Help decoding a file

bbc micro/electron/atom/risc os coding queries and routines
Post Reply
User avatar
pixelblip
Posts: 2233
Joined: Wed Feb 04, 2015 7:19 pm
Location: London
Contact:

Help decoding a file

Post by pixelblip » Sun Jun 30, 2019 2:01 pm

Hi there
I am trying to get some help with something difficult :)
I am using "Movie Maker' as some of you know - now we have the manual it is really great. Like a dream come true!
I do find that designing things it it is very slow....you have to use the cursor keys.....so to build up scenes takes ages.

What I'd like to ask is if someone might be able to help me get a picture inside the program....
The trouble is Movie Maker on the BBC has it's own format. You can save a teletext screen but you can't load one in.
So the question is how can you do it?
Well it let's you load shapes in....and they can be over a certain size....(say a quarter of the screen).
What is needed is someone who could peer inside a Movie Maker file to see how the shapes are made up. Is anyone up for that? :)
I haven't come across a better animation package.....but trying to build a scene is like trying to paint the Forth Bridge!

If anyone can spare any time then maybe it might be possible to get a teletext screen into Movie Maker....we need to split the screen up into chunks and somehow assign it a shape and give it a name...say 8 times...it's not easy!
Alternatively if someone can suggest a way of peering inside a file that would help - I tried opening a MM file in notepad and it's gibberish.

Thanks
Last edited by pixelblip on Sun Jun 30, 2019 2:02 pm, edited 1 time in total.

User avatar
jgharston
Posts: 4129
Joined: Thu Sep 24, 2009 12:22 pm
Location: Whitby/Sheffield
Contact:

Re: Help decoding a file

Post by jgharston » Sun Jun 30, 2019 8:54 pm

Can you post a sample file and a photo of what it's supposed to look like?

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.32
(C) Copyright J.G.Harston 1989,2005-2020
>_

User avatar
pixelblip
Posts: 2233
Joined: Wed Feb 04, 2015 7:19 pm
Location: London
Contact:

Re: Help decoding a file

Post by pixelblip » Tue Jul 02, 2019 5:36 pm

Thanks for trying to help me here.
If you have a look at the attached picture it has a '400' logo on it.
I exported the frame out from mm called 'frame' on the bbc disc.
I also exported the full file out with everything called 'full' on the bbc disc.
You can't export the entry on it's own - only a teletext frame.

So the thing to see is how is the 400 made up? The sprite edge handles take up e.g. a quarter of the screen.

I also saved the saved state in Beeb em....so you can have a look...you are brave trying to help me!

I also included the files I saved from MM on the disk SSD here....

It would be super to be able to get a picture into this program. Would be amazing!
Attachments
400.ssd
(1.75 KiB) Downloaded 23 times
mmstate.uef
(269.46 KiB) Downloaded 23 times
sc.png

User avatar
tautology
Posts: 442
Joined: Wed Sep 01, 2010 3:26 pm
Contact:

Re: Help decoding a file

Post by tautology » Tue Jul 02, 2019 8:23 pm

The file FRAME is just a MODE 7 screen (i.e. you can just *LOAD FRAME 7C00). Looking at FULL now

User avatar
tautology
Posts: 442
Joined: Wed Sep 01, 2010 3:26 pm
Contact:

Re: Help decoding a file

Post by tautology » Tue Jul 02, 2019 9:04 pm

It appears to just have a chunk of MODE 7 data and translate it to its own format.

At the start we have a shape header:

00 DA - Appears to be the size of the shape
00 40 00 00 80 - Unknown
27 - width of image in characters
00 00 80 - unknown
05 - height of image in rows
0F C6 - unknown
34 30 30 0D - Name of shape: "400"+CR

The unknown data will include size information (I'm guessing that that's the 27 and 05 bytes).

Then we have a line of data for the shape, on the left here is the moviemaker file, on the right; the meta characters (i.e. colours are the same). The graphics characters are the MODE 7 character - &A0. Why they do this I don't know.

97 97
00 A0
9A 9A
00 A0
00 A0
00 A0
00 A0
00 A0
00 A0
00 A0
00 A0
00 A0
00 A0
00 A0
00 A0
00 A0
00 A0
00 A0
00 A0
00 A0
00 A0
91 91
00 A0
00 A0
00 A0
00 A0
00 A0
00 A0
20 E0
3C FC
00 A0
00 A0
38 F8
3C FC
3C FC
10 B0
38 F8
3C FC
3C FC
Last edited by tautology on Sat Jul 06, 2019 8:50 pm, edited 1 time in total.

User avatar
FourthStone
Posts: 1030
Joined: Thu Nov 17, 2016 2:29 am
Location: Brisbane, Australia
Contact:

Re: Help decoding a file

Post by FourthStone » Tue Jul 02, 2019 11:49 pm

Seems the colour codes all have top bit set and the rest of the data has the top two bits stripped off ; C0 - 11000000

Not sure of significance but thought it might be useful, if I get a chance I'll have a closer look :-k

They're probably reusing top two bits for special codes including colours.

User avatar
pixelblip
Posts: 2233
Joined: Wed Feb 04, 2015 7:19 pm
Location: London
Contact:

Re: Help decoding a file

Post by pixelblip » Wed Jul 03, 2019 7:19 am

Thanks for your detective work everyone.

The aim is to get something like this in a Movie Maker.....somehow.....

http://edit.tf/#0:LoECBAgQIECBAgQIECDUg ... ECBAgQIECA
Last edited by pixelblip on Wed Jul 03, 2019 7:19 am, edited 1 time in total.

User avatar
pixelblip
Posts: 2233
Joined: Wed Feb 04, 2015 7:19 pm
Location: London
Contact:

Re: Help decoding a file

Post by pixelblip » Sun Jul 12, 2020 12:21 pm

Hi
I still can't give up on this. It's in my head.
Can you answer a question I am puzzled by.
When I open the file "4" in DFS explorer (as hex) and save it again as "TEST3" from DFS explorer and import it back to the ssd without any changes the file size completely changes. It goes from 04000 to 013002 Movie maker can't read it.
Why is that? Screenshot included.
I'm basically trying to work out if I can import a teletext screen into this software. I include the disc so you can see for yourself.
Thanks for any help everyone.
Attachments
BERKTEST.dsd
(316 KiB) Downloaded 11 times
Capture.PNG

User avatar
pixelblip
Posts: 2233
Joined: Wed Feb 04, 2015 7:19 pm
Location: London
Contact:

Re: Help decoding a file

Post by pixelblip » Sun Jul 12, 2020 12:32 pm

It could be I shouldn't be viewing it as hex. How do I decode this file...............

User avatar
pixelblip
Posts: 2233
Joined: Wed Feb 04, 2015 7:19 pm
Location: London
Contact:

Re: Help decoding a file

Post by pixelblip » Sun Jul 12, 2020 2:10 pm

This is probably to difficult to work out so don't worry........

Post Reply

Return to “programming”