[Question] SendingBufferProfile details about pldroidmediastreaming HOT 4 CLOSED

SendingBuffer is the buffer queue which storing the frame for the adaptive bit-rate.

SendingBufferProfile is the profile for SendingBuffer. There are some thresholds as following:

public static final float LOW_THRESHOLD_MIN = 0;
public static final float LOW_THRESHOLD_MAX = 1.0f;
public static final float LOW_THRESHOLD_DEFAULT = 0.2f;

public static final float HIGH_THRESHOLD_MIN = 0;
public static final float HIGH_THRESHOLD_MAX = 1.0f;
public static final float HIGH_THRESHOLD_DEFAULT = 0.8f;

public static final float DURATION_LIMIT_MIN = HIGH_THRESHOLD_MAX + 0.1f;
public static final float DURATION_LIMIT_MAX = 5.0f;
public static final float DURATION_LIMIT_DEFAULT = 3.0f;

public static final long LOW_THRESHOLD_TIMEOUT_MIN     = 10 * 1000; // ms
public static final long DEFAULT_LOW_THRESHOLD_TIMEOUT = 60 * 1000; // ms

// [LOW_THRESHOLD_MIN, LOW_THRESHOLD_MAX] && [LOW_THRESHOLD_MIN, high - 0.1)
private float mLowThreshold;

// [HIGH_THRESHOLD_MIN, HIGH_THRESHOLD_MAX] && (low + 0.1, HIGH_THRESHOLD_MAX]
private float mHighThreshold;

// [DURATION_LIMIT_MIN, DURATION_LIMIT_MAX]
private float mDurationLimit;

// [LOW_THRESHOLD_TIMEOUT_MIN, Long.MAX_VALUE)
// To measure the low buffering case
private long mLowThresholdTimeout;

SendingBuffer have some related states:
STATE.SENDING_BUFFER_EMPTY
STATE.SENDING_BUFFER_FULL // means the sending buffer is full and some frames will be removed tactically

STATE.SENDING_BUFFER_HAS_FEW_ITEMS // means the network is in good condition as few buffers to be sent out. mLowThreshold is the threshold for this.
STATE.SENDING_BUFFER_HAS_MANY_ITEMS // means the network is in bad condition as many buffers to be send out. mHighThreshold is the threshold for this.

mLowThresholdTimeout: if the network switch to good from bad , it needs mLowThresholdTimeout to wait . It's difficult to change to good except the network is really in good condition.

Hope this helps!

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What does DURATION_LIMIT_MIN control?
Also what exactly does the value mLowThreshold and mHighThreshold indicate? How do we know what value should be set? Does it indicate the number of items in the buffer or size of buffer etc?

By the way, thanks for the info. This also brings me to the 2nd question. Assume we have a stable internet connection at 1mbps. Assume all SendingBufferProfile settings at default and mLowThresholdTimeout at 10s. Now looking at the code below

case CameraStreamingManager.STATE.SENDING_BUFFER_HAS_FEW_ITEMS:
mProfile.improveVideoQuality(1);
mCameraStreamingManager.notifyProfileChanged(mProfile);
return true;
case CameraStreamingManager.STATE.SENDING_BUFFER_HAS_MANY_ITEMS:
mProfile.reduceVideoQuality(1);
mCameraStreamingManager.notifyProfileChanged(mProfile);
return true;

Suppose with start at Quality MEDIUM 1 (30fps, 500kbps). After 10 secs SENDING_BUFFER_HAS_FEW_ITEMS will be called and quality will be improved to MEDIUM_2. After 10 secs again SENDING_BUFFER_HAS_MANY_ITEMS will be called and so on..

And if the internet speed is very very good (eg 10mbps) then SENDING_BUFFER_HAS_FEW_ITEMS will be called over and over again.

What are your suggestions as to what should the upper limit and lower limit for changing quality be, assuming we start at Medium_1.

For example, if we start at MEDIUM_1, should be go to a maximum of HIGH_1 and minimum of LOW_1. Or do you think it does not matter how high or low we go, depending on the internet speed.

from pldroidmediastreaming.

mDurationLimit can be only between DURATION_LIMIT_MIN and DURATION_LIMIT_MAX. That's what exactly this means:

// [DURATION_LIMIT_MIN, DURATION_LIMIT_MAX]
private float mDurationLimit;

mLowThreshold and mHighThreshold are the thresholds to trigger the STATE.SENDING_BUFFER_HAS_FEW_ITEMS and STATE.SENDING_BUFFER_HAS_MANY_ITEMS. Let me take an example, if you set mLowThreshold to 0.2 and mHighThreshold to 0.8, and

1. BufferQueue remained <= 0.2 buffers, STATE.SENDING_BUFFER_HAS_FEW_ITEMS triggered
2. BufferQueue remained >= 0.8 buffers, STATE.SENDING_BUFFER_HAS_MANY_ITEMS triggered

Thus, mDurationLimit is useful to restrict the STATE.SENDING_BUFFER_HAS_FEW_ITEMS triggered. That means,

Only if BufferQueue remained <= 0.2 buffers with mDurationLimit, the STATE.SENDING_BUFFER_HAS_FEW_ITEMS triggered.

Your second question:

We have the algorithm to avoid the quality being changed all the time in stable network condition. To be honest, the algorithm need to be improved. We trust we will do the best thing.

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Thanks, very helpful

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