Okay. Re-reading your code, I think that you only want to replace the paired bits on even bit boundaries?

Substitute this for the other regex.

$bits =~ s[(..)][     ## Look at every pair of bits
    $1 eq '00'        ## If they are 00 
        ? '11'        ## replace them 11
        : $1 eq '11'  ## If they are 11
            ? '00'    ## replace them with 00
            : $1      ## else leave them alone
]ge;
[download]

That will slow it down a bit, but it will still run quicker than splitting the string into and array etc.

OK, that piece of code worked perfect. However, now when I look at the file the first frame is on synce but the rest are off by a few bits. I believe this to be because when we remove the bits prior to the sync and then pack it up the frame is no longer on a byte boundary. This is the problem I've been dealing with. If I remove a couple bits from the beginning then when I pack it up the files being padded to place it back on a byte boundary. I'm starting to think I'm going to have to just suck it up and either deal with the slowness or get a C programmer to do it. Any thoughts??

... the rest are off by a few bits.

The only way that can be true, is if

• the sync mark itself is not meant to be on a byte boundary.

  Ie. If it is meant be a few bits into each frame?

  This is possible and easily dealt with.

• Or the frames are themselves are "a few bits" longer than 960 bytes, which doesn't makes much sense.

  Could you unpack the first 3 or 4 frames of the (raw) file to binascii and post them on your scratchpad?

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