CN102546716A - Buffer management method, device and streaming media on-demand system - Google Patents

Abstract

The invention discloses a buffer management method, which comprises the following steps of: A, dividing each media file into more than two file sections; and B, determining a priority value of each file section according to broadcasting popularity, and storing M file sections with the greatest priority values into a buffer of a proxy server, wherein M is a positive integer. The invention also discloses a buffer management device and a streaming media on-demand system. By the method, the device and the system, the cache hit rate can be increased.

Description

A kind of buffer queue management method, device and demand stream media system

Technical field

The present invention relates to the streaming media on demand technology, particularly a kind of buffer queue management method, device and demand stream media system.

Background technology

At present; Exist a large amount of demand stream media systems on the market; Usually all can be provided with jumbo buffer area (being positioned on the acting server) in these demand stream media systems; And with the hot broadcast media file, i.e. the higher media file of user capture (promptly watching) rate leaves in the buffer area, so that respond user's access request fast.Fig. 1 is the existing buffer area sketch map of depositing the hot broadcast media file.

In case buffer memory does not hit; Be that the media file that the user asks to visit does not leave in the buffer area, then need go to read this media file in the hard disk of video server, can reduce the overall performance of system so undoubtedly; And can increase user's wait duration, reduce user experience.

Summary of the invention

In view of this, main purpose of the present invention is to provide a kind of buffer queue management method, can improve cache hit rate.

Another object of the present invention is to provide a kind of buffer queue management device, can improve cache hit rate.

A purpose more of the present invention is to provide a kind of demand stream media system, can improve cache hit rate.

For achieving the above object, technical scheme of the present invention is achieved in that

A kind of buffer queue management method comprises:

A, to each media file, respectively it is divided into two above file sections;

B, according to the hot broadcast degree, confirm the preferred value of each file section respectively, the file section of M position was stored in the buffer area of acting server before preferred value was in, M is a positive integer.

A kind of buffer queue management device comprises:

First processing unit is used for respectively it being divided into two above file sections to each media file;

Second processing unit is used for according to the hot broadcast degree, confirms the preferred value of each file section respectively, and the file section of M position was stored in the buffer area of acting server before preferred value was in, and M is a positive integer.

A kind of demand stream media system comprises said apparatus.

It is thus clear that, adopt technical scheme of the present invention, each media file is divided into a plurality of file sections, and the hot broadcast file section is left in the buffer area, thereby improved cache hit rate, and then improved the overall performance and the user experience of system.

Description of drawings

Fig. 1 is the existing buffer area sketch map of depositing the hot broadcast media file.

Fig. 2 is the flow chart of buffer queue management method embodiment of the present invention.

Fig. 3 is the composition structural representation of buffer queue management device embodiment of the present invention.

Embodiment

To the problem that exists in the prior art, the buffer queue management scheme among the present invention after a kind of improvement of proposition can improve cache hit rate.

For make technical scheme of the present invention clearer, understand, below with reference to the accompanying drawing embodiment that develops simultaneously, scheme according to the invention is done to specify further.

Fig. 2 is the flow chart of buffer queue management method embodiment of the present invention.As shown in Figure 2, may further comprise the steps:

Step 21:, respectively it is divided into two above file sections to each media file.

In this step, can each media file be divided into two above file sections respectively according to the mode that duration increases progressively.Because for the user, when its program request behind a certain media file, can at first watch the beginning part of this media file usually, if feel plain; Then withdraw from and watch,, then continue to watch if feel good-looking; And the time that the user watches is long more, explains that the complete possibility of finishing watching this media file of user is big more, therefore; When each media file is divided, the mode that can increase progressively according to duration, thus improve cache hit rate better.

In addition; System can be each file section and each media file is safeguarded an access log respectively; Be used to write down each file section respectively when by the visit and each media file (arbitrary file section is wherein visited, and thinks that then this media file is visited) respectively when by the visit etc.

Specifically, to each media file, confirm that at first respectively its corresponding segmentation factor-alpha and section sequence number are 1 file section, the duration L of promptly first section (or being called base segment), α are less than or equal to 1 positive number, and promptly the span of α is 0＜α≤1; Afterwards, be the 1+ α mode doubly of the duration of last file section according to the duration of back one file section, each media file is divided into two above file sections respectively.

Promptly have:

the n section of expression sequence number.

Distinguishingly; Latter two file section for each media file; Possibly can't satisfy the above-mentioned relation formula, promptly divide after the second-to-last file section, remaining duration is with 1+ α times of the duration of not enough second-to-last file section; In this case, can be directly with remaining duration as last 1 file section.

First section duration L of each media file can be identical also can be different, the concrete value of L can be decided according to the actual requirements.

Below be example with arbitrary media file i, the concrete value of α is done explanation further.

If R _i≤B _S-p, then

If R _i＞B _S-p, then

B _S-pThe bandwidth of expression from the video server to the acting server, R _iThe code check of presentation medium file i (code check of each media file all is known), Popularity _iThe popularity of presentation medium file i, ASL _iThe average length of session of presentation medium file i, f () representes any predetermined formula, as long as satisfy α and the Popularity that finally calculates _iBe inversely proportional to, with ASL _iBe directly proportional and get final product.

In addition, above-mentioned Popularity _iAnd ASL _iCalculating relate to following parameter:

1) T0: predetermined start constantly;

2) Ti1: the moment that media file i is at first visited;

3) Tr: current time;

4) Ti:Max{T0, Ti1}, promptly among T0 and the Ti1 more near of Tr;

5) N: the number of times that media file i is visited in this time period from Tr to T0;

Visit duration when 6) the j time quilt of

media file i visited;

Correspondingly, $\mathrm{Popularit}{y}_i=\frac{N}{T_r-T_i};---\left(3\right)$

${\mathrm{ASL}}_i=\frac{\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{Session}}_i^j}{N}.---\left(4\right)$

In the scheme according to the invention, can periodically confirm the value of α, promptly every at a distance from scheduled duration, like 1 week, promptly each media file is carried out a file section again and divide, so that improve cache hit rate better.Suppose that on Monday weekly 0: 0: 0 repartitions each media file; So above-mentioned T0 then can be meant 0: 0: 0 of Monday in last week; If media file i joins in the system in a certain moment before 0: 0: 0 of the Monday in last week; Its corresponding Ti1 may be less than T0 so, if after join in the system, its corresponding Ti1 is then necessarily greater than T0.

Step 22: according to the hot broadcast degree, confirm the preferred value of each file section respectively, the file section of M position was stored in the buffer area of acting server before preferred value was in, and M is a positive integer.

Promptly each file section is sorted, the file section that is in preceding M position after the ordering is stored in the buffer area of acting server according to the descending order of preferred value.

Leave entire media file in the buffering area mode than existing, only the hot broadcast file section is left in the buffer area in the mode according to the invention, thereby improved cache hit rate.

Follow-up; When the user asks to visit a file section z who is not stored in the buffer area; Can confirm file section z and the preferred value that leaves each file section in the buffer area in again; And when the file section that exists preferred value to be lower than file section z in the buffer area and do not visited the time, with file section z replace that said preferred value is lower than file section z and the file section of not visited in a file section, this file section that is replaced is generally the minimum file section of preferred value in the file section of not visited.

In the present embodiment,, can calculate its preferred value respectively in such a way to each file section x:

Calculate $\mathrm{Priori}{\mathrm{Ty}}_o^x=\mathrm{Object}\_\mathrm{Priority}+\mathrm{Segment}\_\mathrm{Priority}+\mathrm{Position}\_\mathrm{Priority};---\left(5\right)$

The preferred value of

expression file section x; The number of times that media file was visited under the file section x in Object_Priority represented from current time to this time period in the predetermined start moment before; Segment_Priority representes from the current time to the division, to obtain the number of times that file section x is visited in this time period in the moment of file section x; Position_Priority is relevant with the section sequence number of file section x; The section sequence number is more near 1, and the value of Position_Priority is big more.

Suppose that on Monday weekly 0: 0: 0 repartitions each media file, and hypothesis T0 is 0: 0: 0 of Monday in last week, though step 22 is carried out after step 21; But during time of differing can ignore, so, in the step 22 when calculating formula (5); The represented implication of Object_Priority wherein and value all with step 21 in N identical, in addition, the value of Segment_Priority will be 0; And after the user asks to visit a file section z who is not stored in the buffer area; When needs calculating formula (5), because " current time " change than step 22, so the represented implication of Object_Priority will be different with the N in the step 21; Value also maybe be different, and the value of Segment_Priority possibly no longer be 0 also.

In addition; In the step 22, can in buffer area, reserve certain space, promptly buffer area not taken fully; Main like this is to consider when follow-up to replace a certain file section in the buffer area with file section z; When being assumed to be file section m, if the size of file section z, may cause not having enough spaces to come the problem of store files section z so greater than file section m.

From step 22 beginning,, return execution in step 21 when through after the scheduled duration.

Have again, in practical application, if can not carry out the distribution of continuous uninterrupted Media Stream to the user; Shake will appear playing, such as, user capture is intact leave a certain file section in the buffer area in after; Request continues to visit next file section that belongs to same media file with this document section; And next file section does not leave in the buffer area, so then need from hard disk, read, thereby cause the Media Stream distribution to occur being interrupted.

To this problem, a kind of prefetch mechanisms has been proposed in the scheme according to the invention, the concrete realization comprises:

When the arbitrary file section y in the user capture buffer area, confirm whether next file section that belongs to same media file with file section y leaves in the buffer area, if then do not deal with; If not, then confirm the preferred value of each file section in the buffer area again, and look ahead opportunity what determine, use next file section that belongs to same media file with file section y to replace the file section that preferred value in the buffer area is minimum and do not visited.

The section sequence number of supposing file section y is n, Seg _N+1Expression is the file section of n+1 with the section sequence number that file section y belongs to same media file, i.e. the duration of next file section, and so, next file section is sent to the required time T of acting server from video server _S-p=Seg _N+1/ B _S-pX in total duration of hypothesis media file under arriving file section y is during the moment again, next file section of looking ahead, and X must satisfy so:

$\frac{\underset{k=1}{\overset{k=n}{\mathrm{\Σ}}}{\mathrm{Seg}}_k-X+{\mathrm{Seg}}_{n+1}}{R_i}\≥\frac{{\mathrm{Seg}}_{n+1}}{B_{s-p}};---\left(6\right)$

Seg _kExpression is the duration of the file section of k with the section sequence number that file section y belongs to same media file, R _iThe code check of media file under the expression file section y.

Can release according to formula (6):

When X gets maximum (next file section of must looking ahead, otherwise will cause Media Stream to be interrupted; Do not want too early looking ahead; To avoid in the buffer area existing file section) by too early replacing; Promptly when

; Next file section of looking ahead, and replace the file section that preferred value in the buffer area is minimum and do not visited with next file section.

Since the duration that belongs to a back file section of same media file be last file section duration 1+ α doubly, and X is bound to greater than 0, can release based on formula (7) so:

$(n+1)>\frac{\ln \frac{B_{s-p}}{(1+\mathrm{\α})B_{s-p}-{\mathrm{\αR}}_i}}{\ln (1+\mathrm{\α})};---\left(8\right)$

In addition,

Must be greater than 0, and B _S-pGreater than 0, (1+ α) B so _S-p-α R _iMust promptly have greater than 0:

$\frac{B_{s-p}}{R_i}>\frac{\mathrm{\α}}{1+\mathrm{\α}};---\left(9\right)$

Through type (9) can obtain: (R _i-B _S-p) * α＜B _S-p(10)

If R _i≤B _S-p, α value arbitrarily so in principle, but consider the popularity and the average length of session of media file is then in steps described in 21

If R _i＞B _S-p, then α must satisfy

Utilize formula (8) further to release; When

part of file section y is arrived in user capture; Next file section of need looking ahead; This essence with the X that mentions before is the same; Just the form with the moment representes that the form with percentage is represented.

Based on above-mentioned introduction, Fig. 3 is the composition structural representation of buffer queue management device embodiment of the present invention.As shown in Figure 3, comprising:

First processing unit 31 is used for respectively it being divided into two above file sections to each media file;

Second processing unit 32 is used for according to the hot broadcast degree, confirms the preferred value of each file section respectively, and the file section of M position was stored in the buffer area of acting server before preferred value was in, and M is a positive integer;

In addition; When the user asks to visit a file section z who is not stored in the buffer area; Again confirm file section z and the preferred value that leaves each file section in the buffer area in; And when the file section that exists preferred value to be lower than file section z in the buffer area and do not visited the time, with file section z replace that said preferred value is lower than file section z and the file section of not visited in a file section.Certainly, optimum is the minimum file section of replacement preferred value.

Wherein, can specifically comprise (, not shown) in first processing unit 31 for simplifying accompanying drawing:

First handles subelement, is used for to each media file, confirms that respectively its corresponding segmentation factor-alpha and section sequence number are the duration L of 1 file section, and α is less than or equal to 1 positive number;

If R _i≤B _S-p, then

If R _i＞B _S-p, then

I representes arbitrary media file, B _S-pThe bandwidth of expression from the video server to the acting server, R _iThe code check of presentation medium file i, Popularity _iThe popularity of presentation medium file i, ASL _iThe average length of session of presentation medium file i, f () representes any predetermined formula;

N represent from current time Tr to before the predetermined start T0 number of times that media file i is visited in this time period constantly, Ti representes among the moment Ti1 that T0 and media file i visited first more near Tr;

i represents the j times the media file is accessed the visit length;

Second handles subelement, and the duration that is used for according to back one file section is the 1+ α mode doubly of the duration of last file section, and each media file is divided into two above file sections respectively.

Second processing unit 32 can be further used for, and through after the scheduled duration, notifies first processing unit 31 to repeat self function.

In addition, specifically, second processing unit 32 calculates Object_Priority+Segment_Priority+Position_Priority respectively, with the preferred value of result of calculation as file section x to each file section x; Wherein, The number of times that media file was visited under the file section x in Object_Priority represented from current time to this time period in the predetermined start moment before; Segment_Priority representes from the current time to the division, to obtain the number of times that file section x is visited in this time period in the moment of file section x; Position_Priority is relevant with the section sequence number of file section x, and the section sequence number is more near 1, and the value of Position_Priority is big more.

Also can further comprise in the device shown in Figure 3:

The 3rd processing unit 33 when being used for the arbitrary file section y when the user capture buffer area, confirms whether next file section that belongs to same media file with file section y leaves in the buffer area, if then do not deal with; If not; Then confirm the preferred value of each file section in the buffer area again; And the X in total duration of media file uses next file section that belongs to same media file with file section y to replace the file section that preferred value in the buffer area is minimum and do not visited constantly under file section y;

N representes the section sequence number of file section y, Seg _kExpression is the duration of the file section of k with the section sequence number that file section y belongs to same media file, Seg _N+1Expression is the duration of the file section of n+1 with the section sequence number that file section y belongs to same media file, B _S-pThe bandwidth of expression from the video server to the acting server, R _iThe code check of media file under the expression file section y.

The concrete workflow of device embodiment shown in Figure 3 is please with reference to the respective description among the method embodiment shown in Figure 2.

In addition, disclose a kind of demand stream media system among the present invention simultaneously, comprised device shown in Figure 3, specifically realized repeating no more at this referring to foregoing description.

In a word, adopt technical scheme of the present invention, can improve cache hit rate preferably.

The above is merely preferred embodiment of the present invention, and is in order to restriction the present invention, not all within spirit of the present invention and principle, any modification of being made, is equal to replacement, improvement etc., all should be included within the scope that the present invention protects.

Claims (17)

1. a buffer queue management method is characterized in that, comprising:

A, to each media file, respectively it is divided into two above file sections;

B, according to the hot broadcast degree, confirm the preferred value of each file section respectively, the file section of M position was stored in the buffer area of acting server before preferred value was in, M is a positive integer.

2. method according to claim 1 is characterized in that, after the said step B, further comprises:

When the user asks to visit a file section z who is not stored in the buffer area; Again confirm file section z and the preferred value that leaves each file section in the buffer area in; And when the file section that exists preferred value to be lower than file section z in the buffer area and do not visited the time, with file section z replace that said preferred value is lower than file section z and the file section of not visited in a file section.

3. method according to claim 1 is characterized in that, said steps A comprises:

To each media file, the mode that increases progressively according to duration respectively is divided into two above file sections with it.

4. method according to claim 3 is characterized in that, after the said step B, further comprises: through after the scheduled duration, return execution in step A.

5. method according to claim 4 is characterized in that, said to each media file, the mode that increases progressively according to duration respectively is divided into two above file sections with it and comprises:

To each media file, confirm that respectively its corresponding segmentation factor-alpha and section sequence number are the duration L of 1 file section, α is less than or equal to 1 positive number;

Duration according to back one file section is the 1+ α mode doubly of the duration of last file section, and each media file is divided into two above file sections respectively.

6. method according to claim 5 is characterized in that, and is said to each media file, confirms that respectively its corresponding α comprises:

If R _i≤B _S-p, then

If R _i＞B _S-p, then

I representes arbitrary media file, B _S-pThe bandwidth of expression from the video server to the acting server, R _iThe code check of presentation medium file i, Popularity _iThe popularity of presentation medium file i, ASL _iThe average length of session of presentation medium file i, f () representes any predetermined formula.

7. method according to claim 6 is characterized in that,

Said

N represent from current time Tr to before the predetermined start T0 number of times that media file i is visited in this time period constantly, Ti representes among the moment Ti1 that T0 and media file i visited first more near Tr;

The

i represents the j times the media file is accessed when accessing long.

8. method according to claim 2 is characterized in that, the preferred value of said definite each file section comprises: to each file section x, carry out following processing respectively:

Calculate $\mathrm{Priori}{\mathrm{Ty}}_o^x=\mathrm{Object}\_\mathrm{Priority}+\mathrm{Segment}\_\mathrm{Priority}+\mathrm{Position}\_\mathrm{Priority};$

The preferred value of

expression file section x; The number of times that media file was visited under the file section x in Object_Priority represented from current time to this time period in the predetermined start moment before; Segment_Priority representes from the current time to the division, to obtain the number of times that file section x is visited in this time period in the moment of file section x; Position_Priority is relevant with the section sequence number of file section x; The section sequence number is more near 1, and the value of Position_Priority is big more.

9. according to each described method in the claim 1～8, it is characterized in that, after the said step B, further comprise:

When the arbitrary file section y in the user capture buffer area, confirm whether next file section that belongs to same media file with file section y leaves in the buffer area, if then do not deal with;

If not, then confirm the preferred value of each file section in the buffer area again, and look ahead opportunity what determine, use next file section that belongs to same media file with file section y to replace the file section that preferred value in the buffer area is minimum and do not visited.

10. method according to claim 9 is characterized in that, definite mode on the said opportunity of looking ahead comprises:

Calculate $X=\underset{k=1}{\overset{k=n}{\mathrm{\Σ}}}{\mathrm{Seg}}_k-\frac{{\mathrm{Seg}}_{n+1}*(R_i-B_{s-p})}{B_{s-p}};$

Wherein, n representes the section sequence number of file section y, Seg _kExpression is the duration of the file section of k with the section sequence number that file section y belongs to same media file, Seg _N+1Expression is the duration of the file section of n+1 with the section sequence number that file section y belongs to same media file, B _S-pThe bandwidth of expression from the video server to the acting server, R _iThe code check of media file under the expression file section y;

With the X in total duration of media file under the file section y constantly as the opportunity of looking ahead.

11. a buffer queue management device is characterized in that, comprising:

First processing unit is used for respectively it being divided into two above file sections to each media file;

Second processing unit is used for according to the hot broadcast degree, confirms the preferred value of each file section respectively, and the file section of M position was stored in the buffer area of acting server before preferred value was in, and M is a positive integer.

12. device according to claim 11; It is characterized in that; Said second processing unit is further used for, and when the user asks to visit a file section z who is not stored in the buffer area, confirms file section z and the preferred value that leaves each file section in the buffer area in again; And when the file section that exists preferred value to be lower than file section z in the buffer area and do not visited the time, with file section z replace that said preferred value is lower than file section z and the file section of not visited in a file section.

13. device according to claim 11 is characterized in that, said first processing unit comprises:

First handles subelement, is used for to each media file, confirms that respectively its corresponding segmentation factor-alpha and section sequence number are the duration L of 1 file section, and α is less than or equal to 1 positive number;

If R _i≤B _S-p, then

If R _i＞B _S-p, then

I representes arbitrary media file, B _S-pThe bandwidth of expression from the video server to the acting server, R _iThe code check of presentation medium file i, Popularity _iThe popularity of presentation medium file i, ASL _iThe average length of session of presentation medium file i, f () representes any predetermined formula;

Said

N represent from current time Tr to before the predetermined start T0 number of times that media file i is visited in this time period constantly, Ti representes among the moment Ti1 that T0 and media file i visited first more near Tr;

The

i represents the j times the media file is accessed the visit length;

Second handles subelement, and the duration that is used for according to back one file section is the 1+ α mode doubly of the duration of last file section, and each media file is divided into two above file sections respectively.

14. device according to claim 13 is characterized in that, said second processing unit is further used for, and through after the scheduled duration, notifies said first processing unit to repeat self function.

15. according to claim 11,12,13 or 14 described devices; It is characterized in that; Said second processing unit calculates Object_Priority+Segment_Priority+Position_Priority respectively, with the preferred value of result of calculation as file section x to each file section x; Wherein, The number of times that media file was visited under the file section x in Object_Priority represented from current time to this time period in the predetermined start moment before; Segment_Priority representes from the current time to the division, to obtain the number of times that file section x is visited in this time period in the moment of file section x; Position_Priority is relevant with the section sequence number of file section x, and the section sequence number is more near 1, and the value of Position_Priority is big more.

16. according to claim 11,12,13 or 14 described devices, it is characterized in that, further comprise in this device:

The 3rd processing unit when being used for the arbitrary file section y when the user capture buffer area, confirms whether next file section that belongs to same media file with file section y leaves in the buffer area, if then do not deal with; If not; Then confirm the preferred value of each file section in the buffer area again; And the X in total duration of media file uses next file section that belongs to same media file with file section y to replace the file section that preferred value in the buffer area is minimum and do not visited constantly under file section y;

Said

N representes the section sequence number of file section y, Seg _kExpression is the duration of the file section of k with the section sequence number that file section y belongs to same media file, Seg _N+1Expression is the duration of the file section of n+1 with the section sequence number that file section y belongs to same media file, B _S-pThe bandwidth of expression from the video server to the acting server, R _iThe code check of media file under the expression file section y.

17. a demand stream media system is characterized in that, comprising: like each described device in the claim 11～16.

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