From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Arkver Subject: Re: [PATCH v3 3/9] DocBook/v4l: Add compressed video formats used on MT8173 codec driver Date: Tue, 12 Jul 2016 20:31:10 +0100 Message-ID: References: <1464611363-14936-1-git-send-email-tiffany.lin@mediatek.com> <1464611363-14936-2-git-send-email-tiffany.lin@mediatek.com> <1464611363-14936-3-git-send-email-tiffany.lin@mediatek.com> <1464611363-14936-4-git-send-email-tiffany.lin@mediatek.com> <5a793171-24a7-4e9e-8bfd-f668c789f8e0@xs4all.nl> <1468205771.3725.8.camel@mtksdaap41> <1468350511.8843.16.camel@gmail.com> <1468350842.8843.18.camel@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1468350842.8843.18.camel@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: nicolas@ndufresne.ca, =?UTF-8?B?V3UtQ2hlbmcgTGkgKOadjuWLmeiqoCk=?= , tiffany lin Cc: Hans Verkuil , Hans Verkuil , Daniel Thompson , Rob Herring , Mauro Carvalho Chehab , Matthias Brugger , Daniel Kurtz , Pawel Osciak , Eddie Huang , Yingjoe Chen , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, linux-mediatek@lists.infradead.org, Lin PoChun List-Id: devicetree@vger.kernel.org On 12/07/16 20:14, Nicolas Dufresne wrote: > Le mardi 12 juillet 2016 =C3=A0 15:08 -0400, Nicolas Dufresne a =C3=A9= crit : >> Le mardi 12 juillet 2016 =C3=A0 16:16 +0800, Wu-Cheng Li (=E6=9D=8E=E5= =8B=99=E8=AA=A0) a =C3=A9crit : >>> Decoder hardware produces MT21 (compressed). Image processor can >>> convert it to a format that can be input of display driver. >>> Tiffany. >>> When do you plan to upstream image processor (mtk-mdp)? >>>> It can be as input format for encoder, MDP and display drivers in >>> our >>>> platform. >>> I remember display driver can only accept uncompressed MT21. Right? >>> Basically V4L2_PIX_FMT_MT21 is compressed and is like an opaque >>> format. It's not usable until it's decompressed and converted by >>> image >>> processor. >> Previously it was described as MediaTek block mode, and now as a >> MediaTek compressed format. It makes me think you have no idea what >> this pixel format really is. Is that right ? >> >> The main reason why I keep asking, is that we often find similaritie= s >> between what vendor like to call their proprietary formats. Doing th= e >> proper research helps not creating a mess like in Android where you >> have a lot of formats that all point to the same format. I believe >> there was the same concern when Samsung wanted to introduce their Z- >> flip-Z NV12 tile format. In the end they simply provided sufficient >> documentation so we could document it and implement software >> converters >> for test and validation purpose. > Here's the kind of information we want in the documentation. > > https://chromium.googlesource.com/chromium/src/media/+/master/base/vi= de > o_types.h#40 > > // MediaTek proprietary format. MT21 is similar to NV21 except the= memory > // layout and pixel layout (swizzles). 12bpp with Y plane followed= by a 2x2 > // interleaved VU plane. Each image contains two buffers -- Y plan= e and VU > // plane. Two planes can be non-contiguous in memory. The starting= addresses > // of Y plane and VU plane are 4KB alignment. > // Suppose image dimension is (width, height). For both Y plane an= d VU plane: > // Row pitch =3D ((width+15)/16) * 16. > // Plane size =3D Row pitch * (((height+31)/32)*32) > > Now obviously this is incomplete, as the swizzling need to be documen= ted of course. Not sure where that chromium comment came from, but if MT21 really is=20 similar to NV21 (a 4:2:0 format) and has 2x2 downsampled chroma, then=20 the combined VU plane will be half the size of the Y plane. Maybe that's not relevant to this discussion. Regards, Ian > >> regards, >> Nicolas > -- > To unsubscribe from this list: send the line "unsubscribe linux-media= " in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html