SGAudioFormatter: Add finish func.

SGPlayer/Classes/Core/SGProcessor/SGAudioFormatter.h

@@ -22,6 +22,11 @@
  */
 - (SGAudioFrame *)format:(SGAudioFrame *)frame;
 
+/**
+ *
+ */
+- (SGAudioFrame *)finish;
+
 /**
  *
  */

SGPlayer/Classes/Core/SGProcessor/SGAudioFormatter.m

@@ -12,12 +12,22 @@
 
 @interface SGAudioFormatter ()
 
+@property (nonatomic, readonly) SGTrack *track;
+@property (nonatomic, readonly) CMTime nextTimeStamp;
 @property (nonatomic, strong, readonly) SGSWResample *context;
 
 @end
 
 @implementation SGAudioFormatter
 
+- (instancetype)init
+{
+    if (self = [super init]) {
+        [self flush];
+    }
+    return self;
+}
+
 - (SGAudioFrame *)format:(SGAudioFrame *)frame
 {
     if (![frame isKindOfClass:[SGAudioFrame class]]) {
@@ -26,7 +36,7 @@ - (SGAudioFrame *)format:(SGAudioFrame *)frame
     }
     if (![self->_context.inputDescriptor isEqualToDescriptor:frame.descriptor] ||
         ![self->_context.outputDescriptor isEqualToDescriptor:self->_descriptor]) {
-        self->_context = nil;
+        [self flush];
         SGSWResample *context = [[SGSWResample alloc] init];
         context.inputDescriptor = frame.descriptor;
         context.outputDescriptor = self->_descriptor;
@@ -38,27 +48,48 @@ - (SGAudioFrame *)format:(SGAudioFrame *)frame
         [frame unlock];
         return nil;
     }
-    int nb_planes = self->_descriptor.numberOfPlanes;
+    self->_track = frame.track;
     int nb_samples = [self->_context write:frame.data nb_samples:frame.numberOfSamples];
-    CMTime start = frame.timeStamp;
-    CMTime duration = CMTimeMake(nb_samples, self->_descriptor.sampleRate);
-    SGAudioFrame *ret = [SGAudioFrame audioFrameWithDescriptor:self->_descriptor numberOfSamples:nb_samples];
+    SGAudioFrame *ret = [self frameWithStart:frame.timeStamp nb_samples:nb_samples];
+    self->_nextTimeStamp = CMTimeAdd(ret.timeStamp, ret.duration);
+    [frame unlock];
+    return ret;
+}
+
+- (SGAudioFrame *)finish
+{
+    if (!self->_track || !self->_context || CMTIME_IS_INVALID(self->_nextTimeStamp)) {
+        return nil;
+    }
+    int nb_samples = [self->_context write:NULL nb_samples:0];
+    if (nb_samples <= 0) {
+        return nil;
+    }
+    SGAudioFrame *frame = [self frameWithStart:self->_nextTimeStamp nb_samples:nb_samples];
+    return frame;
+}
+
+- (SGAudioFrame *)frameWithStart:(CMTime)start nb_samples:(int)nb_samples
+{
+    SGAudioFrame *frame = [SGAudioFrame audioFrameWithDescriptor:self->_descriptor numberOfSamples:nb_samples];
+    uint8_t nb_planes = self->_descriptor.numberOfPlanes;
     uint8_t *data[SGFramePlaneCount] = {NULL};
     for (int i = 0; i < nb_planes; i++) {
-        data[i] = ret.core->data[i];
+        data[i] = frame.core->data[i];
     }
     [self->_context read:data nb_samples:nb_samples];
     SGCodecDescriptor *cd = [[SGCodecDescriptor alloc] init];
-    cd.track = frame.track;
-    [ret setCodecDescriptor:cd];
-    [ret fillWithTimeStamp:start decodeTimeStamp:start duration:duration];
-    [frame unlock];
-    return ret;
+    cd.track = self->_track;
+    [frame setCodecDescriptor:cd];
+    [frame fillWithTimeStamp:start decodeTimeStamp:start duration:CMTimeMake(nb_samples, self->_descriptor.sampleRate)];
+    return frame;
 }
 
 - (void)flush
 {
+    self->_track = nil;
     self->_context = nil;
+    self->_nextTimeStamp = kCMTimeInvalid;
 }
 
 @end

SGPlayer/Classes/Core/SGProcessor/SGSWResample.h

@@ -32,4 +32,9 @@
  */
 - (int)read:(uint8_t **)data nb_samples:(int)nb_samples;
 
+/**
+ *
+ */
+- (int)delay;
+
 @end

SGPlayer/Classes/Core/SGProcessor/SGSWResample.m

@@ -83,4 +83,11 @@ - (int)read:(uint8_t **)data nb_samples:(int)nb_samples
     return nb_samples;
 }
 
+- (int)delay
+{
+    int64_t delay = swr_get_delay(self->_context, self->_outputDescriptor.sampleRate);
+    NSAssert(delay < INT32_MAX, @"Invalid ");
+    return (int)delay;
+}
+
 @end