Method and apparatus for receiving adaptive media streaming and adaptive media streaming system
Disclosed herein is a method for receiving adaptive media streaming. The method may include calculating segment download time for each video quality level based on network throughput, a segment bitrate for the video quality level, segment duration, and a standard deviation of segment bitrates, determining a segment bitrate for maximizing the quality of viewing experience of a user based on the segment download time for each video quality level and a buffer level received from a playback buffer, making a request for the determined segment bitrate, transferring the request to a server, and transferring a corresponding video segment received in response to the request to the playback buffer.
1. A method for receiving adaptive media streaming, comprising:
calculating segment download time for each video quality level based on network throughput, a segment bitrate for the video quality level, segment duration, and a standard deviation of segment bitrates;
determining a segment bitrate for maximizing quality of viewing experience of a user based on the segment download time for each video quality level and a buffer level received from a playback buffer and making a request for the segment bitrate; and
transferring the request to a server and transferring a corresponding video segment received in response to the request to the playback buffer,
wherein determining the segment bitrate for maximizing the quality of viewing experience of the user includes:
calculating rebuffering time using the segment download time for each video quality level and the buffer level received from the playback buffer;
calculating the quality of viewing experience of the user using the segment bitrate, a bitrate of a previously downloaded segment, and the rebuffering time; and
selecting the segment bitrate for maximizing the quality of viewing experience of the user.
2. The method of claim 1 , wherein the segment download time for each video quality level is calculated using Equation (1):
T
n
,
k
D
=
(
R
n
,
k
+
v
σ
)
·
T
n
S
C
n
(
1
)
where C n denotes the network throughput, R n,k denotes a k-th segment bitrate in an n-th segment index, v denotes a positive integer, σ denotes the standard deviation of the segment bitrates, and T n S denotes the segment duration.
3. The method of claim 2 , wherein the standard deviation of the segment bitrates is acquired from a Media Presentation Description (MPD) of the server.
4. The method of claim 2 , wherein the standard deviation of the segment bitrates is calculated based on a mean bitrate acquired by interpreting a Media Presentation Description (MPD) of the server.
5. The method of claim 4 , wherein the standard deviation of the segment bitrates is calculated using Equation (2):
σ
n
,
k
=
1
N
∑
n
=
1
N
(
R
n
,
k
-
R
k
)
2
(
2
)
where N denotes a number of downloaded segments, R k denotes a mean segment bitrate for a k-th video quality level, and R n,k denotes a segment bitrate for a k-th video quality level in an n-th segment index.
6. An apparatus for receiving adaptive media streaming, comprising:
memory in which a control program for receiving adaptive media streaming is stored; and
a processor for executing the control program stored in the memory,
wherein the processor calculates segment download time for each video quality level based on network throughput, a segment bitrate for the video quality level, segment duration, and a standard deviation of segment bitrates, determines a segment bitrate for maximizing quality of viewing experience of a user based on the segment download time for each video quality level and a buffer level received from a playback buffer, makes a request for the determined segment bitrate, transfers the request to a server, and transfers a corresponding video segment received in response to the request to the playback buffer, and
wherein the processor calculates rebuffering time using the segment download time for each video quality level and the buffer level received from the playback buffer, calculates the quality of viewing experience of the user using the segment bitrate, a bitrate of a previously downloaded segment, and the rebuffering time, and selects the segment bitrate for maximizing the quality of viewing experience of the user.
7. The apparatus of claim 6 , wherein the segment download time for each video quality level is calculated using Equation (1):
T
n
,
k
D
=
(
R
n
,
k
+
v
σ
)
·
T
n
S
C
n
(
1
)
where C n denotes the network throughput, R n,k denotes a segment bitrate of the k-th video quality level in the n-th segment index, v denotes a positive integer, σ denotes the standard deviation of the segment bitrates, and T n S denotes the segment duration.
8. The apparatus of claim 7 , wherein the standard deviation of the segment bitrates is acquired from a Media Presentation Description (MPD) of the server.
9. The apparatus of claim 7 , wherein the standard deviation of the segment bitrates is calculated based on a mean bitrate acquired by interpreting a Media Presentation Description (MPD) of the server.
10. The apparatus of claim 9 , wherein the standard deviation of the segment bitrates is calculated using Equation (2):
σ
n
,
k
=
1
N
∑
n
=
1
N
(
R
n
,
k
-
R
k
)
2
(
2
)
where N denotes a number of downloaded segments, R k denotes a mean segment bitrate for a k-th video quality level, and R n,k denotes the segment bitrate for a k-th video quality level in an n-th segment index.
11. An adaptive media streaming system, comprising:
a client including a network throughput predictor module for predicting network throughput, a bitrate control module for calculating segment download time for each video quality level based on the network throughput, a segment bitrate for the video quality level, segment duration, and a standard deviation of segment bitrates, determining a segment bitrate for maximizing quality of viewing experience of a user based on the segment download time for each video quality level and a buffer level received from a playback buffer, and making a request for the determined segment bitrate, and an HTTP module for transferring the request to a server; and
the server for transferring a corresponding video segment to the HTTP module in response to the request,
wherein the client calculates rebuffering time using the segment download time for each video quality level and the buffer level received from the playback buffer, calculates the quality of viewing experience of the user using the segment bitrate, a bitrate of a previously downloaded segment, and the rebuffering time, and selects the segment bitrate for maximizing the quality of viewing experience of the user.
12. The adaptive media streaming system of claim 11 , wherein the server stores video segments encoded in advance at different bitrates and a Media Presentation Description (MPD) in which segment-related information is described.
13. The adaptive media streaming system of claim 12 , wherein the MPD includes the standard deviation of the segment bitrates.
14. The adaptive media streaming system of claim 11 , wherein the segment download time for each video quality level is calculated using Equation (1):
T
n
,
k
D
=
(
R
n
,
k
+
v
σ
)
·
T
n
S
C
n
(
1
)
where C n denotes the network throughput, R n,k denotes a segment bitrate of the k-th video quality level in the n-th segment index, v denotes a positive integer, σ denotes the standard deviation of the segment bitrates, and T n S denotes the segment duration.
15. The adaptive media streaming system of claim 14 , wherein the standard deviation of the segment bitrates is calculated based on a mean bitrate acquired by interpreting a Media Presentation Description (MPD) of the server.
16. The adaptive media streaming system of claim 15 , wherein the standard deviation of the segment bitrates is calculated using Equation (2):
σ
n
,
k
=
1
N
∑
n
=
1
N
(
R
n
,
k
-
R
k
)
2
(
2
)
where N denotes a number of downloaded segments, R k denotes a mean segment bitrate for a k-th video quality level, and R n,k denotes the segment bitrate for a k-th video quality level in an n-th segment index.