Add minimal support of DVB AIT

This is used by broadcast channels to provide interactive contents.

library/common/src/main/java/com/google/android/exoplayer2/util/MimeTypes.java

@@ -97,6 +97,7 @@ public final class MimeTypes {
   public static final String APPLICATION_DVBSUBS = BASE_TYPE_APPLICATION + "/dvbsubs";
   public static final String APPLICATION_EXIF = BASE_TYPE_APPLICATION + "/x-exif";
   public static final String APPLICATION_ICY = BASE_TYPE_APPLICATION + "/x-icy";
+  public static final String APPLICATION_AIT = BASE_TYPE_APPLICATION + "/ait";
 
   private static final ArrayList<CustomMimeType> customMimeTypes = new ArrayList<>();
 

library/core/src/main/java/com/google/android/exoplayer2/metadata/MetadataDecoderFactory.java

@@ -17,6 +17,7 @@ package com.google.android.exoplayer2.metadata;
 
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.Format;
+import com.google.android.exoplayer2.metadata.dvbsi.AitDecoder;
 import com.google.android.exoplayer2.metadata.emsg.EventMessageDecoder;
 import com.google.android.exoplayer2.metadata.icy.IcyDecoder;
 import com.google.android.exoplayer2.metadata.id3.Id3Decoder;
@@ -67,7 +68,8 @@ public interface MetadataDecoderFactory {
           return MimeTypes.APPLICATION_ID3.equals(mimeType)
               || MimeTypes.APPLICATION_EMSG.equals(mimeType)
               || MimeTypes.APPLICATION_SCTE35.equals(mimeType)
-              || MimeTypes.APPLICATION_ICY.equals(mimeType);
+              || MimeTypes.APPLICATION_ICY.equals(mimeType)
+              || MimeTypes.APPLICATION_AIT.equals(mimeType);
         }
 
         @Override
@@ -83,6 +85,8 @@ public interface MetadataDecoderFactory {
                 return new SpliceInfoDecoder();
               case MimeTypes.APPLICATION_ICY:
                 return new IcyDecoder();
+              case MimeTypes.APPLICATION_AIT:
+                return new AitDecoder();
               default:
                 break;
             }

library/core/src/main/java/com/google/android/exoplayer2/metadata/dvbsi/Ait.java

@@ -0,0 +1,58 @@
+package com.google.android.exoplayer2.metadata.dvbsi;
+
+import android.os.Parcel;
+import android.os.Parcelable;
+
+import com.google.android.exoplayer2.metadata.Metadata;
+
+public class Ait implements Metadata.Entry {
+  /*
+  The application shall be started when the service is selected, unless the
+  application is already running.
+   */
+  public static final int CONTROL_CODE_AUTOSTART = 0x01;
+  /*
+  The application is allowed to run while the service is selected, however it
+  shall not start automatically when the service becomes selected.
+   */
+  public static final int CONTROL_CODE_PRESENT = 0x02;
+
+  public final int controlCode;
+  public final String url;
+
+  Ait(int controlCode, String url) {
+    this.controlCode = controlCode;
+    this.url = url;
+  }
+
+  @Override
+  public String toString() {
+    return "Ait(controlCode = " + controlCode + ", url = " + url + ")";
+  }
+
+  @Override
+  public int describeContents() {
+    return 0;
+  }
+
+  @Override
+  public void writeToParcel(Parcel parcel, int i) {
+    parcel.writeString(url);
+    parcel.writeInt(controlCode);
+  }
+
+  public static final Parcelable.Creator<Ait> CREATOR =
+      new Parcelable.Creator<Ait>() {
+        @Override
+        public Ait createFromParcel(Parcel in) {
+          String url = in.readString();
+          int controlCode = in.readInt();
+          return new Ait(controlCode, url);
+        }
+
+        @Override
+        public Ait[] newArray(int size) {
+          return new Ait[size];
+        }
+      };
+}

library/core/src/main/java/com/google/android/exoplayer2/metadata/dvbsi/AitDecoder.java

@@ -0,0 +1,195 @@
+package com.google.android.exoplayer2.metadata.dvbsi;
+
+import com.google.android.exoplayer2.metadata.Metadata;
+import com.google.android.exoplayer2.metadata.MetadataDecoder;
+import com.google.android.exoplayer2.metadata.MetadataInputBuffer;
+import com.google.android.exoplayer2.util.ParsableByteArray;
+import com.google.android.exoplayer2.util.TimestampAdjuster;
+
+import java.nio.ByteBuffer;
+import java.nio.charset.Charset;
+import java.util.ArrayList;
+
+public class AitDecoder implements MetadataDecoder {
+    // Specification of AIT can be found in 5.3.4 of TS 102 809 v1.1.1
+    // https://www.etsi.org/deliver/etsi_ts/102800_102899/102809/01.01.01_60/ts_102809v010101p.pdf
+    private final static int DESCRIPTOR_TRANSPORT_PROTOCOL = 0x02;
+
+    private final static int DESCRIPTOR_SIMPLE_APPLICATION_LOCATION = 0x15;
+
+    private final static int TRANSPORT_PROTOCOL_HTTP = 3;
+
+    private TimestampAdjuster timestampAdjuster;
+
+    private final ParsableByteArray sectionData;
+
+    public AitDecoder() {
+        sectionData = new ParsableByteArray();
+    }
+
+    @Override
+    public Metadata decode(MetadataInputBuffer inputBuffer) {
+        if (timestampAdjuster == null
+                || inputBuffer.subsampleOffsetUs != timestampAdjuster.getTimestampOffsetUs()) {
+            timestampAdjuster = new TimestampAdjuster(inputBuffer.timeUs);
+            timestampAdjuster.adjustSampleTimestamp(inputBuffer.timeUs - inputBuffer.subsampleOffsetUs);
+        }
+
+        ByteBuffer buffer = inputBuffer.data;
+        byte[] data = buffer.array();
+        int size = buffer.limit();
+        sectionData.reset(data, size);
+
+        int tableId = sectionData.peekUnsignedByte();
+
+        //Only this table is allowed in AIT streams
+        if (tableId == 0x74) {
+            return parseAit(sectionData);
+        }
+
+        return new Metadata();
+    }
+
+    private Metadata parseAit(ParsableByteArray sectionData) {
+        int tmp;
+
+        int tableId = sectionData.readUnsignedByte();
+
+        tmp = sectionData.readUnsignedShort();
+        int endOfSection = sectionData.getPosition() + (tmp & 4095) - 4 /* Ignore leading CRC */;
+
+        tmp = sectionData.readUnsignedShort();
+        int applicationType = tmp & 0x7fff;
+
+        tmp = sectionData.readUnsignedByte();
+        int versionNumber = (tmp & 0x3e) >> 1;
+        boolean current = (tmp & 1) == 1;
+
+        int section_number = sectionData.readUnsignedByte();
+        int last_section_number = sectionData.readUnsignedByte();
+
+        tmp = sectionData.readUnsignedShort();
+        int commonDescriptorsLength = tmp & 4095;
+
+        //Since we currently only keep url and control code, which are unique per application,
+        //there is no useful information in common descriptor.
+        sectionData.skipBytes(commonDescriptorsLength);
+
+        tmp = sectionData.readUnsignedShort();
+        int appLoopLength = tmp & 4095;
+
+        ArrayList<Ait> aits = new ArrayList<>();
+        while(sectionData.getPosition() < endOfSection) {
+            // Values that will be stored in Ait()
+            String aitUrlBase = null;
+            String aitUrlExtension = null;
+            int aitControlCode = -1;
+
+            long application_identifier = sectionData.readUnsignedInt24() << 24L;
+            application_identifier |= sectionData.readUnsignedInt24();
+            int controlCode = sectionData.readUnsignedByte();
+
+            aitControlCode = controlCode;
+
+            tmp = sectionData.readUnsignedShort();
+            int sectionLength = tmp & 4095;
+            int positionOfNextSection = sectionData.getPosition() + sectionLength;
+            while(sectionData.getPosition() < positionOfNextSection) {
+                int type = sectionData.readUnsignedByte();
+                int l = sectionData.readUnsignedByte();
+                int positionOfNextSection2 = sectionData.getPosition() + l;
+
+                if(type == DESCRIPTOR_TRANSPORT_PROTOCOL) {
+                    int protocolId = sectionData.readUnsignedShort();
+                    int label = sectionData.readUnsignedByte();
+
+                    if(protocolId == TRANSPORT_PROTOCOL_HTTP) {
+                        while (sectionData.getPosition() < positionOfNextSection2) {
+                            int urlBaseLength = sectionData.readUnsignedByte();
+                            String urlBase = sectionData.readString(urlBaseLength);
+                            int extensionCount = sectionData.readUnsignedByte();
+                            aitUrlBase = urlBase;
+                            for (int i = 0; i < extensionCount; i++) {
+                                int len = sectionData.readUnsignedByte();
+                                sectionData.skipBytes(len);
+                            }
+                        }
+                    }
+                } else if(type == DESCRIPTOR_SIMPLE_APPLICATION_LOCATION) {
+                    String url = sectionData.readString(l);
+                    aitUrlExtension = url;
+                }
+
+                sectionData.setPosition(positionOfNextSection2);
+            }
+
+            sectionData.setPosition(positionOfNextSection);
+
+            if(aitControlCode != -1 && aitUrlBase != null && aitUrlExtension != null) {
+                aits.add(new Ait(aitControlCode, aitUrlBase + aitUrlExtension));
+            }
+        }
+
+        return new Metadata(aits);
+    }
+
+    static final String dvbCharset[] = {
+        "ISO-8859-15",
+        "ISO-8859-5",
+        "ISO-8859-6",
+        "ISO-8859-7",
+        "ISO-8859-8",
+        "ISO-8859-9",
+        null,
+        "ISO-8859-11",
+        null,
+        "ISO-8859-13",
+        null,
+        "ISO-8859-15",
+        null,
+        null,
+        null,
+        null,
+        //0x10
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+        null,
+    };
+
+    static String readDvbString(ParsableByteArray data, int length) {
+        if(length == 0) return null;
+        int charsetSelect = data.peekUnsignedByte();
+        if(charsetSelect >= 0x20)
+            return data.readString(length, Charset.forName("ISO-8859-15"));
+        data.skipBytes(1);
+        if(charsetSelect == 0x1f) {
+            data.skipBytes(length - 1);
+            return null;
+        }
+        if(charsetSelect != 0x10)
+            return data.readString(length-1, Charset.forName(dvbCharset[charsetSelect]));
+        if(length == 2) {
+            data.skipBytes(1);
+            return null;
+        }
+        charsetSelect = data.readUnsignedShort();
+        if(charsetSelect > 1 && charsetSelect < 0x10) {
+            String charsetName = "ISO-8859-" + charsetSelect;
+            return data.readString(length-3, Charset.forName(charsetName));
+        }
+        return null;
+    }
+}

library/extractor/src/main/java/com/google/android/exoplayer2/extractor/ts/DefaultTsPayloadReaderFactory.java

@@ -18,11 +18,17 @@ package com.google.android.exoplayer2.extractor.ts;
 import android.util.SparseArray;
 import androidx.annotation.IntDef;
 import androidx.annotation.Nullable;
+
+import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
+import com.google.android.exoplayer2.extractor.ExtractorOutput;
+import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.EsInfo;
 import com.google.android.exoplayer2.util.CodecSpecificDataUtil;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableByteArray;
+import com.google.android.exoplayer2.util.TimestampAdjuster;
+
 import java.lang.annotation.Documented;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -176,11 +182,41 @@ public final class DefaultTsPayloadReaderFactory implements TsPayloadReader.Fact
       case TsExtractor.TS_STREAM_TYPE_DVBSUBS:
         return new PesReader(
             new DvbSubtitleReader(esInfo.dvbSubtitleInfos));
+      case TsExtractor.TS_STREAM_TYPE_AIT:
+        return new SectionReader(new SectionPassthrough(MimeTypes.APPLICATION_AIT));
       default:
         return null;
     }
   }
 
+  public class SectionPassthrough implements SectionPayloadReader {
+    private TimestampAdjuster timestampAdjuster = null;
+    private final String mimeType;
+    private TrackOutput output;
+
+    SectionPassthrough(String mimeType) {
+      this.mimeType = mimeType;
+    }
+
+    @Override
+    public void init(TimestampAdjuster timestampAdjuster, ExtractorOutput extractorOutput, TsPayloadReader.TrackIdGenerator idGenerator) {
+      this.timestampAdjuster = timestampAdjuster;
+      idGenerator.generateNewId();
+      output = extractorOutput.track(idGenerator.getTrackId(), C.TRACK_TYPE_METADATA);
+      output.format(Format.createSampleFormat(null, mimeType,
+              timestampAdjuster.getTimestampOffsetUs()));
+    }
+
+    @Override
+    public void consume(ParsableByteArray sectionData) {
+      int sampleSize = sectionData.bytesLeft();
+      output.sampleData(sectionData, sampleSize);
+      output.sampleMetadata(timestampAdjuster.getLastAdjustedTimestampUs(), C.BUFFER_FLAG_KEY_FRAME,
+              sampleSize, 0, null);
+    }
+  }
+
+
   /**
    * If {@link #FLAG_OVERRIDE_CAPTION_DESCRIPTORS} is set, returns a {@link SeiReader} for
    * {@link #closedCaptionFormats}. If unset, parses the PMT descriptor information and returns a

library/extractor/src/main/java/com/google/android/exoplayer2/extractor/ts/TsExtractor.java

@@ -96,6 +96,9 @@ public final class TsExtractor implements Extractor {
   public static final int TS_STREAM_TYPE_SPLICE_INFO = 0x86;
   public static final int TS_STREAM_TYPE_DVBSUBS = 0x59;
 
+  //Those are special IDs, which don't have actual TS definitions
+  public static final int TS_STREAM_TYPE_AIT = 0x101;
+
   public static final int TS_PACKET_SIZE = 188;
   public static final int TS_SYNC_BYTE = 0x47; // First byte of each TS packet.
 
@@ -494,6 +497,7 @@ public final class TsExtractor implements Extractor {
     private static final int TS_PMT_DESC_REGISTRATION = 0x05;
     private static final int TS_PMT_DESC_ISO639_LANG = 0x0A;
     private static final int TS_PMT_DESC_AC3 = 0x6A;
+    private static final int TS_PMT_DESC_AIT = 0x6F;
     private static final int TS_PMT_DESC_EAC3 = 0x7A;
     private static final int TS_PMT_DESC_DTS = 0x7B;
     private static final int TS_PMT_DESC_DVB_EXT = 0x7F;
@@ -578,7 +582,7 @@ public final class TsExtractor implements Extractor {
         pmtScratch.skipBits(4); // reserved
         int esInfoLength = pmtScratch.readBits(12); // ES_info_length.
         EsInfo esInfo = readEsInfo(sectionData, esInfoLength);
-        if (streamType == 0x06) {
+        if (streamType == 0x06 || streamType == 0x05) {
           streamType = esInfo.streamType;
         }
         remainingEntriesLength -= esInfoLength + 5;
@@ -688,6 +692,8 @@ public final class TsExtractor implements Extractor {
             dvbSubtitleInfos.add(new DvbSubtitleInfo(dvbLanguage, dvbSubtitlingType,
                 initializationData));
           }
+        } else if (descriptorTag == TS_PMT_DESC_AIT) {
+          streamType = TS_STREAM_TYPE_AIT;
         }
         // Skip unused bytes of current descriptor.
         data.skipBytes(positionOfNextDescriptor - data.getPosition());