From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=34184 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OWrGb-0007Tl-HX for qemu-devel@nongnu.org; Thu, 08 Jul 2010 09:35:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OWrGV-0000YF-KJ for qemu-devel@nongnu.org; Thu, 08 Jul 2010 09:35:53 -0400 Received: from mail-fx0-f45.google.com ([209.85.161.45]:58612) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OWrGV-0000YA-G7 for qemu-devel@nongnu.org; Thu, 08 Jul 2010 09:35:47 -0400 Received: by fxm5 with SMTP id 5so443443fxm.4 for ; Thu, 08 Jul 2010 06:35:46 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20100708131901.GH32528@redhat.com> References: <1278529086-10391-1-git-send-email-corentincj@iksaif.net> <1278529086-10391-9-git-send-email-corentincj@iksaif.net> <20100708094805.GC32528@redhat.com> <20100708131901.GH32528@redhat.com> Date: Thu, 8 Jul 2010 15:35:46 +0200 Message-ID: Subject: Re: [Qemu-devel] [PATCH v2 08/18] vnc: tight add PNG encoding From: Corentin Chary Content-Type: text/plain; charset=ISO-8859-1 List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: Anthony Liguori , qemu-devel@nongnu.org, Alexander Graf On Thu, Jul 8, 2010 at 3:19 PM, Daniel P. Berrange wrote: > On Thu, Jul 08, 2010 at 03:10:31PM +0200, Corentin Chary wrote: >> On Thu, Jul 8, 2010 at 11:48 AM, Daniel P. Berrange wrote: >> > On Wed, Jul 07, 2010 at 08:57:56PM +0200, Corentin Chary wrote: >> >> Introduce a new encoding: VNC_ENCODING_TIGHT_PNG [1] (-269) with a new >> >> tight filter VNC_TIGHT_PNG (0x0A). When the client tells it supports the Tight PNG >> >> encoding, the server will use tight, but will always send encoding pixels using >> >> PNG instead of zlib. If the client also told it support JPEG, then the server can >> >> send JPEG, because PNG will only be used in the cases zlib was used in normal tight. >> > >> > I know that VNC_ENCODING_TIGHT_PNG / -260 is already allocated to >> > QEMU in the RFB specification. Who is the authority for allocating >> > tight filter numbers, and have they recorded/approved use of 0x0A >> > for this PNG capability ? >> > >> >> Tight PNG should considered as a new encoding, not as a tight pseudo encoding. >> When using Tight PNG, the server will send rect updates with -260, not 7. > > Why layer this into the rest of the Tight protocol decoding then ? What > benefit does it offer over a more straightforward standalone "PNG" encoding, > that was completely independant of any tight based encoding. > Because: - we also want a lossy encoding (Jpeg) for some parts (adaptive choice between jpeg and png/zlib based on update frequency is comming soon). - we want the "fill" encoding for solid color rectangles A standalone "PNG" encoding would work for some use case, and could be added later, but Tight PNG is more than that. -- Corentin Chary http://xf.iksaif.net