Creating a time range for AVAssetExportSession

Question

I was wondering how to make a time range for `AVAssetExportSession` from time stamps such as: ``` NSTimeInterval start = [[NSDate date] timeIntervalSince1970]; NSTimeInterval end = [[NSDate date] timeIntervalSince1970]; ``` The code that I am using for my export session is as follows: ``` AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:asset presetName:AVAssetExportPresetHighestQuality]; exportSession.outputURL = videoURL; exportSession.outputFileType = AVFileTypeQuickTimeMovie; exportSession.timeRange = CMTimeRangeFromTimeToTime(start, end); ``` Thanks for your help!

Accepted Answer

The property `timeRange` in `AVAssetExportSession` allows you to do a partial export of an asset specifying where to start and which duration. If not specified it'll export the whole video, in other words, it'll start at zero and will export the total duration.

Both start and duration should be expressed as `CMTime`.

For instance, if you want to export the first half of the asset:

```
CMTime half = CMTimeMultiplyByFloat64(exportSession.asset.duration, 0.5);
exportSession.timeRange = CMTimeRangeMake(kCMTimeZero, half);
```

or the second half:

```
exportSession.timeRange = CMTimeRangeMake(half, half);
```

or 10 seconds at the end:

```
CMTime _10 = CMTimeMakeWithSeconds(10, 600);
CMTime tMinus10 = CMTimeSubtract(exportSession.asset.duration, _10);
exportSession.timeRange = CMTimeRangeMake(tMinus10, _10);
```

Check `CMTime` reference for other ways to calculate the exact timing you need.

Creating a time range for AVAssetExportSession

Solution

Problem