MP4 Conversion and Video Merging in iOS

MP4 Conversion

Sometimes we need to develop applications both for android and iOS that uses the videos captured from the devices.By default iOS saves the video in .mov format which can not be played on the android devices.To make the iOS videos compatible for all devices(android and iOS) we use a common video format and that is .mp4. Now we can achieve this by using AVFoundation framework. This blog will provide the steps to convert video in mp4 format.

// Create the asset url with the video file

AVURLAsset *avAsset = [AVURLAsset URLAssetWithURL:videoURL options:nil];

NSArray *compatiblePresets = [AVAssetExportSession exportPresetsCompatibleWithAsset:avAsset];

// Check if video is supported for conversion or not

if ([compatiblePresets containsObject:AVAssetExportPresetLowQuality])

{

//Create Export session

     AVAssetExportSession *exportSession = [[AVAssetExportSession       alloc]initWithAsset:avAsset presetName:AVAssetExportPresetLowQuality];

//Creating temp path to save the converted video

     NSString* documentsDirectory=     [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];

     NSString* myDocumentPath= [documentsDirectory stringByAppendingPathComponent:@"temp.mp4"];

     NSURL *url = [[NSURL alloc] initFileURLWithPath:myDocumentPath];

//Check if the file already exists then remove the previous file

     if ([[NSFileManager defaultManager]fileExistsAtPath:myDocumentPath])

     {

          [[NSFileManager defaultManager]removeItemAtPath:myDocumentPath error:nil];

     }

     exportSession.outputURL = url;

     //set the output file format if you want to make it in other file format (ex .3gp)

     exportSession.outputFileType = AVFileTypeMPEG4;

     exportSession.shouldOptimizeForNetworkUse = YES;

     [exportSession exportAsynchronouslyWithCompletionHandler:^{

     switch ([exportSession status])

     {

          case AVAssetExportSessionStatusFailed:

               NSLog(@"Export session failed");

               break;

          case AVAssetExportSessionStatusCancelled:

               NSLog(@"Export canceled");

               break;

          case AVAssetExportSessionStatusCompleted:

          {

               //Video conversion finished

               NSLog(@"Successful!");

          }

               break;

          default:

               break;

      }

     }];

}

else

{

       NSLog(@"Video file not supported!");

}

Videos Merging(Adding two videos)

While developing iOS applications some times we required a functionality where we have to merge small video clips in one large video file. Now this we can achieve through iOS AVFoundation framework.

//Create the AVMutable composition to add tracks

AVMutableComposition* composition = [[AVMutableComposition alloc]init];

//Create assets url for first video

AVURLAsset* video1 = [[AVURLAsset alloc]initWithURL:[NSURL fileURLWithPath:path1]options:nil];

//Create assets url for second video

AVURLAsset* video2 = [[AVURLAsset alloc]initWithURL:[NSURL fileURLWithPath:path2]options:nil];

//Create the mutable composition track with video media type. You can also create the tracks depending on your need if you want to merge audio files and other stuffs.

AVMutableCompositionTrack* composedTrack = [composition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];

//Set the video time ranges of both the videos in composition

[composedTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, video1.duration)

ofTrack:[[video1 tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0]

atTime:kCMTimeZero error:nil];

[composedTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, video2.duration)

ofTrack:[[video2 tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0]

atTime:video1.duration error:nil];

// Create a temp path to save the video in the documents dir.

NSString* documentsDirectory= [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];

NSString* myDocumentPath= [documentsDirectory stringByAppendingPathComponent:@"merge_video.mp4"];

NSURL *url = [[NSURL alloc] initFileURLWithPath: myDocumentPath];

//Check if the file exists then delete the old file to save the merged video file.

if([[NSFileManager defaultManager]fileExistsAtPath:myDocumentPath])

{

          [[NSFileManager defaultManager]removeItemAtPath:myDocumentPath error:nil];

}

// Create the export session to merge and save the video

AVAssetExportSession*exporter = [[AVAssetExportSession alloc]initWithAsset:composition presetName:AVAssetExportPresetHighestQuality];

exporter.outputURL=url;

exporter.outputFileType=@"com.apple.quicktime-movie";

exporter.shouldOptimizeForNetworkUse=YES;

[exporter exportAsynchronouslyWithCompletionHandler:^{

          switch([exporter status])

          {

                    case AVAssetExportSessionStatusFailed:

                         NSLog(@"Failed to export video");

                    break;

                    case AVAssetExportSessionStatusCancelled:

                         NSLog(@"export cancelled");

                    break;

                    case AVAssetExportSessionStatusCompleted:

                         //Here you go you have got the merged video :)

                         NSLog(@"Merging completed");

                    break;

                    default:

                    break;

          }

}];

For Mixing audio and video

//From above code to mix a audio with video simply create a mutable composition of audio track and insert it in the video time range.

NSArray *pathComponents = [NSArray arrayWithObjects:

[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject],@"MyAudio.m4a",nil];

NSURL *outputFileURL = [NSURL fileURLWithPathComponents:pathComponents];

AVAsset *audioAsset = [AVAsset assetWithURL:outputFileURL];

//Create mutable composition of audio type

AVMutableCompositionTrack *audioTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];

[audioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero,firstAsset.duration)

ofTrack:[[audioAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:kCMTimeZero error:nil];

Here is sample project with all of the code from the above tutorial.