git.sesse.net Git - vlc/blob - projects/macosx/framework/Sources/VLCMediaThumbnailer.m

   1 //
   2 //  VLCMediaThumbnailer.m
   3 //  VLCKit
   4 //
   5 //  Created by Pierre d'Herbemont on 7/10/10.
   6 //  Copyright 2010 __MyCompanyName__. All rights reserved.
   7 //
   8
   9 #import <vlc/vlc.h>
  10
  11 #import "VLCMediaThumbnailer.h"
  12 #import "VLCLibVLCBridging.h"
  13
  14
  15 @interface VLCMediaThumbnailer ()
  16 - (void)didFetchThumbnail;
  17 - (void)notifyDelegate;
  18 - (void)fetchThumbnail;
  19 - (void)startFetchingThumbnail;
  20 @property (readonly, assign) void *dataPointer;
  21 @end
  22
  23 static void *lock(void *opaque, void **pixels)
  24 {
  25     VLCMediaThumbnailer *thumbnailer = opaque;
  26
  27     *pixels = [thumbnailer dataPointer];
  28     assert(*pixels);
  29     return NULL;
  30 }
  31
  32 static const size_t kDefaultImageWidth = 320;
  33 static const size_t kDefaultImageHeight = 240;
  34 static const float kSnapshotPosition = 0.5;
  35
  36 void unlock(void *opaque, void *picture, void *const *p_pixels)
  37 {
  38     VLCMediaThumbnailer *thumbnailer = opaque;
  39     assert(!picture);
  40
  41     assert([thumbnailer dataPointer] == *p_pixels);
  42
  43     // We may already have a thumbnail if we are receiving picture after the first one.
  44     // Just ignore.
  45     if ([thumbnailer thumbnail])
  46         return;
  47
  48     [thumbnailer performSelectorOnMainThread:@selector(didFetchThumbnail) withObject:nil waitUntilDone:YES];
  49 }
  50
  51 void display(void *opaque, void *picture)
  52 {
  53 }
  54
  55 @implementation VLCMediaThumbnailer
  56 @synthesize media=_media;
  57 @synthesize delegate=_delegate;
  58 @synthesize thumbnail=_thumbnail;
  59 @synthesize dataPointer=_data;
  60 @synthesize thumbnailWidth=_thumbnailWidth;
  61 @synthesize thumbnailHeight=_thumbnailHeight;
  62
  63 + (VLCMediaThumbnailer *)thumbnailerWithMedia:(VLCMedia *)media andDelegate:(id<VLCMediaThumbnailerDelegate>)delegate
  64 {
  65     id obj = [[[self class] alloc] init];
  66     [obj setMedia:media];
  67     [obj setDelegate:delegate];
  68     return [obj autorelease];
  69 }
  70
  71 - (void)dealloc
  72 {
  73     NSAssert(!_data, @"Data not released");
  74     NSAssert(!_mp, @"Not properly retained");
  75     if (_thumbnail)
  76         CGImageRelease(_thumbnail);
  77     [_media release];
  78     [super dealloc];
  79 }
  80
  81
  82 - (void)fetchThumbnail
  83 {
  84     NSAssert(!_data, @"We are already fetching a thumbnail");
  85
  86     [self retain]; // Balanced in -notifyDelegate
  87
  88     if (![_media isParsed]) {
  89         [_media addObserver:self forKeyPath:@"parsed" options:0 context:NULL];
  90         [_media parse];
  91         NSAssert(!_parsingTimeoutTimer, @"We already have a timer around");
  92         _parsingTimeoutTimer = [[NSTimer scheduledTimerWithTimeInterval:10 target:self selector:@selector(mediaParsingTimedOut) userInfo:nil repeats:NO] retain];
  93         return;
  94     }
  95
  96     [self startFetchingThumbnail];
  97 }
  98
  99
 100 - (void)startFetchingThumbnail
 101 {
 102     NSArray *tracks = [_media tracksInformation];
 103
 104     // Find the video track
 105     NSDictionary *videoTrack = nil;
 106     for (NSDictionary *track in tracks) {
 107         NSString *type = [track objectForKey:VLCMediaTracksInformationType];
 108         if ([type isEqualToString:VLCMediaTracksInformationTypeVideo]) {
 109             videoTrack = track;
 110             break;
 111         }
 112     }
 113
 114     unsigned imageWidth = _thumbnailWidth > 0 ? _thumbnailWidth : kDefaultImageWidth;
 115     unsigned imageHeight = _thumbnailHeight > 0 ? _thumbnailHeight : kDefaultImageHeight;
 116
 117     if (!videoTrack)
 118         NSLog(@"WARNING: Can't find video track info, still attempting to thumbnail in doubt");
 119     else {
 120         int videoHeight = [[videoTrack objectForKey:VLCMediaTracksInformationVideoHeight] intValue];
 121         int videoWidth = [[videoTrack objectForKey:VLCMediaTracksInformationVideoWidth] intValue];
 122
 123         // Constraining to the aspect ratio of the video.
 124         double ratio;
 125         if ((double)imageWidth / imageHeight < (double)videoWidth / videoHeight)
 126             ratio = (double)imageHeight / videoHeight;
 127         else
 128             ratio = (double)imageWidth / videoWidth;
 129
 130         int newWidth = round(videoWidth * ratio);
 131         int newHeight = round(videoHeight * ratio);
 132         NSLog(@"video %dx%d from %dx%d or %dx%d", newWidth, newHeight, videoWidth, videoHeight, imageWidth, imageHeight);
 133         imageWidth = newWidth > 0 ? newWidth : imageWidth;
 134         imageHeight = newHeight > 0 ? newHeight : imageHeight;
 135     }
 136
 137     _effectiveThumbnailHeight = imageHeight;
 138     _effectiveThumbnailWidth = imageWidth;
 139
 140     _data = calloc(1, imageWidth * imageHeight * 4);
 141     NSAssert(_data, @"Can't create data");
 142
 143     NSAssert(!_mp, @"We are already fetching a thumbnail");
 144     _mp = libvlc_media_player_new([VLCLibrary sharedInstance]);
 145
 146     libvlc_media_add_option([_media libVLCMediaDescriptor], "no-audio");
 147
 148     libvlc_media_player_set_media(_mp, [_media libVLCMediaDescriptor]);
 149     libvlc_video_set_format(_mp, "RGBA", imageWidth, imageHeight, 4 * imageWidth);
 150     libvlc_video_set_callbacks(_mp, lock, unlock, display, self);
 151     libvlc_media_player_play(_mp);
 152     libvlc_media_player_set_position(_mp, kSnapshotPosition);
 153 }
 154
 155 - (void)mediaParsingTimedOut
 156 {
 157     NSLog(@"WARNING: media thumbnailer media parsing timed out");
 158     [_media removeObserver:self forKeyPath:@"parsed"];
 159
 160     [self startFetchingThumbnail];
 161 }
 162
 163 - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
 164 {
 165     if (object == _media && [keyPath isEqualToString:@"parsed"]) {
 166         if ([_media isParsed]) {
 167             [_parsingTimeoutTimer invalidate];
 168             [_parsingTimeoutTimer release];
 169             _parsingTimeoutTimer = nil;
 170             [_media removeObserver:self forKeyPath:@"parsed"];
 171             [self startFetchingThumbnail];
 172         }
 173         return;
 174     }
 175     return [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
 176 }
 177
 178 - (void)didFetchThumbnail
 179 {
 180     // The video thread is blocking on us. Beware not to do too much work.
 181
 182     // Make sure we are getting the right frame
 183     if (libvlc_media_player_get_position(_mp) < kSnapshotPosition &&
 184         // Arbitrary choice to work around broken files.
 185         libvlc_media_player_get_length(_mp) > 1000)
 186         return;
 187
 188     NSAssert(_data, @"We have no data");
 189     CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
 190     const CGFloat width = _effectiveThumbnailWidth;
 191     const CGFloat height = _effectiveThumbnailHeight;
 192     const CGFloat pitch = 4 * width;
 193     CGContextRef bitmap = CGBitmapContextCreate(_data,
 194                                  width,
 195                                  height,
 196                                  8,
 197                                  pitch,
 198                                  colorSpace,
 199                                  kCGImageAlphaNoneSkipLast);
 200
 201     CGColorSpaceRelease(colorSpace);
 202     NSAssert(bitmap, @"Can't create bitmap");
 203
 204     // Create the thumbnail image
 205     //NSAssert(!_thumbnail, @"We already have a thumbnail");
 206     if (_thumbnail)
 207         CGImageRelease(_thumbnail);
 208     _thumbnail = CGBitmapContextCreateImage(bitmap);
 209
 210     // Put a new context there.
 211     CGContextRelease(bitmap);
 212
 213     // Make sure we don't block the video thread now
 214     [self performSelector:@selector(notifyDelegate) withObject:nil afterDelay:0];
 215 }
 216
 217 - (void)notifyDelegate
 218 {
 219     // Stop the media player
 220     NSAssert(_mp, @"We have already destroyed mp");
 221     libvlc_media_player_stop(_mp);
 222     libvlc_media_player_release(_mp);
 223     _mp = NULL;
 224
 225     // Now release data
 226     free(_data);
 227     _data = NULL;
 228
 229     // Call delegate
 230     [_delegate mediaThumbnailer:self didFinishThumbnail:_thumbnail];
 231
 232     [self release]; // Balancing -fetchThumbnail
 233 }
 234
 235 @end