From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8AAE6C4363A for ; Tue, 20 Oct 2020 14:53:50 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AEE9121741 for ; Tue, 20 Oct 2020 14:53:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b="iOJrK/kn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AEE9121741 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=igalia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:49092 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kUt1I-0004L1-IS for qemu-devel@archiver.kernel.org; Tue, 20 Oct 2020 10:53:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48922) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kUswr-000870-UW; Tue, 20 Oct 2020 10:49:14 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:43697) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kUswp-0003E4-JY; Tue, 20 Oct 2020 10:49:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Type:MIME-Version:Message-ID:Date:References:In-Reply-To:Subject:Cc:To:From; bh=LbMiPL9FFt0EQVo9WJDMUq62Xsx5XI3dp90IFeWpWq4=; b=iOJrK/knkDlQQ4fJwPydnCeTCnteg5g6rvKXRA8L2TtMZpf/+rpK8Vpjq2dK1dfvSQ3NvlzSbu/D6u38KlbC29zqnyNxmGLZkGU196bMyn4Q4e12HbrrRZRu2/d1LMVGfeSC3ETj3CmjBUA5xDnC3VlaWlvtRgD26mmOVs0lZxlSxDI7pk8ysojTwCeN6wSwkJpmuyH9oeWFf/cxQgb4csfh6JqvRYXvEyylPd5FUpZefbDpbWBlg9UQFrW+3nWtmJvo0QRN42x73XHaBObrLM7nRHDCgb5RNtR9qy3jWgPwKGPDmBNmWjskBhH5fOnszUFJdxb+JaPLCR4H485TJw==; Received: from maestria.local.igalia.com ([192.168.10.14] helo=mail.igalia.com) by fanzine.igalia.com with esmtps (Cipher TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim) id 1kUswg-0008M1-Kg; Tue, 20 Oct 2020 16:49:02 +0200 Received: from berto by mail.igalia.com with local (Exim) id 1kUswg-00059k-B5; Tue, 20 Oct 2020 16:49:02 +0200 From: Alberto Garcia To: Eric Blake , "Wang\, Wei W" , Kevin Wolf Subject: Re: Question on Compression for Raw Image In-Reply-To: References: <516589845d6f42d0b00784d16b59b5dc@intel.com> <20201020080051.GA4452@merkur.fritz.box> <6124d55766e4477299a5796a002276a0@intel.com> User-Agent: Notmuch/0.18.2 (http://notmuchmail.org) Emacs/24.4.1 (i586-pc-linux-gnu) Date: Tue, 20 Oct 2020 16:49:02 +0200 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=178.60.130.6; envelope-from=berto@igalia.com; helo=fanzine.igalia.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/20 10:36:44 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x (no timestamps) [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "lersek@redhat.com" , "qemu-devel@nongnu.org" , "qemu-block@nongnu.org" , "mreitz@redhat.com" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue 20 Oct 2020 04:32:23 PM CEST, Eric Blake wrote: > My recommendation would be implementing a new BDS filter that does > uncompression. Then, you could do things like: > > raw -> decompress -> file.xz This would work, although read-only and you would need a compression format that supports random access (I think that's the case with xz, at least if you compress it using small blocks). Berto