1MP4(3)                      MP4 File Format Library                     MP4(3)
2
3
4

NAME

6       MP4WriteSample - Write a track sample
7

SYNTAX

9       #include <mp4.h>
10
11       bool MP4WriteSample(
12            MP4FileHandle hFile,
13            MP4TrackId trackId,
14            u_int8_t* pBytes,
15            u_int32_t numBytes,
16            MP4Duration duration = MP4_INVALID_DURATION,
17            MP4Duration renderingOffset = 0,
18            bool isSyncSample = true
19       );
20

ARGUMENTS

22       hFile  Specifies the mp4 file to which the operation applies.
23
24       trackId
25              Specifies the track to which the operation applies.
26
27       pBytes Pointer to the sample data.
28
29       numBytes
30              The size in bytes of the sample.
31
32       duration
33              The  duration for this sample. Caveat: The duration should be in
34              the track timescale units.
35
36       renderingOffset
37              The rendering offset for this sample. Currently the  only  media
38              type  that  needs this feature is MPEG video. Caveat: The offset
39              should be in the track timescale units.
40
41       isSyncSample
42              The sync/random access flag for this sample.
43

RETURN VALUES

45       Upon success, true (1). Upon an error, false (0).
46

DESCRIPTION

48       MP4WriteSample writes the given sample at  the  end  of  the  specified
49       track.  Currently the library does not support random insertion of sam‐
50       ples into the track timeline. Note that with mp4 there  cannot  be  any
51       holes  or  overlapping  samples  in  the track timeline. The last three
52       arguments give optional sample information.
53
54       The value of duration can be given as MP4_INVALID_DURATION if all  sam‐
55       ples  in  the  track have the same duration. This can be specified with
56       MP4AddTrack() and related functions.
57
58       Typically for audio none of the optional  arguments  are  needed.  MPEG
59       audio  such  as MP3 or AAC has a fixed sample duration and every sample
60       can be accessed at random.
61
62       For video, all of the optional arguments could be  needed.  MPEG  video
63       can  be  encoded  at a variable frame rate, with only occasional random
64       access points, and with "B frames" which cause the rendering  (display)
65       order of the video frames to differ from the storage/decoding order.
66
67       Other media types fall between these two extremes.
68

SEE ALSO

70       MP4(3)
71
72
73
74Cisco Systems Inc.                Version 0.9                           MP4(3)
Impressum