mp4(3)
NAME
MP4FindTrackId - Find a track id
SYNTAX
#include <mp4.h>
- MP4TrackId MP4FindTrackId(
- MP4FileHandle hFile,
u_int16_t index,
const char* type = NULL,
u_int8_t subType = 0 - )
ARGUMENTS
hFile Specifies the mp4 file to which the operation applies.
index Specifies which track is desired from matching tracks.
- type Specifies the type of track to be matched. A NULL value implies
- any type of track. See MP4GetTrackType() for predefined values.
- subType
- Specifies the subtype of the track to be matched. Subtypes are only defined for audio and video tracks, see MP4GetAudioTrackType() and MP4GetVideoTrackType() for predefined values. A zero value implies any subtype.
RETURN VALUES
Upon success, the track id of the specified track. Upon an error,
MP4_INVALID_TRACK_ID.
DESCRIPTION
- MP4FindTrackId gets the track id associated with the index'th track of
the specified track type. For example, to get the track id of the first
video track:
- MP4FindTrackId(hFile, 0, MP4_VIDEO_TRACK_TYPE);
- For audio and video tracks, a subtype can be specified to find a track of a particular encoding. For example, to get the track id of the first audio track encoded with MPEG-1 audio:
MP4FindTrackId(hFile, 0, MP4_AUDIO_TRACK_TYPE,- MP4_MPEG1_AUDIO_TYPE);
- Caveat: The track id's do not imply anything about the ordering of the track information within the mp4 file.