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mp4dmx

ISOBMFF/QT demultiplexer

Register name used to load filter: mp4dmx
This filter may be automatically loaded during graph resolution.

This filter demultiplexes ISOBMF and QT files.
Input ISOBMFF/QT can be regular or fragmented, and available as files or as raw bytestream.

Track Selection

The filter can use fragment identifiers of source to select a single track for playback. The allowed fragments are: 

- #audio: only use the first audio track  
- #video: only use the first video track  
- #auxv: only use the first auxiliary video track  
- #pict: only use the first picture track  
- #text: only use the first text track  
- #trackID=VAL: only use the track with given ID  
- #itemID=VAL: only use the item with given ID  
- #ID=VAL: only use the track/item with given ID  
- #VAL: only use the track/item with given ID

Scalable Tracks

When scalable tracks are present in a file, the reader can operate in 3 modes using smode option:

  • smode=single: resolves all extractors to extract a single bitstream from a scalable set. The highest level is used

In this mode, there is no enhancement decoder config, only a base one resulting from the merge of the layers configurations

  • smode=split: all extractors are removed and every track of the scalable set is declared. In this mode, each enhancement track has no base decoder config

and an enhancement decoder config.

  • smode=splitx: extractors are kept in the bitstream, and every track of the scalable set is declared. In this mode, each enhancement track has a base decoder config

(copied from base) and an enhancement decoder config. This is mostly used for DASHing content.

Warning: smode=splitx will result in extractor NAL units still present in the output bitstream, which shall only be true if the output is ISOBMFF based

Options

src (cstr): local file name of source content (only used when explicitly loading the filter)
allt (bool, default: false): load all tracks even if unknown media type
edits (enum, default: auto): do not use edit lists

  • auto: track delay and no edit list when possible
  • no: ignore edit list
  • strict: use edit list even if only signaling a delay

itt (bool, default: false): convert all items of root meta into a single PID
itemid (bool, default: true): keep item IDs in PID properties
smode (enum, default: split): load mode for scalable/tile tracks

  • split: each track is declared, extractors are removed
  • splitx: each track is declared, extractors are kept
  • single: a single track is declared (highest level for scalable, tile base for tiling)

alltk (bool, default: false): declare disabled tracks
frame_size (uint, default: 1024): frame size for raw audio samples (dispatches frame_size samples per packet)
expart (bool, default: false): expose cover art as a dedicated video PID
sigfrag (bool, default: false): signal fragment and segment boundaries of source on output packets, fails if source is not fragmented
tkid (str): declare only track based on given param

  • integer value: declares track with the given ID
  • audio: declares first audio track
  • video: declares first video track
  • 4CC: declares first track with matching 4CC for handler type

stsd (uint, default: 0): only extract sample mapped to the given sample description index (0 means extract all)
nocrypt (bool): signal encrypted tracks as non encrypted (mostly used for export)
mstore_size (uint, default: 1000000): target buffer size in bytes when reading from memory stream (pipe etc...)
mstore_purge (uint, default: 50000): minimum size in bytes between memory purges when reading from memory stream, 0 means purge as soon as possible
mstore_samples (uint, default: 50): minimum number of samples to be present before purging sample tables when reading from memory stream (pipe etc...), 0 means purge as soon as possible
strtxt (bool, default: false): load text tracks (apple/tx3g) as MPEG-4 streaming text tracks
xps_check (enum, default: auto): parameter sets extraction mode from AVC/HEVC/VVC samples

  • keep: do not inspect sample (assumes input file is compliant when generating DASH/HLS/CMAF)
  • rem: removes all inband xPS and notify configuration changes accordingly
  • auto: resolves to keep for smode=splitx (dasher mode), rem otherwise

nodata (enum, default: no): control sample data loading

  • no: regular load
  • yes: skip data loading
  • fake: allocate sample but no data copy

lightp (bool, default: false): load minimal set of properties
initseg (str): local init segment name when input is a single ISOBMFF segment
ctso (sint): value to add to CTS offset for tracks using negative ctts

  • set to -1 to use the cslg box info or the minimum cts offset present in the track
  • set to -2 to use the minimum cts offset present in the track (cslg ignored)

norw (bool, default: false): skip reformating of samples - should only be used when rewriting fragments
keepc (bool, default: false): keep corrupted samples - should only be used in multicast modes