{"id":321040,"date":"2021-02-05T12:51:07","date_gmt":"2021-02-05T04:51:07","guid":{"rendered":"http:\/\/4563.org\/?p=321040"},"modified":"2021-02-05T12:51:07","modified_gmt":"2021-02-05T04:51:07","slug":"avassetreader-%e8%a7%86%e9%a2%91%e6%95%b0%e6%8d%ae%e8%af%bb%e5%8f%96","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=321040","title":{"rendered":"AVAssetReader \u89c6\u9891\u6570\u636e\u8bfb\u53d6"},"content":{"rendered":"<div>\n<div>\n<div>\n<h1>                  AVAssetReader \u89c6\u9891\u6570\u636e\u8bfb\u53d6               <\/h1>\n<p> <\/p>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : zoule <\/span>  <span><i><\/i> 9<\/span> <\/div>\n<div> <\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<div isfirst=\"1\"> <\/p>\n<h1>AVAssetReader \u4ecb\u7ecd<\/h1>\n<p> <\/p>\n<p>\u53ef\u4ee5\u901a\u8fc7 AVAssetReader \u83b7\u53d6\u89c6\u9891\u6587\u4ef6\u91cc\u5a92\u4f53\u6837\u672c\uff0c\u53ef\u4ee5\u76f4\u63a5\u4ece\u5b58\u50a8\u5668\u4e2d\u8bfb\u53d6\u672a\u89e3\u7801\u7684\u539f\u59cb\u5a92\u4f53\u6837\u672c\uff0c\u83b7\u5f97\u89e3\u7801\u6210\u53ef\u6e32\u67d3\u5f62\u5f0f\u7684\u6837\u672c\u3002 \u6587\u6863\u91cc\u8bf4\u660e AVAssetrader \u7ba1\u9053\u5185\u90e8\u662f\u591a\u7ebf\u7a0b\u7684\u3002\u521d\u59cb\u5316\u4e4b\u540e\uff0c\u8bfb\u53d6\u5668\u5728\u4f7f\u7528\u524d\u52a0\u8f7d\u5e76\u5904\u7406\u5408\u7406\u6570\u91cf\u7684\u6837\u672c\u6570\u636e\uff0c\u4ee5 copyNextSampleBuffer \uff08 AVAssetReaderOutput \uff09\u7b49\u68c0\u7d22\u64cd\u4f5c\u7684\u5ef6\u8fdf\u975e\u5e38\u4f4e\u3002\u4f46 AVAssetReader \u8fd8\u662f\u4e0d\u9002\u7528\u4e8e\u5b9e\u65f6\u6e90\uff0c\u5e76\u4e14\u5b83\u7684\u6027\u80fd\u4e5f\u4e0d\u80fd\u4fdd\u8bc1\u7528\u4e8e\u5b9e\u65f6\u64cd\u4f5c\u3002 \u7531\u4e8e\u4f7f\u7528\u524d\u9700\u8981\u52a0\u8f7d\u5e76\u5904\u7406\u4e00\u4e9b\u6837\u672c\u6570\u636e\uff0c\u5bfc\u81f4\u5360\u7528\u7684\u5185\u5b58\u53ef\u80fd\u4f1a\u6bd4\u8f83\u5927\uff0c\u9700\u8981\u6ce8\u610f\u540c\u4e00\u65f6\u95f4\u4f7f\u7528\u7684 reader \u4e2a\u6570\u4e0d\u8981\u8fc7\u591a\uff0c\u89c6\u9891\u50cf\u7d20\u8d8a\u9ad8\uff0c\u5360\u7528\u7684\u5185\u5b58\u4e5f\u4f1a\u8d8a\u5927\u3002 \u00a0<\/p>\n<h1>AVAssetReader \u521d\u59cb\u5316<\/h1>\n<p> <\/p>\n<p>\u4f7f\u7528 AVAsset \u5bf9 AVAssetReader \u8fdb\u884c\u521d\u59cb\u5316\uff0c\u524d\u9762\u4e5f\u8bf4\u4e86\u521d\u59cb\u5316\u4e4b\u540e\u5c31\u4f1a\u52a0\u8f7d\u6837\u672c\u6570\u636e\uff0c\u6240\u4ee5\u8fd9\u4e00\u6b65\u5c31\u5df2\u7ecf\u4f1a\u5bf9\u5185\u5b58\u4ea7\u751f\u5370\u8c61\uff0c\u5982\u679c\u5185\u5b58\u7d27\u5f20\u5c31\u4e0d\u8981\u9884\u5148\u521d\u59cb\u5316\u3002<\/p>\n<pre><code> NSError *createReaderError;  _reader = [[AVAssetReader alloc]initWithAsset:_asset error:&amp;createReaderError]; <\/code><\/pre>\n<p>\u00a0<\/p>\n<h1>AVAssetReader \u8bbe\u7f6e Output<\/h1>\n<p> <\/p>\n<p>\u5728\u5f00\u59cb\u8bfb\u53d6\u4e4b\u524d\uff0c\u9700\u8981\u6dfb\u52a0 output \u6765\u63a7\u5236\u8bfb\u53d6\u521d\u59cb\u5316\u4f7f\u7528\u7684 asset \u4e2d\u54ea\u4e9b track\uff0c\u4ee5\u53ca\u914d\u7f6e\u5982\u4f55\u8bfb\u53d6\u3002 AVAssetReaderOutput \u8fd8\u6709\u5176\u4ed6\u7684\u5b50\u7c7b\u5b9e\u73b0\uff0c\u5982 AVAssetReaderVideoCompositionOutput\uff0cAVAssetReaderAudioMixOutput \u548c AVAssetReaderSampleReferenceOutput \u3002 \u8fd9\u91cc\u4f7f\u7528 AVAssetReaderTrackOutput \u6f14\u793a\u3002\u9700\u8981\u4e00\u4e2a track \u6765\u521d\u59cb\u5316\uff0ctrack \u4ece asset \u4e2d\u83b7\u53d6\u3002<\/p>\n<pre><code>NSArray tracks = [_asset tracksWithMediaType:AVMediaTypeAudio]; if (tracks.count &gt; 0) {     AVAssetTrack audioTrack = [tracks objectAtIndex:0]; } <\/code><\/pre>\n<p>\u6216\u8005<\/p>\n<pre><code> NSArray tracks = [_asset tracksWithMediaType:AVMediaTypeVideo]; if (tracks.count &gt; 0) {     AVAssetTrack videoTrack = [tracks objectAtIndex:0]; } <\/code><\/pre>\n<p>\u8fd8\u53ef\u4ee5\u5bf9\u8f93\u51fa\u7684\u683c\u5f0f\u8fdb\u884c\u914d\u7f6e\uff0c\u66f4\u591a\u914d\u7f6e\u53ef\u4ee5\u67e5\u9605\u6587\u6863\u3002<\/p>\n<pre><code>NSDictionary * const VideoAssetTrackReaderOutputOptions = @{(id) kCVPixelBufferOpenGLESCompatibilityKey : @(YES),                                                             (id) kCVPixelBufferIOSurfacePropertiesKey : [NSDictionary dictionary],                                                             (NSString*)kCVPixelBufferPixelFormatTypeKey: @(kCVPixelFormatType_32BGRA)}; _readerOutput = [AVAssetReaderTrackOutput assetReaderTrackOutputWithTrack:_track                                                            outputSettings:VideoAssetTrackReaderOutputOptions]; if ([_reader canAddOutput:_readerOutput]) {     [_reader addOutput:_readerOutput]; } <\/code><\/pre>\n<p>\u00a0<\/p>\n<h1>seek \u64cd\u4f5c<\/h1>\n<p> <\/p>\n<p>AVAssetReader \u5e76\u4e0d\u9002\u5408\u9891\u7e41\u968f\u673a\u8bfb\u53d6\u7684\u64cd\u4f5c\uff0c\u5982\u679c\u9700\u8981\u9891\u7e41 seek \u53ef\u80fd\u9700\u8981\u522b\u7684\u65b9\u5f0f\u5b9e\u73b0\u3002 \u5728\u5f00\u59cb\u8bfb\u53d6\u4e4b\u524d\uff0c\u53ef\u4ee5\u5bf9\u8bfb\u53d6\u7684\u8303\u56f4\u8fdb\u884c\u8bbe\u7f6e\uff0c\u5f53\u5f00\u59cb\u8bfb\u53d6\u540e\u4e0d\u53ef\u4ee5\u4fee\u6539\uff0c\u53ea\u80fd\u987a\u5e8f\u5411\u540e\u8bfb\u3002 \u6709\u4e24\u79cd\u65b9\u6848\u6765\u8c03\u6574\u8bfb\u53d6\u8303\u56f4\uff1a<\/p>\n<ol>\n<li>output \u4e2d\u53ef\u4ee5\u8bbe\u7f6e supportsRandomAccess\uff0c\u5f53\u4e3a true \u65f6\uff0c\u53ef\u4ee5\u91cd\u7f6e\u8bfb\u53d6\u8303\u56f4\uff0c\u4f46\u9700\u8981\u8c03\u7528\u65b9\u8c03\u7528 copyNextSampleBuffer\uff0c\u76f4\u5230\u8be5\u65b9\u6cd5\u8fd4\u56de NULL \u3002<\/li>\n<li>\u6216\u8005\u91cd\u65b0\u521d\u59cb\u5316\u4e00\u4e2a AVAssetReader \u6765\u8bbe\u7f6e\u8bfb\u53d6\u65f6\u95f4\u3002 \u5982\u679c\u5c1d\u8bd5\u7b2c\u4e00\u79cd\u65b9\u6848\uff0c\u9700\u8981\u4f7f\u7528 seek\uff0c\u53ef\u4ee5\u5c1d\u8bd5\u6bcf\u6b21\u8bbe\u7f6e\u4e00\u4e2a\u4e0d\u592a\u957f\u7684\u533a\u95f4\uff0c\u4ee5\u4fdd\u8bc1\u8bfb\u53d6\u5b8c\u6574\u4e2a\u533a\u95f4\u4e0d\u4f1a\u8017\u65f6\u592a\u591a\uff0c\u4e14\u65f6\u95f4\u95f4\u9694\u6700\u597d\u4ee5\u5173\u952e\u5e27\u5212\u5206\u3002<\/li>\n<\/ol>\n<p>\u00a0<\/p>\n<h1>\u8bfb\u53d6\u6570\u636e<\/h1>\n<p> <\/p>\n<pre><code>_reader.timeRange = range; [_reader startReading];  _sampleBuffer = [_readerOutput copyNextSampleBuffer]; <\/code><\/pre>\n<p>CMSampleBuffer \u4e2d\u63d0\u4f9b\u4e86\u65b9\u6cd5\u83b7\u53d6\u89e3\u7801\u6570\u636e\uff0c\u6bd4\u5982\u83b7\u53d6\u56fe\u50cf\u4fe1\u606f\u53ef\u4ee5\u4f7f\u7528<\/p>\n<pre><code>CVImageBufferRef pixelBuffer =  <\/code><\/pre>\n<pre><code>CMSampleBufferGetImageBuffer(_sampleBuffer); <\/code><\/pre>\n<p>\u9700\u8981\u6ce8\u610f\uff0c\u5f53 CMSampleBuffer \u4f7f\u7528\u5b8c\u6bd5\uff0c\u9700\u8981\u8c03\u7528 release \u6765\u91ca\u653e<\/p>\n<pre><code>CFRelease(_sampleBuffer); <\/code><\/pre>\n<p>\u00a0<\/p>\n<h1>\u4ee3\u7801\u793a\u4f8b<\/h1>\n<p> <\/p>\n<pre><code>NSDictionary * const AssetOptions = @{AVURLAssetPreferPreciseDurationAndTimingKey:@YES}; NSDictionary * const VideoAssetTrackReaderOutputOptions = @{(id) kCVPixelBufferOpenGLESCompatibilityKey : @(YES),                                                                 (id) kCVPixelBufferIOSurfacePropertiesKey : [NSDictionary dictionary],                                                                 (NSString*)kCVPixelBufferPixelFormatTypeKey: @(kCVPixelFormatType_32BGRA)}; _videoAsset = [[AVURLAsset alloc] initWithURL:[NSURL fileURLWithPath: filePath]                                                                     options:AssetOptions]; _videoTrack = [[mPrivate-&amp;gt;mVideoAsset tracksWithMediaType:AVMediaTypeVideo] firstObject]; if (_videoTrack) {     NSError *createReaderError;     _reader = [[AVAssetReader alloc] initWithAsset:_videoAsset error:&amp;amp;createReaderError];     if (!createReaderError) {         _readerOutput = [AVAssetReaderTrackOutput assetReaderTrackOutputWithTrack:mPrivate-&amp;gt;_videoTrack                                                                              outputSettings:VideoAssetTrackReaderOutputOptions];         _readerOutput.supportsRandomAccess = YES;         if ([_reader canAddOutput:_readerOutput])         {             [_reader addOutput:_readerOutput];         }         [_reader startReading];          if (_reader.status == AVAssetReaderStatusReading || _reader.status == AVAssetReaderStatusCompleted) {             CMSampleBufferRef samplebuffer = [_readerOutput copyNextSampleBuffer];             if (samplebuffer) {             \/\/\u7ed8\u5236 samepleBuffer \u4e2d\u7684\u753b\u9762                 CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(samplebuffer);                 CVPixelBufferLockBaseAddress(imageBuffer, 0);                 uint8_t *baseAddress = (uint8_t *)CVPixelBufferGetBaseAddress(imageBuffer);                 size_t width = CVPixelBufferGetWidth(imageBuffer);                 size_t height = CVPixelBufferGetHeight(imageBuffer);                 size_t bytesPerRow = CVPixelBufferGetBytesPerRowOfPlane(imageBuffer, 0);                 size_t bufferSize = CVPixelBufferGetDataSize(imageBuffer);                  CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();                 CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, baseAddress, bufferSize, NULL);                 CGImageRef cgImage = CGImageCreate(width, height, 8, 32, bytesPerRow, rgbColorSpace, kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrderDefault, provider, NULL, true, kCGRenderingIntentDefault);                 CGImageRelease(cgImage);                 CVPixelBufferUnlockBaseAddress(imageBuffer, 0);                 CFRelease(samplebuffer);             }         }     }  } <\/code><\/pre>\n<\/p><\/div>\n<div> <b>\u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (<span>0<\/span>)        <\/div>\n<div> <\/div>\n<\/p><\/div>\n<\/p><\/div>\n<ul>\n<li>\n","protected":false},"excerpt":{"rendered":"<p>AVAssetReader \u89c6\u9891\u6570&hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[],"tags":[],"_links":{"self":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/321040"}],"collection":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=321040"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/321040\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=321040"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=321040"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=321040"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}