Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E6803C433EF for ; Tue, 23 Nov 2021 10:24:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235304AbhKWK1K (ORCPT ); Tue, 23 Nov 2021 05:27:10 -0500 Received: from mga02.intel.com ([134.134.136.20]:51540 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231838AbhKWK1J (ORCPT ); Tue, 23 Nov 2021 05:27:09 -0500 X-IronPort-AV: E=McAfee;i="6200,9189,10176"; a="222218952" X-IronPort-AV: E=Sophos;i="5.87,257,1631602800"; d="scan'208";a="222218952" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Nov 2021 02:24:01 -0800 X-IronPort-AV: E=Sophos;i="5.87,257,1631602800"; d="scan'208";a="571020561" Received: from paasikivi.fi.intel.com ([10.237.72.42]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Nov 2021 02:23:58 -0800 Received: from paasikivi.fi.intel.com (localhost [127.0.0.1]) by paasikivi.fi.intel.com (Postfix) with ESMTP id 3A09A20762; Tue, 23 Nov 2021 12:23:56 +0200 (EET) Date: Tue, 23 Nov 2021 12:23:56 +0200 From: Sakari Ailus To: Jammy Huang Cc: "eajames@linux.ibm.com" , "mchehab@kernel.org" , "joel@jms.id.au" , "andrew@aj.id.au" , "hverkuil-cisco@xs4all.nl" , "gregkh@linuxfoundation.org" , "laurent.pinchart@ideasonboard.com" , "linux-media@vger.kernel.org" , "openbmc@lists.ozlabs.org" , "linux-arm-kernel@lists.infradead.org" , "linux-aspeed@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v5 05/10] media: v4l: Add definition for the Aspeed JPEG format Message-ID: References: <20211118074030.685-1-jammy_huang@aspeedtech.com> <20211118074030.685-6-jammy_huang@aspeedtech.com> <0bed6093-0af6-4fc4-716f-6cf8b1302320@aspeedtech.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <0bed6093-0af6-4fc4-716f-6cf8b1302320@aspeedtech.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jammy, On Fri, Nov 19, 2021 at 10:02:40AM +0800, Jammy Huang wrote: > Hi Sakari, > > On 2021/11/18 下午 08:33, Sakari Ailus wrote: > > Hi Jammy, > > > > On Thu, Nov 18, 2021 at 03:40:26PM +0800, Jammy Huang wrote: > > > This introduces support for the Aspeed JPEG format, where the new frame > > > can refer to previous frame to reduce the amount of compressed data. The > > > concept is similar to I/P frame of video compression. I will compare the > > > new frame with previous one to decide which macroblock's data is > > > changed, and only the changed macroblocks will be compressed. > > > > > > This Aspeed JPEG format is used by the video engine on Aspeed platforms, > > > which is generally adapted for remote KVM. > > > > > > Signed-off-by: Jammy Huang > > > --- > > > v5: > > > - no update > > > v4: > > > - new > > > --- > > > Documentation/media/uapi/v4l/pixfmt-reserved.rst | 12 ++++++++++++ > > > drivers/media/v4l2-core/v4l2-ioctl.c | 1 + > > > include/uapi/linux/videodev2.h | 1 + > > > 3 files changed, 14 insertions(+) > > > > > > diff --git a/Documentation/media/uapi/v4l/pixfmt-reserved.rst b/Documentation/media/uapi/v4l/pixfmt-reserved.rst > > > index b2cd155e691b..23c05063133d 100644 > > > --- a/Documentation/media/uapi/v4l/pixfmt-reserved.rst > > > +++ b/Documentation/media/uapi/v4l/pixfmt-reserved.rst > > > @@ -264,6 +264,18 @@ please make a proposal on the linux-media mailing list. > > > of tiles, resulting in 32-aligned resolutions for the luminance plane > > > and 16-aligned resolutions for the chrominance plane (with 2x2 > > > subsampling). > > > + * .. _V4L2-PIX-FMT-AJPG: > > > + > > > + - ``V4L2_PIX_FMT_AJPG`` > > > + - 'AJPG' > > > + - ASPEED JPEG format used by the aspeed-video driver on Aspeed platforms, > > > + which is generally adapted for remote KVM. > > > + On each frame compression, I will compare the new frame with previous > > > + one to decide which macroblock's data is changed, and only the changed > > > + macroblocks will be compressed. > > > + > > > + You could reference to chapter 36, Video Engine, of AST2600's datasheet > > > + for more information. > > Is this datasheet publicly available? Do you have a URL? > > Sorry, this datasheet is not publicly available. > Hans mentioned this as well in the discussion below: > > https://lkml.org/lkml/2021/11/10/101 If the vendor documentation is not publicly available, you'll need to have the format documented here. Alternatively an open source implementation (e.g. LGPL) is presumably fine, too. -- Regards, Sakari Ailus