Add extradata to the beginning of the filtered packets except when said packets already exactly begin with the extradata that is intended to be added.

freq

The additional argument specifies which packets should be filtered. It accepts the values:

k, keyframe

add extradata to all key packets

e, all

add extradata to all packets

If not specified it is assumed k.

For example the following ffmpeg command forces a global header (thus disabling individual packet headers) in the H.264 packets generated by the libx264 encoder, but corrects them by adding the header stored in extradata to the key packets:

ffmpeg -i INPUT -map 0 -flags:v +global_header -c:v libx264 -bsf:v dump_extra out.ts