AVSampleBufferDisplayLayer 如何显示 H.264

我想分享我几天来学到的知识。没有太多可找到的。

我仍然对声音感到困惑。欢迎提出意见和建议。 ;-)

这是我的代码片段。声明一下

@property (nonatomic, retain) AVSampleBufferDisplayLayer *videoLayer;

首先设置视频层

self.videoLayer = [[AVSampleBufferDisplayLayer alloc] init];
self.videoLayer.bounds = self.bounds;
self.videoLayer.position = CGPointMake(CGRectGetMidX(self.bounds), CGRectGetMidY(self.bounds));
self.videoLayer.videoGravity = AVLayerVideoGravityResizeAspect;
self.videoLayer.backgroundColor = [[UIColor greenColor] CGColor];

//set Timebase
CMTimebaseRef controlTimebase;
CMTimebaseCreateWithMasterClock( CFAllocatorGetDefault(), CMClockGetHostTimeClock(), &controlTimebase );

self.videoLayer.controlTimebase = controlTimebase;
CMTimebaseSetTime(self.videoLayer.controlTimebase, CMTimeMake(5, 1));
CMTimebaseSetRate(self.videoLayer.controlTimebase, 1.0);

// connecting the videolayer with the view

[[self layer] addSublayer:_videoLayer];

向图层提供视频数据

__block AVAssetReaderTrackOutput *outVideo = [AVAssetReaderTrackOutput assetReaderTrackOutputWithTrack:video outputSettings:dic];

if( [assetReaderVideo startReading] )
{
    [_videoLayer requestMediaDataWhenReadyOnQueue: assetQueue usingBlock: ^{
        while( [_videoLayer isReadyForMoreMediaData] )
        {
            CMSampleBufferRef *sampleVideo = [outVideo copyNextSampleBuffer];

            [_videoLayer enqueueSampleBuffer:sampleVideo.data];
        }
    }];
}

有关更多详细信息：WWDC 2014 中的第 513 次会议内容非常丰富。