CN110753242B - Method and system for adjusting quantization parameters of transcoding slice source frame layer - Google Patents
Method and system for adjusting quantization parameters of transcoding slice source frame layer Download PDFInfo
- Publication number
- CN110753242B CN110753242B CN201911061721.2A CN201911061721A CN110753242B CN 110753242 B CN110753242 B CN 110753242B CN 201911061721 A CN201911061721 A CN 201911061721A CN 110753242 B CN110753242 B CN 110753242B
- Authority
- CN
- China
- Prior art keywords
- frame
- transcoding
- current
- complexity change
- complexity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000013139 quantization Methods 0.000 title claims abstract description 112
- 238000000034 method Methods 0.000 title claims abstract description 43
- 230000008859 change Effects 0.000 claims description 180
- 239000013598 vector Substances 0.000 claims description 12
- 230000006835 compression Effects 0.000 claims description 11
- 238000007906 compression Methods 0.000 claims description 11
- 238000004364 calculation method Methods 0.000 claims description 10
- 230000032683 aging Effects 0.000 claims description 8
- 238000007796 conventional method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 238000009432 framing Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/80—Generation or processing of content or additional data by content creator independently of the distribution process; Content per se
- H04N21/83—Generation or processing of protective or descriptive data associated with content; Content structuring
- H04N21/845—Structuring of content, e.g. decomposing content into time segments
- H04N21/8456—Structuring of content, e.g. decomposing content into time segments by decomposing the content in the time domain, e.g. in time segments
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
- H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
- H04N21/234—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs
- H04N21/2343—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
- H04N21/25—Management operations performed by the server for facilitating the content distribution or administrating data related to end-users or client devices, e.g. end-user or client device authentication, learning user preferences for recommending movies
- H04N21/266—Channel or content management, e.g. generation and management of keys and entitlement messages in a conditional access system, merging a VOD unicast channel into a multicast channel
- H04N21/2662—Controlling the complexity of the video stream, e.g. by scaling the resolution or bitrate of the video stream based on the client capabilities
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Databases & Information Systems (AREA)
- Compression Or Coding Systems Of Tv Signals (AREA)
Abstract
The invention provides a method and a system for adjusting a quantization parameter of a source frame layer of a transcoding slice. According to the method, according to the prior coding information of the input code stream, a frame with changed complexity is found firstly, then the influence timeliness of the frame with changed complexity is determined, and then the quantization parameters of the input code stream are adjusted in a self-adaptive mode on the basis of the influence timeliness of the frame at a transcoding end, so that the rate distortion performance of a transcoded video is improved while the calculated amount is reduced.
Description
Technical Field
The invention relates to the field of video coding, in particular to a method and a system for adjusting quantization parameters of a source frame layer of a transcoding slice.
Background
The current transcoding technology adopts a quantization parameter multiplexing mechanism simply, but can restrict the improvement of rate distortion performance; or the rate-distortion performance is improved by recalculating new quantization parameters through rate control. Because the input end of the transcoder is a compressed code stream and has prior coding information of the input code stream, if a quantization strategy is specially designed and adjusted based on the compressed information, the transcoding performance can be further improved.
Disclosure of Invention
The embodiment of the invention aims to provide a transcoding slice source frame layer quantization parameter adjusting method, and aims to solve the problems of large calculation amount or low transcoding performance of a transcoding method in the prior art.
The embodiment of the invention is realized in such a way that a method for adjusting the quantization parameters of the source frame layer of a transcoding slice comprises the following steps:
identifying complexity change frames in the transcoded frames and calculating influence timeliness of the complexity change frames;
and adaptively adjusting the quantization parameters of the transcoded frames according to the influence timeliness of the complexity change frames, and then transcoding.
Further, before the identifying the complexity change frame in the transcoded frame and calculating the influence aging of the complexity change frame, the method further includes:
assigning initial values to the quantization parameters of the transcoding frames according to the threshold range of the absolute value of the difference value between the original bit and the target bit of the transcoding code stream in advance;
presetting current transcoding frame as initial frame
The self-adaptive adjustment of the transcoding frame quantization parameter according to the influence timeliness of the complexity change frame, and then the transcoding further comprises:
if the next frame to be transcoded of the end frame of the complexity change frame stage exists, the comp is ordered2＝comp1Setting the next transcoding frame of the complexity change frame stage ending frame as the current transcoding frame and the previous complexity change frame as the current complexity change frame, and then returning the complexity change frame in the identification transcoding frame and calculating the influence aging of the complexity change frame; otherwise, ending;
therein, comp1Representing the complexity of the current complexity change frame; comp2Representing the complexity of the previous complexity change frame.
Another objective of the embodiments of the present invention is to provide a system for adjusting quantization parameters of a source frame layer of a transcoding slice. The system comprises:
the complexity change frame identification and influence timeliness calculation device is used for identifying complexity change frames in the transcoding frames and calculating influence timeliness of the complexity change frames;
and the transcoding frame quantization parameter adjusting device is used for adaptively adjusting the transcoding frame quantization parameters according to the influence timeliness of the complexity change frame and then transcoding.
Further, the system comprises:
the transcoding frame quantization parameter initial value assigning module is used for assigning an initial value to the transcoding frame quantization parameter in advance according to a threshold range of an absolute value of a difference value between an original bit and a target bit of a transcoding code stream;
the current transcoding frame initial value assigning module is connected with the complexity change frame identifier and the influence timeliness calculating device and is used for presetting the current transcoding frame as an initial frame;
a first judgment processing module connected with the transcoding frame quantization parameter adjusting device and used for judging the existence of the next frame to be transcoded of the complexity change frame stage ending frame,make comp2＝comp1Setting the next transcoding frame of the complexity change frame stage ending frame as the current transcoding frame, setting the previous complexity change frame as the current complexity change frame, and then returning the complexity change frame identification and the influence aging calculation device; otherwise, ending;
therein, comp2Representing the complexity of a previous complexity change frame; comp1Representing the complexity of the current complexity change frame.
The invention has the advantages of
The invention provides a method and a system for adjusting a quantization parameter of a source frame layer of a transcoding slice. According to the method, according to the prior coding information of the input code stream, a frame with changed complexity is found firstly, then the influence timeliness of the frame with changed complexity is determined, and then the quantization parameters of the input code stream are adjusted in a self-adaptive mode on the basis of the influence timeliness of the frame at a transcoding end, so that the rate distortion performance of a transcoded video is improved while the calculated amount is reduced.
Drawings
Fig. 1 is a flowchart of a method for adjusting quantization parameters of a source frame layer of a transcoding source frame according to a preferred embodiment of the present invention;
fig. 2 is a diagram of a system for adjusting quantization parameters of a source frame layer of a transcoding source frame according to a preferred embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and examples, and for convenience of description, only parts related to the examples of the present invention are shown. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The invention provides a method and a system for adjusting a quantization parameter of a source frame layer of a transcoding slice. According to the method, according to the prior coding information of an input code stream, a frame with changed complexity is found firstly, then the influence timeliness of the frame with changed complexity is determined, and then the quantization parameters of the input code stream are adjusted in a self-adaptive mode at a transcoding end based on the influence timeliness of the frame, so that the rate distortion performance of a transcoded video is improved while the calculated amount is reduced.
Example one
Fig. 1 is a flowchart of a method for adjusting quantization parameters of a source frame layer of a transcoding source frame according to a preferred embodiment of the present invention; the method comprises the following steps:
step 0: assigning initial values to the quantization parameters of the transcoding frames according to the threshold range of the absolute value of the difference value between the original bit and the target bit of the transcoding code stream in advance;
the method specifically comprises the following steps: if bito-bit|＜Thres1Then, the quantization parameter QP of each transcoding frame is assigned with an initial value as the quantization parameter QP of the current transcoding frame corresponding to the original code streamo(ii) a Otherwise, each frame quantization parameter QP is transcoded, and an initial value is assigned to be the current transcoding frame quantization value output by the rate control module.
Wherein bitoBit represents the original bit of the code stream and the target bit of the code stream respectively; thres1Representing a first threshold, typically Thres1＜10％*bito。
Step 1: and presetting the current transcoding frame as an initial frame.
Step 2: identifying a complexity change frame in a transcoding frame and calculating an influence aging compl of the complexity change frame;
specifically, in an embodiment, first, the current transcoded frame is identified as the current complexity change frame, and the start sequence number cur1 is the play sequence number of the current transcoded frame. Then, judging that if the playing sequence number is larger than that of the frame of the current transcoding frame, the number of prediction blocks in the frame is not larger than Thres2In the frame of wb hb, let comp numF-cur1, and set a stage end frame (i.e., a complexity change frame stage end frame, abbreviated as a stage end frame) as the last frame of the transcoding slice source; otherwise, in the frames with the playing sequence number greater than the current transcoding frame, the frame with the minimum playing sequence number is set as the next complexity change frame, and the minimum playing sequence number is recorded as cur2, so that comp is cur2-cur1 and note is 1, and the stage ending frame is set as the previous frame of the next complexity change frame.
Wherein wb and hb represent the column width and row width of the image in units of blocks; numF represents the frame number of the current transcoding source; thres2Representing a second threshold, typically Thres2Is more than 0.8; note represents the next complexity changeThe frame presence identifier.
Step 3: and adaptively adjusting the quantization parameters of the transcoded frames according to the influence timeliness of the complexity change frames, and then transcoding.
Specifically, if compl < Thres3Directly transcoding (without adjusting the quantization parameters of each frame from the current complexity change frame to the phase end frame); otherwise, calculating the complexity of the current complexity change frame by using the compression information of the current transcoding frame in the frame corresponding to the original code stream; and then, according to the calculated value of the complexity change identifier delta, adjusting the quantization parameters of each frame from the current complexity change frame to the stage ending frame, and then carrying out transcoding.
Wherein, Thres3Representing a third threshold, typically Thres3The sampling frame rate of the film source is more than 2; the transcoding method adopts a conventional method in the technical field, and is not described herein again.
The compression information of the current transcoding frame in the frame corresponding to the original code stream comprises the fluctuation of the current transcoding frame in the frame code rate corresponding to the original code stream, the proportion of the current transcoding frame in the motion vector of the frame corresponding to the original code stream, and the proportion of the current transcoding frame in the Skip block of the frame corresponding to the original code stream.
In the embodiment of the invention, the complexity of the current complexity change frame is calculated by using the compression information of the current transcoding frame in the frame corresponding to the original code stream by any one of the following methods 1 to 3:
the method comprises the following steps: utilizing the fluctuation of the current transcoding frame in the code rate of the corresponding frame of the original code stream
comp1＝int(bitcur1/bitnext1)；
The method 2 comprises the following steps: the proportion of motion vectors in the frames corresponding to the original code stream is utilized to carry out transcoding at present
The method 3 comprises the following steps: utilizing the ratio of Skip blocks in the frames corresponding to the original code stream of the current transcoding frame
Therein, comp1Representing the complexity of the current complexity change frame; bitcur1、bitnext1Respectively representing the bit of the current complexity change frame in the frame corresponding to the original code stream and the bit of the current complexity change frame in the frame next to the playing sequence of the frame corresponding to the original code stream; mvbitcur1、mvbitnext1To indicate bitcur1、bitnext1The code rate occupied by the medium motion vector; numb, numkipcur1、numskipnext1Respectively representing the number of blocks of a current transcoding frame in a frame corresponding to an original code stream, the number of Skip blocks of a current complexity change frame in a frame corresponding to the original code stream, and the number of Skip blocks of the current complexity change frame in a frame after the playing sequence of the frame corresponding to the original code stream; int denotes a rounding operation.
Specifically, adjusting the quantization parameter of each frame from the current complexity change frame to the phase end frame according to the calculated value of the complexity change identifier δ is as follows: if delta is calculated and is equal to 0, acquiring a quantization parameter; otherwise, adjusting the quantization parameter according to the complexity change frame type;
specifically, the calculation formula of the obtained quantization parameter is as follows:
wherein, QPp、dQPoAnd respectively representing the quantization parameter of the previous complexity change frame, the difference value of the quantization parameter of the previous complexity change frame corresponding to the original code stream and the quantization parameter of the current transcoding frame. clip (x) represents a quantization parameter defining function known in the art; complexity change identifier
comp1/comp2＞Thres4And condition 2: comp2/comp1＞Thres4，Thres4Represents a fourth threshold;
specifically, the quantization parameter is adjusted according to the complexity change frame type as follows:
case 1: when the current complexity change frame is an I frame or a P frame,
case 2: when the current complexity change frame is a B frame,
wherein dQP is weight1*weight2；
weight1＝(compl＞(4*Thres3))+(compl＞(2*Thres3))+1；
weight2＝(comp1＜Thres5)+(comp1＜2*Thres5)；Thres5Representing a fifth threshold having a value equal to the mean of the computed complexity of the complexity change frames; the first type of frame represents the current complexity change frame to a frame that is prior to the first P frame after the current complexity change frame.
Step 4: if the next frame to be transcoded of the end frame of the complexity change frame stage exists, the comp is ordered2＝comp1Setting the next transcoding frame of the complexity change frame stage ending frame as the current transcoding frame, setting the previous complexity change frame as the current complexity change frame, and then returning to Step 2; otherwise, ending.
Therein, comp2Representing the complexity of a previous complexity change frame;
example two
Fig. 2 is a diagram of a system for adjusting quantization parameters of a source frame layer of a transcoding source frame according to a preferred embodiment of the present invention. The system comprises:
the transcoding frame quantization parameter initial value assigning module is used for assigning an initial value to the transcoding frame quantization parameter in advance according to a threshold range of an absolute value of a difference value between an original bit and a target bit of a transcoding code stream;
and the current transcoding frame initial value assigning module is used for presetting the current transcoding frame as an initial frame.
The complexity change frame identification and influence timeliness calculation device is used for identifying complexity change frames in the transcoding frames and calculating influence timeliness of the complexity change frames;
and the transcoding frame quantization parameter adjusting device is used for adaptively adjusting the transcoding frame quantization parameters according to the influence timeliness of the complexity change frame and then transcoding.
A first judgment processing module, configured to judge that a next frame to be transcoded of the end frame of the complexity change frame stage exists, and command comp2＝comp1Setting the next transcoding frame of the complexity change frame stage ending frame as the current transcoding frame, setting the previous complexity change frame as the current complexity change frame, and then returning to Step 2; otherwise, ending.
Therein, comp2Representing the complexity of a previous complexity change frame;
further, the "assigning an initial value to the quantization parameter of the transcoded frame according to the threshold range of the absolute value of the difference between the original bit and the target bit of the transcoded code stream in advance" specifically includes: if bito-bit|＜Thres1Then, the quantization parameter QP of each transcoding frame is assigned with an initial value as the quantization parameter QP of the current transcoding frame corresponding to the original code streamo(ii) a Otherwise, each frame quantization parameter QP is transcoded, and an initial value is assigned to be the current transcoding frame quantization value output by the rate control module.
Wherein bitoBit represents the original bit of the code stream and the target bit of the code stream respectively; thres1Representing a first threshold, typically Thres1＜10％*bito。
Further, the "identifying a complexity change frame in a transcoded frame and calculating an influence age compl of the complexity change frame" specifically includes: first, identify the current transcoding frame as the current complexity change frame, and make the starting sequence number cur1 be the playing sequence number of the current transcoding frame. Then, judging that if the playing sequence number is larger than that of the frame of the current transcoding frame, the number of prediction blocks in the frame is not larger than Thres2Wb hb frame, let comp numF-cur1, set the end-of-phase frame (i.e., complexity change)A framing phase end frame, referred to as a phase end frame for short) as the last frame of the transcoding slice source; otherwise, in the frames with the playing sequence number greater than the current transcoding frame, the frame with the minimum playing sequence number is set as the next complexity change frame, and the minimum playing sequence number is recorded as cur2, so that comp is cur2-cur1 and note is 1, and the stage ending frame is set as the previous frame of the next complexity change frame.
Wherein wb and hb represent the column width and row width of the image in units of blocks; numF represents the frame number of the current transcoding source; thres2Representing a second threshold, typically Thres2Is more than 0.8; note indicates that the next complexity change frame exists identifier.
Further, the "adaptively adjusting the transcoding frame quantization parameter according to the influence aging of the complexity change frame, and then transcoding" specifically includes: if comp < Thres3Directly transcoding (without adjusting the quantization parameters of each frame from the current complexity change frame to the phase end frame); otherwise, calculating the complexity of the current complexity change frame by using the compression information of the current transcoding frame in the frame corresponding to the original code stream; and then, according to the calculated value of the complexity change identifier delta, adjusting the quantization parameters of each frame from the current complexity change frame to the stage ending frame, and then carrying out transcoding.
Wherein, Thres3Representing a third threshold, typically Thres3The sampling frame rate of the film source is more than 2; the transcoding method adopts a conventional method in the technical field, and is not described herein again.
The compression information of the current transcoding frame in the frame corresponding to the original code stream comprises the fluctuation of the current transcoding frame in the frame code rate corresponding to the original code stream, the proportion of the current transcoding frame in the motion vector of the frame corresponding to the original code stream, and the proportion of the current transcoding frame in the Skip block of the frame corresponding to the original code stream.
In the embodiment of the invention, the complexity of the current complexity change frame is calculated by using the compression information of the current transcoding frame in the frame corresponding to the original code stream by any one of the following methods 1 to 3:
the method comprises the following steps: utilizing the fluctuation of the current transcoding frame in the code rate of the corresponding frame of the original code stream
comp1＝int(bitcur1/bitnext1)；
The method 2 comprises the following steps: the proportion of motion vectors in the frames corresponding to the original code stream is utilized to carry out transcoding at present
The method 3 comprises the following steps: utilizing the ratio of Skip blocks in the frames corresponding to the original code stream of the current transcoding frame
Therein, comp1Representing the complexity of the current complexity change frame; bitcur1、bitnext1Respectively representing the bit of the current complexity change frame in the frame corresponding to the original code stream and the bit of the current complexity change frame in the frame next to the playing sequence of the frame corresponding to the original code stream; mvbitcur1、mvbitnext1To indicate bitcur1、bitnext1The code rate occupied by the medium motion vector; numb, numkipcur1、numskipnext1Respectively representing the number of blocks of a current transcoding frame in a frame corresponding to an original code stream, the number of Skip blocks of a current complexity change frame in a frame corresponding to the original code stream, and the number of Skip blocks of the current complexity change frame in a frame after the playing sequence of the frame corresponding to the original code stream; int denotes a rounding operation.
Specifically, adjusting the quantization parameter of each frame from the current complexity change frame to the phase end frame according to the calculated value of the complexity change identifier δ is as follows: if delta is calculated and is equal to 0, acquiring a quantization parameter; otherwise, adjusting the quantization parameter according to the complexity change frame type;
specifically, the calculation formula of the obtained quantization parameter is as follows:
wherein, QPp、dQPoIndividual watchAnd displaying the difference value of the quantization parameter of the previous complexity change frame, the quantization parameter of the previous complexity change frame corresponding to the original code stream and the quantization parameter of the current transcoding frame. clip (x) represents a quantization parameter defining function known in the art; complexity change identifier
comp1/comp2＞Thres4And condition 2: comp2/comp1＞Thres4，Thres4Represents a fourth threshold;
specifically, the quantization parameter is adjusted according to the complexity change frame type as follows:
case 1: when the current complexity change frame is an I frame or a P frame,
case 2: when the current complexity change frame is a B frame,
wherein dQP is weight1*weight2；
weight1＝(compl＞(4*Thres3))+(compl＞(2*Thres3))+1；
weight2＝(comp1＜Thres5)+(comp1＜2*Thres5)；Thres5Representing a fifth threshold having a value equal to the mean of the computed complexity of the complexity change frames; the first type of frame represents the current complexity change frame to a frame that is prior to the first P frame after the current complexity change frame.
It will be understood by those skilled in the art that all or part of the steps in the method according to the above embodiments may be implemented by hardware related to program instructions, and the program may be stored in a computer readable storage medium, such as ROM, RAM, magnetic disk, optical disk, etc.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (8)
1. A method for adjusting quantization parameters of a source frame layer of a transcoded slice comprises
Identifying a complexity change frame in a transcoding frame and calculating an influence aging compl of the complexity change frame;
adaptively adjusting quantization parameters of the transcoded frames according to the influence timeliness of the complexity change frames, and then transcoding;
before the identifying the complexity change frame in the transcoded frame and calculating the influence aging of the complexity change frame, the method further comprises the following steps:
assigning initial values to the quantization parameters of the transcoding frames according to the threshold range of the absolute value of the difference value between the original bit and the target bit of the transcoding code stream in advance;
presetting current transcoding frame as initial frame
The self-adaptive adjustment of the transcoding frame quantization parameter according to the influence timeliness of the complexity change frame, and then the transcoding further comprises:
if the next frame to be transcoded of the end frame of the complexity change frame stage exists, the comp is ordered2＝comp1Setting the next transcoding frame of the complexity change frame stage ending frame as a current transcoding frame, setting the current complexity change frame as a previous complexity change frame, and then returning the complexity change frame in the marked transcoding frame and calculating the influence timeliness of the complexity change frame; otherwise, ending;
therein, comp1Representing the complexity of the current complexity change frame; comp2Representing the complexity of a previous complexity change frame;
the method for assigning initial values to the quantization parameters of the transcoding frame in advance according to the threshold range of the absolute value of the difference value between the original bit and the target bit of the transcoding code stream specifically comprises the following steps:
if bito-bit|＜Thres1Then, the quantization parameter QP of each transcoding frame is assigned with an initial value as the quantization parameter QP of the current transcoding frame corresponding to the original code streamo(ii) a Otherwise, transcoding each frame quantization parameter QP and assigning an initial value as the current transcoding frame quantization value output by the rate control module;
wherein bitoBit represents the original bit of the code stream and the target bit of the code stream respectively; thres1Denotes a first threshold value, Thres1＜10％*bito；
The identifying the complexity change frame in the transcoding frame and calculating the influence timeliness of the complexity change frame specifically include:
firstly, identifying a current transcoding frame as a current complexity change frame, and enabling an initial sequence number cur1 to be a playing sequence number of the current transcoding frame;
then, judging that if the playing sequence number is larger than that of the frame of the current transcoding frame, the number of prediction blocks in the frame is not larger than Thres2In the frame of wb hb, command comp numF-cur1, and set the end-of-stage frame as the last frame of the transcoding film source; otherwise, in the frames with the playing sequence number larger than the current transcoding frame, setting the frame with the minimum playing sequence number as the next complexity change frame, marking the minimum playing sequence number as cur2, making comp (cur 2-cur1 and note (1), and setting the stage ending frame as the previous frame of the next complexity change frame;
wherein wb and hb represent the column width and row width of the image in units of blocks; numF represents the frame number of the current transcoding source; thres2Denotes a second threshold value, Thres2Is more than 0.8; note indicates that the next complexity change frame exists identifier.
2. The method of transcoding source frame layer quantization parameter adjustment of claim 1,
the self-adaptive adjustment of the transcoding frame quantization parameter according to the influence timeliness of the complexity change frame, and then the transcoding specifically comprises the following steps:
if comp < Thres3Then transcoding directly; otherwise, calculating the current complexity by using the compression information of the current transcoding frame in the frame corresponding to the original code streamChanging the complexity of the frame; then, according to the calculated value of the complexity change identifier delta, adjusting the quantization parameters of each frame from the current complexity change frame to the stage ending frame, and then carrying out transcoding;
the compression information of the current transcoding frame in the frame corresponding to the original code stream comprises the fluctuation of the current transcoding frame in the frame code rate corresponding to the original code stream, the proportion of the current transcoding frame in the motion vector of the frame corresponding to the original code stream or the proportion of the current transcoding frame in the Skip block of the frame corresponding to the original code stream;
wherein, Thres3Denotes a third threshold value, Thres3> slice source sample frame rate/2.
3. The method for adjusting quantization parameters of a transcoding source frame layer of claim 2, wherein the calculating the complexity of the current complexity change frame is performed by any one of the following methods 1 to 3:
the method comprises the following steps: utilizing the fluctuation of the current transcoding frame in the code rate of the corresponding frame of the original code stream
comp1＝int(bitcur1/bitnext1)；
The method 2 comprises the following steps: the proportion of motion vectors in the frames corresponding to the original code stream is utilized to carry out transcoding at present
The method 3 comprises the following steps: utilizing the ratio of Skip blocks in the frames corresponding to the original code stream of the current transcoding frame
Therein, comp1Representing the complexity of the current complexity change frame; bitcur1、bitnext1Respectively representing the bit of the current complexity change frame in the frame corresponding to the original code stream and the bit of the current complexity change frame in the frame next to the playing sequence of the frame corresponding to the original code stream; mvbitcur1、mvbitnext1To indicate bitcur1、bitnext1The code rate occupied by the medium motion vector; numb, numkipcur1、numskipnext1Respectively representing the number of blocks of a current transcoding frame in a frame corresponding to an original code stream, the number of Skip blocks of a current complexity change frame in a frame corresponding to the original code stream, and the number of Skip blocks of the current complexity change frame in a frame after the playing sequence of the frame corresponding to the original code stream; int denotes a rounding operation.
4. The method for adjusting quantization parameters of a source frame layer of a transcoding slice of claim 3, wherein the adjusting of the quantization parameters of each frame from a current complexity change frame to a phase end frame according to the calculated value of the complexity change identifier δ is: if delta is calculated and is equal to 0, acquiring a quantization parameter; otherwise, adjusting the quantization parameter according to the complexity change frame type;
the calculation formula of the acquired quantization parameter is as follows:
wherein, QPp、dQPoRespectively representing the quantization parameter of the previous complexity change frame, the difference value of the quantization parameter of the previous complexity change frame corresponding to the original code stream and the quantization parameter of the current transcoding frame, and clip (x) representing the quantization parameter limiting function known in the industry; complexity change identifier
Condition 1: comp1/comp2＞Thres4And condition 2: comp2/comp1＞Thres4，Thres4Represents a fourth threshold;
the adjusting the quantization parameter according to the complexity change frame type is as follows:
case 1: when the current complexity change frame is an I frame or a P frame,
case 2: when the current complexity change frame is a B frame,
wherein dQP is weight1*weight2；
weight1＝(compl＞(4*Thres3))+(compl＞(2*Thres3))+1；
weight2＝(comp1＜Thres5)+(comp1＜2*Thres5)；Thres5Representing a fifth threshold having a value equal to the mean of the computed complexity of the complexity change frames; the first type of frame represents the current complexity change frame to a frame that is prior to the first P frame after the current complexity change frame.
5. A system for transcoding slice source frame layer quantization parameter adjustment, the system comprising:
the complexity change frame identification and influence timeliness calculation device is used for identifying the complexity change frame in the transcoding frame and calculating the influence timeliness compl of the complexity change frame;
the transcoding frame quantization parameter adjusting device is used for adaptively adjusting the quantization parameters of the transcoding frame according to the influence timeliness of the complexity change frame and then transcoding;
the system comprises:
the transcoding frame quantization parameter initial value assigning module is used for assigning an initial value to the transcoding frame quantization parameter in advance according to a threshold range of an absolute value of a difference value between an original bit and a target bit of a transcoding code stream;
the current transcoding frame initial value assigning module is connected with the complexity change frame identifier and the influence timeliness calculating device and is used for presetting the current transcoding frame as an initial frame;
a first judgment processing module connected with the transcoding frame quantization parameter adjusting device and used for judging the next frame to be transcoded of the complexity change frame stage end frameIf present, make comp2＝comp1Setting the next transcoding frame of the complexity change frame stage ending frame as the current transcoding frame, setting the current complexity change frame as the previous complexity change frame, and then returning the complexity change frame identification and the influence aging calculation device; otherwise, ending;
therein, comp2Representing the complexity of a previous complexity change frame; comp1Representing the complexity of the current complexity change frame;
the "assigning an initial value to the quantization parameter of the transcoded frame according to the threshold range of the absolute value of the difference between the original bit and the target bit of the transcoded code stream in advance" specifically includes:
if bito-bit|＜Thres1Then, the quantization parameter QP of each transcoding frame is assigned with an initial value as the quantization parameter QP of the current transcoding frame corresponding to the original code streamo(ii) a Otherwise, transcoding each frame quantization parameter QP and assigning an initial value as the current transcoding frame quantization value output by the rate control module;
wherein bitoBit represents the original bit of the code stream and the target bit of the code stream respectively; thres1Denotes a first threshold value, Thres1＜10％*bito；
The "identifying a complexity change frame in a transcoded frame and calculating an influence timeliness of the complexity change frame" specifically includes:
firstly, identifying a current transcoding frame as a current complexity change frame, and enabling an initial sequence number cur1 to be a playing sequence number of the current transcoding frame; then, judging that if the playing sequence number is larger than that of the frame of the current transcoding frame, the number of prediction blocks in the frame is not larger than Thres2In the frame of wb hb, command comp numF-cur1, and set the end-of-stage frame as the last frame of the transcoding film source; otherwise, in the frames with the playing sequence number larger than the current transcoding frame, setting the frame with the minimum playing sequence number as the next complexity change frame, marking the minimum playing sequence number as cur2, making comp (cur 2-cur1 and note (1), and setting the stage ending frame as the previous frame of the next complexity change frame;
wherein wb and hb represent the column width and row width of the image in units of blocks; numF represents the frame number of the current transcoding source; thres2Denotes a second threshold value, Thres2Is more than 0.8; note indicates that the next complexity change frame exists identifier.
6. The system of claim 5, wherein the system for transcoding source frame layer quantization parameter adjustment,
the step of adaptively adjusting the transcoding frame quantization parameter according to the influence timeliness of the complexity change frame and then transcoding specifically comprises the following steps:
if comp < Thres3Then transcoding directly; otherwise, calculating the complexity of the current complexity change frame by using the compression information of the current transcoding frame in the frame corresponding to the original code stream; then, according to the calculated value of the complexity change identifier delta, adjusting the quantization parameters of each frame from the current complexity change frame to the stage ending frame, and then carrying out transcoding;
the compression information of the current transcoding frame in the frame corresponding to the original code stream comprises the fluctuation of the current transcoding frame in the frame code rate corresponding to the original code stream, the proportion of the current transcoding frame in the motion vector of the frame corresponding to the original code stream or the proportion of the current transcoding frame in the Skip block of the frame corresponding to the original code stream;
wherein, Thres3Denotes a third threshold value, Thres3> slice source sample frame rate/2.
7. The system of claim 6,
the method for calculating the complexity of the current complexity change frame by utilizing the compression information of the current transcoding frame in the frame corresponding to the original code stream is any one of the following methods 1 to 3:
the method comprises the following steps: utilizing the fluctuation of the current transcoding frame in the code rate of the corresponding frame of the original code stream
comp1＝int(bitcur1/bitnext1)；
The method 2 comprises the following steps: the proportion of motion vectors in the frames corresponding to the original code stream is utilized to carry out transcoding at present
The method 3 comprises the following steps: utilizing the ratio of Skip blocks in the frames corresponding to the original code stream of the current transcoding frame
Therein, comp1Representing the complexity of the current complexity change frame; bitcur1、bitnext1Respectively representing the bit of the current complexity change frame in the frame corresponding to the original code stream and the bit of the current complexity change frame in the frame next to the playing sequence of the frame corresponding to the original code stream; mvbitcur1、mvbitnext1To indicate bitcur1、bitnext1The code rate occupied by the medium motion vector; numb, numkipcur1、numskipnext1Respectively representing the number of blocks of a current transcoding frame in a frame corresponding to an original code stream, the number of Skip blocks of a current complexity change frame in a frame corresponding to the original code stream, and the number of Skip blocks of the current complexity change frame in a frame after the playing sequence of the frame corresponding to the original code stream; int denotes a rounding operation.
8. The system of claim 7, wherein the system for transcoding source frame layer quantization parameter adjustment,
adjusting the quantization parameter of each frame from the current complexity change frame to the phase ending frame according to the calculated value of the complexity change identifier delta as follows: if delta is calculated and is equal to 0, acquiring a quantization parameter; otherwise, adjusting the quantization parameter according to the complexity change frame type;
the calculation formula of the acquired quantization parameter is as follows:
wherein, QPp、dQPoRespectively representing the quantization parameter of the previous complexity change frame, the difference value of the quantization parameter of the previous complexity change frame corresponding to the original code stream and the quantization parameter of the current transcoding frameClip (x) represents a quantization parameter defining function known in the art; complexity change identifier
Condition 1: comp1/comp2＞Thres4And condition 2: comp2/comp1＞Thres4，Thres4Represents a fourth threshold;
the adjusting the quantization parameter according to the complexity change frame type is as follows:
case 1: when the current complexity change frame is an I frame or a P frame,
case 2: when the current complexity change frame is a B frame,
wherein dQP is weight1*weight2；weight1＝(compl＞(4*Thres3))+(compl＞(2*Thres3))+1；weight2＝(comp1＜Thres5)+(comp1＜2*Thres5)；Thres5Representing a fifth threshold having a value equal to the mean of the computed complexity of the complexity change frames; the first type of frame represents the current complexity change frame to a frame that is prior to the first P frame after the current complexity change frame.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911061721.2A CN110753242B (en) | 2019-11-01 | 2019-11-01 | Method and system for adjusting quantization parameters of transcoding slice source frame layer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911061721.2A CN110753242B (en) | 2019-11-01 | 2019-11-01 | Method and system for adjusting quantization parameters of transcoding slice source frame layer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110753242A CN110753242A (en) | 2020-02-04 |
| CN110753242B true CN110753242B (en) | 2021-10-12 |
Family
ID=69281874
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911061721.2A Active CN110753242B (en) | 2019-11-01 | 2019-11-01 | Method and system for adjusting quantization parameters of transcoding slice source frame layer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110753242B (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1315118A (en) * | 1998-08-27 | 2001-09-26 | 通用仪器公司 | Dynamic bit allocation for statistical multiplexing of compressed and uncompressed digital divdeo signals |
| CN1393109A (en) * | 2000-10-10 | 2003-01-22 | 皇家菲利浦电子有限公司 | Video bitrate control method and device for digital video recording |
| CN1726709A (en) * | 2002-12-10 | 2006-01-25 | Tut系统公司 | Rate control with picture-based lookahead window |
| CN101102494A (en) * | 2007-07-23 | 2008-01-09 | 武汉大学 | A control method for macro block code rate in video code conversion |
| CN101594525A (en) * | 2008-05-31 | 2009-12-02 | 华为技术有限公司 | The acquisition methods of quantization parameter, device and transcoder |
| CN104202660A (en) * | 2014-09-15 | 2014-12-10 | 乐视网信息技术（北京）股份有限公司 | Video dividing and transcoding method and device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7263126B2 (en) * | 2003-09-15 | 2007-08-28 | Sharp Laboratories Of America, Inc. | System and method for transcoding with adaptive bit rate control |
-
2019
- 2019-11-01 CN CN201911061721.2A patent/CN110753242B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1315118A (en) * | 1998-08-27 | 2001-09-26 | 通用仪器公司 | Dynamic bit allocation for statistical multiplexing of compressed and uncompressed digital divdeo signals |
| CN1393109A (en) * | 2000-10-10 | 2003-01-22 | 皇家菲利浦电子有限公司 | Video bitrate control method and device for digital video recording |
| CN1726709A (en) * | 2002-12-10 | 2006-01-25 | Tut系统公司 | Rate control with picture-based lookahead window |
| CN101102494A (en) * | 2007-07-23 | 2008-01-09 | 武汉大学 | A control method for macro block code rate in video code conversion |
| CN101594525A (en) * | 2008-05-31 | 2009-12-02 | 华为技术有限公司 | The acquisition methods of quantization parameter, device and transcoder |
| CN104202660A (en) * | 2014-09-15 | 2014-12-10 | 乐视网信息技术（北京）股份有限公司 | Video dividing and transcoding method and device |
Non-Patent Citations (2)
| Title |
|---|
| Temporal Video Transcoding Based on Frame Complexity Analysis for Mobile Video Communication;C. Yeh等;《 IEEE Transactions on Broadcasting》;20130331;第59卷(第1期);38-46 * |
| 基于H.264的转码初始量化参数自适应选择;张安娜等;《计算机工程》;20170531;281-285 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110753242A (en) | 2020-02-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP3179720B1 (en) | Quantization method and apparatus in encoding/decoding | |
| US7925108B2 (en) | Encoding device and dynamic image recording system having the encoding device | |
| CN110178374B (en) | Segment-based shaping for encoding high dynamic range video | |
| KR20180100368A (en) | Image decoding and encoding method, decoding and encoding device, decoder and encoder | |
| KR20220013024A (en) | Decoding device, method, and program | |
| JP2003018603A (en) | Method and device for encoding moving image | |
| US11330263B1 (en) | Machine learning based coded size estimation in rate control of video encoding | |
| US11012698B2 (en) | Image encoding apparatus and method for controlling the same | |
| US20080075164A1 (en) | Motion picture encoding apparatus and method | |
| US7961787B2 (en) | Method of video content complexity estimation, scene change detection and video encoding | |
| US10536696B2 (en) | Image encoding device and image encoding method | |
| US20090096878A1 (en) | Digital image stabilization method | |
| JP2019110376A (en) | Decode error detection estimation device, video decoding device, and program for the devices | |
| US9014255B2 (en) | System and method for identifying unique portions of videos with validation and predictive scene changes | |
| US20100027617A1 (en) | Method and apparatus for compressing a reference frame in encoding/decoding moving images | |
| CN110753242B (en) | Method and system for adjusting quantization parameters of transcoding slice source frame layer | |
| JP2004040811A (en) | Method and apparatus for controlling amount of dct computation performed to encode motion image | |
| JP2000059792A (en) | High efficiency encoding device of dynamic image signal | |
| CN110636330B (en) | Film source scene complexity analysis method and system based on compressed information | |
| US20090185620A1 (en) | Video encoding apparatus and method for the same | |
| CN112822493A (en) | Adaptively encoding video frames based on complexity | |
| KR101461365B1 (en) | A method and apparatus for encoding and decoding image for controlling quantization parameter considering contents type | |
| JP4793150B2 (en) | Video signal processing apparatus, video signal information processing method, and program | |
| US20230269380A1 (en) | Encoding method, decoding method, encoder, decoder and storage medium | |
| CN104837015B (en) | Low latency coding adaptation QP Offset adjusting methods |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB02 | Change of applicant information | ||
| CB02 | Change of applicant information |
Address after: 518000 Guangdong city of Shenzhen province Nanshan District Guangdong streets high in the four Longtaili Technology Building Room 325 No. 30 Applicant after: Shenzhen mengwang video Co., Ltd Address before: 518000 Guangdong city of Shenzhen province Nanshan District Guangdong streets high in the four Longtaili Technology Building Room 325 No. 30 Applicant before: SHENZHEN MONTNETS ENCYCLOPEDIA INFORMATION TECHNOLOGY Co.,Ltd. |
|
| GR01 | Patent grant | ||
| GR01 | Patent grant |