From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 33095125C9; Fri, 3 May 2024 01:47:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714700843; cv=none; b=G4Zn8Vc1dd8dwpZWmnQCfPotUXsOaKeoZTEJtOxrLjLrJkUx9XNILruxFdOXPw6/bBb80PGs3/hAkhaZlIfx+iP4Hc92GizjGdK58MaQzhHZ30MXbHZMuppxSAdIMEftwl74E5+mc4tCSHdIU8VAx/lDftZ/GmDKZWhp6XnWZzE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714700843; c=relaxed/simple; bh=jnztmxuaRUJ/EUjiAcJ6LSXXmWw6auqF5LGM5XsjF8A=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=EXodj5zcdND99yW5yNsTCjvpTWtIijJ1o29wDKVDWSCPHZvq5y47zqnuI8PUBeKzZe5YyDhbepO3pYma6FmPTmEbKgQctZVOihdDOUDtaBXTRfkfmTOXBEDm5Z553UA6zRi6UwL6aZILpJycgSXYo4KORvEqReW6LTaIOAG1pKE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=huJ8dvqB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="huJ8dvqB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4DB22C113CC; Fri, 3 May 2024 01:47:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1714700842; bh=jnztmxuaRUJ/EUjiAcJ6LSXXmWw6auqF5LGM5XsjF8A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=huJ8dvqB+TN/5IgJ6rtnCXfVgXOlZfAdZYA/7vs7YuLO962TFb+avL/V+5+Rni204 u9/f/fRre6WsTm1XAt3biIJ7MtrAkKMlIcdBiezfCUBrbLhc4GQOvDOFdoMrywy15G HVDUuTPVvWfCo/LWmMR/YAYd76bJuAAZMqubdIdTqLpUHdoyUTiJr/OhqWHi1DQwX/ TTfuZAYA+OBxUo5XMadmDCz6i1lMZq0CwsUh/khAN9yCvtk9LCjCamRsZktG50n/EX TDY9n+egIwFoWC/EpRvSADEFoGvRx918hONbY9legxC9/dh+ROPGl1a4VHgQWky9Ab R0tQiZIJgiz0A== Date: Fri, 3 May 2024 10:47:19 +0900 From: Mark Brown To: Mauro Carvalho Chehab Cc: Takashi Iwai , Sebastian Fricke , Shengjiu Wang , hverkuil@xs4all.nl, sakari.ailus@iki.fi, tfiga@chromium.org, m.szyprowski@samsung.com, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, shengjiu.wang@gmail.com, Xiubo.Lee@gmail.com, festevam@gmail.com, nicoleotsuka@gmail.com, lgirdwood@gmail.com, perex@perex.cz, tiwai@suse.com, alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v15 00/16] Add audio support in v4l2 framework Message-ID: References: <1710834674-3285-1-git-send-email-shengjiu.wang@nxp.com> <20240430082112.jrovosb6lgblgpfg@basti-XPS-13-9310> <20240430172752.20ffcd56@sal.lan> <87sez0k661.wl-tiwai@suse.de> <20240502095956.0a8c5b26@sal.lan> <20240502102643.4ee7f6c2@sal.lan> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="YhSjxC/xCHptpvaf" Content-Disposition: inline In-Reply-To: <20240502102643.4ee7f6c2@sal.lan> X-Cookie: lisp, v.: --YhSjxC/xCHptpvaf Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, May 02, 2024 at 10:26:43AM +0100, Mauro Carvalho Chehab wrote: > Mauro Carvalho Chehab escreveu: > > There are still time control associated with it, as audio and video > > needs to be in sync. This is done by controlling the buffers size=20 > > and could be fine-tuned by checking when the buffer transfer is done. =2E.. > Just complementing: on media, we do this per video buffer (or > per half video buffer). A typical use case on cameras is to have > buffers transferred 30 times per second, if the video was streamed=20 > at 30 frames per second.=20 IIRC some big use case for this hardware was transcoding so there was a desire to just go at whatever rate the hardware could support as there is no interactive user consuming the output as it is generated. > I would assume that, on an audio/video stream, the audio data > transfer will be programmed to also happen on a regular interval. With audio the API is very much "wake userspace every Xms". --YhSjxC/xCHptpvaf Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmY0QicACgkQJNaLcl1U h9DEDgf+OxkntU8LcfqnvW2Z51UqNQJ0p62Te/DmJ+wZWQotYcbwAQdb4fMKfeyw TU+Kka5bvWBtYfhoCnXFlDqQUh4Ldk7wZEWfHS2KCCM+o3mr/WHvxCRqSvy2geXZ +76U6qA5/RPQnAFUlNe9Kp4LK4LpvGg9KONljKpsIdFBEDvJG84wr+zLwDuboy4O rVP1hJQmucWST9qsBWFT+7VmJt9tbK2I3iwIB2Z3utiJvBFvyyj8bVMx5I1ssxfj Rh5yL+iQ+aEQkTwEBTzuAS055XYNxzl/eBa25iRWCgoYOrMiphGpWBDWp5qUoPiB SWVL9dU2q9I5o4Y+GNohSdEw9Rctfw== =OLs5 -----END PGP SIGNATURE----- --YhSjxC/xCHptpvaf--