最近做視頻壓縮上傳功能 剛開始用的蘋果已經簡單封裝好的 AVAssetExportSession 框架 視頻壓縮上傳後 發現有些視頻壓縮後 反而變大了
後來參考了近期視頻優化做的比較不錯的douyin 發現不論上傳多大的視頻 被douyin壓縮以後比特率（視頻每秒傳輸的大小 單位：比特率（bps） / 千比特率（kbps））基本都維持在1500 kbps左右 經測試 這是對視頻壓縮後 文件大小 影響最大的一個參數
另外 還有比如幀率 視頻寬高 等參數 也對視頻壓縮有一定的影響
用此方法 在項目中實測 基本可以滿足絕大多數需求
如果你僅僅是想完成需求 不想研究代碼的話
到這裏可以結束閱讀了
直接翻到最下面下載Demo 複製我封裝好的方法 調用 就行了
繼續往下看的話：
代碼用到了訪問相機 訪問相冊 訪問麥克風 添加視頻到相冊四個權限
使用前 先把info中相機相冊對應權限打開
info.plist 用Source Code方式打開的話 這樣寫：
1. `<key>NSCameraUsageDescription</key>`
2. `<string>是否允許訪問相機</string>`
3. `<key>NSMicrophoneUsageDescription</key>`
4. `<string>App需要您的同意才能訪問麥克風</string>`
5. `<key>NSPhotoLibraryUsageDescription</key>`
6. `<string>是否允許訪問相冊</string>`
7. `<key>NSPhotoLibraryAddUsageDescription</key>`
8. `<string>是否允許添加視頻或圖片到相冊</string>`
info.plist 用Property List方式打開的話 這樣配置：
配置好了 開始寫代碼：
ViewController.m
使用系統的UIImagePickerController選擇或者拍攝對應的視頻
使用前 先遵守<UIImagePickerControllerDelegate, UINavigationControllerDelegate>這倆協議
然後寫這個
1. `@property (nonatomic, strong) UIImagePickerController *imagePicker;`
從相冊中選擇視頻 代碼註釋寫的比較詳細了
1. `//從相冊中選擇視頻`
2. `- (IBAction)chooseVideoBtnClick:(id)sender {`
3. `if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeSavedPhotosAlbum])`
4. `{`
5. `self.imagePicker = [[UIImagePickerController alloc] init];`
6. `self.imagePicker.delegate = self;`
7. `/*`
8. `* 設置資源文件來源 圖庫 相機 相冊`
9. `* UIImagePickerControllerSourceTypePhotoLibrary,`
10. `* UIImagePickerControllerSourceTypeCamera,`
11. `* UIImagePickerControllerSourceTypeSavedPhotosAlbum`
12. `**/`
13. `self.imagePicker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;`
14. `/*`
15. `* 設置媒體類型`
16. `* (NSString *)kUTTypeVideo 無聲視頻`
17. `* (NSString *)kUTTypeMovie 有聲視頻`
18. `* (NSString *)kUTTypeAudio 音頻`
19. `* 等...`
20. `**/`
21. `[self.imagePicker setMediaTypes:@[(NSString *)kUTTypeMovie]];`
22. `self.imagePicker.videoQuality = UIImagePickerControllerQualityTypeHigh;`
23. `[self presentViewController:self.imagePicker animated:YES completion:nil];`
25. `}else{`
26. `[self showAlertViewWithTitle:@"相機不可用" message:@"" withCancelButtonTitle:@"知道了"];`
27. `}`
28. `}`
相機拍攝視頻
1. `//拍攝視頻`
2. `- (IBAction)recordVideoBtnClick:(id)sender {`
3. `if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])`
4. `{`
5. `self.imagePicker = [[UIImagePickerController alloc] init];`
6. `self.imagePicker.delegate = self;`
7. `/*`
8. `* 設置資源文件來源 圖庫 相機 相冊`
9. `* UIImagePickerControllerSourceTypePhotoLibrary,`
10. `* UIImagePickerControllerSourceTypeCamera,`
11. `* UIImagePickerControllerSourceTypeSavedPhotosAlbum`
12. `**/`
13. `self.imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;`
14. `/*`
15. `* 設置媒體類型`
16. `* (NSString *)kUTTypeVideo 無聲視頻`
17. `* (NSString *)kUTTypeMovie 有聲視頻`
18. `* (NSString *)kUTTypeAudio 音頻`
19. `* 等...`
20. `**/`
21. `[self.imagePicker setMediaTypes:@[(NSString *)kUTTypeMovie]];`
22. `self.imagePicker.videoQuality = UIImagePickerControllerQualityTypeHigh;`
23. `[self presentViewController:self.imagePicker animated:YES completion:nil];`
25. `}else{`
26. `[self showAlertViewWithTitle:@"相機不可用" message:@"" withCancelButtonTitle:@"知道了"];`
27. `}`
28. `}`
取消選擇或者拍攝時的回調
UIImagePickerControllerDelegate
1. `-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{`
2. `[self.imagePicker dismissViewControllerAnimated:YES completion:nil];`
3. `[self showAlertViewWithTitle:@"用戶取消操作" message:@"" withCancelButtonTitle:@"好的"];`
5. `}`
視頻選擇 或者拍攝好以後回調
1. `-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<UIImagePickerControllerInfoKey,id> *)info{`
2. `//獲取媒體類型`
3. `NSString *type = [info objectForKey:UIImagePickerControllerMediaType];`
4. `//媒體類型是視頻時`
5. `if ([type isEqualToString:@"public.movie"])`
6. `{`
7. `NSLog(@"===video URL = %@===", [info objectForKey:UIImagePickerControllerMediaURL]);`
8. `//視頻路徑URL`
9. `NSURL *outputUrl = [info objectForKey:UIImagePickerControllerMediaURL];`
10. `//關閉相冊界面`
11. `[picker dismissViewControllerAnimated:YES completion:^{`
12. `//執行視頻壓縮功能`
13. `[self compressVideoWithVideoUrl:outputUrl];`
14. `}];`
15. `}`
16. `}`
//壓縮視頻
1. `/*`
2. `* 自定義視頻壓縮`
3. `* videoUrl 原視頻url路徑 必傳`
4. `* outputBiteRate 壓縮視頻至指定比特率(bps) 可傳nil 默認1500kbps`
5. `* outputFrameRate 壓縮視頻至指定幀率 可傳nil 默認30fps`
6. `* outputWidth 壓縮視頻至指定寬度 可傳nil 默認960`
7. `* outputWidth 壓縮視頻至指定高度 可傳nil 默認540`
8. `* compressComplete 壓縮後的視頻信息回調 (id responseObjc) 可自行打印查看`
9. `**/`
10. `- (void)compressVideoWithVideoUrl:(NSURL *)outputUrl{`
11. `[VideoCompress compressVideoWithVideoUrl:outputUrl withBiteRate:@(1500 * 1024) withFrameRate:@(30) withVideoWidth:@(960) withVideoHeight:@(540) compressComplete:^(id responseObjc) {`
12. `NSString *filePathStr = [responseObjc objectForKey:@"urlStr"];`
13. `AVURLAsset *asset = [AVURLAsset assetWithURL:[NSURL fileURLWithPath:filePathStr]];`
14. `AVAssetTrack *videoTrack = [asset tracksWithMediaType:AVMediaTypeVideo].firstObject;`
15. `//視頻大小 MB`
16. `unsigned long long fileSize = [[NSFileManager defaultManager] attributesOfItemAtPath:filePathStr error:nil].fileSize;`
17. `float fileSizeMB = fileSize / (1024.0*1024.0);`
18. `//視頻寬高`
19. `NSInteger videoWidth = videoTrack.naturalSize.width;`
20. `NSInteger videoHeight = videoTrack.naturalSize.height;`
21. `//比特率`
22. `NSInteger kbps = videoTrack.estimatedDataRate / 1024;`
23. `//幀率`
24. `NSInteger frameRate = [videoTrack nominalFrameRate];`
25. `NSLog(@"\nfileSize after compress = %.2f MB,\n videoWidth = %ld,\n videoHeight = %ld,\n video bitRate = %ld\n, video frameRate = %ld", fileSizeMB, videoWidth, videoHeight, kbps, frameRate);`
26. `// NSData *videoData = [NSData dataWithContentsOfFile:filePathStr];`
27. `// NSData *videoData = [NSData dataWithContentsOfURL:asset.URL];`
28. `//在這裏上傳或者保存已經處理好的視頻文件`
29. `//保存視頻至相冊`
30. `UISaveVideoAtPathToSavedPhotosAlbum(filePathStr, self, @selector(videoSavedToPhotosAlbum:didFinishSavingWithError:contextInfo:), nil);`
31. `}];`
32. `}`
取消事件的一些彈框
1. `- (void)showAlertViewWithTitle:(NSString*)title message:(NSString*)msg withCancelButtonTitle:(NSString *)cancelButtonTitle{`
2. `UIAlertController* alertController = [UIAlertController alertControllerWithTitle:title message:@"" preferredStyle:UIAlertControllerStyleAlert];`
3. `[alertController addAction:[UIAlertAction actionWithTitle:cancelButtonTitle style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {`
4. `}]];`
5. `[self presentViewController:alertController animated:YES completion:nil];`
6. `}`
//視頻保存成功提示框
1. `#pragma mark 保存視頻後的回調`
2. `- (void)videoSavedToPhotosAlbum:(NSString *)videoUrlStr didFinishSavingWithError:(NSError*)error contextInfo:(id)contextInfo{`
3. `NSString*message =@"提示";`
4. `if(!error) {`
5. `message = @"視頻成功保存到相冊";`
6. `}else{`
7. `message = [error description];`
8. `}`
9. `[self showAlertViewWithTitle:@"提示" message:message withCancelButtonTitle:@"確定"];`
10. `}`
VideoCompress.m
1. `/*`
2. `* 自定義視頻壓縮`
3. `* videoUrl 原視頻url路徑 必傳`
4. `* outputBiteRate 壓縮視頻至指定比特率(bps) 可傳nil 默認1500kbps`
5. `* outputFrameRate 壓縮視頻至指定幀率 可傳nil 默認30fps`
6. `* outputWidth 壓縮視頻至指定寬度 可傳nil 默認960`
7. `* outputWidth 壓縮視頻至指定高度 可傳nil 默認540`
8. `* compressComplete 壓縮後的視頻信息回調 (id responseObjc) 可自行打印查看`
9. `**/`
10. `+ (void)compressVideoWithVideoUrl:(NSURL *)videoUrl withBiteRate:(NSNumber * _Nullable)outputBiteRate withFrameRate:(NSNumber * _Nullable)outputFrameRate withVideoWidth:(NSNumber * _Nullable)outputWidth withVideoHeight:(NSNumber * _Nullable)outputHeight compressComplete:(void(^)(id responseObjc))compressComplete{`
11. `if (!videoUrl) {`
12. `[SVProgressHUD showErrorWithStatus:@"視頻路徑不能爲空"];`
13. `return;`
14. `}`
15. `NSLog(@"===videoUrl.abs = %@, videoUrl.path = %@", videoUrl.absoluteString, videoUrl.path);`
16. `NSInteger compressBiteRate = outputBiteRate ? [outputBiteRate integerValue] : 1500 * 1024;`
17. `NSInteger compressFrameRate = outputFrameRate ? [outputFrameRate integerValue] : 30;`
18. `NSInteger compressWidth = outputWidth ? [outputWidth integerValue] : 960;`
19. `NSInteger compressHeight = outputHeight ? [outputHeight integerValue] : 540;`
20. `//取出原視頻詳細資料`
21. `AVURLAsset *asset = [AVURLAsset assetWithURL:videoUrl];`
22. `//視頻時長 S`
23. `CMTime time = [asset duration];`
24. `NSInteger seconds = ceil(time.value/time.timescale);`
25. `if (seconds < 3) {`
26. `[SVProgressHUD showErrorWithStatus:@"請上傳3秒以上的視頻"];`
27. `return;`
28. `}`
29. `//壓縮前原視頻大小MB`
30. `unsigned long long fileSize = [[NSFileManager defaultManager] attributesOfItemAtPath:videoUrl.path error:nil].fileSize;`
31. `float fileSizeMB = fileSize / (1024.0*1024.0);`
32. `//取出asset中的視頻文件`
33. `AVAssetTrack *videoTrack = [asset tracksWithMediaType:AVMediaTypeVideo].firstObject;`
34. `//壓縮前原視頻寬高`
35. `NSInteger videoWidth = videoTrack.naturalSize.width;`
36. `NSInteger videoHeight = videoTrack.naturalSize.height;`
37. `//壓縮前原視頻比特率`
38. `NSInteger kbps = videoTrack.estimatedDataRate / 1024;`
39. `//壓縮前原視頻幀率`
40. `NSInteger frameRate = [videoTrack nominalFrameRate];`
41. `NSLog(@"\noriginalVideo\nfileSize = %.2f MB,\n videoWidth = %ld,\n videoHeight = %ld,\n video bitRate = %ld\n, video frameRate = %ld", fileSizeMB, videoWidth, videoHeight, kbps, frameRate);`
42. `NSMutableDictionary *dic = [NSMutableDictionary dictionaryWithDictionary:@{@"urlStr" : videoUrl.path}];`
43. `//原視頻比特率小於指定比特率 不壓縮 返回原視頻`
44. `if (kbps <= (compressBiteRate / 1024)) {`
45. `compressComplete(dic);`
46. `return;`
47. `}`
48. `//指定壓縮視頻沙盒根目錄`
49. `NSString *cachesDir = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject];`
50. `//添加文件完整路徑`
51. `NSString *outputUrlStr = [[cachesDir stringByAppendingPathComponent:@"videoTest"] stringByAppendingPathExtension:@"mp4"];`
52. `NSLog(@"===壓縮視頻存放的指定路徑%@===", outputUrlStr);`
53. `//如果指定路徑下已存在其他文件 先移除指定文件`
54. `if ([[NSFileManager defaultManager] fileExistsAtPath:outputUrlStr]) {`
55. `BOOL removeSuccess = [[NSFileManager defaultManager] removeItemAtPath:outputUrlStr error:nil];`
56. `if (!removeSuccess) {`
57. `[SVProgressHUD showErrorWithStatus:@"舊文件移除失敗"];`
58. `return;`
59. `}`
60. `}`
61. `//創建視頻文件讀取者`
62. `AVAssetReader *reader = [AVAssetReader assetReaderWithAsset:asset error:nil];`
63. `//從指定文件讀取視頻`
64. `AVAssetReaderTrackOutput *videoOutput = [AVAssetReaderTrackOutput assetReaderTrackOutputWithTrack:videoTrack outputSettings:[VideoCompress configVideoOutput]];`
65. `//取出原視頻中音頻詳細資料`
66. `AVAssetTrack *audioTrack = [asset tracksWithMediaType:AVMediaTypeAudio].firstObject;`
67. `//從音頻資料中讀取音頻`
68. `AVAssetReaderTrackOutput *audioOutput = [AVAssetReaderTrackOutput assetReaderTrackOutputWithTrack:audioTrack outputSettings:[VideoCompress configAudioOutput]];`
69. `//將讀取到的視頻信息添加到讀者隊列中`
70. `if ([reader canAddOutput:videoOutput]) {`
71. `[reader addOutput:videoOutput];`
72. `}`
73. `//將讀取到的音頻信息添加到讀者隊列中`
74. `if ([reader canAddOutput:audioOutput]) {`
75. `[reader addOutput:audioOutput];`
76. `}`
77. `//視頻文件寫入者`
78. `AVAssetWriter *writer = [AVAssetWriter assetWriterWithURL:[NSURL fileURLWithPath:outputUrlStr] fileType:AVFileTypeMPEG4 error:nil];`
79. `//根據指定配置創建寫入的視頻文件`
80. `AVAssetWriterInput *videoInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:[VideoCompress videoCompressSettingsWithBitRate:compressBiteRate withFrameRate:compressFrameRate withWidth:compressWidth WithHeight:compressHeight withOriginalWidth:videoWidth withOriginalHeight:videoHeight]];`
81. `//根據指定配置創建寫入的音頻文件`
82. `AVAssetWriterInput *audioInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:[VideoCompress audioCompressSettings]];`
83. `if ([writer canAddInput:videoInput]) {`
84. `[writer addInput:videoInput];`
85. `NSLog(@"videoInput==========videoInput");`
86. `}`
87. `if ([writer canAddInput:audioInput]) {`
88. `[writer addInput:audioInput];`
89. `NSLog(@"audioInput==========audioInput");`
90. `}`
91. `[SVProgressHUD showWithStatus:@"視頻壓縮中..."];`
92. `[reader startReading];`
93. `[writer startWriting];`
94. `[writer startSessionAtSourceTime:kCMTimeZero];`
95. `//創建視頻寫入隊列`
96. `dispatch_queue_t videoQueue = dispatch_queue_create("Video Queue", DISPATCH_QUEUE_SERIAL);`
97. `//創建音頻寫入隊列`
98. `dispatch_queue_t audioQueue = dispatch_queue_create("Audio Queue", DISPATCH_QUEUE_SERIAL);`
99. `//創建一個線程組`
100. `dispatch_group_t group = dispatch_group_create();`
101. `//進入線程組`
102. `dispatch_group_enter(group);`
103. `//隊列準備好後 usingBlock`
104. `[videoInput requestMediaDataWhenReadyOnQueue:videoQueue usingBlock:^{`
105. `BOOL completedOrFailed = NO;`
106. `while ([videoInput isReadyForMoreMediaData] && !completedOrFailed) {`
107. `CMSampleBufferRef sampleBuffer = [videoOutput copyNextSampleBuffer];`
108. `if (sampleBuffer != NULL) {`
109. `[videoInput appendSampleBuffer:sampleBuffer];`
110. `NSLog(@"===%@===", sampleBuffer);`
111. `CFRelease(sampleBuffer);`
112. `} else {`
113. `completedOrFailed = YES;`
114. `[videoInput markAsFinished];`
115. `dispatch_group_leave(group);`
116. `}`
117. `}`
118. `}];`
119. `dispatch_group_enter(group);`
120. `//隊列準備好後 usingBlock`
121. `[audioInput requestMediaDataWhenReadyOnQueue:audioQueue usingBlock:^{`
122. `BOOL completedOrFailed = NO;`
123. `while ([audioInput isReadyForMoreMediaData] && !completedOrFailed) {`
124. `CMSampleBufferRef sampleBuffer = [audioOutput copyNextSampleBuffer];`
125. `if (sampleBuffer != NULL) {`
126. `BOOL success = [audioInput appendSampleBuffer:sampleBuffer];`
127. `NSLog(@"===%@===", sampleBuffer);`
128. `CFRelease(sampleBuffer);`
129. `completedOrFailed = !success;`
130. `} else {`
131. `completedOrFailed = YES;`
132. `}`
133. `}`
134. `if (completedOrFailed) {`
135. `[audioInput markAsFinished];`
136. `dispatch_group_leave(group);`
137. `}`
138. `}];`
139. `//完成壓縮`
140. `dispatch_group_notify(group, dispatch_get_main_queue(), ^{`
141. `if ([reader status] == AVAssetReaderStatusReading) {`
142. `[reader cancelReading];`
143. `}`
144. `switch (writer.status) {`
145. `case AVAssetWriterStatusWriting:`
146. `{`
147. `[SVProgressHUD showSuccessWithStatus:@"視頻壓縮完成"];`
148. `[writer finishWritingWithCompletionHandler:^{`
149. `[dic setObject:outputUrlStr forKey:@"urlStr"];`
150. `compressComplete(dic);`
151. `}];`
152. `}`
153. `break;`
154. `case AVAssetWriterStatusCancelled:`
155. `[SVProgressHUD showInfoWithStatus:@"取消壓縮"];`
156. `break;`
157. `case AVAssetWriterStatusFailed:`
158. `NSLog(@"===error：%@===", writer.error);`
159. `[SVProgressHUD showErrorWithStatus:[NSString stringWithFormat:@"%@",writer.error]];`
160. `break;`
161. `case AVAssetWriterStatusCompleted:`
162. `{`
163. `[SVProgressHUD showSuccessWithStatus:@"視頻壓縮完成"];`
164. `[writer finishWritingWithCompletionHandler:^{`
165. `[dic setObject:outputUrlStr forKey:@"urlStr"];`
166. `compressComplete(dic);`
167. `}];`
168. `}`
169. `break;`
170. `default:`
171. `break;`
172. `}`
173. `});`
174. `}`
視頻壓縮的參數配置
1. `+ (NSDictionary *)videoCompressSettingsWithBitRate:(NSInteger)biteRate withFrameRate:(NSInteger)frameRate withWidth:(NSInteger)width WithHeight:(NSInteger)height withOriginalWidth:(NSInteger)originalWidth withOriginalHeight:(NSInteger)originalHeight{`
2. `/*`
3. `* AVVideoAverageBitRateKey： 比特率（碼率）每秒傳輸的文件大小 kbps`
4. `* AVVideoExpectedSourceFrameRateKey：幀率 每秒播放的幀數`
5. `* AVVideoProfileLevelKey：畫質水平`
6. `BP-Baseline Profile：基本畫質。支持I/P 幀，只支持無交錯（Progressive）和CAVLC；`
7. `EP-Extended profile：進階畫質。支持I/P/B/SP/SI 幀，只支持無交錯（Progressive）和CAVLC；`
8. `MP-Main profile：主流畫質。提供I/P/B 幀，支持無交錯（Progressive）和交錯（Interlaced），也支持CAVLC 和CABAC 的支持；`
9. `HP-High profile：高級畫質。在main Profile 的基礎上增加了8×8內部預測、自定義量化、 無損視頻編碼和更多的YUV 格式；`
10. `**/`
11. `NSInteger returnWidth = originalWidth > originalHeight ? width : height;`
12. `NSInteger returnHeight = originalWidth > originalHeight ? height : width;`
14. `NSDictionary *compressProperties = @{`
15. `AVVideoAverageBitRateKey : @(biteRate),`
16. `AVVideoExpectedSourceFrameRateKey : @(frameRate),`
17. `AVVideoProfileLevelKey : AVVideoProfileLevelH264HighAutoLevel`
18. `};`
19. `if (@available(iOS 11.0, *)) {`
20. `NSDictionary *compressSetting = @{`
21. `AVVideoCodecKey : AVVideoCodecTypeH264,`
22. `AVVideoWidthKey : @(returnWidth),`
23. `AVVideoHeightKey : @(returnHeight),`
24. `AVVideoCompressionPropertiesKey : compressProperties,`
25. `AVVideoScalingModeKey : AVVideoScalingModeResizeAspectFill`
26. `};`
27. `return compressSetting;`
28. `}else {`
29. `NSDictionary *compressSetting = @{`
30. `AVVideoCodecKey : AVVideoCodecTypeH264,`
31. `AVVideoWidthKey : @(returnWidth),`
32. `AVVideoHeightKey : @(returnHeight),`
33. `AVVideoCompressionPropertiesKey : compressProperties,`
34. `AVVideoScalingModeKey : AVVideoScalingModeResizeAspectFill`
35. `};`
36. `return compressSetting;`
37. `}`
38. `}`
音頻壓縮的參數配置
1. `//音頻設置`
2. `+ (NSDictionary *)audioCompressSettings{`
3. `AudioChannelLayout stereoChannelLayout = {`
4. `.mChannelLayoutTag = kAudioChannelLayoutTag_Stereo,`
5. `.mChannelBitmap = kAudioChannelBit_Left,`
6. `.mNumberChannelDescriptions = 0,`
7. `};`
8. `NSData *channelLayoutAsData = [NSData dataWithBytes:&stereoChannelLayout length:offsetof(AudioChannelLayout, mChannelDescriptions)];`
9. `NSDictionary *audioCompressSettings = @{`
10. `AVFormatIDKey : @(kAudioFormatMPEG4AAC),`
11. `AVEncoderBitRateKey : @(128000),`
12. `AVSampleRateKey : @(44100),`
13. `AVNumberOfChannelsKey : @(2),`
14. `AVChannelLayoutKey : channelLayoutAsData`
15. `};`
16. `return audioCompressSettings;`
17. `}`
讀取音頻參數配置
1. `/** 音頻解碼 */`
2. `+ (NSDictionary *)configAudioOutput`
3. `{`
4. `NSDictionary *audioOutputSetting = @{`
5. `AVFormatIDKey: @(kAudioFormatLinearPCM)`
6. `};`
7. `return audioOutputSetting;`
8. `}`
讀取視頻參數配置
1. `/** 視頻解碼 */`
2. `+ (NSDictionary *)configVideoOutput`
3. `{`
4. `NSDictionary *videoOutputSetting = @{`
5. `(__bridge NSString *)kCVPixelBufferPixelFormatTypeKey:[NSNumber numberWithUnsignedInt:kCVPixelFormatType_422YpCbCr8],`
6. `(__bridge NSString *)kCVPixelBufferIOSurfacePropertiesKey:[NSDictionary dictionary]`
7. `};`
9. `return videoOutputSetting;`
10. `}`
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