[libcamera-devel] [PATCH 0/3] Initial EXIF metadata support

[Umang Jain]

Hi all,

This patch series targets adding initial EXIF metadata support
for the frames captured in Android/Libcamera framework.

It is initial in the sense, it adds the base infrastructure for
Exif metadata support via 'libexif' and also encodes a initial
set of metadata tags into the frames.

Testing:
The testing of this work was carried out via vivid pipeline-handler
in conjunction with patch in `cam` using EncoderLibJpeg as the
file sink [1]. That way we could see what EXIF metadata could be written
and inspect that `exif` or `exiv2` commandline tools.

($) ./build/src/cam/cam -c vivid -C5 -F -s pixelformat=NV12

Sample output (1):  exif  frame-stream0-000000.jpg
EXIF tags in 'frame-stream0-000000.jpg' ('Intel' byte order):
--------------------+----------------------------------------------------------
Tag                 |Value
--------------------+----------------------------------------------------------
Image Width         |1280
Image Length        |720
Manufacturer        |Libcamera
Model               |Camera2111
Orientation         |Bottom-left
X-Resolution        |72
Y-Resolution        |72
Resolution Unit     |Inch
Date and Time       |Sun Oct 13 07:03:20 734137

YCbCr Positioning   |Centered
Exif Version        |Exif Version 2.1
Date and Time (Origi|Sun Oct 13 07:03:20 734137

Date and Time (Digit|Sun Oct 13 07:03:20 734137

Components Configura|Y Cb Cr -
FlashPixVersion     |FlashPix Version 1.0
Color Space         |Internal error (unknown value 65535)
Pixel X Dimension   |1280
Pixel Y Dimension   |720



Sample output (2): exiv2  frame-stream0-000000.jpg 
File name       : frame-stream0-000000.jpg
File size       : 38787 Bytes
MIME type       : image/jpeg
Image size      : 1280 x 720
Camera make     : Libcamera
Camera model    : Camera2111
Image timestamp : Sun Oct 13 07:03:20 734137

Image number    : 
Exposure time   : 
Aperture        : 
Exposure bias   : 
Flash           : 
Flash bias      : 
Focal length    : 
Subject distance: 
ISO speed       : 
Exposure mode   : 
Metering mode   : 
Macro mode      : 
Image quality   : 
Exif Resolution : 1280 x 720
White balance   : 
Thumbnail       : None
Copyright       : 
Exif comment    : 

There are still a lot of tags that needs to be populated,
that can be built on top of this groundwork.

[1]: https://github.com/kbingham/libcamera/commit/10ed8ec

Kieran Bingham (1):
  libcamera: android: Add EXIF infrastructure

Umang Jain (2):
  android: jpeg: Pass a Exif object while encoding
  android: Support initial set of EXIF metadata tags

 src/android/camera_device.cpp        |  12 +-
 src/android/jpeg/encoder.h           |   5 +-
 src/android/jpeg/encoder_libjpeg.cpp |  15 +-
 src/android/jpeg/encoder_libjpeg.h   |   3 +-
 src/android/jpeg/exif.cpp            | 210 +++++++++++++++++++++++++++
 src/android/jpeg/exif.h              |  53 +++++++
 src/android/meson.build              |   2 +
 7 files changed, 296 insertions(+), 4 deletions(-)
 create mode 100644 src/android/jpeg/exif.cpp
 create mode 100644 src/android/jpeg/exif.h

-- 
2.25.1