MyMPx.org - SMV format description

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SMV format description

In order to create an SMV encoder for GNU/Linux, I've cracked the SMV format. I don't know how many programmers frequent this forum, but if any do, they may want the format description to create their own encoders, so I'm posting it here. Given the quality of the Windows encoders I had to fight to get sample SMV files, the average amateur Windows programmer with a little bit of experience with media files could probably write a better one.

Anyway, here it is:

Code:

An SMV file has three sections, concatenated together:

1) An IMA ADPCM .wav file, with header.

2) An SMV header, described below.

3) A number of .jpeg files, with headers, each prepended by a 24-bit (3-byte)

   little-endian value representing the size, and buffered at the end with

   nulls such that they are at predictable locations (the jpeg modulo).



The SMV header is a magic string in ASCII followed by a number of 24-bit

(3-byte) little-endian values. The following is an example SMV header. Note

that the first entry is the exact ASCII string as it appears in the SMV file,

but the rest are the decimal representation of 24-bit little-endian values.



SMV002000       magic

128             width

160             height

16              header length in 3-byte words (starting at '002' in magic)

1               apparently constant

8533            jpeg modulo

9               fps

1875            # of frames

1               apparently constant

0               apparently constant

3               frames per jpeg

65793           padding? (65793 == 0x010101)

65793           padding?

65793           padding?

65793           padding?

If anybody's interested, my encoder is at http://www.codu.org/smvconv/

Wow, thanks. I'm by no means a programmer but i do have some knowledge in the internal workings of files and know a little linux too.

I just got a SMV player yesterday and i have noticed that the transcoder is pretty slow. I'm sure your info will be of use. ;)

Hi Gregor,

I tested your encoder with my player and it does not work.
I am trying to find what is the problem.

Re: SMV format description

I made small changes in smvconv and it works for me now.
However, there are still several issues with the movie quality.
I put the modified version at
http://www.cs.bgu.ac.il/~yurac/interests/smv-encode/

Re: SMV format description

Hi yurac;

I've tested your smv-encode, version 0.22, on my Philips GoGear SA3125 mp4player.

It works! I've used the following parameters:

-w 127, -h 159, -f 11, -fps 11, -q 50

and the following change on mencoder calling command: rotate=2 to rotate=1. Can this is specified as option on command line?

There is noise for some files on right headphone, as you said. Another little issue is the input file have to be given as full path.

Thanks for your amazing work. My MP4 can be used on linux now.

Thanks !
Thanks to GregorR who cracked the format.

I will add the rotate parameter you request.
I am also writing a gui now.

Tayroni,

Could you please try the new version 0.27?
It includes the changes you requested.

Relative names are ok now.
The rotate parameter is -r
The framerate is now -f

Your command line should look as follows:
smv-encode <input> -w 127 -h159 -q50 -f 11 -n 11 -r 1

Add -d if you want to see the mencoder,mplayer output.

Thanks.

I added a gui and autotools support (smv_encode0.4)
It works for me on Ubuntu Hardy

Re: SMV format description

Sorry Yurac for the delay to answer. My notebook goes down and I was unable to answer.

I tested version 0.52 with gui and the above parameters work very well.

I'm using Ubuntu Hardy too.

Re: SMV format description

hello , i have tested smv convert with a philips sa 3485 and work very well with this parametres smv_encode -b -g 220x176 -f 24 -n 11 -r2 -q 41 but the only one is tht before ia have to rotate the movie 90º with another program to see it fullscreen .

thanks for your work. hugs masmiguel

Pd: there are some way to rotate 180º the movie with de smv convert ?