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Add support for Caption Format Descriptor

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This allows the TsExtractor to automatically determine the
closed caption tracks to expose by parsing available
descriptors.

Issue:#2161

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=148321380
This commit is contained in:
aquilescanta 2017-02-23 01:55:56 -08:00 committed by Oliver Woodman
parent 698e081eda
commit 3fc3349e95
2 changed files with 71 additions and 18 deletions
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85
library/src/main/java/com/google/android/exoplayer2/extractor/ts/DefaultTsPayloadReaderFactory.java
View file

@ -20,8 +20,10 @@ import android.util.SparseArray;
import com.google.android.exoplayer2.Format;
import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.EsInfo;
import com.google.android.exoplayer2.util.MimeTypes;
import com.google.android.exoplayer2.util.ParsableByteArray;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
@ -35,7 +37,8 @@ public final class DefaultTsPayloadReaderFactory implements TsPayloadReader.Fact
*/
@Retention(RetentionPolicy.SOURCE)
@IntDef(flag = true, value = {FLAG_ALLOW_NON_IDR_KEYFRAMES, FLAG_IGNORE_AAC_STREAM,
FLAG_IGNORE_H264_STREAM, FLAG_DETECT_ACCESS_UNITS, FLAG_IGNORE_SPLICE_INFO_STREAM})
FLAG_IGNORE_H264_STREAM, FLAG_DETECT_ACCESS_UNITS, FLAG_IGNORE_SPLICE_INFO_STREAM,
FLAG_OVERRIDE_CAPTION_DESCRIPTORS})
public @interface Flags {
}
public static final int FLAG_ALLOW_NON_IDR_KEYFRAMES = 1;
@ -43,31 +46,33 @@ public final class DefaultTsPayloadReaderFactory implements TsPayloadReader.Fact
public static final int FLAG_IGNORE_H264_STREAM = 1 << 2;
public static final int FLAG_DETECT_ACCESS_UNITS = 1 << 3;
public static final int FLAG_IGNORE_SPLICE_INFO_STREAM = 1 << 4;
public static final int FLAG_OVERRIDE_CAPTION_DESCRIPTORS = 1 << 5;
private static final int DESCRIPTOR_TAG_CAPTION_SERVICE = 0x86;
@Flags private final int flags;
private final List<Format> closedCaptionFormats;
public DefaultTsPayloadReaderFactory() {
this(0);
this(0, Collections.<Format>emptyList());
}
/**
* @param flags A combination of {@code FLAG_*} values, which control the behavior of the created
* readers.
*/
public DefaultTsPayloadReaderFactory(@Flags int flags) {
this(flags, Collections.singletonList(Format.createTextSampleFormat(null,
MimeTypes.APPLICATION_CEA608, null, Format.NO_VALUE, 0, null, null)));
}
/**
* @param flags A combination of {@code FLAG_*} values, which control the behavior of the created
* readers.
* @param closedCaptionFormats {@link Format}s to be exposed by elementary stream readers for
* streams with embedded closed captions.
* @param closedCaptionFormats {@link Format}s to be exposed by payload readers for streams with
* embedded closed captions when no caption service descriptors are provided. If
* {@link #FLAG_OVERRIDE_CAPTION_DESCRIPTORS} is set, {@code closedCaptionFormats} overrides
* any descriptor information. If not set, and {@code closedCaptionFormats} is empty, a
* closed caption track with {@link Format#accessibilityChannel} {@link Format#NO_VALUE} will
* be exposed.
*/
public DefaultTsPayloadReaderFactory(@Flags int flags, List<Format> closedCaptionFormats) {
this.flags = flags;
if (!isSet(FLAG_OVERRIDE_CAPTION_DESCRIPTORS) && closedCaptionFormats.isEmpty()) {
closedCaptionFormats = Collections.singletonList(Format.createTextSampleFormat(null,
MimeTypes.APPLICATION_CEA608, null, Format.NO_VALUE, 0, null, null));
}
this.closedCaptionFormats = closedCaptionFormats;
}
@ -95,10 +100,10 @@ public final class DefaultTsPayloadReaderFactory implements TsPayloadReader.Fact
return new PesReader(new H262Reader());
case TsExtractor.TS_STREAM_TYPE_H264:
return isSet(FLAG_IGNORE_H264_STREAM) ? null
: new PesReader(new H264Reader(buildSeiReader(), isSet(FLAG_ALLOW_NON_IDR_KEYFRAMES),
isSet(FLAG_DETECT_ACCESS_UNITS)));
: new PesReader(new H264Reader(buildSeiReader(esInfo),
isSet(FLAG_ALLOW_NON_IDR_KEYFRAMES), isSet(FLAG_DETECT_ACCESS_UNITS)));
case TsExtractor.TS_STREAM_TYPE_H265:
return new PesReader(new H265Reader(buildSeiReader()));
return new PesReader(new H265Reader(buildSeiReader(esInfo)));
case TsExtractor.TS_STREAM_TYPE_SPLICE_INFO:
return isSet(FLAG_IGNORE_SPLICE_INFO_STREAM)
? null : new SectionReader(new SpliceInfoSectionReader());
@ -109,8 +114,52 @@ public final class DefaultTsPayloadReaderFactory implements TsPayloadReader.Fact
}
}
private SeiReader buildSeiReader() {
// TODO: Add descriptor parsing to detect channels automatically.
/**
* 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
* {@link SeiReader} for the declared formats, or {@link #closedCaptionFormats} if the descriptor
* is not present.
*
* @param esInfo The {@link EsInfo} passed to {@link #createPayloadReader(int, EsInfo)}.
* @return A {@link SeiReader} for closed caption tracks.
*/
private SeiReader buildSeiReader(EsInfo esInfo) {
if (isSet(FLAG_OVERRIDE_CAPTION_DESCRIPTORS)) {
return new SeiReader(closedCaptionFormats);
}
ParsableByteArray scratchDescriptorData = new ParsableByteArray(esInfo.descriptorBytes);
List<Format> closedCaptionFormats = this.closedCaptionFormats;
while (scratchDescriptorData.bytesLeft() > 0) {
int descriptorTag = scratchDescriptorData.readUnsignedByte();
int descriptorLength = scratchDescriptorData.readUnsignedByte();
int nextDescriptorPosition = scratchDescriptorData.getPosition() + descriptorLength;
if (descriptorTag == DESCRIPTOR_TAG_CAPTION_SERVICE) {
// Note: see ATSC A/65 for detailed information about the caption service descriptor.
closedCaptionFormats = new ArrayList<>();
int numberOfServices = scratchDescriptorData.readUnsignedByte() & 0x1F;
for (int i = 0; i < numberOfServices; i++) {
String language = scratchDescriptorData.readString(3);
int captionTypeByte = scratchDescriptorData.readUnsignedByte();
boolean isDigital = (captionTypeByte & 0x80) != 0;
String mimeType;
int accessibilityChannel;
if (isDigital) {
mimeType = MimeTypes.APPLICATION_CEA708;
accessibilityChannel = captionTypeByte & 0x3F;
} else {
mimeType = MimeTypes.APPLICATION_CEA608;
accessibilityChannel = 1;
}
closedCaptionFormats.add(Format.createTextSampleFormat(null, mimeType, null,
Format.NO_VALUE, 0, language, accessibilityChannel, null));
// Skip easy_reader(1), wide_aspect_ratio(1), reserved(14).
scratchDescriptorData.skipBytes(2);
}
} else {
// Unknown descriptor. Ignore.
}
scratchDescriptorData.setPosition(nextDescriptorPosition);
}
return new SeiReader(closedCaptionFormats);
}

4
library/src/main/java/com/google/android/exoplayer2/source/hls/HlsMediaChunk.java
View file

@ -356,6 +356,10 @@ import java.util.concurrent.atomic.AtomicInteger;
// This flag ensures the change of pid between streams does not affect the sample queues.
@DefaultTsPayloadReaderFactory.Flags
int esReaderFactoryFlags = DefaultTsPayloadReaderFactory.FLAG_IGNORE_SPLICE_INFO_STREAM;
if (!muxedCaptionFormats.isEmpty()) {
// The playlist declares closed caption renditions, we should ignore descriptors.
esReaderFactoryFlags |= DefaultTsPayloadReaderFactory.FLAG_OVERRIDE_CAPTION_DESCRIPTORS;
}
String codecs = trackFormat.codecs;
if (!TextUtils.isEmpty(codecs)) {
// Sometimes AAC and H264 streams are declared in TS chunks even though they don't really