| .TH "MP4" "3" "Version 0.9" "Cisco Systems Inc." "MP4 File Format Library" |
| .SH "NAME" |
| .LP |
| \fBMP4GetNumberOfTracks\fR \- Get the number of tracks |
| .SH "SYNTAX" |
| .LP |
| #include <mp4.h> |
| .LP |
| u_int32_t \fBMP4GetNumberOfTracks\fR( |
| .br |
| MP4FileHandle \fIhFile\fP, |
| .br |
| const char* \fItype\fP = NULL, |
| .br |
| u_int8_t subType = 0 |
| .br |
| ) |
| .SH "ARGUMENTS" |
| .LP |
| .TP |
| \fIhFile\fP |
| Specifies the mp4 file to which the operation applies. |
| .TP |
| \fItype\fP |
| Species the type of track for which a count is desired. A NULL value implies any type of track. See MP4GetTrackType() for predefined values. |
| .TP |
| \fIsubType\fP |
| Specifies the subtype of the tracks to be counted. Subtypes are only defined for audio and video tracks, see MP4GetAudioTrackType() and MP4GetVideoTrackType() for predefined values. A zero value implies any subtype. |
| .SH "RETURN VALUES" |
| .LP |
| The number of tracks of the specified type and subType in the mp4 file. |
| .SH "DESCRIPTION" |
| .LP |
| \fBMP4GetNumberOfTracks\fR returns how many tracks of the specified type and subtype exist in the mp4 file. This can be used to determine if an mp4 file contains a track of a given type of media, for instance audio or video. It can also be used to determine if multiple options may be available. For instance multiple audio tracks in different languages. |
| .LP |
| For audio and video tracks, a subtype can be specified to only count tracks of a particular encoding. |
| .SH "SEE ALSO" |
| .LP |
| MP4(3) |
