CN101184229A - Fast switch method of video sequence - Google Patents
Fast switch method of video sequence Download PDFInfo
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- CN101184229A CN101184229A CNA2006101497892A CN200610149789A CN101184229A CN 101184229 A CN101184229 A CN 101184229A CN A2006101497892 A CNA2006101497892 A CN A2006101497892A CN 200610149789 A CN200610149789 A CN 200610149789A CN 101184229 A CN101184229 A CN 101184229A
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Abstract
The invention discloses a fast switching method for video sequence, comprising following steps: inserting a switching frame in the video coding flow when the video sequence is coded,; performing a video decoding processing of the switching frame to get a decoding image of the switching frame when a video switching request and the switching frame are received; restoring the decoding image according to a zoom coefficient to get a switching reference image; and the switching reference image is used as a reference frame of a follow-up video image decoding. The invention has the advantages of enabling fast video switching at the decoder terminal under the condition of slightly reduced video encoding efficiency, and shortening the switching time.
Description
Technical field
The present invention relates to a kind of transmission and treatment technology of image information, specifically, relate to a kind of fast switch over method of video sequence.
Background technology
Along with the development of wired broadband network and wireless network and the driving of user's request, multimedia technology has obtained increasing concern with relevant application.Particularly digital video technology has obtained using widely, for example IPTV, mobile TV, Digital Television, video conferencing, videodisc etc.One of them common user operation is to carry out video switch, and promptly user side switches to the another one video sequence from an in progress video sequence.
For digital video, because existing digital video frequency encoding method has all been taked the mode of picture frame coding, the switching of video sequence can't be finished fast.These picture frames contain intracoded frame (I frame) and non-intracoded frame, and wherein non-intracoded frame has predictive frame (P frame) and bi-directional predicted frames (B frame).The I frame is the frame that can independently decode, does not need other picture frame as the reference image.And the P frame is a forward predicted frame, needs with the image before the P two field picture of current decoding as the reference frame, and the B frame is a bi-directional predicted frames, need with the B frame of current decoding before with afterwards image as the reference image.
In traditional video sequence changing method,, begin to carry out immediately the video decode processing of standard from switching position if the picture frame of video switch position is intra-frame encoding mode (an I frame).Decoded picture can show, and as the reference picture of next code video code flow.
As shown in Figure 1, if the picture frame of video switch position is not an intra-frame encoding mode, for example P frame or B frame.Afterwards to reconstructed image can not carry out video decode immediately and handle as the reference frame because P frame or B frame need use forward direction.When t+i carries out video switch constantly because the encoded image frame of this moment is not intraframe coding, need be with reference to forward direction or/and the back to the reconstructed image frame decode.In this case, Video Decoder must suspend, and waits for that extremely next in-frame encoding picture frame could begin to carry out video decode, need wait for the moment to t+n, receives in-frame encoding picture and could recover decoding.Therefore in traditional video switching method, the wait time delay of video switch is n-i.
Owing to have only the I frame independently to decode in the video code flow, therefore one section video code flow must be with the I frame as start frame.When carrying out the channel switching, after needing to wait for correct reception of I frame of video code flow, just can decode and show.
Therefore in order to realize the switching of video code flow, need in the video code flow of coding, insert I frame coded image.But can cause code efficiency to reduce because the code efficiency of I frame, is frequently inserted the I frame far below the code efficiency of P frame or B frame in the encoded video code stream, thereby influence the picture quality that the user watches.
Summary of the invention
Technical problem solved by the invention provides a kind of fast switch over method of video sequence, can different video sequences be switched fast, and can guarantee that the user watches the quality of image.
Technical scheme is as follows:
The fast switch over method of video sequence, step is as follows:
When (1) video sequence being encoded, in video code flow, insert switch frame;
(2) when receiving video switch request and switch frame, carry out the video decode of switch frame and handle, obtain the decoded picture of switch frame;
(3) decoded picture is recovered according to zoom factor, obtain switching reference picture;
(4) will switch the reference frame of reference picture as the subsequent video images decoding.
Further, in the step (1), the concrete steps that obtain switch frame are as follows:
A, in video code flow, choose the moment of inserting switch frame;
B, corresponding original image frame or the reconstructed image frame of extraction;
C, original image frame or reconstructed image frame are carried out intraframe coding according to method for video coding, obtain switch frame.
Further, in the step (a): the interval between the adjacent switch frame is less than the interval between the adjacent I frame.
Further in, step (c) is specially:
(c1) selected zoom factor carries out the convergent-divergent processing to described original image frame or reconstructed image frame;
(c2) original image frame or reconstructed image frame after the convergent-divergent processing are carried out intraframe coding, obtain switch frame.
Further, step (2) is specially:
When receiving the video switch request, the video code flow of accepting is judged; If be the normal image frame of non-intra-frame encoding mode, then do not carry out decoding processing; If be the normal image frame of intra-frame encoding mode, then carry out the decoding processing of standard; If be the video switch frame, then carry out the video decode of switch frame and handle, obtain decoded picture.
Further, when carrying out the convergent-divergent of image, if zoom factor less than 1, is represented image is dwindled; If zoom factor is greater than 1, expression is amplified image; If zoom factor equals 1, presentation video keeps original size.
Further, the video decode processing of switch frame is finished by sampling filter.
The technique effect of technical scheme is as follows:
The inventive method can realize that the fast video of decoder end switches under the condition of not obvious reduction video coding efficient, carry out video switch with original I frame according to video sequence and compare, and be shortened switching time.
Because switch frame is that the common video picture frame has been carried out carrying out behind the convergent-divergent intraframe coding again, and when switch frame is encoded, taked to improve the method for compression ratio, for example slightly quantification, more effective entropy coding method, more effective intra-frame prediction method etc., data volume is much smaller than common I frame coding behind the coding of switch frame.In this case, when being separated by far between the adjacent common I frame of encoded video code stream, by between adjacent common I frame, inserting a plurality of switch frames, thereby can realize that fast video sequence switches in decoding end, and the switch frame that inserts can obviously not increase the video codeword data stream amount behind the coding.
The present invention is under the situation that does not need video switch, and the switch frame of insertion just as additional invalid data, does not influence the Video Decoder normal decoder; Needing under the situation of video switch, the switch frame of insertion can independently be decoded, and need not with reference to other decoded picture, and new video sequence can begin from the switch frame position to carry out video decode, thereby realizes that video sequence switches fast.
Description of drawings
Fig. 1 is a video switching method schematic diagram of the prior art;
Fig. 2 is the video switching method schematic diagram that uses switch frame among the present invention;
Fig. 3 is two video sequence schematic diagrames behind the insertion switch frame among the present invention;
Fig. 4 is based on the video switch process schematic diagram of switch frame among the present invention.
Embodiment
Below with reference to accompanying drawing, the preferred embodiments of the present invention are described in detail.
The fast switch over method of video sequence proposed by the invention comprises two parts of decode procedure of the cataloged procedure and the Video Decoder of video encoder on the whole.
1, the cataloged procedure of video encoder.
The first step is encoded according to the method for video coding of standard to the video sequence of needs coding.H.261 video coding can take, H.263, H.264, method such as AVS, MPEG4, MPEG2, the image encoded frame type can be I frame, P frame or B frame, in order to improve code efficiency, between the adjacent I frame any large-spacing can be arranged.
In second step, in the encoded video code stream of standard, insert switch frame.
With reference to shown in Figure 2, in the process of carrying out video coding, the in-frame encoding picture frame except standard has inserted the picture frame-switch frame of another intraframe coding in video code flow.
The implementation method of switch frame comprises following several steps:
(1) the selected moment of inserting switch frame.
For example, the selected j moment or the k moment are as the insertion moment of switch frame.The position of switch frame can determine according to actual needs that in general the frequency of switch frame is greater than the I frame rate in the video code flow, and the interval between the promptly adjacent switch frame is less than the interval between the adjacent I frame.
(2) at switch frame moment j or k place, extract corresponding original image frame or reconstructed image frame, be designated as F
jPerhaps F
k
(3) with F
jPerhaps F
kAccording to zoom factor given in advance (scale), handle through filter (Filter1), obtain a scaled images, be designated as Scaled_F
jPerhaps Scaled_F
k
To F
jPerhaps F
kWhen carrying out convergent-divergent, if zoom factor less than 1, is represented image is dwindled; If zoom factor is greater than 1, expression is amplified image; If zoom factor equals 1, presentation video keeps original size.
(4) to Scaled_F
jPerhaps Scaled_F
kMethod for video coding according to standard carries out intraframe coding, obtains switch frame, is designated as Switch_F
jPerhaps Switch_F
k
To Switch_F
jPerhaps Switch_F
kWhen carrying out intraframe coding,, can take the strategy of suitable raising compression ratio, for example slightly quantification, more effective entropy coding method, more effective intra-frame prediction method etc. in order to reduce the amount of coded data of switch frame.
After j has inserted switch frame constantly, original non-in-frame encoding picture F
jAfter increased a switch frame.If when i carries out video switch constantly because the encoded image frame of this moment is not intraframe coding, need with reference to forward direction or back to the reconstructed image frame decode.In this case, Video Decoder must suspend, and wait to next in-frame encoding picture frame or switch frame could begin to carry out video decode.Exist owing to when the j of n before constantly, be carved with switch frame, therefore, decoder do not need to wait for to n constantly, receive in-frame encoding picture and could recover to decode.But at j constantly, just begin to decode after receiving switch frame.Therefore in the video switching method that adds switch frame, the wait time delay of video switch is j-i, switches comparison with original constantly at n, and handover delay has shortened n-j.
Because switch frame is that the common video picture frame has been carried out carrying out behind the convergent-divergent intraframe coding again, and when switch frame is encoded, taked to improve the method for compression ratio, for example slightly quantification, more effective entropy coding method, more effective intra-frame prediction method etc., data volume is much smaller than common I frame coding behind the coding of switch frame.In this case, it is far away to be separated by between the adjacent common I frame of encoded video code stream, between adjacent common I frame, insert a plurality of switch frames, thereby can realize that video sequence switches fast, and the switch frame that inserts can obviously not increase the video codeword data stream amount behind the coding in decoding end.
2, the decode procedure of Video Decoder.
(1) detects the video switch request that whether receives.
First kind of situation, if do not receive the video switch request, then carry out the following step:
A, the video code flow that receives is judged.
If the video code flow that receives is the normal image frame, for example I frame, P frame or B frame are then handled according to the video decode of standard; If the video code flow that receives is a switch frame, then do not carry out decoding processing.
B, decode procedure finish, and with the reference frame of decoded picture as the subsequent video images decoding, and send it to display terminal.
C, enter next decoding processing constantly.
Second kind of situation if receive the video switch request, then carried out the following step.
I, the video code flow that receives is judged.
If the video code flow that receives is the normal image frame, and is non-intra-frame encoding mode, for example P frame or B frame then do not carry out decoding processing, and Video Decoder is in wait state; If the video code flow that receives is the normal image frame, and is intra-frame encoding mode, I frame for example then carries out the decoding processing of standard; If the video code flow that receives contains video switch frame, for example Switch_F
j, then carry out the video decode of switch frame and handle, obtain decoded picture Scaled_F
j, then to Scaled_F
jCarry out the picture frame F that the up-sampling Filtering Processing is restored according to zoom factor scale
j', up-sampling filtering is finished by up-sampling filter Filter2, obtains switching reference picture.
II, will switch the reference frame of reference picture, and send it to display terminal as subsequent video images decoding.
III, enter next decoding processing constantly.
With reference to shown in Figure 3, sequence 1 is in progress sequence, and sequence 2 is to prepare the sequence of switching.
In the coded video sequence after two are inserted switch frame, sequence 1 and sequence 2 all are CIF form (352 pixels * 288 pixels), so I frame in the sequence and P frame all are the CIF forms, be designated as respectively I (seq, t) and P (seq, t), wherein seq represents sequence numbering, and t represents constantly.In the present embodiment, the zoom factor of switch frame gets 0.5, and promptly the form of switch frame is SQCIF, and size is (176 pixels * 144 pixels).
For sequence 1, be selected in t+2 and insert switch frame constantly, be designated as S (seq1, t+2).S (seq1, t+2) be by P (seq1, t+2) be reduced into the QCIF form after, take intraframe coding to obtain again.
The concrete steps of inserting switch frame in t+2 moment sequence 1 are as follows:
(1) the selected moment t+2 that inserts switch frame.
T+2 constantly the P frame is the CIF form, be designated as P (seq1, t+2).
(2) at switch frame moment t+2 place, extract corresponding original image frame or reconstructed image frame.
(3) original image frame or the reconstructed image frame that extract are handled through filter (Filter1) according to zoom factor given in advance (scale=0.5), obtained a scaled images.
(4) scaled images is carried out intraframe coding according to the method for video coding of standard, obtains switch frame, be designated as S (seq1, t+2).
For sequence 2, be selected in t+4 and insert switch frame constantly, be designated as S (seq2, t+4).S (seq2, t+4) be by P (seq2, t+4) be reduced into the QCIF form after, take intraframe coding to obtain again.
The concrete steps of inserting switch frames in t+4 moment sequence 2 are as follows:
(1) the selected moment t+4 that inserts switch frame.
T+4 constantly the P frame is the CIF form, be designated as P (seq2, t+4).
(2) at switch frame moment t+4 place, extract corresponding original image frame or reconstructed image frame.
(3) original image frame or the reconstructed image frame that extract are handled through filter (Filter1) according to zoom factor given in advance (scale=0.5), obtained a scaled images.
(4) scaled images is carried out intraframe coding according to the method for video coding of standard, obtains switch frame, be designated as S (seq2, t+4).
With reference to shown in Figure 4, under situation shown in Figure 3, when needs at t+2 constantly when video sequence 1 switches to video sequence 2, this moment, the decoding end video switch processing procedure of video sequence 2 was as follows.
The t+2 moment: from t+2 constantly, terminal begins the video code flow of receiving sequence 2, is expressed as P, P, and P, S, P, P, I, P, P ....
In the t+2 moment, the reconstructed image that non-in-frame encoding picture P (t+2) can't use the front is as the reference frame, and P (t+2) can not carry out decode operation.
The reconstructed image that the t+3 moment: in-frame encoding picture P (t+3) can't use the front is as the reference frame, and P (t+3) can not carry out decode operation.
The reconstructed image that the t+4 moment: non-in-frame encoding picture P (t+4) can't use the front is as the reference frame, and P (t+4) can not carry out decode operation.But at t+4 constantly, there is a switch frame S (t+4) who uses the intraframe coding method coding.Therefore, the decoder of terminal is decoded to switch frame S (t+4), obtains the decoded picture of a QCIF form.Then this QCIF format-pattern is handled by up-sampling filter, the switching reference picture F ' that obtains a CIF form (t+4).Detailed process in t+4 moment video decoder decodes is as follows:
(1) Video Decoder detects the video switch request that whether receives.
If do not receive the video switch request, then carry out the following step:
A, the video code flow that receives is judged.
If the video code flow that receives is the normal image frame, for example I frame, P frame or B frame are then handled according to the video decode of standard; If the video code flow that receives is a switch frame, then do not carry out decoding processing.
B, decode procedure finish, and with the reference frame of decoded picture as the subsequent video images decoding, and send it to display terminal.
C, enter next decoding processing constantly.
If receive the video switch request, then the video code flow that receives is judged, and is carried out the following step:
If the video code flow that receives is the normal image frame, and be non-intra-frame encoding mode, for example P frame or B frame then do not carry out decoding processing, and Video Decoder is in wait state; If the video code flow that receives is the normal image frame, and is intra-frame encoding mode, I frame for example then carries out the decoding processing of standard.
If contain video switch frame S (t+4) in the video code flow that receives, then carrying out the video decode of switch frame S (t+4) handles, obtain decoded picture, then decoded picture is carried out the up-sampling Filtering Processing according to zoom factor (scale=0.5), obtain the decoded picture of a QCIF form.Then this QCIF format-pattern is handled by up-sampling filter, the switching reference picture F ' that obtains a CIF form (t+4), this switches reference picture F ' (t+4) as the reference frame of successive image decoding.
T+5 is constantly: non-in-frame encoding picture P (t+5) utilizes the switching reference picture F ' that obtains from switch frame S (t+4) (t+4) as with reference to frame, carries out the video decode of standard and handles, and obtains t+5 decoded picture constantly.
T+6 is constantly: non-in-frame encoding picture P (t+6) utilizes decoded picture from P (t+5) as the reference frame, carries out the video decode of standard and handles, and obtains t+6 decoded picture constantly.
The t+7 moment: in-frame encoding picture P (t+7) does not need to utilize the reference frame of front, can carry out the video decode of standard, obtains t+7 decoded picture constantly.
The video decoding process of t+8 after the moment is the same with the video sequence decode procedure of standard.
In the application based on digital video such as IPTV, mobile TV, Digital Television, the switching of video sequence is a kind of very important client operation.Because wait in the process that digital video is switched to in-frame encoding picture and just can carry out video decode, therefore carrying out video switch in client needs the long stand-by period.The present invention proposes a kind of switch frame method that independently to decode of in the encoded video code stream, inserting.On the one hand, when not carrying out video switch, can not influence decoding and the broadcast of terminal to normal video code flow; On the other hand, when carrying out video switch, terminal can realize that fast video switches from the switch frame position, thereby shortens the video switch time of user when watching video frequency program.
Claims (7)
1. the fast switch over method of a video sequence, step is as follows:
When (1) video sequence being encoded, in video code flow, insert switch frame;
(2) when receiving video switch request and switch frame, carry out the video decode of switch frame and handle, obtain the decoded picture of switch frame;
(3) decoded picture is recovered according to zoom factor, obtain switching reference picture;
(4) will switch the reference frame of reference picture as the subsequent video images decoding.
2. the fast switch over method of video sequence according to claim 1 is characterized in that, in the step (1), the concrete steps that obtain switch frame are as follows:
A, in video code flow, choose the moment of inserting switch frame;
B, corresponding original image frame or the reconstructed image frame of extraction;
C, original image frame or reconstructed image frame are carried out intraframe coding according to method for video coding, obtain switch frame.
3. the fast switch over method of video sequence according to claim 2 is characterized in that, in the step (a): the interval between the adjacent switch frame is less than the interval between the adjacent I frame.
4. the fast switch over method of video sequence according to claim 2 is characterized in that, step (c) is specially:
(c1) selected zoom factor carries out the convergent-divergent processing to described original image frame or reconstructed image frame;
(c2) original image frame or reconstructed image frame after the convergent-divergent processing are carried out intraframe coding, obtain switch frame.
5. the fast switch over method of video sequence according to claim 1 is characterized in that, step (2) is specially:
When receiving the video switch request, the video code flow of accepting is judged; If be the normal image frame of non-intra-frame encoding mode, then do not carry out decoding processing; If be the normal image frame of intra-frame encoding mode, then carry out the decoding processing of standard; If be the video switch frame, then carry out the video decode of switch frame and handle, obtain decoded picture.
6. the fast switch over method of video sequence according to claim 4 is characterized in that, when carrying out the convergent-divergent of image, if zoom factor less than 1, is represented image is dwindled; If zoom factor is greater than 1, expression is amplified image; If zoom factor equals 1, presentation video keeps original size.
7. the fast switch over method of video sequence according to claim 1 is characterized in that, the video decode of switch frame is handled finished by sampling filter.
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| CNA2006101497892A CN101184229A (en) | 2006-11-13 | 2006-11-27 | Fast switch method of video sequence |
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| CN200610145123 | 2006-11-13 | ||
| CN200610145123.X | 2006-11-13 | ||
| CNA2006101497892A CN101184229A (en) | 2006-11-13 | 2006-11-27 | Fast switch method of video sequence |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102055984A (en) * | 2011-01-27 | 2011-05-11 | 山东大学 | Three-dimensional video decoding structure for smoothly switching 2D and 3D play modes and operating method |
| CN104506866A (en) * | 2014-11-28 | 2015-04-08 | 北京奇艺世纪科技有限公司 | Video coding processing method suitable for multiple code streams and video coder |
-
2006
- 2006-11-27 CN CNA2006101497892A patent/CN101184229A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102055984A (en) * | 2011-01-27 | 2011-05-11 | 山东大学 | Three-dimensional video decoding structure for smoothly switching 2D and 3D play modes and operating method |
| CN102055984B (en) * | 2011-01-27 | 2012-10-03 | 山东大学 | Three-dimensional video decoding structure for smoothly switching 2D and 3D play modes and operating method |
| CN104506866A (en) * | 2014-11-28 | 2015-04-08 | 北京奇艺世纪科技有限公司 | Video coding processing method suitable for multiple code streams and video coder |
| CN104506866B (en) * | 2014-11-28 | 2018-03-27 | 北京奇艺世纪科技有限公司 | A kind of video coding processing method and video encoder suitable for more code streams |
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