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Re: [Qemu-devel] [PATCH v2 08/18] vnc: tight add PNG encoding
From: |
Corentin Chary |
Subject: |
Re: [Qemu-devel] [PATCH v2 08/18] vnc: tight add PNG encoding |
Date: |
Thu, 8 Jul 2010 15:35:46 +0200 |
On Thu, Jul 8, 2010 at 3:19 PM, Daniel P. Berrange <address@hidden> 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 <address@hidden> 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
- [Qemu-devel] [PATCH v2 16/18] vnc: tight: fix rgb_prepare_row, (continued)
- [Qemu-devel] [PATCH v2 16/18] vnc: tight: fix rgb_prepare_row, Corentin Chary, 2010/07/07
- [Qemu-devel] [PATCH v2 10/18] vnc: tight: stop using qdict for palette stuff, Corentin Chary, 2010/07/07
- [Qemu-devel] [PATCH v2 17/18] vnc: tight: split send_sub_rect, Corentin Chary, 2010/07/07
- [Qemu-devel] [PATCH v2 13/18] qemu-thread: add qemu_mutex/cond_destroy and qemu_mutex_exit, Corentin Chary, 2010/07/07
- [Qemu-devel] [PATCH v2 18/18] vnc: better default values for VNC options, Corentin Chary, 2010/07/07
- [Qemu-devel] [PATCH v2 15/18] vnc: add missing lock for vnc_cursor_define(), Corentin Chary, 2010/07/07
- [Qemu-devel] [PATCH v2 08/18] vnc: tight add PNG encoding, Corentin Chary, 2010/07/07
[Qemu-devel] [PATCH v2 11/18] vnc: encapsulate encoding members, Corentin Chary, 2010/07/07
[Qemu-devel] [PATCH v2 14/18] vnc: threaded VNC server, Corentin Chary, 2010/07/07
Re: [Qemu-devel] [PATCH v2 00/18] [PATCH v2 00/18] VNC Updates for 0.13, Rick Vernam, 2010/07/13