用AVPlayer播放AVMutableComposition？ [英] Play AVMutableComposition with AVPlayer?

问题描述

我正在尝试按顺序播放两个视频。我尝试过AVQueuePlayer，但两个片段之间有一个巨大的打嗝。我需要他们不间断地玩。

I'm trying to get two videos to play sequentially. I've tried AVQueuePlayer but there's a huge "burp" between the two clips. I need to them to play without interruption.

所以我正在尝试使用AVMutableComposition和AVPlayer，但无法正确使用。

So I'm trying to use AVMutableComposition and an AVPlayer but can't get it right.

这里是我的代码（忽略内存泄漏，只在空项目中测试..）：

Here's my code (ignore memory leaks, just testing in an empty project..):

composition = [[AVMutableComposition alloc] init];

NSString * path = [[NSBundle mainBundle] pathForResource:@"test" ofType:@"mp4"];
NSURL * url = [NSURL fileURLWithPath:path];
AVURLAsset * asset = [[AVURLAsset alloc] initWithURL:url options:nil];

NSError * error = NULL;
[composition insertTimeRange:CMTimeRangeMake(CMTimeMake(0,1000),CMTimeMake(4,1000)) ofAsset:asset atTime:CMTimeMake(0,1000) error:&error];
if(error) NSLog(@"error: %@",error);

path = [[NSBundle mainBundle] pathForResource:@"chug1" ofType:@"mp4"];
url = [NSURL fileURLWithPath:path];
asset = [[AVURLAsset alloc] initWithURL:url options:nil];

error = NULL;
[composition insertTimeRange:CMTimeRangeMake(CMTimeMake(0,1000),CMTimeMake(3,1000)) ofAsset:asset atTime:CMTimeMake(4.1,1000) error:&error];
if(error) NSLog(@"error: %@",error);

AVPlayerItem * item = [[AVPlayerItem alloc] initWithAsset:composition];
AVPlayer * player = [AVPlayer playerWithPlayerItem:item];
AVPlayerLayer * layer = [AVPlayerLayer playerLayerWithPlayer:player];

[layer setFrame:CGRectMake(0, 0, 320, 480)];
[[[self view] layer] addSublayer:layer];
[player play];

代码似乎对我而言。每个视频的第一帧实际上呈现在屏幕上。但视频根本不播放。我错过了什么？我是否需要弄清楚如何使用MutableTrack的东西？

The code seems right to me. The first frame of each video is actually rendered to the screen. But the video doesn't play at all. I'm I missing something? Do I need to figure out how to use the MutableTrack stuff?

推荐答案

也许你使用错误的时间插入点和持续时间，两者都取决于实际的视频资产。我写的是这样的：

Maybe you're using the wrong time insertion points and durations, both depends on actual video assets. I'd write something like this:

CMTime insertionPoint = kCMTimeZero;
NSError * error = nil;
composition = [AVMutableComposition composition];
asset = /* obtain asset #1 */
if (![composition insertTimeRange:CMTimeRangeMake(kCMTimeZero, asset.duration) 
                          ofAsset:asset 
                           atTime:insertionPoint 
                            error:&error]) 
{
    NSLog(@"error: %@",error);
}
insertionPoint = CMTimeAdd(insertionPoint, asset.duration);

asset = /* obtain asset #2 */
if (![composition insertTimeRange:CMTimeRangeMake(kCMTimeZero, asset.duration) 
                          ofAsset:asset 
                           atTime:insertionPoint 
                            error:&error]) 
{
    NSLog(@"error: %@",error);
}
...
/* playback stuff */

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