AVSampleBufferDisplayLayer如何显示H.264 [英] How AVSampleBufferDisplayLayer displays H.264

问题描述

我想分享我几天来所积累的知识.没有很多可以找到的.

I want to share my knowledge which I worked out in some days about it. There isnt a lot to find about it.

我仍然对声音不满.欢迎评论和提示. ;-)

I am still fizzeling about the sound. Comments and tips are welcomed. ;-)

推荐答案

此处是我的代码段.声明

here my code snippets. Declare it

@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];

将视频数据提供给图层

__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:2014年WWDC的Session 513内容非常丰富.

For further details: the Session 513 in WWDC 2014 is very informative.

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