KCSP/ProductApp/ProductApp/ProductMain/ShouYe/saveManger/VChangeManager.m

//
//  VChangeManager.m
//  ProductApp
//
//  Created by 工作 on 2025/4/8.
//

#import "VChangeManager.h"
#import <AVFoundation/AVFoundation.h>

@interface VChangeManager ()
{
    AVAssetReader *assetReader;
    AVAssetReaderTrackOutput *readerVideoTrackOutput, *readerAudioTrackOutput;
    AVAssetWriter *assetWriter;
    AVAssetWriterInput *assetVideoWriterInput, *assetAudioWriterInput;
}

@end
@implementation VChangeManager
+(id)manager
{
    static dispatch_once_t once;
    static VChangeManager *manager;
    dispatch_once(&once, ^ {
        manager = [[VChangeManager alloc] init];
    });
    return manager;
}
-(void)kaiShiZHUrl:(NSURL *)fileUrl back:(VChangeManagerBack)backValue
{
    NSString *writerPath = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/12345.mp4"];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    if ([fileManager fileExistsAtPath:writerPath]) {
        [fileManager removeItemAtPath:writerPath error:nil];
    }
    
    AVAsset *asset = [AVAsset assetWithURL:fileUrl];
    NSError *error;
    //创建AVAssetReader对象用来读取asset数据
    assetReader = [AVAssetReader assetReaderWithAsset:asset error:&error];
    AVAsset *localAsset = assetReader.asset;

    if([localAsset tracksWithMediaType:AVMediaTypeVideo].count==0 || [localAsset tracksWithMediaType:AVMediaTypeAudio].count==0)
    {
        backValue(NO,@"");
        return;
    }
    AVAssetTrack *videoTrack = [[localAsset tracksWithMediaType:AVMediaTypeVideo] firstObject];
    AVAssetTrack *audioTrack = [[localAsset tracksWithMediaType:AVMediaTypeAudio] firstObject];

    NSDictionary *videoSetting = @{(id)kCVPixelBufferPixelFormatTypeKey     : [NSNumber numberWithUnsignedInt:kCVPixelFormatType_32BGRA],
                                   (id)kCVPixelBufferIOSurfacePropertiesKey : [NSDictionary dictionary],
                                   };
//    AVAssetReaderTrackOutput用来设置怎么读数据
    readerVideoTrackOutput = [[AVAssetReaderTrackOutput alloc] initWithTrack:videoTrack outputSettings:videoSetting];
    //音频以pcm流的形似读数据
    NSDictionary *audioSetting = @{AVFormatIDKey : [NSNumber numberWithUnsignedInt:kAudioFormatLinearPCM]};
    readerAudioTrackOutput = [[AVAssetReaderTrackOutput alloc] initWithTrack:audioTrack outputSettings:audioSetting];
    
    if ([assetReader canAddOutput:readerVideoTrackOutput]) {
        [assetReader addOutput:readerVideoTrackOutput];
    }
    
    if ([assetReader canAddOutput:readerAudioTrackOutput]) {
        [assetReader addOutput:readerAudioTrackOutput];
    }
    //开始读
    [assetReader startReading];
    
    NSURL *writerUrl = [NSURL fileURLWithPath:writerPath];
    //创建一个写数据对象
    assetWriter = [[AVAssetWriter alloc] initWithURL:writerUrl fileType:AVFileTypeMPEG4 error:nil];
    //配置写数据，设置比特率，帧率等
    NSDictionary *compressionProperties = @{ AVVideoAverageBitRateKey : @(1.38*1024*1024),
                                             AVVideoExpectedSourceFrameRateKey: @(30),
                                             AVVideoProfileLevelKey : AVVideoProfileLevelH264HighAutoLevel };
    
    
    // 获取视频尺寸
    CGSize videoSize = videoTrack.naturalSize;
    int videoWidth = (int)videoSize.width;
    int videoHeight = (int)videoSize.height;
    //配置编码器宽高等
    NSDictionary *compressionVideoSetting = @{
                              AVVideoCodecKey                   : AVVideoCodecTypeH264,
                              AVVideoWidthKey                   : @(videoWidth),
                              AVVideoHeightKey                  : @(videoHeight),
                              AVVideoCompressionPropertiesKey   : compressionProperties
                              };

    AudioChannelLayout stereoChannelLayout = {
        .mChannelLayoutTag = kAudioChannelLayoutTag_Stereo,
        .mChannelBitmap = 0,
        .mNumberChannelDescriptions = 0
    };
    NSData *channelLayoutAsData = [NSData dataWithBytes:&stereoChannelLayout length:offsetof(AudioChannelLayout, mChannelDescriptions)];
    //写入音频配置
    NSDictionary *compressionAudioSetting = @{
                                               AVFormatIDKey         : [NSNumber numberWithUnsignedInt:kAudioFormatMPEG4AAC],
                                               AVEncoderBitRateKey   : [NSNumber numberWithInteger:64000],
                                               AVSampleRateKey       : [NSNumber numberWithInteger:44100],
                                               AVChannelLayoutKey    : channelLayoutAsData,
                                               AVNumberOfChannelsKey : [NSNumber numberWithUnsignedInteger:2]
                                               };
    //AVAssetWriterInput用来说明怎么写数据
    assetVideoWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:compressionVideoSetting];
    assetAudioWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:compressionAudioSetting];
    
    if ([assetWriter canAddInput:assetVideoWriterInput]) {
        [assetWriter addInput:assetVideoWriterInput];
    }
    if ([assetWriter canAddInput:assetAudioWriterInput]) {
        [assetWriter addInput:assetAudioWriterInput];
    }
    //开始写
    [assetWriter startWriting];
    [assetWriter startSessionAtSourceTime:kCMTimeZero];
    dispatch_group_t group = dispatch_group_create();
    dispatch_queue_t videoWriter = dispatch_queue_create("videoWriter", DISPATCH_QUEUE_CONCURRENT);
    dispatch_queue_t audioWriter = dispatch_queue_create("audioWriter", DISPATCH_QUEUE_CONCURRENT);
    __block BOOL isVideoComplete = NO;
    dispatch_group_enter(group);
    //要想写数据，就带有数据源，以下是将readerVideoTrackOutput读出来的数据加入到assetVideoWriterInput中再写入本地，音频和视频读取写入方式一样
    __block BOOL issaveVideo = NO;
    [assetVideoWriterInput requestMediaDataWhenReadyOnQueue:videoWriter usingBlock:^{
        while (!isVideoComplete && assetVideoWriterInput.isReadyForMoreMediaData) {
            //样本数据
            @autoreleasepool {
                //每次读取一个buffer
                if(issaveVideo==NO)
                {
                    issaveVideo = YES;
                    CMSampleBufferRef buffer = [readerVideoTrackOutput copyNextSampleBuffer];
                    if (buffer) {
                        //将读来的buffer加入到写对象中开始写
                        [assetVideoWriterInput appendSampleBuffer:buffer];
                        
                        CFRelease(buffer);
                        buffer = NULL;
                    } else {
                        isVideoComplete = YES;
                    }
                    issaveVideo = NO;
                }
            }
            
        }
        if (isVideoComplete) {
            //关闭写入会话
            [assetVideoWriterInput markAsFinished];
            dispatch_group_leave(group);
        }
    }];
    __block BOOL isAudioComplete = NO;
    __block BOOL issaveAudio = NO;
    dispatch_group_enter(group);
    [assetAudioWriterInput requestMediaDataWhenReadyOnQueue:audioWriter usingBlock:^{
        while (!isAudioComplete && assetAudioWriterInput.isReadyForMoreMediaData) {
            if(issaveAudio==NO)
            {
                issaveAudio = YES;
                //样本数据
                CMSampleBufferRef buffer = [readerAudioTrackOutput copyNextSampleBuffer];
                if (buffer) {
                    [assetAudioWriterInput appendSampleBuffer:buffer];
                    CFRelease(buffer);
                    buffer = NULL;
                } else {
                    isAudioComplete = YES;
                }
                issaveAudio = NO;
            }
        }
        if (isAudioComplete) {
            //关闭写入会话
            [assetAudioWriterInput markAsFinished];
            dispatch_group_leave(group);
        }
    }];
    
    dispatch_group_notify(group, dispatch_get_main_queue(), ^{
        [assetWriter finishWritingWithCompletionHandler:^{
            AVAssetWriterStatus status = assetWriter.status;
            if (status == AVAssetWriterStatusCompleted) {
                [assetReader cancelReading];
                [assetWriter cancelWriting];
                ///成功
                backValue(YES,writerPath);
            } else {
                ///失败
                backValue(NO,@"");
            }
            
        }];
    });
}
@end