Merge "HLS: temporarily blacklist a variant if failed to fetch" into mnc-dev
diff --git a/media/libstagefright/httplive/LiveSession.cpp b/media/libstagefright/httplive/LiveSession.cpp
index 27509cb..2fc5135 100644
--- a/media/libstagefright/httplive/LiveSession.cpp
+++ b/media/libstagefright/httplive/LiveSession.cpp
@@ -58,15 +58,21 @@
BandwidthEstimator();
void addBandwidthMeasurement(size_t numBytes, int64_t delayUs);
- bool estimateBandwidth(int32_t *bandwidth, bool *isStable = NULL);
+ bool estimateBandwidth(
+ int32_t *bandwidth,
+ bool *isStable = NULL,
+ int32_t *shortTermBps = NULL);
private:
// Bandwidth estimation parameters
+ static const int32_t kShortTermBandwidthItems = 3;
static const int32_t kMinBandwidthHistoryItems = 20;
static const int64_t kMinBandwidthHistoryWindowUs = 5000000ll; // 5 sec
static const int64_t kMaxBandwidthHistoryWindowUs = 30000000ll; // 30 sec
+ static const int64_t kMaxBandwidthHistoryAgeUs = 60000000ll; // 60 sec
struct BandwidthEntry {
+ int64_t mTimestampUs;
int64_t mDelayUs;
size_t mNumBytes;
};
@@ -74,6 +80,7 @@
Mutex mLock;
List<BandwidthEntry> mBandwidthHistory;
List<int32_t> mPrevEstimates;
+ int32_t mShortTermEstimate;
bool mHasNewSample;
bool mIsStable;
int64_t mTotalTransferTimeUs;
@@ -83,6 +90,7 @@
};
LiveSession::BandwidthEstimator::BandwidthEstimator() :
+ mShortTermEstimate(0),
mHasNewSample(false),
mIsStable(true),
mTotalTransferTimeUs(0),
@@ -93,7 +101,9 @@
size_t numBytes, int64_t delayUs) {
AutoMutex autoLock(mLock);
+ int64_t nowUs = ALooper::GetNowUs();
BandwidthEntry entry;
+ entry.mTimestampUs = nowUs;
entry.mDelayUs = delayUs;
entry.mNumBytes = numBytes;
mTotalTransferTimeUs += delayUs;
@@ -115,7 +125,10 @@
// and total transfer time at least kMaxBandwidthHistoryWindowUs.
while (mBandwidthHistory.size() > kMinBandwidthHistoryItems) {
List<BandwidthEntry>::iterator it = mBandwidthHistory.begin();
- if (mTotalTransferTimeUs - it->mDelayUs < bandwidthHistoryWindowUs) {
+ // remove sample if either absolute age or total transfer time is
+ // over kMaxBandwidthHistoryWindowUs
+ if (nowUs - it->mTimestampUs < kMaxBandwidthHistoryAgeUs &&
+ mTotalTransferTimeUs - it->mDelayUs < bandwidthHistoryWindowUs) {
break;
}
mTotalTransferTimeUs -= it->mDelayUs;
@@ -125,7 +138,7 @@
}
bool LiveSession::BandwidthEstimator::estimateBandwidth(
- int32_t *bandwidthBps, bool *isStable) {
+ int32_t *bandwidthBps, bool *isStable, int32_t *shortTermBps) {
AutoMutex autoLock(mLock);
if (mBandwidthHistory.size() < 2) {
@@ -137,6 +150,9 @@
if (isStable) {
*isStable = mIsStable;
}
+ if (shortTermBps) {
+ *shortTermBps = mShortTermEstimate;
+ }
return true;
}
@@ -147,6 +163,21 @@
}
mHasNewSample = false;
+ int64_t totalTimeUs = 0;
+ size_t totalBytes = 0;
+ if (mBandwidthHistory.size() >= kShortTermBandwidthItems) {
+ List<BandwidthEntry>::iterator it = --mBandwidthHistory.end();
+ for (size_t i = 0; i < kShortTermBandwidthItems; i++, it--) {
+ totalTimeUs += it->mDelayUs;
+ totalBytes += it->mNumBytes;
+ }
+ }
+ mShortTermEstimate = totalTimeUs > 0 ?
+ (totalBytes * 8E6 / totalTimeUs) : *bandwidthBps;
+ if (shortTermBps) {
+ *shortTermBps = mShortTermEstimate;
+ }
+
int32_t minEstimate = -1, maxEstimate = -1;
List<int32_t>::iterator it;
for (it = mPrevEstimates.begin(); it != mPrevEstimates.end(); it++) {
@@ -158,10 +189,14 @@
maxEstimate = estimate;
}
}
- mIsStable = (maxEstimate <= minEstimate * 4 / 3);
+ // consider it stable if long-term average is not jumping a lot
+ // and short-term average is not much lower than long-term average
+ mIsStable = (maxEstimate <= minEstimate * 4 / 3)
+ && mShortTermEstimate > minEstimate * 7 / 10;
if (isStable) {
- *isStable = mIsStable;
+ *isStable = mIsStable;
}
+
#if 0
{
char dumpStr[1024] = {0};
@@ -251,6 +286,7 @@
mCurBandwidthIndex(-1),
mOrigBandwidthIndex(-1),
mLastBandwidthBps(-1ll),
+ mLastBandwidthStable(false),
mBandwidthEstimator(new BandwidthEstimator()),
mMaxWidth(720),
mMaxHeight(480),
@@ -713,6 +749,20 @@
}
}
+ // remember the failure index (as mCurBandwidthIndex will be restored
+ // after cancelBandwidthSwitch()), and record last fail time
+ size_t failureIndex = mCurBandwidthIndex;
+ mBandwidthItems.editItemAt(
+ failureIndex).mLastFailureUs = ALooper::GetNowUs();
+
+ if (mSwitchInProgress) {
+ // if error happened when we switch to a variant, try fallback
+ // to other variant to save the session
+ if (tryBandwidthFallback()) {
+ break;
+ }
+ }
+
if (mInPreparationPhase) {
postPrepared(err);
}
@@ -887,6 +937,13 @@
}
// static
+bool LiveSession::isBandwidthValid(const BandwidthItem &item) {
+ static const int64_t kBlacklistWindowUs = 300 * 1000000ll;
+ return item.mLastFailureUs < 0
+ || ALooper::GetNowUs() - item.mLastFailureUs > kBlacklistWindowUs;
+}
+
+// static
int LiveSession::SortByBandwidth(const BandwidthItem *a, const BandwidthItem *b) {
if (a->mBandwidth < b->mBandwidth) {
return -1;
@@ -986,6 +1043,7 @@
BandwidthItem item;
item.mPlaylistIndex = i;
+ item.mLastFailureUs = -1ll;
sp<AMessage> meta;
AString uri;
@@ -1223,6 +1281,13 @@
X/T < bw1 / (bw1 + bw0 - bw)
*/
+ // abort old bandwidth immediately if bandwidth is fluctuating a lot.
+ // our estimate could be far off, and fetching old bandwidth could
+ // take too long.
+ if (!mLastBandwidthStable) {
+ return 0.0f;
+ }
+
// Taking the measured current bandwidth at 50% face value only,
// as our bandwidth estimation is a lagging indicator. Being
// conservative on this, we prefer switching to lower bandwidth
@@ -1250,6 +1315,16 @@
mBandwidthEstimator->addBandwidthMeasurement(numBytes, delayUs);
}
+ssize_t LiveSession::getLowestValidBandwidthIndex() const {
+ for (size_t index = 0; index < mBandwidthItems.size(); index++) {
+ if (isBandwidthValid(mBandwidthItems[index])) {
+ return index;
+ }
+ }
+ // if playlists are all blacklisted, return 0 and hope it's alive
+ return 0;
+}
+
size_t LiveSession::getBandwidthIndex(int32_t bandwidthBps) {
if (mBandwidthItems.size() < 2) {
// shouldn't be here if we only have 1 bandwidth, check
@@ -1284,14 +1359,18 @@
}
}
- // Pick the highest bandwidth stream below or equal to estimated bandwidth.
+ // Pick the highest bandwidth stream that's not currently blacklisted
+ // below or equal to estimated bandwidth.
index = mBandwidthItems.size() - 1;
- while (index > 0) {
+ ssize_t lowestBandwidth = getLowestValidBandwidthIndex();
+ while (index > lowestBandwidth) {
// be conservative (70%) to avoid overestimating and immediately
// switching down again.
size_t adjustedBandwidthBps = bandwidthBps * 7 / 10;
- if (mBandwidthItems.itemAt(index).mBandwidth <= adjustedBandwidthBps) {
+ const BandwidthItem &item = mBandwidthItems[index];
+ if (item.mBandwidth <= adjustedBandwidthBps
+ && isBandwidthValid(item)) {
break;
}
--index;
@@ -2172,21 +2251,57 @@
notify->post();
}
+bool LiveSession::tryBandwidthFallback() {
+ if (mInPreparationPhase || mReconfigurationInProgress) {
+ // Don't try fallback during prepare or reconfig.
+ // If error happens there, it's likely unrecoverable.
+ return false;
+ }
+ if (mCurBandwidthIndex > mOrigBandwidthIndex) {
+ // if we're switching up, simply cancel and resume old variant
+ cancelBandwidthSwitch(true /* resume */);
+ return true;
+ } else {
+ // if we're switching down, we're likely about to underflow (if
+ // not already underflowing). try the lowest viable bandwidth if
+ // not on that variant already.
+ ssize_t lowestValid = getLowestValidBandwidthIndex();
+ if (mCurBandwidthIndex > lowestValid) {
+ cancelBandwidthSwitch();
+ changeConfiguration(-1ll, lowestValid);
+ return true;
+ }
+ }
+ // return false if we couldn't find any fallback
+ return false;
+}
+
/*
* returns true if a bandwidth switch is actually needed (and started),
* returns false otherwise
*/
bool LiveSession::switchBandwidthIfNeeded(bool bufferHigh, bool bufferLow) {
// no need to check bandwidth if we only have 1 bandwidth settings
- if (mSwitchInProgress || mBandwidthItems.size() < 2) {
+ if (mBandwidthItems.size() < 2) {
return false;
}
- int32_t bandwidthBps;
+ if (mSwitchInProgress) {
+ if (mBuffering) {
+ tryBandwidthFallback();
+ }
+ return false;
+ }
+
+ int32_t bandwidthBps, shortTermBps;
bool isStable;
- if (mBandwidthEstimator->estimateBandwidth(&bandwidthBps, &isStable)) {
- ALOGV("bandwidth estimated at %.2f kbps", bandwidthBps / 1024.0f);
+ if (mBandwidthEstimator->estimateBandwidth(
+ &bandwidthBps, &isStable, &shortTermBps)) {
+ ALOGV("bandwidth estimated at %.2f kbps, "
+ "stable %d, shortTermBps %.2f kbps",
+ bandwidthBps / 1024.0f, isStable, shortTermBps / 1024.0f);
mLastBandwidthBps = bandwidthBps;
+ mLastBandwidthStable = isStable;
} else {
ALOGV("no bandwidth estimate.");
return false;
@@ -2203,9 +2318,13 @@
if (canSwitchDown || canSwitchUp) {
// bandwidth estimating has some delay, if we have to downswitch when
- // it hasn't stabilized, be very conservative on bandwidth.
+ // it hasn't stabilized, use the short term to guess real bandwidth,
+ // since it may be dropping too fast.
+ // (note this doesn't apply to upswitch, always use longer average there)
if (!isStable && canSwitchDown) {
- bandwidthBps /= 2;
+ if (shortTermBps < bandwidthBps) {
+ bandwidthBps = shortTermBps;
+ }
}
ssize_t bandwidthIndex = getBandwidthIndex(bandwidthBps);
diff --git a/media/libstagefright/httplive/LiveSession.h b/media/libstagefright/httplive/LiveSession.h
index 21be413..90d56d0 100644
--- a/media/libstagefright/httplive/LiveSession.h
+++ b/media/libstagefright/httplive/LiveSession.h
@@ -146,6 +146,7 @@
struct BandwidthItem {
size_t mPlaylistIndex;
unsigned long mBandwidth;
+ int64_t mLastFailureUs;
};
struct FetcherInfo {
@@ -199,6 +200,7 @@
ssize_t mCurBandwidthIndex;
ssize_t mOrigBandwidthIndex;
int32_t mLastBandwidthBps;
+ bool mLastBandwidthStable;
sp<BandwidthEstimator> mBandwidthEstimator;
sp<M3UParser> mPlaylist;
@@ -268,8 +270,10 @@
ssize_t currentBWIndex, ssize_t targetBWIndex) const;
void addBandwidthMeasurement(size_t numBytes, int64_t delayUs);
size_t getBandwidthIndex(int32_t bandwidthBps);
+ ssize_t getLowestValidBandwidthIndex() const;
HLSTime latestMediaSegmentStartTime() const;
+ static bool isBandwidthValid(const BandwidthItem &item);
static int SortByBandwidth(const BandwidthItem *, const BandwidthItem *);
static StreamType indexToType(int idx);
static ssize_t typeToIndex(int32_t type);
@@ -287,6 +291,7 @@
sp<AMessage> &msg, int64_t delayUs, bool *needResumeUntil);
bool switchBandwidthIfNeeded(bool bufferHigh, bool bufferLow);
+ bool tryBandwidthFallback();
void schedulePollBuffering();
void cancelPollBuffering();
diff --git a/media/libstagefright/httplive/PlaylistFetcher.cpp b/media/libstagefright/httplive/PlaylistFetcher.cpp
index 4851528..72d832e 100644
--- a/media/libstagefright/httplive/PlaylistFetcher.cpp
+++ b/media/libstagefright/httplive/PlaylistFetcher.cpp
@@ -511,6 +511,13 @@
msg->post();
}
+/*
+ * pauseAsync
+ *
+ * threshold: 0.0f - pause after current fetch block (default 47Kbytes)
+ * -1.0f - pause after finishing current segment
+ * 0.0~1.0f - pause if remaining of current segment exceeds threshold
+ */
void PlaylistFetcher::pauseAsync(
float thresholdRatio, bool disconnect) {
setStoppingThreshold(thresholdRatio, disconnect);