iOS AVFoundation - 在视频上显示时间并导出

发布于 2024-10-13 13:47:43 字数 196 浏览 1 评论 0原文

我想在视频上显示显示叠加并导出包含此显示的视频。我研究了 AVFoundation Framework、AVCompositions、AVAssets 等，但我仍然不知道如何实现这一点。有一个名为 AVSynchronizedLayer 的类，它可以让您对与视频同步的事物进行动画处理，但我不想动画化，我只是想将时间显示覆盖到视频的每个帧中。有什么建议吗？

问候

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怀里藏娇 2024-10-20 13:47:43

像这样的东西......

（注意：从一个更大的项目中挑选出来，所以我可能不小心包含了一些不必要的部分）。

您需要获取时钟/动画的 CALayer，并将其设置为 var myClockLayer（由动画工具使用 1/3）。

这还假设您传入的视频只有两个轨道 - 音频和视频。如果您有更多，则需要更仔细地在“asTrackID:2”中设置曲目 ID。

AVURLAsset* url = [AVURLAsset URLAssetWithURL:incomingVideo options:nil];
AVMutableComposition *videoComposition = [AVMutableComposition composition];

AVMutableCompositionTrack *compositionVideoTrack = [videoComposition  addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
AVAssetTrack *clipVideoTrack = [[url tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
[compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, [url duration])  ofTrack:clipVideoTrack atTime:kCMTimeZero error:&error];

AVMutableVideoComposition* videoComposition = [[AVMutableVideoComposition videoComposition]retain];
videoComposition.renderSize = CGSizeMake(320, 240);
videoComposition.frameDuration = CMTimeMake(1, 30);
videoComposition.animationTool = [AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithAdditionalLayer:myClockLayer asTrackID:2];

AVMutableVideoCompositionInstruction *instruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
instruction.timeRange = CMTimeRangeMake(kCMTimeZero, CMTimeMakeWithSeconds(60, 30) );

AVMutableVideoCompositionLayerInstruction* layerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:clipVideoTrack];
instruction.layerInstructions = [NSArray arrayWithObject:layerInstruction];

videoComposition.instructions = [NSArray arrayWithObject: instruction];

exporter = [[AVAssetExportSession alloc] initWithAsset:saveComposition presetName:AVAssetExportPresetHighestQuality] ;
exporter.videoComposition = videoComposition;
exporter.outputURL=url3;
exporter.outputFileType=AVFileTypeQuickTimeMovie;

[exporter exportAsynchronouslyWithCompletionHandler:^(void){}];

Something like this...

(NB: culled from a much larger project, so I may have included some unnecessary pieces by accident).

You'll need to grab the CALayer of your clock / animation, and set it to the var myClockLayer (used 1/3 of the way down by the andimation tool).

This also assumes your incoming video has just two tracks - audio and video. If you have more, you'll need to set the track id in "asTrackID:2" more carefully.

AVURLAsset* url = [AVURLAsset URLAssetWithURL:incomingVideo options:nil];
AVMutableComposition *videoComposition = [AVMutableComposition composition];

AVMutableCompositionTrack *compositionVideoTrack = [videoComposition  addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
AVAssetTrack *clipVideoTrack = [[url tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
[compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, [url duration])  ofTrack:clipVideoTrack atTime:kCMTimeZero error:&error];

AVMutableVideoComposition* videoComposition = [[AVMutableVideoComposition videoComposition]retain];
videoComposition.renderSize = CGSizeMake(320, 240);
videoComposition.frameDuration = CMTimeMake(1, 30);
videoComposition.animationTool = [AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithAdditionalLayer:myClockLayer asTrackID:2];

AVMutableVideoCompositionInstruction *instruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
instruction.timeRange = CMTimeRangeMake(kCMTimeZero, CMTimeMakeWithSeconds(60, 30) );

AVMutableVideoCompositionLayerInstruction* layerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:clipVideoTrack];
instruction.layerInstructions = [NSArray arrayWithObject:layerInstruction];

videoComposition.instructions = [NSArray arrayWithObject: instruction];

exporter = [[AVAssetExportSession alloc] initWithAsset:saveComposition presetName:AVAssetExportPresetHighestQuality] ;
exporter.videoComposition = videoComposition;
exporter.outputURL=url3;
exporter.outputFileType=AVFileTypeQuickTimeMovie;

[exporter exportAsynchronouslyWithCompletionHandler:^(void){}];

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