UnderwaterMapping

GoPro to bag

It is possible to crop the .mp4 GoPro video while keeping metadata using the following command: ffmpeg -i INPUT_FILE -ss MM:SS -to MM:SS -map_metadata 0 -map 0:u -c copy OUTPUT_FILE

The conversion from GoPro to bag is done in two main step: 1) Data extraction, 2) Bag conversion

1) Data extraction (Folder: "Utilities/GoPro-data-extraction")

• Extract the individual frames from the video using "extract_frames.py". Changeable parameters for the output are: frames to remove (framerate), downscaling, color space
• Extract the IMU metadata from the video using "gopro_data_extraction.c". Compile the file using make and run the file.
  • Note: If submodule "gpmf-parser" is empty, you first need to initialise it using git submodule update --init

The output of the data should be in the "Output/$CHOSEN_NAME$/Images" and "Output/$CHOSEN_NAME$/Metadata" folder, respectively. The sample rates for the camera and IMU should be saved for use in the bag conversion.

2) Bag conversion (Folder: "Utilities/Bag-conversion")

• Convert the previously extracted data to a .bag file using "gopro_to_bag.py". Remember to specify topics according to used format in SVO and make sure the sample rates are correct. To check that the conversion worked as intended, you can run "view_bag.py" with the obtained .bag file.
  • Note: If the topics don't match the required format, use "remap_bag.py" to change the topic names.

The output of the .bag file should be in the "Output" folder.