@Zachary-Lowell-0 I managed to fix the code. Essentially I was updating the already existing jpeg exif block. Here is my solution. Its a little messy cuz I haven't had the time to clean it up. But I tested and it works.
Would you guys be interested in pulling in my changes?
// Function to create a new tag or update an existing one
static ExifEntry* create_or_update_tag(ExifData* exif, ExifIfd ifd, ExifTag tag, ExifFormat fmt, unsigned int size, unsigned int components) {
ExifEntry* entry = exif_content_get_entry(exif->ifd[ifd], tag);
if (!entry) {
// Create a new entry if it doesn't exist
printf("Creating entry: %d\n", (int)tag);
//entry = exif_entry_new();
entry = create_tag(exif, ifd, tag, size);
entry->tag = tag;
entry->components = components;
entry->format = fmt;
///entry->data = (unsigned char*)malloc(size);
//exif_content_add_entry(exif->ifd[ifd], entry);
///exif_entry_unref(entry);
} else {
// Update the existing entry
if (entry->size < size) {
// If the existing entry size is insufficient, reallocate memory
entry->data = (unsigned char*)realloc(entry->data, size);
entry->size = size;
}
entry->components = components;
entry->format = fmt;
}
return entry;
}
void PerCameraMgr::ProcessSnapshotFrame(image_result result)
{
BufferBlock* bufferBlockInfo = bufferGetBufferInfo(&snap_bufferGroup, result.second.buffer);
// first write to pipe if subscribed
camera_image_metadata_t meta;
if(getMeta(result.first, &meta)) {
M_WARN("Trying to process encode buffer without metadata\n");
return;
}
int start_index = 0;
//int start_index2 = 0;
uint8_t* src_data = (uint8_t*)bufferBlockInfo->vaddress;
//int extractJpgSize = bufferBlockInfo->size;
int extractJpgSize = find_jpeg_buffer_size(src_data, bufferBlockInfo->size, &start_index);
assert(start_index == 0);
//int _extractJpgSize = find_jpeg_buffer(src_data, bufferBlockInfo->size, &start_index2);
// find APP1 block start and length
size_t prev_exif_block_start_idx = 0;
size_t prev_exif_block_size = find_exif_start(src_data, bufferBlockInfo->size, &prev_exif_block_start_idx);
if(extractJpgSize == 1){
M_ERROR("Real Size of JPEG is incorrect");
return;
}
printf("Snapshot jpeg start: %6d len %8d\n", start_index, extractJpgSize);
#ifndef APQ8096
// Load the EXIF data from the file
unsigned char *exif_data;
unsigned int exif_data_len;
ExifEntry *entry;
// can create exif data from raw jpeg image
ExifData* exif = exif_data_new_from_data(src_data, extractJpgSize);
//ExifData *exif = createExifData();
if (exif == nullptr) {
printf("Issue getting exif data from origin\n");
return;
}
exif_data_fix(exif);
//printf("Exif data before mods\n");
//exif_data_dump(exif);
//printf("End Exif data before mods\n");
/**
* @brief Good description of exif format https://www.media.mit.edu/pia/Research/deepview/exif.html
*
*/
ExifByteOrder imageByteOrder = exif_data_get_byte_order(exif); /**< Each camera saves its Exif data in a different byte order */
//gps_data_t gps_grabbed_info = grab_gps_info();
// Code to add latitude to exif tag
entry = create_or_update_tag(exif, EXIF_IFD_GPS, (ExifTag)EXIF_TAG_GPS_LATITUDE_REF, (ExifFormat)EXIF_FORMAT_ASCII, 2*sizeof(char), 1);
if (_uav_state.lat_deg >= 0) {
memcpy(entry->data, "N", sizeof(char));
} else {
memcpy(entry->data, "S", sizeof(char));
_uav_state.lat_deg *= -1;
}
entry = create_or_update_tag(exif, EXIF_IFD_GPS, (ExifTag)EXIF_TAG_GPS_LATITUDE, (ExifFormat)EXIF_FORMAT_RATIONAL, 3*sizeof(ExifRational), 3);
ExifLong degrees_lat = static_cast<ExifLong>(_uav_state.lat_deg);
double fractional = (_uav_state.lat_deg - degrees_lat);
ExifLong minutes_lat = static_cast<ExifLong>(fractional*60);
fractional = (fractional*60) - minutes_lat;
double seconds_lat = (fractional * 60);
ExifRational degrees_r = { degrees_lat, 1 };
ExifRational minutes_r = { minutes_lat, 1 };
ExifRational seconds_r = { static_cast<ExifLong>(seconds_lat * 1000000), 1000000 }; // Increased precision for seconds
exif_set_rational(entry->data, imageByteOrder, degrees_r);
exif_set_rational(entry->data + sizeof(ExifRational), imageByteOrder, minutes_r);
exif_set_rational(entry->data + 2 * sizeof(ExifRational), imageByteOrder, seconds_r);
// Code to add longitude to exif tag
entry = create_or_update_tag(exif, EXIF_IFD_GPS, (ExifTag)EXIF_TAG_GPS_LONGITUDE_REF, (ExifFormat)EXIF_FORMAT_ASCII, 2*sizeof(char), 1);
if (_uav_state.lon_deg >= 0) {
memcpy(entry->data, "E", sizeof(char));
} else {
memcpy(entry->data, "W", sizeof(char));
_uav_state.lon_deg *= -1;
}
entry = create_or_update_tag(exif, EXIF_IFD_GPS, (ExifTag)EXIF_TAG_GPS_LONGITUDE, (ExifFormat)EXIF_FORMAT_RATIONAL, 3*sizeof(ExifRational), 3);
ExifLong degrees_lon = static_cast<ExifLong>(_uav_state.lon_deg);
fractional = (_uav_state.lon_deg - degrees_lon);
ExifLong minutes_lon = static_cast<ExifLong>(fractional*60);
fractional = (fractional*60) - minutes_lon;
double seconds_lon = (fractional * 60);
degrees_r = { degrees_lon, 1 };
minutes_r = { minutes_lon, 1 };
seconds_r = { static_cast<ExifLong>(seconds_lon * 1000000), 1000000 }; // Increased precision for seconds
exif_set_rational(entry->data, imageByteOrder, degrees_r);
exif_set_rational(entry->data + sizeof(ExifRational), imageByteOrder, minutes_r);
exif_set_rational(entry->data + 2 * sizeof(ExifRational), imageByteOrder, seconds_r);
// Code to add altitude to exif tag
entry = create_or_update_tag(exif, EXIF_IFD_GPS, (ExifTag)EXIF_TAG_GPS_ALTITUDE, (ExifFormat)EXIF_FORMAT_RATIONAL, sizeof(ExifRational), 1);
double alt_lon = _uav_state.alt_msl_meters;
unsigned int tmp = static_cast<unsigned int>(alt_lon * 1000);
exif_set_rational(entry->data, imageByteOrder, (ExifRational){tmp, 1000});
entry = create_or_update_tag(exif, EXIF_IFD_GPS, (ExifTag)EXIF_TAG_GPS_ALTITUDE_REF, (ExifFormat)EXIF_FORMAT_BYTE, sizeof(uint8_t), 1);
entry->data[0] = 0; /**< 0 for above sea level */
// dumping all exif data
entry = create_or_update_tag(exif, EXIF_IFD_EXIF, (ExifTag)EXIF_TAG_FOCAL_LENGTH, (ExifFormat)EXIF_FORMAT_RATIONAL, sizeof(ExifRational), 1);
ExifRational focal_len_r = {static_cast<ExifLong>(9.99 * 1000000), 1000000};
exif_set_rational(entry->data, EXIF_BYTE_ORDER_MOTOROLA, focal_len_r);
entry = create_or_update_tag(exif, EXIF_IFD_EXIF, (ExifTag)EXIF_TAG_FNUMBER, (ExifFormat)EXIF_FORMAT_RATIONAL, sizeof(ExifRational), 1);
ExifRational f_number_r = {static_cast<ExifLong>(13.6 * 1000000), 1000000};
exif_set_rational(entry->data, EXIF_BYTE_ORDER_MOTOROLA, f_number_r);
entry = create_or_update_tag(exif, EXIF_IFD_EXIF, (ExifTag)EXIF_TAG_FOCAL_LENGTH_IN_35MM_FILM, (ExifFormat)EXIF_FORMAT_SHORT, sizeof(ExifShort), 1);
ExifShort f_35_mm_r = 17;
exif_set_short(entry->data, EXIF_BYTE_ORDER_MOTOROLA, f_35_mm_r);
exif_data_save_data(exif, &exif_data, &exif_data_len);
//printf("Exif data after mods\n");
//exif_data_dump(exif);
//printf("End Exif data after mods\n");
assert(exif_data != NULL);
#endif
meta.magic_number = CAMERA_MAGIC_NUMBER;
meta.width = snap_width;
meta.height = snap_height;
meta.format = IMAGE_FORMAT_JPG;
meta.size_bytes = extractJpgSize;
pipe_server_write_camera_frame(snapshotPipe, meta, &src_data[start_index]);
// now, if there is a filename in the queue, write it too
if(snapshotQueue.size() != 0){
char *filename = snapshotQueue.front();
snapshotQueue.pop();
M_PRINT("Camera: %s writing snapshot to :\"%s\"\n", name, filename);
//WriteSnapshot(bufferBlockInfo, snap_halfmt, filename);
FILE* file_descriptor = fopen(filename, "wb");
if(! file_descriptor){
//Check to see if we were just missing parent directories
CreateParentDirs(filename);
file_descriptor = fopen(filename, "wb");
if(! file_descriptor){
M_ERROR("failed to open file descriptor for snapshot save to: %s\n", filename);
return;
}
}
#ifndef APQ8096
// first write the beginning of jpeg and stop where the previous exif APP1 header started
// this will include the FFD8 marker
printf("Start: 0, end:%lu\n", prev_exif_block_start_idx);
if (fwrite(src_data, prev_exif_block_start_idx, 1, file_descriptor) != 1) {
fprintf(stderr, "Error writing to file with jpeg %s\n", filename);
}
if (fwrite(exif_header, exif_header_len, 1, file_descriptor) != 1) {
fprintf(stderr, "Error writing to file inin exif header %s\n", filename);
}
if (fputc((exif_data_len+2) >> 8, file_descriptor) < 0) {
fprintf(stderr, "Error writing to file in big endian order %s\n", filename);
}
if (fputc((exif_data_len+2) & 0xff, file_descriptor) < 0) {
fprintf(stderr, "Error writing to file with fputc %s\n", filename);
}
if (fwrite(exif_data, exif_data_len, 1, file_descriptor) != 1) {
fprintf(stderr, "Error writing to file with data block %s\n", filename);
}
// next write from the last bits of the prev APP1 block
size_t jpeg_start_idx = prev_exif_block_start_idx + prev_exif_block_size;
size_t jpeg_size = extractJpgSize - prev_exif_block_size;
//size_t jpeg_start_idx = prev_exif_block_start_idx + prev_exif_block_size + (exif_data_len+2+exif_header_len);
//size_t jpeg_size = extractJpgSize - prev_exif_block_size + (exif_data_len+2+exif_header_len);
printf("Start: %lu, end:%lu\n", jpeg_start_idx, jpeg_size);
if (fwrite(src_data + jpeg_start_idx, jpeg_size, 1, file_descriptor) != 1) {
fprintf(stderr, "Error writing to file with jpeg %s\n", filename);
}
free(exif_data);
exif_data_unref(exif);
