unsafe AVAudioMix CreateAudioMix()
{
AVMutableAudioMix audioMix = AVMutableAudioMix.Create();
AVMutableAudioMixInputParameters audioMixInputParameters = AVMutableAudioMixInputParameters.FromTrack(audioAssetTrack);
var callbacks = new MTAudioProcessingTapCallbacks(TapProcess)
{
Initialize = TapInitialization,
Finalize = Finalaze,
Prepare = TapPrepare,
Unprepare = Unprepare,
};
audioProcessingTap = new MTAudioProcessingTap(callbacks, MTAudioProcessingTapCreationFlags.PreEffects);
audioMixInputParameters.AudioTapProcessor = audioProcessingTap;
audioMix.InputParameters = new AVAudioMixInputParameters[] { audioMixInputParameters };
return(audioMix);
}
private void BuildTransitionComposition(AVMutableComposition composition, AVMutableVideoComposition videoComposition, AVMutableAudioMix audioMix)
{
CMTime nextClipStartTime = CMTime.Zero;
int clipsCount = Clips.Count;
// Make transitionDuration no greater than half the shortest clip duration.
CMTime transitionDuration = TransitionDuration;
Console.WriteLine("Clips Count:" + clipsCount);
Console.WriteLine("Clips Range Count:" + ClipTimeRanges.Count);
for (int i = 0; i < clipsCount; i++)
{
NSValue clipTimeRange = ClipTimeRanges [i];
if (clipTimeRange != null)
{
CMTime halfClipDuration = clipTimeRange.CMTimeRangeValue.Duration;
halfClipDuration.TimeScale *= 2;
transitionDuration = CMTime.GetMinimum(transitionDuration, halfClipDuration);
}
}
// Add two video tracks and two audio tracks.
var compositionVideoTracks = new AVMutableCompositionTrack [] {
composition.AddMutableTrack(AVMediaType.Video, 0),
composition.AddMutableTrack(AVMediaType.Video, 0)
};
var compositionAudioTracks = new AVMutableCompositionTrack [] {
composition.AddMutableTrack(AVMediaType.Audio, 0),
composition.AddMutableTrack(AVMediaType.Audio, 0)
};
var passThroughTimeRanges = new CMTimeRange[clipsCount];
var transitionTimeRanges = new CMTimeRange[clipsCount];
// Place clips into alternating video & audio tracks in composition, overlapped by transitionDuration.
for (int i = 0; i < clipsCount; i++)
{
int alternatingIndex = i % 2;
AVAsset asset = Clips [i];
NSValue clipTimeRange = ClipTimeRanges [i];
CMTimeRange timeRangeInAsset;
if (clipTimeRange != null)
{
timeRangeInAsset = clipTimeRange.CMTimeRangeValue;
}
else
{
timeRangeInAsset = new CMTimeRange();
timeRangeInAsset.Start = CMTime.Zero;
timeRangeInAsset.Duration = asset.Duration;
}
NSError error;
AVAssetTrack clipVideoTrack = asset.TracksWithMediaType(AVMediaType.Video) [0];
compositionVideoTracks [alternatingIndex].InsertTimeRange(timeRangeInAsset, clipVideoTrack, nextClipStartTime, out error);
AVAssetTrack clipAudioTrack = asset.TracksWithMediaType(AVMediaType.Audio) [0];
compositionAudioTracks [alternatingIndex].InsertTimeRange(timeRangeInAsset, clipAudioTrack, nextClipStartTime, out error);
// Remember the time range in which this clip should pass through.
// First clip ends with a transition.
// Second clip begins with a transition.
// Exclude that transition from the pass through time ranges
CMTimeRange timeRange = new CMTimeRange();
timeRange.Start = nextClipStartTime;
timeRange.Duration = timeRangeInAsset.Duration;
passThroughTimeRanges [i] = timeRange;
if (i > 0)
{
passThroughTimeRanges[i].Start = CMTime.Add(passThroughTimeRanges[i].Start, transitionDuration);
passThroughTimeRanges[i].Duration = CMTime.Subtract(passThroughTimeRanges[i].Duration, transitionDuration);
}
if (i + 1 < clipsCount)
{
passThroughTimeRanges[i].Duration = CMTime.Subtract(passThroughTimeRanges[i].Duration, transitionDuration);
}
// The end of this clip will overlap the start of the next by transitionDuration.
// (Note: this arithmetic falls apart if timeRangeInAsset.duration < 2 * transitionDuration.)
nextClipStartTime = CMTime.Add(nextClipStartTime, timeRangeInAsset.Duration);
nextClipStartTime = CMTime.Subtract(nextClipStartTime, transitionDuration);
// Remember the time range for the transition to the next item
if (i + 1 < clipsCount)
{
transitionTimeRanges [i] = new CMTimeRange()
{
Start = nextClipStartTime,
Duration = transitionDuration
};
}
}
List <AVVideoCompositionInstruction> instructions = new List <AVVideoCompositionInstruction> ();
List <AVMutableAudioMixInputParameters> trackMixArray = new List <AVMutableAudioMixInputParameters> ();
// Set up the video composition if we are to perform crossfade transitions between clips.
for (int i = 0; i < clipsCount; i++)
{
int alternatingIndex = i % 2;
AVMutableVideoCompositionInstruction passThroughInstructions = AVMutableVideoCompositionInstruction.Create() as AVMutableVideoCompositionInstruction;
passThroughInstructions.TimeRange = passThroughTimeRanges [i];
AVMutableVideoCompositionLayerInstruction passThroughLayerInstructions = AVMutableVideoCompositionLayerInstruction.FromAssetTrack(compositionVideoTracks [alternatingIndex]);
passThroughInstructions.LayerInstructions = new AVVideoCompositionLayerInstruction[] { passThroughLayerInstructions };
instructions.Add(passThroughInstructions);
if (i + 1 < clipsCount)
{
var transitionInstruction = AVMutableVideoCompositionInstruction.Create() as AVMutableVideoCompositionInstruction;
transitionInstruction.TimeRange = transitionTimeRanges [i];
var fromLayer = AVMutableVideoCompositionLayerInstruction.FromAssetTrack(compositionVideoTracks [alternatingIndex]);
var toLayer = AVMutableVideoCompositionLayerInstruction.FromAssetTrack(compositionVideoTracks [1 - alternatingIndex]);
// Fade in the toLayer by setting a ramp from 0.0 to 1.0.
toLayer.SetOpacityRamp(0.0f, 1.0f, transitionTimeRanges [i]);
transitionInstruction.LayerInstructions = new AVVideoCompositionLayerInstruction[]
{
toLayer,
fromLayer,
};
instructions.Add(transitionInstruction);
// Add AudioMix to fade in the volume ramps
var trackMix = AVMutableAudioMixInputParameters.FromTrack(compositionAudioTracks[0]);
trackMix.SetVolumeRamp(1f, 0f, transitionTimeRanges[0]);
trackMixArray.Add(trackMix);
trackMix = AVMutableAudioMixInputParameters.FromTrack(compositionAudioTracks[1]);
trackMix.SetVolumeRamp(0f, 1f, transitionTimeRanges[0]);
trackMix.SetVolumeRamp(1f, 1f, passThroughTimeRanges[1]);
trackMixArray.Add(trackMix);
}
}
videoComposition.Instructions = instructions.ToArray();
audioMix.InputParameters = trackMixArray.ToArray();
}
public Task <OperationResult> AddAudioToVideoTrack(string videoFilePath, string audioFilePath, string outputFilePath,
float volume = 1, float fadeOutDuration = 0)
{
var tcs = new TaskCompletionSource <OperationResult>();
var composition = AVMutableComposition.Create();
var videoCompositionTrack = composition.AddMutableTrack(AVMediaType.Video, 0);
var audioCompositionTrack = composition.AddMutableTrack(AVMediaType.Audio, 0);
var videoUrl = NSUrl.FromFilename(videoFilePath);
var videoAsset = AVAsset.FromUrl(videoUrl);
var videoAssetTrack = videoAsset.TracksWithMediaType(AVMediaType.Video).First();
var audioUrl = NSUrl.FromFilename(audioFilePath);
var audioAsset = AVAsset.FromUrl(audioUrl);
var audioAssetTrack = audioAsset.TracksWithMediaType(AVMediaType.Audio).First();
CGSize size = videoAssetTrack.NaturalSize;
CMTime time = CMTime.Zero;
var range = new CMTimeRange
{
Start = CMTime.Zero,
Duration = videoAssetTrack.TimeRange.Duration
};
NSError error = null;
videoCompositionTrack.InsertTimeRange(range, videoAssetTrack, time, out error);
if (error != null)
{
Console.WriteLine("Error adding video composition track: " + error.LocalizedDescription);
}
error = null;
audioCompositionTrack.InsertTimeRange(range, audioAssetTrack, time, out error);
if (error != null)
{
Console.WriteLine("Error adding audio composition track: " + error.LocalizedDescription);
}
var audioMix = AVMutableAudioMix.Create();
var audioInputParams = AVMutableAudioMixInputParameters.FromTrack(audioCompositionTrack);
audioInputParams.SetVolume(volume, CMTime.Zero);
if (fadeOutDuration > 0)
{
var fadeOutStartTime = CMTime.Subtract(videoAssetTrack.TimeRange.Duration, CMTime.FromSeconds(fadeOutDuration, audioAssetTrack.NaturalTimeScale));
var fadeOutRange = new CMTimeRange
{
Start = fadeOutStartTime,
Duration = CMTime.FromSeconds(fadeOutDuration, audioAssetTrack.NaturalTimeScale)
};
audioInputParams.SetVolumeRamp(volume, 0.0f, fadeOutRange);
}
audioMix.InputParameters = new[] { audioInputParams };
var session = new AVAssetExportSession(composition, AVAssetExportSession.PresetHighestQuality);
session.OutputUrl = NSUrl.FromFilename(outputFilePath);
session.OutputFileType = AVFileType.Mpeg4;
session.AudioMix = audioMix;
session.ExportAsynchronously(() =>
{
if (session.Status == AVAssetExportSessionStatus.Failed)
{
tcs.SetResult(OperationResult.AsFailure(session.Error.LocalizedDescription));
}
else
{
tcs.SetResult(OperationResult.AsSuccess());
}
});
return(tcs.Task);
}
