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Support implicit i-Frame initialization segment.

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In the HLS Spec (https://tools.ietf.org/html/draft-pantos-hls-rfc8216bis-04#section-4.4.3.6), specifically this or condition of this statement:

"... defined by the EXT-X-MAP tag, or is located between the start of the resource
    and the offset of the first I-frame segment in that resource."

Change adds code to add this "implicit" Media Initialization Segment if no EXT-X-MAP defines one explicitly.
This commit is contained in:
Steve Mayhew 2020-03-17 13:56:00 -07:00
parent 64cd4383ad
commit 1f11233ba0
1 changed files with 34 additions and 2 deletions
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36
library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsPlaylistParser.java
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@ -70,6 +70,7 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
private static final String TAG_DEFINE = "#EXT-X-DEFINE";
private static final String TAG_STREAM_INF = "#EXT-X-STREAM-INF";
private static final String TAG_STREAM_IFRAME = "#EXT-X-I-FRAME-STREAM-INF";
private static final String TAG_IFRAME = "#EXT-X-I-FRAMES-ONLY";
private static final String TAG_MEDIA = "#EXT-X-MEDIA";
private static final String TAG_TARGET_DURATION = "#EXT-X-TARGETDURATION";
private static final String TAG_DISCONTINUITY = "#EXT-X-DISCONTINUITY";
@ -560,7 +561,7 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
long targetDurationUs = C.TIME_UNSET;
boolean hasIndependentSegmentsTag = masterPlaylist.hasIndependentSegments;
boolean hasEndTag = false;
Segment initializationSegment = null;
@Nullable Segment initializationSegment = null;
HashMap<String, String> variableDefinitions = new HashMap<>();
List<Segment> segments = new ArrayList<>();
List<String> tags = new ArrayList<>();
@ -574,6 +575,9 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
long segmentStartTimeUs = 0;
long segmentByteRangeOffset = 0;
long segmentByteRangeLength = C.LENGTH_UNSET;
boolean isExplicitInitSegment = false; // Was declared (TAG_INIT_SEGMENT) vs implied.
boolean isIframeOnly = false;
long segmentMediaSequence = 0;
boolean hasGapTag = false;
@ -625,6 +629,7 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
segmentByteRangeLength,
fullSegmentEncryptionKeyUri,
fullSegmentEncryptionIV);
isExplicitInitSegment = false;
segmentByteRangeOffset = 0;
segmentByteRangeLength = C.LENGTH_UNSET;
} else if (line.startsWith(TAG_TARGET_DURATION)) {
@ -706,6 +711,8 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
hasIndependentSegmentsTag = true;
} else if (line.equals(TAG_ENDLIST)) {
hasEndTag = true;
} else if (line.equals(TAG_IFRAME)) {
isIframeOnly = true;
} else if (!line.startsWith("#")) {
String segmentEncryptionIV;
if (fullSegmentEncryptionKeyUri == null) {
@ -716,9 +723,34 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
segmentEncryptionIV = Long.toHexString(segmentMediaSequence);
}
String segmentResourseUri = replaceVariableReferences(line, variableDefinitions);
segmentMediaSequence++;
if (segmentByteRangeLength == C.LENGTH_UNSET) {
segmentByteRangeOffset = 0;
} else if (isIframeOnly) {
// If the I-Frame segment is byte-ranged then check if there is an initialization segment, if not,
// per the spec (https://tools.ietf.org/html/draft-pantos-hls-rfc8216bis-04#section-4.4.3.6)
// it is assumed to be "located between the start of the resource and the offset of the
// first I-frame segment"
// Wipe previous implict init segment if base resource URI changes
if (isExplicitInitSegment && initializationSegment != null) {
if (! segmentResourseUri.equals(initializationSegment.url)) {
initializationSegment = null;
}
}
if (initializationSegment == null) {
isExplicitInitSegment = true;
initializationSegment = new Segment(
segmentResourseUri,
0,
segmentByteRangeOffset - 1,
null, // TODO encryption same as segment?
null
);
}
}
if (cachedDrmInitData == null && !currentSchemeDatas.isEmpty()) {
@ -735,7 +767,7 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
segments.add(
new Segment(
replaceVariableReferences(line, variableDefinitions),
segmentResourseUri,
initializationSegment,
segmentTitle,
segmentDurationUs,