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[MBS] JPEG comparison / delta (MBS Xojo Plugin Mailinglist archive)

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Re: [MBS] MIDI Destinations and External Devices   -   Ron Benditt
  [MBS] JPEG comparison / delta   -   Brian Rathbone
   Re: [MBS] JPEG comparison / delta   -   Matthias Buercher
   Re: [MBS] JPEG comparison / delta   -   Christian Schmitz
    Re: [MBS] JPEG comparison / delta   -   Brian Rathbone
     Re: [MBS] JPEG comparison / delta   -   Christian Schmitz
      Re: [MBS] JPEG comparison / delta   -   Brian Rathbone

[MBS] JPEG comparison / delta
Date: 30.01.04 06:31 (Fri, 30 Jan 2004 00:31:41 -0500)
From: Brian Rathbone
Christian,

I realize I am probably asking for a lot here, but I was hoping you would be
able to help me.

I am sending a series of JPEG images over a socket connection. Many times,
the next picture to be sent will only be slightly different that the
previous image. In order to reduce the bandwidth required and improve the
speed, I was trying to figure out a way to compare the 2 images and only
send the delta.

I am currently using the MBS JPEG exporter and importer fuctions to compress
the image.

Can you think of a way to create export delta and import delta functions
that could be used for this purpose?

I have made some meager attempts at this using straight RB code (some of
which from your recent picture comparison post on the RB NUG), but none of
my attempts have been fast enough.

Your opinion would be greatly appreciated.

Thanks, as always, for all of your help.

Brian

Re: [MBS] JPEG comparison / delta
Date: 30.01.04 09:43 (Fri, 30 Jan 2004 09:43:37 +0100)
From: Matthias Buercher
do you make the delta on the jpeg or on the uncompressed picture?
delta on the jpeg is not likely to work.
for the delta on the uncompressed image, you need to use an offset,
because the difference of the pixel value can go from -255 to 255, so
you have to add 128 to get it in the middle range, and you still need
some houskeeping, because you may need 2 frames to catch up with the
difference. if the image is steady, you will probably be faster
dividing the picture into 16*16 blocks and send the blocks that have
changed with some protocol.

but do you want really to dig in this? there is quicktime broadcaster
which encodes mpeg in realtime.

matthias

On Friday, Jan 30, 2004, at 06:31 Europe/Zurich, Brian Rathbone wrote:

> I am currently using the MBS JPEG exporter and importer fuctions to
> compress
> the image.
>
> Can you think of a way to create export delta and import delta
> functions
> that could be used for this purpose?

Re: [MBS] JPEG comparison / delta
Date: 30.01.04 16:21 (Fri, 30 Jan 2004 16:21:16 +0100)
From: Christian Schmitz
Brian Rathbone <<email address removed>> wrote:

> Christian,
>
> Can you think of a way to create export delta and import delta functions
> that could be used for this purpose?

Technical possible, but quite costy.
The solution with tiles is certainly easier.

Mfg
Christian

Re: [MBS] JPEG comparison / delta
Date: 30.01.04 19:34 (Fri, 30 Jan 2004 13:34:09 -0500)
From: Brian Rathbone
Thanks for the input so far. It is much appreciated.

I can do comparisons based upon uncompressed bitmap data.

I have been thinking about using tiles as well. Perhaps I should divide the
picture up into 16x16 tiles and send them individually over the socket with
x,y coordinates.

Do you have something in mind as a tile based solution that we could talk
about, or should I just plow ahead and see what I can come up with?

You opinions are appreciated.

Brian

----- Original Message -----
From: "Christian Schmitz" <<email address removed>>
To: <<email address removed>>
Sent: Friday, January 30, 2004 10:21 AM
Subject: Re: [MBS] JPEG comparison / delta

> Brian Rathbone <<email address removed>> wrote:
>
> > Christian,
> >
> > Can you think of a way to create export delta and import delta functions
> > that could be used for this purpose?
>
> Technical possible, but quite costy.
> The solution with tiles is certainly easier.
>
> Mfg
> Christian
>
> --
> Six thousand functions in one REALbasic plug-in. The MBS Plugin.
> <http://www.monkeybreadsoftware.de/realbasic/plugins.html>
> --
> Web8REALbasic mailing list
> <email address removed>
> http://mail.huynh.de/mailman/listinfo/web8realbasic

Re: [MBS] JPEG comparison / delta
Date: 30.01.04 20:27 (Fri, 30 Jan 2004 20:27:15 +0100)
From: Christian Schmitz
Brian Rathbone <<email address removed>> wrote:

> Do you have something in mind as a tile based solution that we could talk
> about, or should I just plow ahead and see what I can come up with?

I don't think I have code for you know, but if you write something in
RB, I can of course make a plugin for this to make it faster.

Mfg
Christian

Re: [MBS] JPEG comparison / delta
Date: 30.01.04 20:38 (Fri, 30 Jan 2004 14:38:26 -0500)
From: Brian Rathbone
That works for me!

Thanks,

Brian

----- Original Message -----
From: "Christian Schmitz" <<email address removed>>
To: <<email address removed>>
Sent: Friday, January 30, 2004 2:27 PM
Subject: Re: [MBS] JPEG comparison / delta

> Brian Rathbone <<email address removed>> wrote:
>
> > Do you have something in mind as a tile based solution that we could
talk
> > about, or should I just plow ahead and see what I can come up with?
>
> I don't think I have code for you know, but if you write something in
> RB, I can of course make a plugin for this to make it faster.
>
> Mfg
> Christian
>
> --
> Six thousand functions in one REALbasic plug-in. The MBS Plugin.
> <http://www.monkeybreadsoftware.de/realbasic/plugins.html>
> --
> Web8REALbasic mailing list
> <email address removed>
> http://mail.huynh.de/mailman/listinfo/web8realbasic