public static float CalculateTimeScale(MovieMetadataBox moovBox, TrackBox trackBox)
{
MovieHeaderBox headerBox = moovBox.MovieHeaderBox;
ulong moovDuration = headerBox.Duration;
uint moovTimeScale = headerBox.TimeScale;
MediaHeaderBox mdhdBox = trackBox.MediaBox.MediaHeaderBox;
ulong mediaDuration = mdhdBox.Duration;
float mediaTimeScale = mdhdBox.TimeScale;
// Note that time scales may differ between moov and each media (because sampling rate can differ?)
moovDuration = moovDuration / moovTimeScale;
mediaDuration = (ulong)(mediaDuration / mediaTimeScale);
long diff = Math.Abs((long)moovDuration - (long)mediaDuration);
if ((diff * diff) > (long)((moovDuration * moovDuration) / 100)) // must be within 1%
{
throw new Exception("Media Box Header inconsistent with Track Header");
}
// scale to 10,000,000 ticks per second
mediaTimeScale /= TimeSpan.FromSeconds(1.0).Ticks;
if (mediaTimeScale == 0)
{
throw new Exception("MP4VideoTrack: media time scale is zero");
}
return(mediaTimeScale);
}
public MovieMetadataBox(List<IsochronousTrackInfo> trackInfos, float rate, float volume, uint[] matrix)
: base(BoxTypes.Movie)
{
// initialize movie duration to zero, then increment it for every slice that is written
ulong scaledDuration = (ulong)TimeArithmetic.ConvertToTimeScale(trackInfos[0].MovieTimeScale, trackInfos[0].MovieDurationIn100NanoSecs);
MovieHeaderBox = new MovieHeaderBox(trackInfos[0].MovieTimeScale, scaledDuration, rate, volume, matrix);
this.Size += MovieHeaderBox.Size;
TrackBoxes = new TrackBox[trackInfos.Count]; // may have more than 2 tracks
// MovieExtendsBox should only exist if this is a fragment
if (trackInfos[0].IsFragment)
{
MovieExtendsBox = new MovieExtendsBox(this, trackInfos);
this.Size += MovieExtendsBox.Size;
}
}
public MovieMetadataBox(List <IsochronousTrackInfo> trackInfos, float rate, float volume, uint[] matrix)
: base(BoxTypes.Movie)
{
// initialize movie duration to zero, then increment it for every slice that is written
ulong scaledDuration = (ulong)TimeArithmetic.ConvertToTimeScale(trackInfos[0].MovieTimeScale, trackInfos[0].MovieDurationIn100NanoSecs);
MovieHeaderBox = new MovieHeaderBox(trackInfos[0].MovieTimeScale, scaledDuration, rate, volume, matrix);
this.Size += MovieHeaderBox.Size;
TrackBoxes = new TrackBox[trackInfos.Count]; // may have more than 2 tracks
// MovieExtendsBox should only exist if this is a fragment
if (trackInfos[0].IsFragment)
{
MovieExtendsBox = new MovieExtendsBox(this, trackInfos);
this.Size += MovieExtendsBox.Size;
}
}
public MovieMetadataBox() : base(BoxTypes.Movie)
{
MovieHeaderBox = new MovieHeaderBox();
}
public MovieMetadataBox()
: base(BoxTypes.Movie)
{
MovieHeaderBox = new MovieHeaderBox();
}
