copy /b : What is the interest ???

[Tonio]

Hi everybody,

For example :
In a directory I have 2 WMA files who are OK.
File1 = 10 MB
File2 = 5 MB

I want copied these 2 files on one and last file (test.wma)
I used 'copy /b...' as explain in help...

---------------------------------------------
C:\>copy /b *.wma test.wma
file1.wma
file2.wma
COPY OK !
---------------------------------------------

At the end, I have a big file 15 MB.
When I play test.wma, I listen file1.wma only.....
It isn't concatenate...
What is the interest of "copy /b" ????????????

Thx
Tonio

 

[David Candy]

What makes you think wma files can be combined? Nearly all multimedia and most other files have headers.

 

[Tonio]

David Candy a écrit :

What makes you think wma files can be combined? Nearly all multimedia and most other files have headers.

In an Microsoft example, they do this :

copy /b *.exe combin.exe

So, replace wma by exe... and the result is the same....
What is the interest ?????? Il don't understand the option '/b'.
What is the goal of this option ???

 

[David Candy]

You miss the f*ckin point. Why would they be combinable. Nothing to do with copy or /b.

/b means binary. Combines are ascii by default (and file copies are binary by default). Ascii are text files and follow text file rules. One rule is is Chr(26) terminates a file. Ascii is meant for stream devices (like com and prn ports) and binary for block devices (like hard drives). There is no way to know size on a stream so there is a end of file character.

 

[Matthias Tacke]

David Candy a écrit :

In an Microsoft example, they do this :

copy /b *.exe combin.exe

So, replace wma by exe... and the result is the same....
What is the interest ?????? Il don't understand the option '/b'.
What is the goal of this option ???

The /b option is still useful. The end of file character Ctrl-Z may
occur in non-text file formats. To avoid these files being shortened
you have to use /b for every file - I'm not shure if it will work
with *.wav. The header of a wma contains information on the length
/duratin of the file it is not sufficient to simply copy the fils
to one, you need a tool which understands and corrects the headers
when concatenating the files.
I'll naever use wma or aac so I can't name such a tool ;-)

 

[Al Dunbar [MS-MVP]]

David Candy a écrit :
In an Microsoft example, they do this :

copy /b *.exe combin.exe

So, replace wma by exe... and the result is the same....
What is the interest ?????? Il don't understand the option '/b'.
What is the goal of this option ???

The MS example is a good one too, in that the copy/b operation does exactly
what it is supposed to do: copy and concatenate binary files. The docs NEVER
say that there is a functional ability to concatenate ANY type of binary
file into a similarly working one. If you did take their "advice" and
combine two .exe's into one, would you expect that you could run both
programs by running the combined version.

Then consider that one could copy two binaries that are in completely
different formats. Suppose you combined notepad.exe with a .WMA file, what
would you expect the result to actually be?

IMHO, the binary copy is there for those applications that need it. If you
want to somehow combine two .WMA files, you are likely going to need some
sort of multimedia editor to tell it if you want to run the two in sequence
or somehow mix them in together. No basic command line functionality is
going to do that for you.

/Al

 

[Paul R. Sadowski [MVP]]

Hello, Al:
On Sun, 23 Jan 2005 11:15:45 -0700: you wrote...

ADM> IMHO, the binary copy is there for those applications that need it. If

Such as recombining large files split across flopies or CDs.

ADM> you want to somehow combine two .WMA files, you are likely going to
ADM> need some sort of multimedia editor to tell it if you want to run the
ADM> two in sequence or somehow mix them in together. No basic command line
ADM> functionality is going to do that for you.

Somewhat sideways but one can create a simple playlist:
echo c:\music\one.wma > mylist.m3u
echo c:\music\two.wma >> mylist.m3u
mylist.m3u

Regards, Paul R. Sadowski [MVP].