Re: [PATCH v1] vnc: fix VNC artifacts

[Cameron Esfahani]

Yes.  Personally, I'd also take the change to vnc-enc-zrle.c: because 
vs->zrle->zlib is reset at the top of the function, using vs->zrle->zlib.offset 
in determining zstream->next_out and zstream->avail_out is useless.

Cameron Esfahani
address@hidden

"All that is necessary for the triumph of evil is that good men do nothing."

Edmund Burke



> On Jan 16, 2020, at 11:45 PM, Gerd Hoffmann <address@hidden> wrote:
> 
> On Thu, Jan 16, 2020 at 07:50:58PM -0800, Cameron Esfahani wrote:
>> Remove VNC optimization to reencode framebuffer update as raw if it's
>> smaller than the default encoding.  QEMU's implementation was naive and
>> didn't account for the ZLIB z_stream mutating with each compression.  Just
>> saving and restoring the output buffer offset wasn't sufficient to "rewind"
>> the previous encoding.  Considering that ZRLE is never larger than raw and
>> even though ZLIB can occasionally be fractionally larger than raw, the
>> overhead of implementing this optimization correctly isn't worth it.
> 
> So just revert de3f7de7f4e257 then ...
> 
>> In my investigation, ZRLE always compresses better than ZLIB so
>> prioritize ZRLE over ZLIB, even if the client hints that ZLIB is
>> preferred.
> 
> ... and make this a separate patch?
> 
> cheers,
>  Gerd
>