使用OpenGL-ES在iOS上播放视频

Question

我正在尝试在iOS上播放视频(MP4/H.263),但结果非常模糊.这是初始化资产阅读的代码:

mTextureHandle = [self createTexture:CGSizeMake(400,400)];

NSURL * url = [NSURL fileURLWithPath:file];    
mAsset = [[AVURLAsset alloc] initWithURL:url options:NULL];

NSArray * tracks = [mAsset tracksWithMediaType:AVMediaTypeVideo];

mTrack = [tracks objectAtIndex:0];

NSLog(@"Tracks: %i", [tracks count]);

NSString* key = (NSString*)kCVPixelBufferPixelFormatTypeKey;
NSNumber* value = [NSNumber numberWithUnsignedInt:kCVPixelFormatType_32BGRA];
NSDictionary * settings = [[NSDictionary alloc] initWithObjectsAndKeys:value, key, nil];

mOutput = [[AVAssetReaderTrackOutput alloc] 
            initWithTrack:mTrack outputSettings:settings];


mReader = [[AVAssetReader alloc] initWithAsset:mAsset error:nil];
[mReader addOutput:mOutput];

对于读者init来说,现在是实际的纹理:

CMSampleBufferRef sampleBuffer = [mOutput copyNextSampleBuffer];    
CVImageBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
CVPixelBufferLockBaseAddress( pixelBuffer, 0 );

glBindTexture(GL_TEXTURE_2D, mTextureHandle);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 600, 400, 0, GL_BGRA_EXT, GL_UNSIGNED_BYTE, CVPixelBufferGetBaseAddress( pixelBuffer ));    
CVPixelBufferUnlockBaseAddress( pixelBuffer, 0 );    
CFRelease(sampleBuffer);

一切都很好......除了渲染的图像看起来像这样; 切片和歪斜？

我甚至试图寻找AVAssetTrack首选的转换矩阵,但无济于事,因为它总会回归CGAffineTransformIdentity.

侧注:如果我将源切换到相机,图像会变得很好.我错过了一些减压步骤吗？这不应该由资产读者处理吗？

谢谢!

代码:https://github.com/shaded-enmity/objcpp-opengl-video

Answer 1

我认为CMSampleBuffer出于性能原因使用填充,因此您需要为纹理选择合适的宽度.

尝试使用以下命令设置纹理的宽度:CVPixelBufferGetBytesPerRow(pixelBuffer)/ 4(如果您的视频格式使用每像素4个字节,则更改为其他)