1MP4(3) MP4 File Format Library MP4(3)
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6 MP4AddTrackEdit - Add an edit segment to a track
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9 #include <mp4.h>
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11 MP4TrackId MP4AddTrackEdit(
12 MP4FileHandle hFile,
13 MP4TrackId trackId,
14 MP4EditId editId,
15 MP4Timestamp startTime = 0,
16 MP4Duration duration = 0,
17 bool dwell = false
18 )
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21 hFile Specifies the mp4 file to which the operation applies.
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23 trackId
24 Specifies the track to which the operation applies.
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26 editId Specifies the desired position in the edit list sequence for the
27 new edit segment. If the value is MP4_INVALID_EDIT_ID, then the
28 edit segment is added at the end of the existing edit list. Note
29 editId's start with the value of 1, not 0.
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31 startTime
32 Specifies the starting time of the edit segment in the track
33 time scale.
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35 duration
36 Specifies the duration of the edit segment in the track time
37 scale.
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39 dwell If false, the track media should be played at its normal rate.
40 If true, the media should be paused for the duration of this
41 edit segment. This is a mechanism by which one can delay the
42 start of a media track.
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46 Upon success, the edit id of the new edit segment. Upon an error,
47 MP4_INVALID_EDIT_ID.
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51 MP4AddTrackEdit adds an edit segment to the track edit list.
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53 The track edit list is a feature that allows creation of an alternate
54 timeline for the track, typically cutting out segments of the full
55 track to form an shorten, cleaned up version. The edit segments that
56 form the edit list are a sequence of track start times and durations,
57 they do not alter the track media in any way. I.e. no data can be lost
58 via edit list operations.
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60 To read out the editted version of the track, use MP4ReadSample‐
61 FromEditTime() instead of MP4ReadSample().
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63 To export the editted version of the track to a new track, potentially
64 in a new mp4 file, see MP4CopyTrack().
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66 Note with many media encodings such as MPEG-4, AAC, and MP3, care must
67 be taken when choosing the edit segment start times. E.g. for video
68 tracks a reference or key frame should be selected as the starting sam‐
69 ple of any edit segment. For audio tracks, an audio sample start time
70 should be used.
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75 MP4(3) MP4DeleteTrackEdit(3) MP4ReadSampleFromEditTime(3) MP4Copy‐
76 Track(3)
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80Cisco Systems Inc. Version 0.9 MP4(3)