[libcamera-devel] [PATCH] qcam: dng_writer: Record creation time in the EXIF directory

[Niklas Söderlund]

If the EXIF directory is empty due to no metadata being available tools
such as tiffinfo complains that the directory is malformed.

    TIFFFetchDirectory: Sanity check on directory count failed, this is probably not a valid IFD offset.
    TIFFReadCustomDirectory: Failed to read custom directory at offset 0.

Always record the creation time in the EXIF directory instead of adding
complexity to skip creating the EXIF directory if there is no metadata
to record. This ensures there are at least one entry in the EXIF
directory and that makes tiffinfo happy.

Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
---
 src/qcam/dng_writer.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/qcam/dng_writer.cpp b/src/qcam/dng_writer.cpp
index 330b169af25b7ac7..c1c3833740d96630 100644
--- a/src/qcam/dng_writer.cpp
+++ b/src/qcam/dng_writer.cpp
@@ -426,6 +426,17 @@ int DNGWriter::write(const char *filename, const Camera *camera,
 	/* Create a new IFD for the EXIF data and fill it. */
 	TIFFCreateEXIFDirectory(tif);
 
+	/* Store creation time. */
+	time_t rawtime;
+	struct tm *timeinfo;
+	char strTime[20];
+
+	time(&rawtime);
+	timeinfo = localtime(&rawtime);
+	strftime(strTime, 20, "%Y:%m:%d %H:%M:%S", timeinfo);
+
+	TIFFSetField(tif, EXIFTAG_DATETIMEDIGITIZED, strTime);
+
 	if (metadata.contains(controls::AnalogueGain)) {
 		float gain = metadata.get(controls::AnalogueGain);
 		uint16_t iso = std::min(std::max(gain * 100, 0.0f), 65535.0f);
-- 
2.27.0