Opus Audio packet level statistics

Move the logic for calculating opus audio statistics from the
standalone OpusStatistics class, into OpusAudioData. Based
on work from Gagravarr#14 from @andrm

Author: Gagravarr

core/src/main/java/org/gagravarr/opus/OpusAudioData.java

@@ -20,6 +20,9 @@
  * Raw, compressed audio data
  */
 public class OpusAudioData extends OggStreamAudioData implements OpusPacket {
+    private int numFrames = -1;
+    private int numSamples = -1;
+    
     public OpusAudioData(OggPacket pkt) {
         super(pkt);
     }
@@ -30,4 +33,56 @@ public OpusAudioData(byte[] data) {
     protected boolean isEndOfStream() {
         return getOggPacket().isEndOfStream();
     }
+    
+    public int getNumberOfFrames() {
+        if (numFrames == -1) {
+            calculateStructure();
+        }
+        return numFrames;
+    }
+    public int getNumberOfSamples() {
+        if (numSamples == -1) {
+            calculateStructure();
+        }
+        return numSamples;
+    }
+    
+    private void calculateStructure() {
+        byte[] d = getData();
+        numFrames = packet_get_nb_frames(d);
+        numSamples = numFrames * packet_get_samples_per_frame(d, 48000);
+    }
+    
+    private static int packet_get_samples_per_frame(byte[] data, int fs) {
+        int audiosize;
+        if ((data[0]&0x80) != 0) {
+            audiosize = ((data[0]>>3)&0x3);
+            audiosize = (fs<<audiosize)/400;
+        } else if ((data[0]&0x60) == 0x60) {
+            audiosize = ((data[0]&0x08) != 0) ? fs/50 : fs/100;
+        } else {
+            audiosize = ((data[0]>>3)&0x3);
+            if (audiosize == 3)
+                audiosize = fs*60/1000;
+            else
+                audiosize = (fs<<audiosize)/100;
+        }
+        return audiosize;
+    }
+
+    private static int packet_get_nb_frames(byte[] packet) {
+        int count = 0;
+        if (packet.length < 1) {
+            return -1;
+        }
+        count = packet[0]&0x3;
+        if (count==0)
+            return 1;
+        else if (count!=3)
+            return 2;
+        else if (packet.length<2)
+            return -4;
+        else
+            return packet[1]&0x3F;
+    }
 }

core/src/main/java/org/gagravarr/opus/OpusStatistics.java

@@ -141,59 +141,22 @@ else if (getAudioPacketsCount() == 0) {
             return;
         }
 
-        int spp = packet_get_nb_frames(d);
-        spp *= packet_get_samples_per_frame(d, 48000);
-        if(spp<120 || spp>5760 || (spp%120)!=0) {
+        int samples = audioData.getNumberOfSamples();
+        if (samples<120 || samples>5760 || (samples%120) != 0) {
             System.err.println("WARNING: Invalid packet TOC in stream with sid "+sid);
             return;
         }
-        total_samples += spp;
-        page_samples += spp;
+        total_samples += samples;
+        page_samples += samples;
         total_packets++;
         //last_packet_duration = spp;
-        if (max_packet_duration<spp) max_packet_duration=spp;
-        if (min_packet_duration>spp) min_packet_duration = spp;
+        if (max_packet_duration<samples) max_packet_duration = samples;
+        if (min_packet_duration>samples) min_packet_duration = samples;
         if (max_packet_bytes<d.length) max_packet_bytes = d.length;
         if (min_packet_bytes>d.length) min_packet_bytes = d.length;
     }
 
 
-    private static int packet_get_samples_per_frame(byte[] data, int Fs) {
-        int audiosize;
-        if ((data[0]&0x80) != 0)
-        {
-            audiosize = ((data[0]>>3)&0x3);
-            audiosize = (Fs<<audiosize)/400;
-        } else if ((data[0]&0x60) == 0x60)
-        {
-            audiosize = ((data[0]&0x08) != 0) ? Fs/50 : Fs/100;
-        } else {
-            audiosize = ((data[0]>>3)&0x3);
-            if (audiosize == 3)
-                audiosize = Fs*60/1000;
-            else
-                audiosize = (Fs<<audiosize)/100;
-        }
-        return audiosize;
-
-    }
-
-    private static int packet_get_nb_frames(byte[] packet) {
-        int count = 0;
-        if (packet.length < 1) {
-            return -1;
-        }
-        count = packet[0]&0x3;
-        if (count==0)
-            return 1;
-        else if (count!=3)
-            return 2;
-        else if (packet.length<2)
-            return -4;
-        else
-            return packet[1]&0x3F;
-    }
-
     public double getMaxPacketDuration() {
         return (max_packet_duration/48.0);
     }