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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 E1BA7C433ED for ; Wed, 5 May 2021 15:39:06 +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 9F35B61104 for ; Wed, 5 May 2021 15:39:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F35B61104 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bugs.launchpad.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:52854 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1leJc7-0001Pc-FI for qemu-devel@archiver.kernel.org; Wed, 05 May 2021 11:39:03 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38888) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1leJUS-0001ub-Dk for qemu-devel@nongnu.org; Wed, 05 May 2021 11:31:09 -0400 Received: from indium.canonical.com ([91.189.90.7]:46488) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1leJUQ-0005Id-Ag for qemu-devel@nongnu.org; Wed, 05 May 2021 11:31:08 -0400 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.93 #5 (Debian)) id 1leJUL-0005oc-5Z for ; Wed, 05 May 2021 15:31:01 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id B50BB2E81B9 for ; Wed, 5 May 2021 15:30:59 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Wed, 05 May 2021 15:24:26 -0000 From: Thomas Huth <1861458@bugs.launchpad.net> To: qemu-devel@nongnu.org X-Launchpad-Notification-Type: bug X-Launchpad-Bug: product=qemu; status=Incomplete; importance=Undecided; assignee=None; X-Launchpad-Bug-Tags: audio X-Launchpad-Bug-Information-Type: Public X-Launchpad-Bug-Private: no X-Launchpad-Bug-Security-Vulnerability: no X-Launchpad-Bug-Commenters: noah-bergbauer th-huth X-Launchpad-Bug-Reporter: Noah Bergbauer (noah-bergbauer) X-Launchpad-Bug-Modifier: Thomas Huth (th-huth) References: <158042156192.19296.13362308580628501069.malonedeb@gac.canonical.com> Message-Id: <162022826680.6735.2567247015340604763.malone@wampee.canonical.com> Subject: [Bug 1861458] Re: Clock drift issue with -soundhw hda X-Launchpad-Message-Rationale: Subscriber (QEMU) @qemu-devel-ml X-Launchpad-Message-For: qemu-devel-ml Precedence: bulk X-Generated-By: Launchpad (canonical.com); Revision="d6ba96cccb3d3e356754af3137c6128a6c17e2a8"; Instance="production" X-Launchpad-Hash: 0ae8f56b86599fe4e044bdad4190089bf2d8568a Received-SPF: none client-ip=91.189.90.7; envelope-from=bounces@canonical.com; helo=indium.canonical.com X-Spam_score_int: -65 X-Spam_score: -6.6 X-Spam_bar: ------ X-Spam_report: (-6.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Bug 1861458 <1861458@bugs.launchpad.net> Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The QEMU project is currently considering to move its bug tracking to another system. For this we need to know which bugs are still valid and which could be closed already. Thus we are setting older bugs to "Incomplete" now. If you still think this bug report here is valid, then please switch the state back to "New" within the next 60 days, otherwise this report will be marked as "Expired". Or please mark it as "Fix Released" if the problem has been solved with a newer version of QEMU already. Thank you and sorry for the inconvenience. ** Changed in: qemu Status: New =3D> Incomplete ** Tags added: audio -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1861458 Title: Clock drift issue with -soundhw hda Status in QEMU: Incomplete Bug description: Here's the scenario: I'm working on code for loopback audio recording (i.e. recording what you're hearing) using WASAPI on Windows. As I usually develop on Linux, I'm using qemu to test this on a Windows 10 VM. The heart of WASAPI audio recording is the IAudioCaptureClient::GetBuffer function (https://docs.microsoft.com /en-us/windows/win32/api/audioclient/nf-audioclient- iaudiocaptureclient-getbuffer). Among other things, this function produces a timestamp for when the audio buffer it returned is supposed to be played. When the audio device in question is the qemu hda device, this timestamp is wrong. There is a clock drift error (I measured it to be about 0.1%, i.e. 1ms drift every second =3D a full second after 16 minutes) that causes the audio clock to advance faster than the system clock. Paradoxically, this does not affect audio playback through qemu at all, no delay there. Only the timestamps returned to recording applications are completely bogus. Unfortunately I'm not intimately familiar with the inner workings of Intel HD Audio. All I can tell you is that this timestamp is supposedly obtained directly from the hardware (which would be qemu in this case), which is also why e.g. chromium implements a workaround for buggy hardware that returns incorrect timestamps. Here are the relevant parts of my command line (version 4.2.0): -enable-kvm -machine pc-q35-3.1,kernel-irqchip=3Don -cpu host,kvm=3Doff,h= v_time,hv_relaxed,hv_vapic,hv_spinlocks=3D0x1fff,hv_vendor_id=3DNvidiaFuckU= -rtc base=3Dlocaltime -nodefaults -soundhw hda Just wanted to let you know about this because it took me three days of utter confusion and frustration to figure this out. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1861458/+subscriptions