initial commit of media shit

usm_extract/src/Mpeg1Stream.cs

@@ -0,0 +1,39 @@
+using System;
+using System.IO;
+
+namespace vgm_usm.extract
+{
+    public class Mpeg1Stream : MpegStream
+    {
+        public const string DefaultAudioExtension = ".mp2";
+        public const string DefaultVideoExtension = ".m1v";
+
+        public Mpeg1Stream(string path)
+            : base(path)
+        {
+            this.FileExtensionAudio = DefaultAudioExtension;
+            this.FileExtensionVideo = DefaultVideoExtension;
+
+            base.BlockIdDictionary[BitConverter.ToUInt32(MpegStream.PacketStartBytes, 0)] = new BlockSizeStruct(PacketSizeType.Static, 0xC); // Pack Header
+        }
+
+        protected override int GetAudioPacketHeaderSize(Stream readStream, long currentOffset)
+        {
+            int paddingByteCount = 0;
+            readStream.Position = currentOffset + 6;
+
+            // skip stuffing bytes
+            while (readStream.ReadByte() == 0xFF)
+            {
+                paddingByteCount++;
+            }
+
+            return paddingByteCount + 7;
+        }
+
+        protected override int GetVideoPacketHeaderSize(Stream readStream, long currentOffset)
+        {
+            return 0xC;
+        }
+    }
+}