The audio and video sample entries in an MP4 file carry the codec as a four-character format code (e.g. avc1, mp4a). Mp4VideoHandler and Mp4SoundHandler both read it, but only pass it through Mp4Dictionary.setLookup, which replaces it with a human-readable description and stores that in TAG_COMPRESSION_TYPE / TAG_AUDIO_FORMAT. Mp4Dictionary.lookup returns "Unknown" for any code not in its table, so the raw format code is unavailable for unrecognised codecs, and lost even for recognised ones.
Expected: the raw four-character format code is retained.
The audio and video sample entries in an MP4 file carry the codec as a four-character format code (e.g.
avc1,mp4a).Mp4VideoHandlerandMp4SoundHandlerboth read it, but only pass it throughMp4Dictionary.setLookup, which replaces it with a human-readable description and stores that inTAG_COMPRESSION_TYPE/TAG_AUDIO_FORMAT.Mp4Dictionary.lookupreturns "Unknown" for any code not in its table, so the raw format code is unavailable for unrecognised codecs, and lost even for recognised ones.Expected: the raw four-character format code is retained.