I'm using UIImagePickerController to allow my user to select a video from the asset library.
When the user selects the "Choose" button on the second screen, the view displays a progress bar and a "Compressing Video..." message.
Why is this happening?
Is there some way I can avoid this compression operation?
Answer: There is currently no way to control how UIImagePickerController compresses the picked video.
I just did some quick tests. Using a test app I created, I picked the same video two times -- once with the videoQuality
property set to UIImagePickerControllerQualityTypeHigh
and once with it set to UIImagePickerControllerQualityTypeLow
. The resulting files that were copied over are exactly the same size, 15.1MB with a frame size of 360x480. The original was 72.5MB with a frame size of 480x640. Apparently this property doesn't affect the compression used at all.
Set the videoQuality property of the UIImagePickerController to "High" (UIImagePickerControllerQualityTypeHigh = 0)
From the SDK documentation:
"If displaying a recorded movie in the image picker, specifies that you do not want to reduce the video quality of the movie."
http://developer.apple.com/iphone/library/documentation/uikit/reference/UIImagePickerController_Class/UIImagePickerController/UIImagePickerController.html#//apple_ref/doc/c_ref/UIImagePickerControllerQualityType
Since there is no way yet to avoid compression using UIImagePickerController, I wanted to include some ideas of how you can create your own image picker that will avoid compression.
This will allow access to the raw video files:
iOS 8
PHFetchResult *assetsFetchResult = [PHAsset fetchAssetsWithMediaType:PHAssetMediaTypeVideo options:nil];
for (PHAsset *asset in assetsFetchResult) {
PHVideoRequestOptions *videoRequestOptions = [[PHVideoRequestOptions alloc] init];
videoRequestOptions.version = PHVideoRequestOptionsVersionOriginal;
[[PHImageManager defaultManager] requestAVAssetForVideo:asset options:videoRequestOptions resultHandler:^(AVAsset *asset, AVAudioMix *audioMix, NSDictionary *info) {
// the AVAsset object represents the original video file
}];
}
Look at the PhotoKit documentation for accessing collections (moments) and other options.
Here is a sample app from Apple using PhotoKit that could be modified to be a photo picker: https://developer.apple.com/library/ios/samplecode/UsingPhotosFramework/Introduction/Intro.html
Here is a photo picker library on GitHub that uses PhotoKit that looks promising since it gives you the PHAsset objects for all the selected images/videos: https://github.com/guillermomuntaner/GMImagePicker
iOS 7 and below
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
if (group) {
// If you want, you can filter just pictures or videos
// I just need videos so I do this:
[group setAssetsFilter:[ALAssetsFilter allVideos]];
[group enumerateAssetsUsingBlock:^(ALAsset *asset, NSUInteger index, BOOL *stop){
if (asset){
// You can now add this ALAsset in your own video picker.
// Note that you can only access the ALAsset as long as
// you maintain a reference to the ALAssetsLibrary
// Or if you want to process the video, you can create an AVAsset:
NSURL *url = asset.defaultRepresentation.url;
AVAsset *videoAsset = [AVAsset assetWithURL:url];
}
}];
}
} failureBlock:^(NSError *error) {
NSLog(@"error enumerating AssetLibrary groups %@\n", error);
}];
For those giving the advice to use the videoQuality property, documentation is clearly stating that it is a video capture option, not a picker option.
As Jack is mentioning it below, it is also for transcoding. Looks like I read the doc too quickly because I didn't notice the transcoding mention.