTiKf+jOpPwqhgBfAO4gm8c8/DIrbIxAVXDyXrxVKVEtsO2i Wl8Bv9cg4joOYnui70odWkYSUPVi3pBv2fO9e5uPHDkbxdwfK29K16zuf7Z0+M2Kal5K rO4/k1tlZTwa4+2GVGNLpBO2HVkN0OwgMKvvBf+VH6F75v+KSKCQjqRDn0jxRA+K/+0g 9e5r5BUwVV4j6K6r0CKzuOtDKKZP8jgiBYURKAaqx4hXLQWOuL0MGnILDDN9O7G36Q4v gfOw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:content-language :references:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=dxjp+YKM+jFNuxJgvxBg1IYP7yJf20bFb/4mWKsaUMI=; b=IUtCpEi6JH/yMN4U0OT10vLbqHLZz8eUTcNqaJoJpE5NlBOockDtYtTCWPHUerAGWg jBHr44P0ox7Wfw/QtW8fvuHvvBYMk+XqdbcwOOxcTERkkWOdARKCK+iYd/mSstx1p35L PWZ9nxuY8GlDDYB0u6sHJdvnM+JF5uukFt/DENtbaHin8NXqNiL6USQHofCQxlln2+eL GQJ1TxVqZ1/D4phKJu5nBdhBOzta6iUmIvmRT8iOCXtgd711fBjyRjygiTyk46Zd8IxO gttKqPKWl4ByI0vZ1vSSlKW88lZP4b39xpwyWGtTaXkzGJtlqBAQB0iFq9y/F9Ja4YJy RzCA== X-Gm-Message-State: ACrzQf2/B9XruSsfx5cM12DFrR9I+ZvidpMPKtJFZ8ckHum9rEULcVm3 O/AjPSBElUuKsFTJPouGPn6XVFMC99Q= X-Google-Smtp-Source: AMsMyM4Uszu6SV+Rif3+JjYDY28gZmPbAcXuiyB2xS+rx1yAek8ebBaKA1itRlOQB+dR41dj737vMw== X-Received: by 2002:a05:6e02:1605:b0:2fc:405a:d04d with SMTP id t5-20020a056e02160500b002fc405ad04dmr17539398ilu.320.1667480494286; Thu, 03 Nov 2022 06:01:34 -0700 (PDT) Received: from [192.168.1.35] (c-68-41-54-207.hsd1.mi.comcast.net. [68.41.54.207]) by smtp.gmail.com with ESMTPSA id d15-20020a92680f000000b002ff36cb0a62sm310054ilc.27.2022.11.03.06.01.33 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 03 Nov 2022 06:01:33 -0700 (PDT) Message-ID: <406a2b30-c7ac-c0fd-4354-61aa9791758d@gmail.com> Date: Thu, 3 Nov 2022 09:01:32 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 To: ffmpeg-devel@ffmpeg.org References: <2b7f9605-518a-4cda-6503-7842f22fa620@das-werkstatt.com> <20221026191302.GG4048598@pb2> Content-Language: en-US-large From: Leo Izen In-Reply-To: <20221026191302.GG4048598@pb2> Subject: Re: [FFmpeg-devel] FFV1 slicecrc: "hashxx" instead of "CRC" for speed? 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 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: On 10/26/22 15:13, Michael Niedermayer wrote: > > CRC is not a random pick for error detection, CRC has specfic properties > like for example that whole classes of errors are guranteed to be detected > a random hash will not gurantee that. > for example a properly designed 8bit CRC will detect every single 1 byte change > always. a 8 bit hash like taking 8 bits from SHA256 will detect only 255 out of > 256 1 byte changes I'm a bit confused here, aren't there only 255 one-byte changes in the first place? The 256th is when the byte remains unchanged. That aside I don't believe xxhash is designed to be an error-correcting hash, but rather one that's used for fast database lookup. - Leo Izen (thebombzen) _______________________________________________ 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".