[libcamera-devel] [PATCH v2 2/2] android: jpeg: Support a initial set of EXIF metadata tags
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Wed Aug 26 02:40:25 CEST 2020
Hi Umang,
Thank you for the patch.
On Tue, Aug 25, 2020 at 08:10:53PM +0000, Umang Jain wrote:
> From: Kieran Bingham <kieran.bingham at ideasonboard.com>
>
> Add a Exif data placeholder inside CameraStream, to populate it
> accordingly to the stream properties (size, orientation etc).
> Static EXIF properties (such as make, model, size, orientation)
> can be configured once when the stream is being configured.
> Per-frame related metadata (such as timestamp) needs to set
> just before encoding preferably in CameraDevice::requestComplete().
As explained in the review of 1/2, I don't think we can reuse the EXIF
generator. Sorry :-(
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> Signed-off-by: Umang Jain <email at uajain.com>
> ---
> src/android/camera_device.cpp | 22 +++++++++-
> src/android/camera_device.h | 2 +
> src/android/jpeg/encoder.h | 5 ++-
> src/android/jpeg/encoder_libjpeg.cpp | 9 +++-
> src/android/jpeg/encoder_libjpeg.h | 3 +-
> src/android/jpeg/exif.cpp | 66 ++++++++++++++++++++++++++++
> src/android/jpeg/exif.h | 9 ++++
> 7 files changed, 112 insertions(+), 4 deletions(-)
>
> diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
> index de6f86f..8789a9e 100644
> --- a/src/android/camera_device.cpp
> +++ b/src/android/camera_device.cpp
> @@ -1245,6 +1245,17 @@ int CameraDevice::configureStreams(camera3_stream_configuration_t *stream_list)
> << "Failed to configure encoder";
> return ret;
> }
> +
> + /*
> + * Set EXIF metadata for various tags.
> + * \todo Discuss setMake String, maybe vendor ID?
> + * KB suggested to leave it to "libcamera" for now.
> + * setModel should use the 'model' property of the camera.
Actually this should use the vendor and model of the end-product. We
will need to load this from a platform config/data file. It can stay
as-is for now.
> + */
> + cameraStream->exif.setMake("libcamera");
> + cameraStream->exif.setModel("cameraModel");
> + cameraStream->exif.setOrientation(orientation_);
> + cameraStream->exif.setSize(cfg.size);
> }
> }
>
> @@ -1434,7 +1445,16 @@ void CameraDevice::requestComplete(Request *request)
> continue;
> }
>
> - int jpeg_size = encoder->encode(buffer, mapped.maps()[0]);
> + /*
> + * We set the frame's EXIF timestamp as the time of encode. Since the
"the" ? the precision ?
> + * we need for EXIF is only one second, it is good enough.
> + */
> + struct timespec tp;
> + clock_gettime(CLOCK_REALTIME, &tp);
> + cameraStream->exif.setTimestamp(tp.tv_sec);
This can be simplified to
cameraStream->exif.setTimestamp(std::time(nullptr));
> + Span<uint8_t> exif_data = cameraStream->exif.generate();
> +
> + int jpeg_size = encoder->encode(buffer, mapped.maps()[0], exif_data);
> if (jpeg_size < 0) {
> LOG(HAL, Error) << "Failed to encode stream image";
> status = CAMERA3_BUFFER_STATUS_ERROR;
> diff --git a/src/android/camera_device.h b/src/android/camera_device.h
> index 3934f19..3e8a119 100644
> --- a/src/android/camera_device.h
> +++ b/src/android/camera_device.h
> @@ -42,6 +42,8 @@ struct CameraStream {
> libcamera::Size size;
>
> Encoder *jpeg;
> +
> + Exif exif;
> };
>
> class CameraDevice : protected libcamera::Loggable
> diff --git a/src/android/jpeg/encoder.h b/src/android/jpeg/encoder.h
> index f9eb88e..969f291 100644
> --- a/src/android/jpeg/encoder.h
> +++ b/src/android/jpeg/encoder.h
> @@ -7,6 +7,8 @@
> #ifndef __ANDROID_JPEG_ENCODER_H__
> #define __ANDROID_JPEG_ENCODER_H__
>
> +#include "exif.h"
> +
I don't think you need to include exif.h here.
> #include <libcamera/buffer.h>
> #include <libcamera/span.h>
> #include <libcamera/stream.h>
> @@ -18,7 +20,8 @@ public:
>
> virtual int configure(const libcamera::StreamConfiguration &cfg) = 0;
> virtual int encode(const libcamera::FrameBuffer *source,
> - const libcamera::Span<uint8_t> &destination) = 0;
> + const libcamera::Span<uint8_t> &destination,
> + const libcamera::Span<uint8_t> &exif_data) = 0;
The variable should be named exitData, or just exif.
> };
>
> #endif /* __ANDROID_JPEG_ENCODER_H__ */
> diff --git a/src/android/jpeg/encoder_libjpeg.cpp b/src/android/jpeg/encoder_libjpeg.cpp
> index 977538c..87464a4 100644
> --- a/src/android/jpeg/encoder_libjpeg.cpp
> +++ b/src/android/jpeg/encoder_libjpeg.cpp
> @@ -180,7 +180,8 @@ void EncoderLibJpeg::compressNV(const libcamera::MappedBuffer *frame)
> }
>
> int EncoderLibJpeg::encode(const FrameBuffer *source,
> - const libcamera::Span<uint8_t> &dest)
> + const libcamera::Span<uint8_t> &dest,
> + const libcamera::Span<uint8_t> &exif_data)
> {
> MappedFrameBuffer frame(source, PROT_READ);
> if (!frame.isValid()) {
> @@ -214,5 +215,11 @@ int EncoderLibJpeg::encode(const FrameBuffer *source,
>
> jpeg_finish_compress(&compress_);
>
> + if (exif_data.size())
> + /* Store Exif data in the JPEG_APP1 data block. */
> + jpeg_write_marker(&compress_, JPEG_APP0 + 1,
> + static_cast<const JOCTET *>(exif_data.data()),
> + exif_data.size());
> +
> return size;
> }
> diff --git a/src/android/jpeg/encoder_libjpeg.h b/src/android/jpeg/encoder_libjpeg.h
> index aed081a..88bc6e0 100644
> --- a/src/android/jpeg/encoder_libjpeg.h
> +++ b/src/android/jpeg/encoder_libjpeg.h
> @@ -22,7 +22,8 @@ public:
>
> int configure(const libcamera::StreamConfiguration &cfg) override;
> int encode(const libcamera::FrameBuffer *source,
> - const libcamera::Span<uint8_t> &destination) override;
> + const libcamera::Span<uint8_t> &destination,
> + const libcamera::Span<uint8_t> &exif_data) override;
>
> private:
> void compressRGB(const libcamera::MappedBuffer *frame);
> diff --git a/src/android/jpeg/exif.cpp b/src/android/jpeg/exif.cpp
> index f6a9f5c..d2ef14e 100644
> --- a/src/android/jpeg/exif.cpp
> +++ b/src/android/jpeg/exif.cpp
> @@ -160,6 +160,72 @@ int Exif::setString(ExifIfd ifd, ExifTag tag, ExifFormat format, const std::stri
> return 0;
> }
>
> +int Exif::setMake(const std::string &make)
> +{
> + return setString(EXIF_IFD_0, EXIF_TAG_MAKE, EXIF_FORMAT_ASCII, make);
> +}
> +
> +int Exif::setModel(const std::string &model)
> +{
> + return setString(EXIF_IFD_0, EXIF_TAG_MODEL, EXIF_FORMAT_ASCII, model);
> +}
> +
> +int Exif::setSize(Size size)
> +{
> + setShort(EXIF_IFD_0, EXIF_TAG_IMAGE_LENGTH, size.height);
> + setLong(EXIF_IFD_EXIF, EXIF_TAG_PIXEL_Y_DIMENSION, size.height);
> +
> + setShort(EXIF_IFD_0, EXIF_TAG_IMAGE_WIDTH, size.width);
> + setLong(EXIF_IFD_EXIF, EXIF_TAG_PIXEL_X_DIMENSION, size.width);
> +
> + return 0;
> +}
> +
> +int Exif::setTimestamp(const time_t timestamp)
> +{
> + char str[40];
> + size_t len = std::strftime(str, sizeof(str), "%c %Z",
> + std::localtime(×tamp));
The EXIF specification requires dates to be in the "YYYY:MM:DD HH:MM:SS"
format. str can be shortened to 20.
> + std::string ts(str);
> + int ret = -1;
> +
> + if (len > 0) {
This can't happen if str is large enough, so I'd skip this check.
> + ret = setString(EXIF_IFD_0, EXIF_TAG_DATE_TIME, EXIF_FORMAT_ASCII, ts);
> + if (ret < 0)
> + return ret;
> +
> + ret = setString(EXIF_IFD_EXIF, EXIF_TAG_DATE_TIME_ORIGINAL, EXIF_FORMAT_ASCII, ts);
> + if (ret < 0)
> + return ret;
> +
> + ret = setString(EXIF_IFD_EXIF, EXIF_TAG_DATE_TIME_DIGITIZED, EXIF_FORMAT_ASCII, ts);
> + if (ret < 0)
> + return ret;
> + }
> +
> + return ret;
> +}
> +
> +
Extra blank line.
> +int Exif::setOrientation(int orientation)
> +{
> + /* Orientation's tag value computed similar to Chrome HAL. */
I don't think the Chrome OS HAL is relevant :-) What's relevant is
turning the libcamera orientation into an EXIF orientation.
> + int value = 1;
> + switch (orientation) {
> + case 90:
> + value = 6;
> + break;
> + case 180:
> + value = 3;
> + break;
> + case 270:
> + value = 8;
> + break;
> + }
> +
> + return setShort(EXIF_IFD_0, EXIF_TAG_ORIENTATION, value);
> +}
> +
> Span<uint8_t> Exif::generate()
> {
> if (exif_data_) {
> diff --git a/src/android/jpeg/exif.h b/src/android/jpeg/exif.h
> index 7df83c7..6cca578 100644
> --- a/src/android/jpeg/exif.h
> +++ b/src/android/jpeg/exif.h
> @@ -9,8 +9,10 @@
>
> #include <libexif/exif-data.h>
>
> +#include <libcamera/geometry.h>
> #include <libcamera/span.h>
>
> +#include <ctime>
> #include <string>
>
> class Exif
> @@ -24,6 +26,13 @@ public:
> int setString(ExifIfd ifd, ExifTag tag, ExifFormat format, const std::string &item);
> int setRational(ExifIfd ifd, ExifTag tag, uint32_t numerator, uint32_t denominator);
>
> + int setMake(const std::string &make);
> + int setModel(const std::string &model);
> +
> + int setOrientation(int orientation);
> + int setSize(libcamera::Size size);
> + int setTimestamp(const time_t timestamp);
> +
> libcamera::Span<uint8_t> generate();
> unsigned char *data() const { return exif_data_; }
> unsigned int size() const { return size_; }
--
Regards,
Laurent Pinchart
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