search

gopro / gpmf-parser

Parser for GPMF™ formatted telemetry data used within GoPro® cameras.
Apache License 2.0
535 stars 112 forks source link

Structure of `gpmd` boxes #185

Closed bradh closed 7 months ago

bradh commented 8 months ago

https://github.com/gopro/gpmf-parser?tab=readme-ov-file#inside-the-meta-track identifies that gpmd is a box (under gmhd) and a sample entry (under stsd). Is the content of those intended to be meaningful, or is it more of a flag value?

I only did light checking, but it looks like it is just a 32 bit value set to 0 (or possibly they are version 0x00 and flags 0x00 0x00 0x00, as in a FullBox structure, and there is no body). Just want to make sure my checks are rigorous enough....

dnewman-gpsw commented 7 months ago

That is nothing on importance stored in the headers. Metadata tracks in MP4s were not common when GPMF was introduced, GoPro was the to use this method. Other than indexing, all the data in the required data is in the track (within the mdat.)

bradh commented 7 months ago

Thanks.