From: Hubert F. <hfi...@te...> - 2005-07-25 02:42:49
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Hi, I'm have almost EXIF parsing from TIFF files working from current libexif CVS. Basically the change is to not copy over the 'Exif\0' marker (6 bytes), because it is part of JFIF, not part of the Exif data. Exif data is just TIFF structure, so everything else comes along.... Currently it sort of crashes with TIFF and CR2, but otherwise it works with JPEG, at least with the current test suite. Any comments ? Hub |
From: Lutz <lu...@us...> - 2005-07-25 06:01:33
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On Sun, 2005-07-24 at 22:42 -0400, Hubert Figuiere wrote: > Basically the change is to not copy over the 'Exif\0' marker (6 bytes),= =20 > because it is part of JFIF, not part of the Exif data. Exif data is jus= t=20 > TIFF structure, so everything else comes along... exif_data_save_data should return just the TIFF structure then? Regards --=20 Lutz M=FCller <lu...@us...> |
From: Hubert F. <hfi...@te...> - 2005-07-25 15:04:34
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Lutz Müller wrote: > On Sun, 2005-07-24 at 22:42 -0400, Hubert Figuiere wrote: > >>Basically the change is to not copy over the 'Exif\0' marker (6 bytes), >>because it is part of JFIF, not part of the Exif data. Exif data is just >>TIFF structure, so everything else comes along... > > > exif_data_save_data should return just the TIFF structure then? > Yep. That's what it does now. Hub |
From: Lutz <lu...@us...> - 2005-07-25 19:40:52
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On Mon, 2005-07-25 at 11:04 -0400, Hubert Figuiere wrote: > > exif_data_save_data should return just the TIFF structure then? > Yep. That's what it does now. Then please increment CURRENT. And we need documentation on that. It was pretty easy to just save the EXIF data and pass it on to jpeglib. Please describe somewhere what to prepend to the EXIF data. There is some documentation in exif-data.h, perhaps you can just add a couple of notes there. And update libexif/NEWS, too. I guess exif needs an update, too. I have been asked by a company to release a new version. Can you already tell me when CVS will be ready for packaging? Regards --=20 Lutz M=FCller <lu...@us...> |
From: Hubert F. <hfi...@te...> - 2005-07-26 01:42:56
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Lutz M=FCller wrote: > On Mon, 2005-07-25 at 11:04 -0400, Hubert Figuiere wrote: >=20 >>>exif_data_save_data should return just the TIFF structure then? >> >>Yep. That's what it does now. >=20 >=20 > Then please increment CURRENT. And we need documentation on that. Sure. But does that break the APIs ? I prefer to not break them and rather=20 extend them. > It was > pretty easy to just save the EXIF data and pass it on to jpeglib. Pleas= e > describe somewhere what to prepend to the EXIF data. There is some > documentation in exif-data.h, perhaps you can just add a couple of note= s > there. And update libexif/NEWS, too. I guess exif needs an update, too. One just need to add the Exif ID defined as: ExifHeader[] =3D {0x45, 0x78, 0x69, 0x66, 0x00, 0x00}; I don't know why 6 and not 5 chars, but that is the way it is. > I have been asked by a company to release a new version. Can you alread= y > tell me when CVS will be ready for packaging? I haven't committed anything yet. So CVS is in workable state. Hub |
From: Jan P. <pa...@pi...> - 2005-07-25 07:03:21
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Hi, I've also started investigating the possibility of parsing TIFFs. I've come up with more or less 3 solutions, one of them is yours. None of them is really perfect. However, I see one big possible drawback. With this approach, entire TIFF file is treated as EXIF. This means that entire (possibly multipage) TIFF file is read into memory by exif_loader_copy(). This can easily be dozens of megabytes. -- Jan > I'm have almost EXIF parsing from TIFF files working from current > libexif CVS. > Basically the change is to not copy over the 'Exif\0' marker (6 bytes), > because it is part of JFIF, not part of the Exif data. Exif data is just > TIFF structure, so everything else comes along.... > > Currently it sort of crashes with TIFF and CR2, but otherwise it works > with JPEG, at least with the current test suite. > > Any comments ? > > Hub |
From: Hubert F. <hfi...@te...> - 2005-07-25 15:06:06
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Jan Patera wrote: > Hi, > > I've also started investigating the possibility of parsing TIFFs. > I've come up with more or less 3 solutions, one of them is yours. > None of them is really perfect. > However, I see one big possible drawback. > With this approach, entire TIFF file is treated as EXIF. This means that > entire (possibly multipage) TIFF file is read into memory by > exif_loader_copy(). This can easily be dozens of megabytes. Yep. But it is quite easy to work around given the EXIF spec. We know where to get the data. That is what I have to fix before having things working.... Hub |