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From Mike Jumper <>
Subject Re: general functioning of guacamole
Date Fri, 05 Oct 2018 18:43:06 GMT
On Fri, Oct 5, 2018 at 1:42 AM, Nick Couchman <> wrote:

> On Fri, Oct 5, 2018 at 4:04 AM Galyrith <>
> wrote:
>> ...
>> So I have two questions:
>> 1 / How does guacd manage this translation? does he compress the flow or
>> not?
> guacd attempts to do some analysis of the link between itself and
> Guacamole Client to determine the best image type to send.  I believe it
> uses a combination of JPEG and PNG, but Mike can probably provide more
> accurate information on this.  Obviously JPEGs will be compressed, and PNGs
> may be compressed.  The rest of the stream (commands, keystrokes, etc.) is
> not compressed.  I'm not sure about the audio.

All images sent via Guacamole are compressed - JPEG and PNG are simply two
different compressed image formats, the former being lossy and the latter
being lossless. The internals of guacd will dynamically determine whether
JPEG or PNG is likely to perform better and select automatically between
the two. Only the changed portion of the screen is sent with each update,
though Guacamole will also dynamically reorder, combine, etc. these updates
in an effort to optimize things further.

Timing of updates is also dynamically adjusted based on real-time
measurements of how long each frame takes to generate and how fast the
client is able to process each frame. This is meant to allow Guacamole to
distinguish between time delay due to pure network lag vs. time delay due
to the client being slower than the server, allowing Guacamole to send
updates asynchronously and optimistically.

>> 2 / How much data and how is it managed by the web browser?
In practice, I see typically around 1 or 2 Mbps during normal remote
desktop use. This can go up to around 10 Mbps if you do something rather
intense like watch YouTube.

- Mike

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