Unix administration stuff that was hard to find out using Google and caused a lot of try and error. Hereby given back to the net...
Comparison of FLV and MP4 metadata tagging tools (injectors)
Submitted by Lars Windolf on 14. October 2010 - 10:39.
This post is a comparison of the performance of different tools available to tag FLV and MP4 containers with specific metadata (e.g. title, keyframes, generator or other custom fields...). For FLV containers flvtool2, flvtool++ and yamdi are compared. For the MP4 container MP4box, AtomicParsley and ffmpeg are compared.
Here are the IMO three most important FLV taggers tested on a 125MB FLV:
The performance of flvtool2 is horrendous. For films of 120min it will take hours to process. Therefore: Do not use it! Use Facebooks flvtool++ instead. I guess the bad performance results from it being built in Ruby. Also notice the "Large File" column indicating large file support which officially only yamdi support (by adding compile flag -D_FILE_OFFSET_BITS=64). Another important point is the "In Memory" column indicating that flvtool++ loads the entire file into memory when tagging, which is problematic when tagging large files. Given this results only yamdi should be used for FLV tagging!
Now for the MP4 tagging. Here you can select between a lot of tools from the net, but only a few of them are command line based and available for Unix. The MP4 test file used is 100MB large.
Given that recent ffmpeg brings the tagging for MP4 out of the box (it doesn't for FLV though) you do not even need an external tool to add the metadata,