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Enforce sliding window of available segments for DASH DVB.

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This commit is contained in:
Oliver Woodman 2014-12-15 15:03:10 +00:00
parent 978a4d857a
commit 595147de9b
1 changed files with 32 additions and 16 deletions
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48
library/src/main/java/com/google/android/exoplayer/dash/DashChunkSource.java
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@ -326,13 +326,30 @@ public class DashChunkSource implements ChunkSource {
return;
}
int lastSegmentNum = segmentIndex.getLastSegmentNum();
boolean indexUnbounded = lastSegmentNum == DashSegmentIndex.INDEX_UNBOUNDED;
// TODO: Use UtcTimingElement where possible.
long nowUs = System.currentTimeMillis() * 1000;
int firstAvailableSegmentNum = segmentIndex.getFirstSegmentNum();
int lastAvailableSegmentNum = segmentIndex.getLastSegmentNum();
boolean indexUnbounded = lastAvailableSegmentNum == DashSegmentIndex.INDEX_UNBOUNDED;
if (indexUnbounded) {
// The index is itself unbounded. We need to use the current time to calculate the range of
// available segments.
long liveEdgeTimestampUs = nowUs - currentManifest.availabilityStartTime * 1000;
if (currentManifest.timeShiftBufferDepth != -1) {
long bufferDepthUs = currentManifest.timeShiftBufferDepth * 1000;
firstAvailableSegmentNum = Math.max(firstAvailableSegmentNum,
segmentIndex.getSegmentNum(liveEdgeTimestampUs - bufferDepthUs));
}
// getSegmentNum(liveEdgeTimestampUs) will not be completed yet, so subtract one to get the
// index of the last completed segment.
lastAvailableSegmentNum = segmentIndex.getSegmentNum(liveEdgeTimestampUs) - 1;
}
int segmentNum;
if (queue.isEmpty()) {
if (currentManifest.dynamic) {
seekPositionUs = getLiveSeekPosition(indexUnbounded);
seekPositionUs = getLiveSeekPosition(nowUs, indexUnbounded);
}
segmentNum = segmentIndex.getSegmentNum(seekPositionUs);
} else {
@ -340,20 +357,20 @@ public class DashChunkSource implements ChunkSource {
- representationHolder.segmentNumShift;
}
// TODO: For unbounded manifests, we need to enforce that we don't try and request chunks
// behind or in front of the live window.
if (currentManifest.dynamic) {
if (segmentNum < segmentIndex.getFirstSegmentNum()) {
if (segmentNum < firstAvailableSegmentNum) {
// This is before the first chunk in the current manifest.
fatalError = new BehindLiveWindowException();
return;
} else if (!indexUnbounded && segmentNum > lastSegmentNum) {
// This is beyond the last chunk in the current manifest.
finishedCurrentManifest = true;
} else if (segmentNum > lastAvailableSegmentNum) {
// This chunk is beyond the last chunk in the current manifest. If the index is bounded
// we'll need to refresh it. If it's unbounded we just need to wait for a while before
// attempting to load the chunk.
finishedCurrentManifest = !indexUnbounded;
return;
} else if (!indexUnbounded && segmentNum == lastSegmentNum) {
// This is the last chunk in the current manifest. Mark the manifest as being finished,
// but continue to return the final chunk.
} else if (!indexUnbounded && segmentNum == lastAvailableSegmentNum) {
// This is the last chunk in a dynamic bounded manifest. We'll need to refresh the manifest
// to obtain the next chunk.
finishedCurrentManifest = true;
}
}
@ -457,15 +474,14 @@ public class DashChunkSource implements ChunkSource {
* For live playbacks, determines the seek position that snaps playback to be
* {@link #liveEdgeLatencyUs} behind the live edge of the current manifest
*
* @param nowUs An estimate of the current server time, in microseconds.
* @param indexUnbounded True if the segment index for this source is unbounded. False otherwise.
* @return The seek position in microseconds.
*/
private long getLiveSeekPosition(boolean indexUnbounded) {
private long getLiveSeekPosition(long nowUs, boolean indexUnbounded) {
long liveEdgeTimestampUs;
if (indexUnbounded) {
// TODO: Use UtcTimingElement where possible.
long nowMs = System.currentTimeMillis();
liveEdgeTimestampUs = (nowMs - currentManifest.availabilityStartTime) * 1000;
liveEdgeTimestampUs = nowUs - currentManifest.availabilityStartTime * 1000;
} else {
liveEdgeTimestampUs = Long.MIN_VALUE;
for (RepresentationHolder representationHolder : representationHolders.values()) {