[FFmpeg-devel] [PATCH] png parser

[Kostya]

On Wed, Jun 24, 2009 at 05:54:17PM +0200, Peter Holik wrote:
> Michael Niedermayer schrieb:
> > On Tue, Jun 23, 2009 at 08:51:12AM +0200, Peter Holik wrote:
> >> Michael Niedermayer schrieb:
[...]
> >
> > could you explain why this is not just looking like lets say mpeg4:
> >
> >     if(!vop_found){
> >         for(i=0; i<buf_size; i++){
> >             state= (state<<8) | buf[i];
> >             if(state == 0x1B6){
> >                 i++;
> >                 vop_found=1;
> >                 break;
> >             }
> >         }
> >     }
> 
> png signature is 8 Bytes
 
Why not use 32-bit state variable? If it equals to the first part
('.PNG') then read additional 32-bit variable from buffer. If it matches
second part of PNG signature then end operation, otherwise assign that
variable to state, skip 3 bytes and continue search.
 
[...] 
>
> cu Peter