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/*
* EXIF metadata parser
* Copyright (c) 2013 Thilo Borgmann <thilo.borgmann _at_ mail.de>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* EXIF metadata parser
* @author Thilo Borgmann <thilo.borgmann _at_ mail.de>
*/
#include "exif.h"
#include "tiff_common.h"
#define EXIF_TAG_NAME_LENGTH 32
struct exif_tag {
char name[EXIF_TAG_NAME_LENGTH];
uint16_t id;
};
static const struct exif_tag tag_list[] = { // JEITA CP-3451 EXIF specification:
{"GPSVersionID", 0x00}, // <- Table 12 GPS Attribute Information
{"GPSLatitudeRef", 0x01},
{"GPSLatitude", 0x02},
{"GPSLongitudeRef", 0x03},
{"GPSLongitude", 0x04},
{"GPSAltitudeRef", 0x05},
{"GPSAltitude", 0x06},
{"GPSTimeStamp", 0x07},
{"GPSSatellites", 0x08},
{"GPSStatus", 0x09},
{"GPSMeasureMode", 0x0A},
{"GPSDOP", 0x0B},
{"GPSSpeedRef", 0x0C},
{"GPSSpeed", 0x0D},
{"GPSTrackRef", 0x0E},
{"GPSTrack", 0x0F},
{"GPSImgDirectionRef", 0x10},
{"GPSImgDirection", 0x11},
{"GPSMapDatum", 0x12},
{"GPSDestLatitudeRef", 0x13},
{"GPSDestLatitude", 0x14},
{"GPSDestLongitudeRef", 0x15},
{"GPSDestLongitude", 0x16},
{"GPSDestBearingRef", 0x17},
{"GPSDestBearing", 0x18},
{"GPSDestDistanceRef", 0x19},
{"GPSDestDistance", 0x1A},
{"GPSProcessingMethod", 0x1B},
{"GPSAreaInformation", 0x1C},
{"GPSDateStamp", 0x1D},
{"GPSDifferential", 0x1E},
{"ImageWidth", 0x100}, // <- Table 3 TIFF Rev. 6.0 Attribute Information Used in Exif
{"ImageLength", 0x101},
{"BitsPerSample", 0x102},
{"Compression", 0x103},
{"PhotometricInterpretation", 0x106},
{"Orientation", 0x112},
{"SamplesPerPixel", 0x115},
{"PlanarConfiguration", 0x11C},
{"YCbCrSubSampling", 0x212},
{"YCbCrPositioning", 0x213},
{"XResolution", 0x11A},
{"YResolution", 0x11B},
{"ResolutionUnit", 0x128},
{"StripOffsets", 0x111},
{"RowsPerStrip", 0x116},
{"StripByteCounts", 0x117},
{"JPEGInterchangeFormat", 0x201},
{"JPEGInterchangeFormatLength",0x202},
{"TransferFunction", 0x12D},
{"WhitePoint", 0x13E},
{"PrimaryChromaticities", 0x13F},
{"YCbCrCoefficients", 0x211},
{"ReferenceBlackWhite", 0x214},
{"DateTime", 0x132},
{"ImageDescription", 0x10E},
{"Make", 0x10F},
{"Model", 0x110},
{"Software", 0x131},
{"Artist", 0x13B},
{"Copyright", 0x8298},
{"ExifVersion", 0x9000}, // <- Table 4 Exif IFD Attribute Information (1)
{"FlashpixVersion", 0xA000},
{"ColorSpace", 0xA001},
{"ComponentsConfiguration", 0x9101},
{"CompressedBitsPerPixel", 0x9102},
{"PixelXDimension", 0xA002},
{"PixelYDimension", 0xA003},
{"MakerNote", 0x927C},
{"UserComment", 0x9286},
{"RelatedSoundFile", 0xA004},
{"DateTimeOriginal", 0x9003},
{"DateTimeDigitized", 0x9004},
{"SubSecTime", 0x9290},
{"SubSecTimeOriginal", 0x9291},
{"SubSecTimeDigitized", 0x9292},
{"ImageUniqueID", 0xA420},
{"ExposureTime", 0x829A}, // <- Table 5 Exif IFD Attribute Information (2)
{"FNumber", 0x829D},
{"ExposureProgram", 0x8822},
{"SpectralSensitivity", 0x8824},
{"ISOSpeedRatings", 0x8827},
{"OECF", 0x8828},
{"ShutterSpeedValue", 0x9201},
{"ApertureValue", 0x9202},
{"BrightnessValue", 0x9203},
{"ExposureBiasValue", 0x9204},
{"MaxApertureValue", 0x9205},
{"SubjectDistance", 0x9206},
{"MeteringMode", 0x9207},
{"LightSource", 0x9208},
{"Flash", 0x9209},
{"FocalLength", 0x920A},
{"SubjectArea", 0x9214},
{"FlashEnergy", 0xA20B},
{"SpatialFrequencyResponse", 0xA20C},
{"FocalPlaneXResolution", 0xA20E},
{"FocalPlaneYResolution", 0xA20F},
{"FocalPlaneResolutionUnit", 0xA210},
{"SubjectLocation", 0xA214},
{"ExposureIndex", 0xA215},
{"SensingMethod", 0xA217},
{"FileSource", 0xA300},
{"SceneType", 0xA301},
{"CFAPattern", 0xA302},
{"CustomRendered", 0xA401},
{"ExposureMode", 0xA402},
{"WhiteBalance", 0xA403},
{"DigitalZoomRatio", 0xA404},
{"FocalLengthIn35mmFilm", 0xA405},
{"SceneCaptureType", 0xA406},
{"GainControl", 0xA407},
{"Contrast", 0xA408},
{"Saturation", 0xA409},
{"Sharpness", 0xA40A},
{"DeviceSettingDescription", 0xA40B},
{"SubjectDistanceRange", 0xA40C}
// {"InteroperabilityIndex", 0x1}, // <- Table 13 Interoperability IFD Attribute Information
};
static const char *exif_get_tag_name(uint16_t id)
{
int i;
for (i = 0; i < FF_ARRAY_ELEMS(tag_list); i++) {
if (tag_list[i].id == id)
return tag_list[i].name;
}
return NULL;
}
static int exif_add_metadata(void *logctx, int count, int type,
const char *name, const char *sep,
GetByteContext *gb, int le,
AVDictionary **metadata)
{
switch(type) {
case 0:
av_log(logctx, AV_LOG_WARNING,
"Invalid TIFF tag type 0 found for %s with size %d\n",
name, count);
return 0;
case TIFF_DOUBLE : return ff_tadd_doubles_metadata(count, name, sep, gb, le, metadata);
case TIFF_SSHORT : return ff_tadd_shorts_metadata(count, name, sep, gb, le, 1, metadata);
case TIFF_SHORT : return ff_tadd_shorts_metadata(count, name, sep, gb, le, 0, metadata);
case TIFF_SBYTE : return ff_tadd_bytes_metadata(count, name, sep, gb, le, 1, metadata);
case TIFF_BYTE :
case TIFF_UNDEFINED: return ff_tadd_bytes_metadata(count, name, sep, gb, le, 0, metadata);
case TIFF_STRING : return ff_tadd_string_metadata(count, name, gb, le, metadata);
case TIFF_SRATIONAL:
case TIFF_RATIONAL : return ff_tadd_rational_metadata(count, name, sep, gb, le, metadata);
case TIFF_SLONG :
case TIFF_LONG : return ff_tadd_long_metadata(count, name, sep, gb, le, metadata);
default:
avpriv_request_sample(logctx, "TIFF tag type (%u)", type);
return 0;
};
}
static int exif_decode_tag(void *logctx, GetByteContext *gbytes, int le,
int depth, AVDictionary **metadata)
{
int ret, cur_pos;
unsigned id, count;
enum TiffTypes type;
if (depth > 2) {
return 0;
}
ff_tread_tag(gbytes, le, &id, &type, &count, &cur_pos);
if (!bytestream2_tell(gbytes)) {
bytestream2_seek(gbytes, cur_pos, SEEK_SET);
return 0;
}
// read count values and add it metadata
// store metadata or proceed with next IFD
ret = ff_tis_ifd(id);
if (ret) {
ret = ff_exif_decode_ifd(logctx, gbytes, le, depth + 1, metadata);
} else {
const char *name = exif_get_tag_name(id);
char buf[7];
if (!name) {
name = buf;
snprintf(buf, sizeof(buf), "0x%04X", id);
}
ret = exif_add_metadata(logctx, count, type, name, NULL,
gbytes, le, metadata);
}
bytestream2_seek(gbytes, cur_pos, SEEK_SET);
return ret;
}
int ff_exif_decode_ifd(void *logctx, GetByteContext *gbytes,
int le, int depth, AVDictionary **metadata)
{
int i, ret;
int entries;
entries = ff_tget_short(gbytes, le);
if (bytestream2_get_bytes_left(gbytes) < entries * 12) {
return AVERROR_INVALIDDATA;
}
for (i = 0; i < entries; i++) {
if ((ret = exif_decode_tag(logctx, gbytes, le, depth, metadata)) < 0) {
return ret;
}
}
// return next IDF offset or 0x000000000 or a value < 0 for failure
return ff_tget_long(gbytes, le);
}
int avpriv_exif_decode_ifd(void *logctx, const uint8_t *buf, int size,
int le, int depth, AVDictionary **metadata)
{
GetByteContext gb;
bytestream2_init(&gb, buf, size);
return ff_exif_decode_ifd(logctx, &gb, le, depth, metadata);
}
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