[PATCH 1/2] apps: common: dng_writer: Fix thumbnail generation on BE machines

[Stefan Klug]

On Mon, Jul 01, 2024 at 10:29:06AM +0300, Laurent Pinchart wrote:
> On Mon, Jul 01, 2024 at 09:21:08AM +0200, Stefan Klug wrote:
> > Hi Laurent,
> > 
> > Thanks for the patch.
> > 
> > On Sat, Jun 29, 2024 at 12:35:34AM +0300, Laurent Pinchart wrote:
> > > The 16-bit padded raw 10 and raw 12 formats are stored in memory in
> > > little endian order, regardless of the machine's endianness. Swap the
> > > 16-bit values on big-endian machines when reading pixels from memory to
> > > generate thumbnails.
> > > 
> > > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > 
> > Signed-off-by: Stefan Klug <stefan.klug at ideasonboard.com> 
> 
> Did you mean Reviewed-by ?

Oh, monday morning... yes, that was meant to be
Reviewed-by: Stefan Klug <stefan.klug at ideasonboard.com> 

Regards,
Stefan

> 
> > > ---
> > >  src/apps/common/dng_writer.cpp | 4 +++-
> > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/src/apps/common/dng_writer.cpp b/src/apps/common/dng_writer.cpp
> > > index 9241f23fb806..50db5eb33c83 100644
> > > --- a/src/apps/common/dng_writer.cpp
> > > +++ b/src/apps/common/dng_writer.cpp
> > > @@ -8,6 +8,7 @@
> > >  #include "dng_writer.h"
> > >  
> > >  #include <algorithm>
> > > +#include <endian.h>
> > >  #include <iostream>
> > >  #include <map>
> > >  
> > > @@ -185,7 +186,8 @@ void thumbScanlineRaw(const FormatInfo &info, void *output, const void *input,
> > >  
> > >  	/* Simple averaging that produces greyscale RGB values. */
> > >  	for (unsigned int x = 0; x < width; x++) {
> > > -		uint16_t value = (in[0] + in[1] + in2[0] + in2[1]) >> 2;
> > > +		uint16_t value = (le16toh(in[0]) + le16toh(in[1]) +
> > > +				  le16toh(in2[0]) + le16toh(in2[1])) >> 2;
> > >  		value = value >> shift;
> > >  		*out++ = value;
> > >  		*out++ = value;
> 
> -- 
> Regards,
> 
> Laurent Pinchart