#前言
我最近在接手一個智能盒子的iOS應用，上面有一個功能是這樣的。把你本地的照片和視頻能夠甩屏到你綁定的盒子上。
個人上一位前輩作的時候必需要求再同一個局域網，可是當我作的時候要求不一樣的局域網也要實現這樣的一個功能，優化用戶的使用感覺。javascript
#那麼 咱們下面就進入正題。java
#內容一：圖片上傳
我作的圖片上傳是用的AF，原理就是把你想上傳的照片取出來，若是有文件大小的要求就先作相應的圖片壓縮。
而後用AFHTTPSessionManager 類去作的上傳，下面就是代碼：session
AFHTTPSessionManager *session = [AFHTTPSessionManager manager];
[session.requestSerializer willChangeValueForKey:@"timeoutInterval"];
session.requestSerializer.timeoutInterval = 60.f;
[session.requestSerializer didChangeValueForKey:@"timeoutInterval"];
session.responseSerializer = [AFHTTPResponseSerializer serializer];
NSString *imageTitle =_imageSource[pageIndex].title;
imageTitle = [imageTitle substringToIndex:imageTitle.length-4];
NSDictionary *params = @{
@"fileType":@"jpg",
@"fileName":imageTitle
};
[session POST:@"你上傳的接口地址" parameters:params constructingBodyWithBlock:^(id<AFMultipartFormData> _Nonnull formData) {
for (NSString *key in dict.allKeys) {
[formData appendPartWithFileData:[dict objectForKey:key] name:@"myFile" fileName:[NSString stringWithFormat:@"%@.jpg",key] mimeType:@"image/jpeg"];
}
} progress:nil success:^(NSURLSessionDataTask * _Nonnull task, id _Nullable responseObject) {
} failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
}];複製代碼
這裏主要就是和大家的後臺確認好相應的參數設置就行了。app
#內容二：視頻上傳
視頻上傳和圖片上傳實際上是相似的，只不過就是參數的設置不同而已。也是用上面的方法。關鍵也是設置好參數。
在這裏我想說的是，有的時候視頻太大要作相應的壓縮處理。由於我以前對視頻這面接觸的比較少，也上網找了一些資料而後看到這樣的一個方法：ide
- (void)lowQuailtyWithInputURL:(NSURL*)inputURL
outputURL:(NSURL*)outputURL
blockHandler:(void (^)(AVAssetExportSession*))handler
{
AVURLAsset *asset = [AVURLAsset URLAssetWithURL:inputURL options:nil];
AVAssetExportSession *session = [[AVAssetExportSession alloc] initWithAsset:asset presetName:AVAssetExportPresetMediumQuality];
session.outputURL = outputURL;
session.outputFileType = AVFileTypeQuickTimeMovie;
[session exportAsynchronouslyWithCompletionHandler:^(void)
{
handler(session);
}];
}複製代碼
經過這個方法就能夠對視頻進行相應的壓縮處理。優化
#下面就是視頻內容的旋轉問題了。
一開始我聽到了這個需求的時候個人腦子裏真的是瞬間萬馬飛奔啊！！ 這是什麼鬼需求啊！鬼知道我經歷了什麼？
我想，那我就上網找一下吧！我找了一下，還真的有這麼樣的技術博客。可是一上來就是把他的代碼網上一貼。我先大概的瀏覽了一下那代碼的長度。寫的我實在是沒有耐心去仔細的看究竟是怎麼實現的。我就關掉了。但是後來一看，也沒有別的什麼博客供我參考了。在我走投無路的時候，我看到了這麼一個博客，說是Apple本身就有Demo，我就抱着好奇的態度去看了看。下載了那個Demo仔細的研究了一下。果真就好使了。 那麼，接下來就說一下。ui
再旋轉視頻以前咱們先要確認一下，這個視頻是要旋轉多少度。this
AVURLAsset *asset = [AVURLAsset URLAssetWithURL:inputURL options:nil];
NSArray *tracks = [asset tracksWithMediaType:AVMediaTypeVideo];
NSInteger degress;
if([tracks count] > 0) {
AVAssetTrack *videoTrack = [tracks objectAtIndex:0];
CGAffineTransform t = videoTrack.preferredTransform;//這裏的矩陣有旋轉角度，轉換一下便可
if(t.a == 0 && t.b == 1.0 && t.c == -1.0 && t.d == 0){
// Portrait
degress = 90;
}else if(t.a == 0 && t.b == -1.0 && t.c == 1.0 && t.d == 0){
// PortraitUpsideDown
degress = 270;
}else if(t.a == 1.0 && t.b == 0 && t.c == 0 && t.d == 1.0){
// LandscapeRight
degress = 0;
}else if(t.a == -1.0 && t.b == 0 && t.c == 0 && t.d == -1.0){
// LandscapeLeft
degress = 180;
}
}複製代碼
這樣咱們就能夠經過degress來確認旋轉的角度了。
那麼咱們接下來就開始旋轉視頻spa
AVMutableVideoCompositionInstruction *instruction = nil;
AVMutableVideoCompositionLayerInstruction *layerInstruction = nil;
CGAffineTransform t1;
CGAffineTransform t2;
AVAssetTrack *assetVideoTrack = nil;
AVAssetTrack *assetAudioTrack = nil;
// Check if the asset contains video and audio tracks
if ([[asset tracksWithMediaType:AVMediaTypeVideo] count] != 0) {
assetVideoTrack = [asset tracksWithMediaType:AVMediaTypeVideo][0];
}
if ([[asset tracksWithMediaType:AVMediaTypeAudio] count] != 0) {
assetAudioTrack = [asset tracksWithMediaType:AVMediaTypeAudio][0];
}
CMTime insertionPoint = kCMTimeZero;
NSError *error = nil;
// Step 1
// Create a composition with the given asset and insert audio and video tracks into it from the asset
if (!mutableComposition) {
// Check whether a composition has already been created, i.e, some other tool has already been applied
// Create a new composition
mutableComposition = [AVMutableComposition composition];
// Insert the video and audio tracks from AVAsset
if (assetVideoTrack != nil) {
AVMutableCompositionTrack *compositionVideoTrack = [mutableComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
[compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, [asset duration]) ofTrack:assetVideoTrack atTime:insertionPoint error:&error];
}
if (assetAudioTrack != nil) {
AVMutableCompositionTrack *compositionAudioTrack = [mutableComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
[compositionAudioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, [asset duration]) ofTrack:assetAudioTrack atTime:insertionPoint error:&error];
}
}
// // Step 2
// // Translate the composition to compensate the movement caused by rotation (since rotation would cause it to move out of frame)
// t1 = CGAffineTransformMakeTranslation(assetVideoTrack.naturalSize.height, 0.0);
// // Rotate transformation
// t2 = CGAffineTransformRotate(t1, degreesToRadians(90));
if (degress == 0) {
t1 = CGAffineTransformMakeTranslation(0.0, 0.0);
t2 = CGAffineTransformRotate(t1, degreesToRadians(0));
}else if (degress == 90){
t1 = CGAffineTransformMakeTranslation(assetVideoTrack.naturalSize.height, 0.0);
t2 = CGAffineTransformRotate(t1, degreesToRadians(90));
}else if (degress == 180){
t1 = CGAffineTransformMakeTranslation(assetVideoTrack.naturalSize.width, assetVideoTrack.naturalSize.height);
t2 = CGAffineTransformRotate(t1, degreesToRadians(180));
}else if (degress == 270){
t1 = CGAffineTransformMakeTranslation(0,assetVideoTrack.naturalSize.height*1.78);
t2 = CGAffineTransformRotate(t1, degreesToRadians(-90));
}
// Step 3
// Set the appropriate render sizes and rotational transforms
if (!mutableVideoComposition) {
// Create a new video composition
mutableVideoComposition = [AVMutableVideoComposition videoComposition];
if (degress == 0 || degress == 180) {
mutableVideoComposition.renderSize = CGSizeMake(assetVideoTrack.naturalSize.width,assetVideoTrack.naturalSize.height);
}else{
mutableVideoComposition.renderSize = CGSizeMake(assetVideoTrack.naturalSize.height,assetVideoTrack.naturalSize.width);
}
mutableVideoComposition.frameDuration = CMTimeMake(1, 30);
// The rotate transform is set on a layer instruction
instruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
instruction.timeRange = CMTimeRangeMake(kCMTimeZero, [mutableComposition duration]);
layerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:(mutableComposition.tracks)[0]];
[layerInstruction setTransform:t2 atTime:kCMTimeZero];
} else {
mutableVideoComposition.renderSize = CGSizeMake(mutableVideoComposition.renderSize.height, mutableVideoComposition.renderSize.width);
// Extract the existing layer instruction on the mutableVideoComposition
instruction = (mutableVideoComposition.instructions)[0];
layerInstruction = (instruction.layerInstructions)[0];
// Check if a transform already exists on this layer instruction, this is done to add the current transform on top of previous edits
CGAffineTransform existingTransform;
if (![layerInstruction getTransformRampForTime:[mutableComposition duration] startTransform:&existingTransform endTransform:NULL timeRange:NULL]) {
[layerInstruction setTransform:t2 atTime:kCMTimeZero];
} else {
// Note: the point of origin for rotation is the upper left corner of the composition, t3 is to compensate for origin
CGAffineTransform t3 = CGAffineTransformMakeTranslation(-1*assetVideoTrack.naturalSize.height/2, 0.0);
CGAffineTransform newTransform = CGAffineTransformConcat(existingTransform, CGAffineTransformConcat(t2, t3));
[layerInstruction setTransform:newTransform atTime:kCMTimeZero];
}
}
// Step 4
// Add the transform instructions to the video composition
instruction.layerInstructions = @[layerInstruction];
mutableVideoComposition.instructions = @[instruction];複製代碼
到這個時候呢視頻的旋轉已經完成了。
上面咱們不是寫了一個視頻壓縮的方法嗎？把這個時候生成的mutableVideoComposition賦值給session.videoComposition = mutableVideoComposition;就行了。這樣就是先旋轉視頻而後直接壓縮完成咱們的需求。code