无法从iOS中的设置URL压缩视频？
我从ALASSET获得了视频URL，然后使用imputURL函数将视频转换为LowQuailtyWithinputURL，以压缩视频，但它无法工作。我看到压缩后，视频的大小总是0 此函数用于从视频集获取视频URL：无法从iOS中的设置URL压缩视频？,ios,objective-c,cocoa-touch,compression,alassetslibrary,Ios,Objective C,Cocoa Touch,Compression,Alassetslibrary,我从ALASSET获得了视频URL，然后使用imputURL函数将视频转换为LowQuailtyWithinputURL，以压缩视频，但它无法工作。我看到压缩后，视频的大小总是0 此函数用于从视频集获取视频URL： ALAsset *alasset = [allVideos objectAtIndex:i]; ALAssetRepresentation *rep = [alasset defaultRepresentation]; NSString
ALAsset *alasset = [allVideos objectAtIndex:i];
ALAssetRepresentation *rep = [alasset defaultRepresentation];
NSString * videoName = [rep filename];
//compress video data before uploading
NSURL *videoURL = [rep url];
NSLog(@"videoURL is %@",videoURL);
NSURL *uploadURL = [NSURL fileURLWithPath:[[NSTemporaryDirectory() stringByAppendingPathComponent:videoName] stringByAppendingString:@".mov"]];
NSLog(@"uploadURL temp is %@",uploadURL);
// Compress movie first
[self convertVideoToLowQuailtyWithInputURL:videoURL outputURL:uploadURL handler:^(AVAssetExportSession *session)
{
if (session.status == AVAssetExportSessionStatusCompleted)
{
// Success
}
else
{
// Error Handing
}
}];
NSString *path = [uploadURL path];
NSData *data = [[NSFileManager defaultManager] contentsAtPath:path];
NSLog(@"size after compress video is %d",data.length);
}
- (void)convertVideoToLowQuailtyWithInputURL:(NSURL*)inputURL
outputURL:(NSURL*)outputURL
handler:(void (^)(AVAssetExportSession*))handler
{
[[NSFileManager defaultManager] removeItemAtURL:outputURL error:nil];
AVURLAsset *urlAsset = [AVURLAsset URLAssetWithURL:inputURL options:nil];
AVAssetExportSession *session = [[AVAssetExportSession alloc] initWithAsset: urlAsset presetName:AVAssetExportPresetLowQuality];
session.outputURL = outputURL;
session.outputFileType = AVFileTypeQuickTimeMovie;
[session exportAsynchronouslyWithCompletionHandler:^(void)
{
handler(session);
}];
}
convertVideoToLowQualityWithinputURL处理程序（会话）
和NSLog（@“压缩视频后的大小为%d”，数据长度）始终打印“大小为0”。
我哪里出错了？请给我一些建议。提前感谢。ConvertVideoToLowQuailtyWithiInputURL
是一种异步方法，这就是为什么它需要一个完成处理程序块。您当前的日志代码不在完成处理程序块中，而是在调用convertVideoToLowQuailtyWithiInputUrl
之后-这将在convertVideoToLowQuailtyWithiInputUrl
完成之前运行，因此您将永远不会得到结果
将压缩视频的日志记录（和使用情况）移动到完成块中。ConvertVideoToLowQuailtyWithiInputUrl
是一种异步方法，这就是它需要完成处理程序块的原因。您当前的日志代码不在完成处理程序块中，而是在调用convertVideoToLowQuailtyWithiInputUrl
之后-这将在convertVideoToLowQuailtyWithiInputUrl
完成之前运行，因此您将永远不会得到结果
ALAssetRepresentation* representation = [asset defaultRepresentation];
NSString *fileName = [NSString stringWithFormat:@"VGA_%@",representation.filename]; //prepend with _VGA to avoid overwriting original.
NSURL *TempLowerQualityFileURL = [NSURL fileURLWithPath:[NSTemporaryDirectory() stringByAppendingPathComponent:fileName] ];
NSURL *gallery_url = representation.url;
NSLog(@" \r\n PRE-CONVERSION FILE %@ Size =%lld ; URL=%@\r\n",fileName, representation.size,representation.url );
[self convertVideoToLowQuailtyWithInputURL:representation.url outputURL:TempLowerQualityFileURL handler:^(AVAssetExportSession *session)
{
if (session.status == AVAssetExportSessionStatusCompleted)
{
NSLog(@"\r\n CONVERSION SUCCESS \r\n");
NSString *path = [TempLowerQualityFileURL path];
NSData *data = [[NSFileManager defaultManager] contentsAtPath:path];
NSLog(@" \r\n POST-CONVERSION TEMP FILE %@ Size =%d ; URL=%@\r\n",fileName, data.length, path );
ALAssetsLibrary* library = [[ALAssetsLibrary alloc] init];
[library writeVideoAtPathToSavedPhotosAlbum:TempLowerQualityFileURL completionBlock:^(NSURL *assetURL, NSError *error)
{
if (error)
{
NSLog(@"Error Saving low quality video to Camera Roll%@", error);
}
NSLog(@"\r\n temp low quality file exists before = %d", [self fileExistsAtPath:path] );
[[NSFileManager defaultManager] removeItemAtURL:TempLowerQualityFileURL error:nil];
NSLog(@"\r\n temp low quality file exists after = %d", [self fileExistsAtPath:path] );
NSURL *NewAssetUrlInCameraRoll = assetURL;
[[VideoThumbManager sharedInstance] replaceLink:representation.url withNewLink:NewAssetUrlInCameraRoll];
}];//end writeVideoAtPathToSavedPhotosAlbum completion block.
}
else
{
// Error Handing
NSLog(@"\r\n CONVERSION ERROR \r\n");
}
}];//end convert completion block
将压缩视频的记录（和使用）移动到完成块。SWIFT 3 MP4视频压缩
ALAssetRepresentation* representation = [asset defaultRepresentation];
NSString *fileName = [NSString stringWithFormat:@"VGA_%@",representation.filename]; //prepend with _VGA to avoid overwriting original.
NSURL *TempLowerQualityFileURL = [NSURL fileURLWithPath:[NSTemporaryDirectory() stringByAppendingPathComponent:fileName] ];
NSURL *gallery_url = representation.url;
NSLog(@" \r\n PRE-CONVERSION FILE %@ Size =%lld ; URL=%@\r\n",fileName, representation.size,representation.url );
[self convertVideoToLowQuailtyWithInputURL:representation.url outputURL:TempLowerQualityFileURL handler:^(AVAssetExportSession *session)
{
if (session.status == AVAssetExportSessionStatusCompleted)
{
NSLog(@"\r\n CONVERSION SUCCESS \r\n");
NSString *path = [TempLowerQualityFileURL path];
NSData *data = [[NSFileManager defaultManager] contentsAtPath:path];
NSLog(@" \r\n POST-CONVERSION TEMP FILE %@ Size =%d ; URL=%@\r\n",fileName, data.length, path );
ALAssetsLibrary* library = [[ALAssetsLibrary alloc] init];
[library writeVideoAtPathToSavedPhotosAlbum:TempLowerQualityFileURL completionBlock:^(NSURL *assetURL, NSError *error)
{
if (error)
{
NSLog(@"Error Saving low quality video to Camera Roll%@", error);
}
NSLog(@"\r\n temp low quality file exists before = %d", [self fileExistsAtPath:path] );
[[NSFileManager defaultManager] removeItemAtURL:TempLowerQualityFileURL error:nil];
NSLog(@"\r\n temp low quality file exists after = %d", [self fileExistsAtPath:path] );
NSURL *NewAssetUrlInCameraRoll = assetURL;
[[VideoThumbManager sharedInstance] replaceLink:representation.url withNewLink:NewAssetUrlInCameraRoll];
}];//end writeVideoAtPathToSavedPhotosAlbum completion block.
}
else
{
// Error Handing
NSLog(@"\r\n CONVERSION ERROR \r\n");
}
}];//end convert completion block
100%为我工作
此代码使用12 MB到2 MB的URL（文档目录）压缩视频。
我捕获了.mp4格式的视频，压缩代码返回相同格式的视频
保存压缩的函数
func compressVideo(inputURL: URL, outputURL: URL, handler:@escaping (_ exportSession: AVAssetExportSession?)-> Void) {
let urlAsset = AVURLAsset(url: inputURL, options: nil)
guard let exportSession = AVAssetExportSession(asset: urlAsset, presetName: AVAssetExportPresetMediumQuality) else {
handler(nil)
return
}
exportSession.outputURL = outputURL
exportSession.outputFileType = AVFileTypeQuickTimeMovie // Don't change it to .mp4 format
exportSession.shouldOptimizeForNetworkUse = false
exportSession.exportAsynchronously { () -> Void in
handler(exportSession)
}
}
压缩视频的目标URL代码
let filePath = URL(fileURLWithPath: strVideoPath)
var compressedURL : URL!
let fileManager = FileManager.default
do {
let documentDirectory = try fileManager.url(for: .documentDirectory, in: .userDomainMask, appropriateFor:nil, create:true)
compressedURL = documentDirectory.appendingPathComponent("Video.mp4")
} catch {
print(error)
}
//It is compulsory to remove previous item at same URL. Otherwise it is unable to save file at same URL.
do {
try fileManager.removeItem(at: compressedURL)
print("Removed")
} catch {
print(error)
}
呼叫代码
compressVideo(inputURL: filePath , outputURL: compressedURL) { (exportSession) in
guard let session = exportSession else {
return
}
switch session.status {
case .unknown:
break
case .waiting:
break
case .exporting:
break
case .completed:
print(compressedURL)
let newData : Data!
do {
newData = try Data(contentsOf: compressedURL) as Data?
print("File size after compression: \(Double((newData?.count)! / 1048576)) mb")
} catch {
return
}
case .failed:
print(exportSession?.error.debugDescription)
break
case .cancelled:
break
}
}
SWIFT 3 MP4视频压缩
100%为我工作
此代码使用12 MB到2 MB的URL（文档目录）压缩视频。
我捕获了.mp4格式的视频，压缩代码返回相同格式的视频
保存压缩的函数
func compressVideo(inputURL: URL, outputURL: URL, handler:@escaping (_ exportSession: AVAssetExportSession?)-> Void) {
let urlAsset = AVURLAsset(url: inputURL, options: nil)
guard let exportSession = AVAssetExportSession(asset: urlAsset, presetName: AVAssetExportPresetMediumQuality) else {
handler(nil)
return
}
exportSession.outputURL = outputURL
exportSession.outputFileType = AVFileTypeQuickTimeMovie // Don't change it to .mp4 format
exportSession.shouldOptimizeForNetworkUse = false
exportSession.exportAsynchronously { () -> Void in
handler(exportSession)
}
}
压缩视频的目标URL代码
let filePath = URL(fileURLWithPath: strVideoPath)
var compressedURL : URL!
let fileManager = FileManager.default
do {
let documentDirectory = try fileManager.url(for: .documentDirectory, in: .userDomainMask, appropriateFor:nil, create:true)
compressedURL = documentDirectory.appendingPathComponent("Video.mp4")
} catch {
print(error)
}
//It is compulsory to remove previous item at same URL. Otherwise it is unable to save file at same URL.
do {
try fileManager.removeItem(at: compressedURL)
print("Removed")
} catch {
print(error)
}
呼叫代码
compressVideo(inputURL: filePath , outputURL: compressedURL) { (exportSession) in
guard let session = exportSession else {
return
}
switch session.status {
case .unknown:
break
case .waiting:
break
case .exporting:
break
case .completed:
print(compressedURL)
let newData : Data!
do {
newData = try Data(contentsOf: compressedURL) as Data?
print("File size after compression: \(Double((newData?.count)! / 1048576)) mb")
} catch {
return
}
case .failed:
print(exportSession?.error.debugDescription)
break
case .cancelled:
break
}
}