diff --git a/SGPlayer/Classes/Core/SGData/SGData.h b/SGPlayer/Classes/Core/SGData/SGData.h
index 8c54e688..28c8ff5c 100644
--- a/SGPlayer/Classes/Core/SGData/SGData.h
+++ b/SGPlayer/Classes/Core/SGData/SGData.h
@@ -9,8 +9,20 @@
 #import <Foundation/Foundation.h>
 #import <CoreMedia/CoreMedia.h>
 
+/**
+ *
+ */
+typedef NS_OPTIONS(NSUInteger, SGDataFlags) {
+    SGDataFlagPadding = 1 << 0,
+};
+
 @protocol SGData <NSObject>
 
+/**
+ *
+ */
+@property (nonatomic) SGDataFlags flags;
+
 /**
  *
  */
diff --git a/SGPlayer/Classes/Core/SGData/SGFrame.m b/SGPlayer/Classes/Core/SGData/SGFrame.m
index 6a57479e..af7d61cc 100644
--- a/SGPlayer/Classes/Core/SGData/SGFrame.m
+++ b/SGPlayer/Classes/Core/SGData/SGFrame.m
@@ -21,6 +21,7 @@ @interface SGFrame ()
 
 @implementation SGFrame
 
+@synthesize flags = _flags;
 @synthesize reuseName = _reuseName;
 
 - (instancetype)init
@@ -88,6 +89,7 @@ - (void)clear
         av_frame_unref(self->_core);
     }
     self->_size = 0;
+    self->_flags = 0;
     self->_track = nil;
     self->_duration = kCMTimeZero;
     self->_timeStamp = kCMTimeZero;
diff --git a/SGPlayer/Classes/Core/SGData/SGPacket.m b/SGPlayer/Classes/Core/SGData/SGPacket.m
index a780b612..6e5371d9 100644
--- a/SGPlayer/Classes/Core/SGData/SGPacket.m
+++ b/SGPlayer/Classes/Core/SGData/SGPacket.m
@@ -21,6 +21,7 @@ @interface SGPacket ()
 
 @implementation SGPacket
 
+@synthesize flags = _flags;
 @synthesize reuseName = _reuseName;
 
 - (instancetype)init
@@ -93,6 +94,7 @@ - (void)clear
         av_packet_unref(self->_core);
     }
     self->_size = 0;
+    self->_flags = 0;
     self->_track = nil;
     self->_duration = kCMTimeZero;
     self->_timeStamp = kCMTimeZero;
diff --git a/SGPlayer/Classes/Core/SGDecoder/SGAudioDecoder.m b/SGPlayer/Classes/Core/SGDecoder/SGAudioDecoder.m
index 35764bd4..0fae6e40 100644
--- a/SGPlayer/Classes/Core/SGDecoder/SGAudioDecoder.m
+++ b/SGPlayer/Classes/Core/SGDecoder/SGAudioDecoder.m
@@ -88,33 +88,28 @@ - (void)flush
         [self setup];
     }
     [cd fillToDescriptor:self->_codecDescriptor];
-    switch (packet.codecDescriptor.type) {
-        case SGCodecTypeDecode: {
-            NSArray<SGFrame *> *objs = [self processPacket:packet];
-            for (SGFrame *obj in objs) {
-                [ret addObject:obj];
-            }
+    if (packet.flags & SGDataFlagPadding) {
+        SGAudioDescriptor *ad = self->_audioDescriptor;
+        if (ad == nil) {
+            ad = [[SGAudioDescriptor alloc] init];
         }
-            break;
-        case SGCodecTypePadding: {
-            SGAudioDescriptor *ad = self->_audioDescriptor;
-            if (ad == nil) {
-                ad = [[SGAudioDescriptor alloc] init];
-            }
-            CMTime start = packet.timeStamp;
-            CMTime duration = packet.duration;
-            int nb_samples = (int)CMTimeConvertScale(duration, ad.sampleRate, kCMTimeRoundingMethod_RoundTowardZero).value;
-            if (nb_samples > 0) {
-                duration = CMTimeMake(nb_samples, ad.sampleRate);
-                SGAudioFrame *obj = [SGAudioFrame audioFrameWithDescriptor:ad numberOfSamples:nb_samples];
-                SGCodecDescriptor *cd = [[SGCodecDescriptor alloc] init];
-                cd.track = packet.track;
-                [obj setCodecDescriptor:cd];
-                [obj fillWithTimeStamp:start decodeTimeStamp:start duration:duration];
-                [ret addObject:obj];
-            }
+        CMTime start = packet.timeStamp;
+        CMTime duration = packet.duration;
+        int nb_samples = (int)CMTimeConvertScale(duration, ad.sampleRate, kCMTimeRoundingMethod_RoundTowardZero).value;
+        if (nb_samples > 0) {
+            duration = CMTimeMake(nb_samples, ad.sampleRate);
+            SGAudioFrame *obj = [SGAudioFrame audioFrameWithDescriptor:ad numberOfSamples:nb_samples];
+            SGCodecDescriptor *cd = [[SGCodecDescriptor alloc] init];
+            cd.track = packet.track;
+            [obj setCodecDescriptor:cd];
+            [obj fillWithTimeStamp:start decodeTimeStamp:start duration:duration];
+            [ret addObject:obj];
+        }
+    } else {
+        NSArray<SGFrame *> *objs = [self processPacket:packet];
+        for (SGFrame *obj in objs) {
+            [ret addObject:obj];
         }
-            break;
     }
     return ret;
 }
diff --git a/SGPlayer/Classes/Core/SGDecoder/SGVideoDecoder.m b/SGPlayer/Classes/Core/SGDecoder/SGVideoDecoder.m
index 5795b4ee..c2aa07cd 100644
--- a/SGPlayer/Classes/Core/SGDecoder/SGVideoDecoder.m
+++ b/SGPlayer/Classes/Core/SGDecoder/SGVideoDecoder.m
@@ -94,18 +94,13 @@ - (void)flush
         [self setup];
     }
     [cd fillToDescriptor:self->_codecDescriptor];
-    switch (packet.codecDescriptor.type) {
-        case SGCodecTypeDecode: {
-            NSArray<SGFrame *> *objs = [self processPacket:packet];
-            for (SGFrame *obj in objs) {
-                [ret addObject:obj];
-            }
-        }
-            break;
-        case SGCodecTypePadding: {
-            
+    if (packet.flags & SGDataFlagPadding) {
+        
+    } else {
+        NSArray<SGFrame *> *objs = [self processPacket:packet];
+        for (SGFrame *obj in objs) {
+            [ret addObject:obj];
         }
-            break;
     }
     self->_flags.outputCount += ret.count;
     return ret;
@@ -117,6 +112,7 @@ - (void)flush
     if (objs.count == 0 &&
         self->_lastFrame &&
         self->_flags.outputCount == 0) {
+        self->_lastFrame.flags |= SGDataFlagPadding;
         objs = @[self->_lastFrame];
     } else {
         [self->_lastFrame unlock];
diff --git a/SGPlayer/Classes/Core/SGDemuxer/SGPaddingDemuxer.m b/SGPlayer/Classes/Core/SGDemuxer/SGPaddingDemuxer.m
index 335f776b..d3709185 100644
--- a/SGPlayer/Classes/Core/SGDemuxer/SGPaddingDemuxer.m
+++ b/SGPlayer/Classes/Core/SGDemuxer/SGPaddingDemuxer.m
@@ -75,12 +75,12 @@ - (NSError *)nextPacket:(SGPacket **)packet
     CMTime timeStamp = self->_lasttime;
     CMTime duration = CMTimeSubtract(self->_duration, self->_lasttime);
     SGPacket *pkt = [[SGObjectPool sharedPool] objectWithClass:[SGPacket class] reuseName:[SGPacket commonReuseName]];
+    pkt.flags |= SGDataFlagPadding;
     pkt.core->size = 1;
     pkt.core->pts = av_rescale(AV_TIME_BASE, timeStamp.value, timeStamp.timescale);
     pkt.core->dts = av_rescale(AV_TIME_BASE, timeStamp.value, timeStamp.timescale);
     pkt.core->duration = av_rescale(AV_TIME_BASE, duration.value, duration.timescale);
     SGCodecDescriptor *cd = [[SGCodecDescriptor alloc] init];
-    cd.type = SGCodecTypePadding;
     cd.timebase = AV_TIME_BASE_Q;
     [pkt setCodecDescriptor:cd];
     [pkt fill];
diff --git a/SGPlayer/Classes/Core/SGDescription/SGCodecDescriptor.h b/SGPlayer/Classes/Core/SGDescription/SGCodecDescriptor.h
index 6ea9a8b6..8f3d4a68 100644
--- a/SGPlayer/Classes/Core/SGDescription/SGCodecDescriptor.h
+++ b/SGPlayer/Classes/Core/SGDescription/SGCodecDescriptor.h
@@ -11,18 +11,8 @@
 #import "SGFFmpeg.h"
 #import "SGTrack.h"
 
-typedef NS_ENUM(NSUInteger, SGCodecType) {
-    SGCodecTypeDecode  = 0,
-    SGCodecTypePadding = 1,
-};
-
 @interface SGCodecDescriptor : NSObject <NSCopying>
 
-/**
- *
- */
-@property (nonatomic) SGCodecType type;
-
 /**
  *
  */
diff --git a/SGPlayer/Classes/Core/SGDescription/SGCodecDescriptor.m b/SGPlayer/Classes/Core/SGDescription/SGCodecDescriptor.m
index be54b65a..3a0ae125 100644
--- a/SGPlayer/Classes/Core/SGDescription/SGCodecDescriptor.m
+++ b/SGPlayer/Classes/Core/SGDescription/SGCodecDescriptor.m
@@ -26,7 +26,6 @@ - (id)copyWithZone:(NSZone *)zone
 - (instancetype)init
 {
     if (self = [super init]) {
-        self->_type = SGCodecTypeDecode;
         self->_scale = CMTimeMake(1, 1);
         self->_timebase = AV_TIME_BASE_Q;
         self->_timeRange = CMTimeRangeMake(kCMTimeNegativeInfinity, kCMTimePositiveInfinity);