[Ffmpeg-devel] libavcodec h264 decoder

[michael benzon chua]

On 12/15/06, Loren Merritt <lorenm at u.washington.edu> wrote:
>
> On Fri, 15 Dec 2006, michael benzon chua wrote:
> > On 12/15/06, Stefan Gehrer <stefan.gehrer at gmx.de> wrote:
> >
> >> Interesting concept, but as soon as you use some real cryptography
> instead
> >> of just toggling the sign I think the bitstream size will increase as
> some
> >> seemingly random coefficients will be harder to compress than what the
> >> encoder outputs. Or am I missing something?
> >
> > I think this is the case as well. The size of the output .264 file
> increased
> > when I changed the dct values. I'm hoping the effect isn't too
> significant,
> > and that the encryption is still reversible.
>
> The size of the .264 shouldn't change if you just toggle the coefficient's
> sign, because sign isn't compressed.
> Why do you want to mess with the guts of the codec, rather than encrypting
> the whole stream?


Trying to figure out which is more efficient. The only alternative I've
heard of to encrypting everything is encrypting the dct coefficients.


--Loren Merritt
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