@param pd data to be probed
@param is_opened Whether the file is already opened; determines whether
demuxers with or without AVFMT_NOFILE are probed.
@param score_max A probe score larger that this is required to accept a
detection, the variable is set to the actual detection
score afterwards.
If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
to retry with a larger probe buffer.
Guess the file format.
@param pd data to be probed @param is_opened Whether the file is already opened; determines whether demuxers with or without AVFMT_NOFILE are probed. @param score_max A probe score larger that this is required to accept a detection, the variable is set to the actual detection score afterwards. If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended to retry with a larger probe buffer.