[libcamera-devel] [PATCH 4/4] android: jpeg: exif: change GPS method from UNDEFINED format to ASCII

[Laurent Pinchart]

Hi Paul,

Thank you for the patch.

On Mon, Mar 08, 2021 at 10:26:56AM +0000, Kieran Bingham wrote:
> On 08/03/2021 10:13, Paul Elder wrote:
> > According to the EXIF specification, the GPS method should be UNDEFINED,
> > and the first 8 bytes will designate the type. However, CTS expects the
> > GPS method to be ASCII. Change the format to ASCII to appease CTS.
> 
> If the Spec says it should be UNDEFINED, doesn't that mean that the CTS
> is wrong? (and should be fixed there?)

Does CTS check that the tag type is set to ASCII rather than UNDEFINED,
or does it fail because it it doesn't expect the 8-bytes encoding prefix
? In the latter case, we could switch to the NoEncoding encoding and
keep the UNDEFINED type.

The Exif spec is very confusing here, it documents the tag as UNDEFINED,
but then shows a few examples where it mentions ASCII. It's not clear if
ASCII refers to the tag type or the encoding here.

> > This is part of the fix that allows the following CTS test to pass:
> > - android.hardware.cts.CameraTest#testJpegExif
> > 
> > Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> > ---
> >  src/android/jpeg/exif.cpp | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/src/android/jpeg/exif.cpp b/src/android/jpeg/exif.cpp
> > index 5225d17f..83e6faba 100644
> > --- a/src/android/jpeg/exif.cpp
> > +++ b/src/android/jpeg/exif.cpp
> > @@ -404,7 +404,7 @@ void Exif::setGPSLocation(const double *coords)
> >  void Exif::setGPSMethod(const std::string &method)
> >  {
> >  	setString(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_PROCESSING_METHOD),
> > -		  EXIF_FORMAT_UNDEFINED, method, Unicode);
> > +		  EXIF_FORMAT_ASCII, method);
> >  }
> >  
> >  void Exif::setOrientation(int orientation)

-- 
Regards,

Laurent Pinchart