[Ffmpeg-devel] Last jpeg patch to support multiple-scan JPEGs

[Aurelien Jacobs]

On Tue, 21 Nov 2006 10:15:44 +0100
Cyril Russo <cyril.russo at nexvision.fr> wrote:

> Kostya a ?crit :
> > On Mon, Nov 20, 2006 at 06:56:08PM +0100, Cyril Russo wrote:
> >   
> >> Michael Niedermayer a ?crit :
> >>     
> >>> Hi
> >>>
> >>> On Mon, Nov 20, 2006 at 02:26:34PM +0100, Cyril Russo wrote:
> >>>  
> >>>       
> >>>> Hi,
> >>>>
> >>>>
> >>>>    
> >>>>         
> >>>>>> Worse, the patch from Kostya doesn't solve the multiple scan JPEG   
> >>>>>> decoding errors as (s)he pretends. The problem is fully unrelated.
> >>>>>> Interleaved JPEG != Progressive JPEG != Multiple scan JPEG
> >>>>>>        
> >>>>>>             
> >>>>>  kostya posted a second patch which adds Multiple scan JPEG sipport
> >>>>>  by removing 6 lines and chagning 2, while yours duplicates a whole 
> >>>>>      
> >>>>>           
> >>>>  function (which btw ive complained about in my review and you ignored
> >>>>    
> >>>>         
> >>>>>  it)
> >>>>>      
> >>>>>           
> >>>>   
> >>>> No, it's wrong. Kostya's patch doesn't add multiple scan JPEG support. 
> >>>> He (I make the assumption he is a male)
> >>>> added progressive support. There is a big difference with multiple scan 
> >>>> support.
> >>>>         
> >
> > Actually, progressive JPEG uses multiple scans too so after integrating it
> > was easy to add proper support for multiple scans.
> >
> >   
> >>>>    
> >>>>         
> >>> kostya did send 2 patches one for progressive and one for multiple scan
> >>> jpeg
> >>>
> >>>
> >>>  
> >>>       
> >>>> Again, try to decode the JPEG I've posted before with kostya version, it 
> >>>> will fail.
> >>>>    
> >>>>         
> >>> kostya said it works so ill trust him considering that you seem to be
> >>> a little confused about which patch i speak off
> >>>
> >>> [...]
> >>>  
> >>>       
> >> Ok, let's make things clear. I, and I suppose, all of us too, want to be 
> >> able to decode all standard JPEGs.
> >> I've found both patch from kostya, and only the last one got applied.
> >> Anyway, the previous patch from /Mon Nov 20 06:51:15 CET 2006 /doesn't 
> >> work either (the index in the scan is not used for decoding the scan 
> >> while it should)/
> >>     
> >
> > No, you have missed it (it was posted in your thread 'Incorrect JPEG decoding
> > with patch').
> >
> >   
> >> /Of course you can trust anyone older than me, I'm new here, but I'm not 
> >> new in image processing.
> >> Again, if you don't want to believe me, believe yourself by compiling 
> >> lastest kostya version, and launch :
> >> wget http://xryl669ny.free.fr/MyFile000.jpg && mv MyFile000.jpg 
> >> test.mjpeg && ffmpeg -i test.mjpeg -vframes 1 -f mjpeg output.jpg
> >>
> >> You'll get a very beautiful (and uniform) grey picture in output.
> >>     
> >
> > Try SVN r7143, it is already there.
> >   
> I've tried with the last SVN.
> It's working with the said file because the said file is simple (Y scan 
> is index 0).

Care to share a more complex file which don't decode correctly with
current SVN ?

Aurel