Global import options

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<a id="add" data-level="basic">__-add__</a> (string): add given file tracks to file. Multiple inputs can be specified using `+`, e.g. `-add url1+url2`  
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<a id="cat" data-level="basic">__-cat__</a> (string): concatenate given file samples to file, creating tracks if needed. Multiple inputs can be specified using `+`, e.g/ `-cat url1+url2`.    
_Note: This aligns initial timestamp of the file to be concatenated_  
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<a id="catx" data-level="basic">__-catx__</a> (string): same as [-cat](#cat) but new tracks can be imported before concatenation by specifying `+ADD_COMMAND` where `ADD_COMMAND` is a regular [-add](#add) syntax  
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<a id="catpl" data-level="basic">__-catpl__</a> (string): concatenate files listed in the given playlist file (one file per line, lines starting with # are comments).    
_Note: Each listed file is concatenated as if called with -cat_  
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<a id="unalign-cat" data-level="basic">__-unalign-cat__</a>: do not attempt to align timestamps of samples in-between tracks  
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<a id="force-cat" data-level="basic">__-force-cat__</a>: skip media configuration check when concatenating file.    

__Warning: THIS MAY BREAK THE CONCATENATED TRACK(S)__  
  
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<a id="keep-sys" data-level="basic">__-keep-sys__</a>: keep all MPEG-4 Systems info when using [-add](#add) and [-cat](#cat) (only used when adding IsoMedia files)  
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<a id="dref" data-level="basic">__-dref__</a>: keep media data in original file using `data referencing`. The resulting file only contains the meta-data of the presentation (frame sizes, timing, etc...) and references media data in the original file. This is extremely useful when developing content, since importing and storage of the MP4 file is much faster and the resulting file much smaller.    
_Note: Data referencing may fail on some files because it requires the framed data (e.g. an IsoMedia sample) to be continuous in the original file, which is not always the case depending on the original interleaving or bitstream format (_AVC_ or _HEVC_ cannot use this option)_  
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<a id="no-drop" data-level="basic">__-no-drop__</a>,__-nodrop__: force constant FPS when importing AVI video  
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<a id="packed" data-level="basic">__-packed__</a>: force packed bitstream when importing raw MPEG-4 part 2 Advanced Simple Profile  
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<a id="sbr" data-level="basic">__-sbr__</a>: backward compatible signaling of AAC-SBR  
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<a id="sbrx" data-level="basic">__-sbrx__</a>: non-backward compatible signaling of AAC-SBR  
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<a id="ps" data-level="basic">__-ps__</a>: backward compatible signaling of AAC-PS  
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<a id="psx" data-level="basic">__-psx__</a>: non-backward compatible signaling of AAC-PS  
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<a id="ovsbr" data-level="basic">__-ovsbr__</a>: oversample SBR import (SBR AAC, PS AAC and oversampled SBR cannot be detected at import time)  
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<a id="fps" data-level="basic">__-fps__</a> (string): force frame rate for video and SUB subtitles import to the given value, expressed as a number, as `TS-inc` or `TS/inc`.    
_Note: For raw H263 import, default FPS is `15`, otherwise `25`. This is accepted for ISOBMFF import but `:rescale` option should be preferred_  
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<a id="mpeg4" data-level="basic">__-mpeg4__</a>: force MPEG-4 sample descriptions when possible. For AAC, forces MPEG-4 AAC signaling even if MPEG-2  
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<a id="agg" data-level="basic">__-agg__</a> (int): aggregate N audio frames in 1 sample (3GP media only, maximum value is 15)  
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