CN102970524B - Video transmission method, equipment and system in wireless network - Google Patents
Video transmission method, equipment and system in wireless network Download PDFInfo
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Abstract
The present invention provides video transmission method, equipment and system in a kind of wireless network。The method includes the average radio channel information and the error concealment information that send according to coding information corresponding to different application layer coding parameters, different transport parameters for physical layer, Access Network, it is determined that different application layer coding parameters and the distortion factor corresponding to different transport parameters for physical layer and occupation condition；By the distortion factor less than the threshold value arranged and transport parameters for physical layer when taking least resource and application layer coding parameter, it is determined that be the first transport parameters for physical layer and the first application layer coding parameter；Adopt the video unit coding that video server is sent by described first application layer coding parameter, and the video unit after coding is sent to Access Network。The embodiment of the present invention can improve transmission of video performance。
Description
Technical Field
The present invention relates to wireless communication technologies, and in particular, to a method, device, and system for video transmission in a wireless network.
Background
Video becomes the service with the largest flow in network communication, and the video service occupies a large amount of system bandwidth and reduces the system capacity while providing rich information. Due to the scarcity of wireless resources, from the perspective of operators, a good wireless video communication system should be able to achieve the maximum system capacity, and at the same time, provide satisfactory user experience, where the maximum system capacity supports the maximum number of users, and the user experience is, for example, the received video quality, the video continuity, and the like.
According to the hierarchical concept of the network, each layer of a typical video communication system has its corresponding key parameters, for example, the application layer is a Discrete Cosine Transform (DCT) coefficient including a DCT Quantization Parameter (QP) and/or a DCT truncation amount, and the physical layer is a Modulation Coding Scheme (MCS). The value of each layer of key parameters seriously affects the performance of the system. At present, each layer of key parameters is designed in a layered manner, and the key parameters of each layer are the optimal selection of the corresponding layer. However, the hierarchical design scheme can only achieve local optimal selection of parameter values of each layer, and cannot achieve the optimal video communication effect on the whole, that is, the user experience cannot be met, and a large system capacity cannot be achieved.
Disclosure of Invention
The embodiment of the invention provides a video transmission method, equipment and a system in a wireless network, which can improve the system capacity on the basis of meeting the user experience.
In one aspect, an embodiment of the present invention provides a method for transmitting video in a wireless network, including:
the first equipment determines distortion degrees and resource occupation conditions corresponding to different application layer coding parameters and different physical layer transmission parameters according to coding information corresponding to the different application layer coding parameters, different physical layer transmission parameters, average wireless channel information sent by an access network and error compensation information;
the method comprises the steps that first equipment determines a physical layer transmission parameter and an application layer coding parameter when distortion degree is smaller than a set threshold value and minimum resources are occupied as a first physical layer transmission parameter and a first application layer coding parameter, and sends video stream information determined according to coding information and video stream transmission requirement information corresponding to the first physical layer transmission parameter to an access network, so that the access network determines a second physical layer transmission parameter according to the video stream information and the video stream transmission requirement information;
and the first equipment adopts the first application layer coding parameter to code the video unit sent by the video server and sends the coded video unit to the access network, so that the access network adopts the second physical layer transmission parameter to carry out physical layer processing on the received video unit and then sends the processed video unit.
In another aspect, an embodiment of the present invention provides a method for transmitting video in a wireless network, including:
the second equipment sends the average wireless channel information to the first equipment, so that the first equipment determines a first physical layer transmission parameter and a first application layer coding parameter when the distortion degree is smaller than a set threshold value and occupies the minimum resource according to the average wireless channel information;
the second equipment receives the video stream information sent by the first equipment and the video stream transmission requirement information corresponding to the first physical layer transmission parameter, and determines a second physical layer transmission parameter according to the real-time wireless channel information, the video stream information and the video stream transmission requirement information;
and the second equipment receives the video unit coded by the first equipment by adopting the first application layer coding parameter, and sends the video unit after the second physical layer transmission parameter is adopted to carry out physical layer processing on the video unit.
In one aspect, an embodiment of the present invention provides a video transmission device in a wireless network, including:
the distortion degree evaluation and occupied resource block calculation module is used for determining the distortion degrees and resource occupation conditions corresponding to different application layer coding parameters and different physical layer transmission parameters according to coding information corresponding to different application layer coding parameters, different physical layer transmission parameters, average wireless channel information sent by an access network and error compensation information;
an optimal parameter combination selection module, configured to determine a physical layer transmission parameter and an application layer coding parameter when the distortion obtained by the distortion evaluation and resource block occupation calculation module is smaller than a set threshold and occupies a minimum resource, as a first physical layer transmission parameter and a first application layer coding parameter, and send video stream information determined according to the coding information and video stream transmission requirement information corresponding to the first physical layer transmission parameter to an access network, so that the access network determines a second physical layer transmission parameter according to the video stream information and the video stream transmission requirement information;
and the coding module is used for coding the video unit sent by the video server by adopting the first application layer coding parameter obtained by the optimal parameter combination selection module and sending the coded video unit to the access network, so that the access network performs physical layer processing on the received video unit by adopting the second physical layer transmission parameter and then sends the processed video unit.
In another aspect, an embodiment of the present invention provides a video transmission device in a wireless network, including:
the channel information collection module is used for sending average wireless channel information to first equipment, so that the first equipment determines a first physical layer transmission parameter and a first application layer coding parameter when the distortion degree is smaller than a set threshold value and the minimum resource is occupied according to the average wireless channel information;
the selection module is used for receiving the video stream information sent by the first equipment and the video stream transmission requirement information corresponding to the first physical layer transmission parameter, and determining a second physical layer transmission parameter according to the real-time wireless channel information, the video stream information and the video stream transmission requirement information;
and the transmission module is used for receiving the video unit coded by the first device by adopting the first application layer coding parameter, and sending the video unit after the video unit is subjected to physical layer processing by adopting the second physical layer transmission parameter.
The embodiment of the invention also provides a video transmission system in a wireless network, which comprises:
two devices as described above.
According to the technical scheme, when the parameters of each layer are determined, the parameters of other layers are combined for determination, the information of each layer is combined and considered, the overall optimal parameters including each layer can be realized, the overall optimization is realized, and the system capacity is improved on the basis of meeting the user experience.
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In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive labor.
Fig. 1 is a flowchart illustrating a video transmission method in a wireless network according to an embodiment of the present invention;
FIG. 2 is a flowchart illustrating an embodiment of distortion estimation;
FIG. 3 is a schematic diagram of error compensation in an embodiment of the invention;
FIG. 4 is a flowchart illustrating a video transmission method in a wireless network according to another embodiment of the present invention;
FIG. 5 is a flowchart illustrating a video transmission method in a wireless network according to another embodiment of the present invention;
FIG. 6 is a block diagram of a video transmission device in a wireless network according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a video transmission device in a wireless network according to another embodiment of the present invention;
fig. 8 is a schematic structural diagram of a video transmission system in a wireless network according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a schematic flowchart of a video transmission method in a wireless network according to an embodiment of the present invention, including:
step 11: the first device determines the distortion degree and the resource occupation condition corresponding to different application layer coding parameters and different physical layer transmission parameters according to coding information corresponding to the different application layer coding parameters, different physical layer transmission parameters, average wireless channel information sent by an access network and error compensation information.
The first device may be located in a video server (video server), or in a core network, or in a network element in an access network, such as a base station.
The application layer coding parameter may be a DCT coefficient, and specifically may be a DCT quantization parameter QP or a DCT truncation amount, or a combination of both.
The physical layer transmission parameter may be an MCS.
The average wireless channel information may be an average signal-to-noise ratio (SNR).
The encoded information may include: code rate, pixel values, and offset information.
Further, the coding information corresponding to different application layer coding parameters can be obtained as follows:
and coding the video unit sent by the video server by adopting different application layer coding parameters to obtain coding information corresponding to the different application layer coding parameters.
For example, taking DCT coefficients as QP as an example, coding a video unit by using QP1, and outputting code rate, pixel value and offset information corresponding to QP1 in the coding process; and encoding the video unit by using the QP2, and outputting the code rate, the pixel value and the offset information corresponding to the QP2 in the encoding process. By analogy, the coding information corresponding to all QPs can be obtained through traversal.
It should be noted that, if the first device is located in the video server, the video unit generated by the video server and not subjected to encoding can be directly subjected to the above-mentioned encoding. If the first device is located in the core network or the access network, the encoded video unit sent by the video server needs to be decoded, and then the decoded video unit is encoded.
One video unit may be a group of pictures (GOP), a frame (frame), or a Slice (Slice).
The distortion metric (dist) may be implemented using an existing video distortion estimation algorithm (ROPE). In this algorithm, taking a DCT coefficient as QP as an example, the distortion degree is a function of a Packet Loss Ratio (PLR), a pixel value and offset information corresponding to the QP and QP, and error compensation information of the video terminal, that is, the distortion degree can be expressed as:
dist ═ f (PLR, QP, pixel value and offset information, error compensation information),
since the specific expression is complicated and is also prior art, specific contents can be found in the prior literature.
Fig. 2 is a schematic flow chart of estimating distortion in the embodiment of the present invention, and referring to fig. 2, PLR may be determined according to a physical block error rate (PER) and a packet length L, where a calculation formula may be expressed as:
PLR＝1-(1-PER)L/block_size
the PER can be obtained by looking up a table, the table is an existing simulation experience table, the corresponding relation of SNR, MCS and PER is recorded, and the PER value when the average SNR and the different MCS are found according to the table.
L may be obtained by multiplying the duration of the video unit by the code rate, block size is a value associated with the communication system and MCS, and the block _ size value corresponding to a different MCS in the current communication system may be determined by table lookup.
Thus, at different QPs and different MCS, corresponding distortion levels can be obtained, e.g., when QP is qjMCS being ckThen, the corresponding distortion factor is:
Djk＝f(PLR(ck)，qjpixel value and offset information, error compensation information).
The above-mentioned error compensation information can be obtained as follows:
receiving error compensation information reported by a video terminal; or,
determining macroblock information corresponding to a position of a macroblock lost by the video unit in a video unit adjacent to the video unit as error compensation information of the lost macroblock.
For example, fig. 3 is a schematic diagram of error compensation in an embodiment of the present invention, and referring to fig. 3, a macroblock (macroblock) in a slice lost in the nth frame picture is compensated by a macroblock in the same position in the n-1 th frame picture.
In addition, the resource occupation situation can be obtained by adopting the following calculation formula:
wherein N isjkNumber of resource blocks occupied for one video unit, l (q)j) For using QP of qjNumber of bits occupied, theta (c)k) For the adopted MCS to be ckSpectral efficiency of time, N0The number of bits occupied for a single resource block. For example, in an LTE system, assuming that one resource block contains 12 subcarriers and 14 symbols, N0＝12×14。
Step 12: the first device determines a physical layer transmission parameter and an application layer coding parameter when the distortion degree is smaller than a set threshold value and occupies a minimum resource as a first physical layer transmission parameter and a first application layer coding parameter, and sends video stream information determined according to the coding information and video stream transmission requirement information corresponding to the first physical layer transmission parameter to an access network, so that the access network determines a second physical layer transmission parameter according to the video stream information and the video stream transmission requirement information.
Taking DCT coefficient as QP as an example, q can be obtained by the above operationjAnd ckCorresponding DjkAnd NjkAfter that, D is putjk＜DmaxAnd N isjkThe minimum QP and MCS combination is determined to be the optimal combination, where the QP is referred to as the first application layer coding parameter and the MCS is referred to as the first physical layer transmission parameter.
Step 13: and the first equipment adopts the first application layer coding parameter to code the video unit sent by the video server and sends the coded video unit to the access network, so that the access network adopts the second physical layer transmission parameter to carry out physical layer processing on the received video unit and then sends the processed video unit.
When the first device is positioned in the video server, the first device adopts the first application layer coding parameters to code the video unit generated by the video server; if the first device is located in the core network or the access network, the first device first decodes the video unit sent by the video server, and then re-encodes (or transcodes) the video unit by using the first application layer encoding parameters.
In the embodiment, the DCT coefficient and the MCS which satisfy the requirement of the distortion degree and occupy the minimum resource are calculated, the DCT coefficient is used for final application layer processing, and the video transmission requirement corresponding to the MCS is used for the access network to calculate the physical layer transmission parameter, so that a cross-layer optimal scheme can be realized, and the system capacity is maximized on the basis of satisfying the user experience.
Fig. 4 is a flowchart illustrating a video transmission method in a wireless network according to another embodiment of the present invention, including:
step 41: the second equipment sends the average wireless channel information to the first equipment, so that the first equipment determines a first physical layer transmission parameter and a first application layer coding parameter when the distortion degree is smaller than a set threshold value and occupies the minimum resource according to the average wireless channel information.
The second device may be located in the access network, and the first device may be located in the video server, the core network, or the access network.
The average wireless channel information may be an average SNR.
The process of the first device calculating the first application layer coding parameter and the first physical layer transmission parameter after receiving the average SNR may refer to the above embodiment.
The average SNR may be statistically averaged by the second device based on the real-time SNR.
The second device can receive the real-time SNR reported by the video terminal and can also actively detect to obtain the real-time SNR.
Step 42: and the second equipment receives the video stream information sent by the first equipment and the video stream transmission requirement information corresponding to the first physical layer transmission parameter, and determines a second physical layer transmission parameter according to the real-time wireless channel information, the video stream information and the video stream transmission requirement information.
The video stream information may be a packet length L.
The video streaming requirement information may be PLR.
The real-time wireless channel information may be a real-time SNR.
Taking the physical layer transmission parameter as MCS as an example, the second physical layer transmission parameter can be determined as follows:
according to the real-time SNR and different MCS, obtaining the block error rate of the physical layer when the MCS is different through table look-up; obtaining packet loss rates of different MCS according to the physical layer block error rate and the packet length of the different MCS;
the details of the above two steps can be found in the above embodiment, i.e., corresponding to ckCan obtain PLRk。
And then, determining the MCS with the highest modulation level as a second physical layer transmission parameter, wherein the corresponding packet loss rate is smaller than the PLR. I.e. mixing PLRkThe MCS at the time of the PLR sent by the first device is set as the optional MCS, and when there are a plurality of optional MCSs, the MCS with the highest modulation level is determined as the second physical layer transmission parameter. Each MCS has a corresponding modulation level, and for example, the modulation level of 64 Quadrature Amplitude Modulation (QAM) is higher than the modulation levels of Quadrature Phase Shift Keying (QPSK) and Binary Phase Shift Keying (BPSK).
Step 43: and the second equipment receives the video unit coded by the first equipment by adopting the first application layer coding parameter, and sends the video unit after the second physical layer transmission parameter is adopted to carry out physical layer processing on the video unit.
For example, after receiving the video unit encoded by the first device using the first application layer encoding parameter, the second device performs physical layer modulation using the second physical layer transmission parameter.
In the embodiment, the application layer is processed by adopting the DCT coefficient which meets the requirement of distortion degree and occupies the minimum resource, and the physical layer is processed by adopting the video transmission requirement corresponding to the MCS under the optimization condition in real time, so that a cross-layer optimal scheme can be realized, and the system capacity is maximized on the basis of meeting the user experience.
The above describes the flow of video transmission with one side, and the embodiment of the present invention may combine the first device and the second device to perform joint processing to achieve cross-layer optimization.
Fig. 5 is a flowchart illustrating a video transmission method in a wireless network according to another embodiment of the present invention, including:
step 51: the second device sends the average wireless channel information to the first device;
the wireless channel information may be SNR, and the second device may be obtained by performing statistical averaging according to the real-time SNR.
Step 52: the first device determines distortion degrees and resource occupation conditions corresponding to different application layer coding parameters and different physical layer transmission parameters according to coding information corresponding to the different application layer coding parameters, different physical layer transmission parameters, average wireless channel information sent by the second device and error compensation information, and determines the physical layer transmission parameters and the application layer coding parameters when the distortion degrees are smaller than a set threshold value and occupy minimum resources as first physical layer transmission parameters and first application layer coding parameters.
Step 53: and the first equipment sends the video stream information determined according to the coding information and the video stream transmission requirement information corresponding to the first physical layer transmission parameter to the second equipment.
Step 54: and the first equipment adopts the first application layer coding parameter to code the video unit sent by the video server and sends the coded video unit to the second equipment.
Step 55: and the second equipment receives the video stream information sent by the first equipment and the video stream transmission requirement information corresponding to the first physical layer transmission parameter, and determines a second physical layer transmission parameter according to the real-time wireless channel information, the video stream information and the video stream transmission requirement information.
Step 56: and the second equipment receives the video unit which is coded by the first equipment by adopting the first application layer coding parameter, and sends the video unit after the second physical layer transmission parameter is adopted to carry out physical layer processing on the video unit.
The details of the above steps can be seen in the embodiment shown in fig. 3 or fig. 4.
In the embodiment, the first device processes the video transmission requirement corresponding to the MCS when the first device uses the DCT coefficient satisfying the distortion requirement and occupying the minimum resource in the application layer, and the second device processes the video transmission requirement corresponding to the MCS when the second device uses the above optimization condition in the real-time corresponding MCS, so that a cross-layer optimal scheme can be realized, and the system capacity is maximized on the basis of satisfying the user experience.
Fig. 6 is a schematic structural diagram of an embodiment of a video transmission device in a wireless network according to the present invention, where the device may be specifically the first device described above, and the device may be located in a video server, a core network, or an access network, and the device includes a distortion estimation and occupation resource block calculation module 61, an optimal parameter combination selection module 62, and an encoding module 63, where the distortion estimation and occupation resource block calculation module 61 is configured to determine distortion degrees and resource occupation situations corresponding to different application layer encoding parameters and different physical layer transmission parameters according to encoding information corresponding to the different application layer encoding parameters, the different physical layer transmission parameters, average wireless channel information sent by the access network, and error compensation information; the optimal parameter combination selection module 62 is configured to determine a physical layer transmission parameter and an application layer coding parameter when the distortion obtained by the distortion evaluation and resource block occupation calculation module 61 is smaller than a set threshold and occupies a minimum resource, as a first physical layer transmission parameter and a first application layer coding parameter, and send video stream information determined according to the coding information and video stream transmission requirement information corresponding to the first physical layer transmission parameter to an access network, so that the access network determines a second physical layer transmission parameter according to the video stream information and the video stream transmission requirement information; the encoding module 63 is configured to encode the video unit sent by the video server by using the first application layer encoding parameter obtained by the optimal parameter combination selection module 62, and send the encoded video unit to the access network, so that the access network performs physical layer processing on the received video unit by using the second physical layer transmission parameter and then sends the video unit.
In one embodiment, the encoding module 63 is further configured to: and coding the video unit by adopting different application layer coding parameters to obtain coding information corresponding to the different application layer coding parameters.
In one embodiment, the average wireless channel information is an average SNR, the physical layer transmission parameter is an MCS, the application layer coding parameter is a DCT coefficient, the DCT coefficient is a DCT quantization parameter QP and/or a DCT truncation amount, the coding information includes a code rate, a pixel value, and offset information, and the distortion estimation and resource block occupation calculation module 61 is specifically configured to: according to the average SNR and the MCS, obtaining the block error rate of the physical layer when different MCS are obtained through table look-up; obtaining the packet length of a data packet according to the code rate; obtaining packet loss rates of different MCS according to the physical layer block error rate and the packet length of the different MCS; and obtaining the distortion degree and the resource occupation condition when the MCS and the DCT coefficient are different according to the packet loss rate when the MCS is different, the DCT coefficient, the corresponding pixel value and the offset information thereof and the error compensation information.
In one embodiment, the distortion factor evaluation and occupied resource block calculation module is further configured to: receiving error compensation information reported by a video terminal; or, determining macroblock information corresponding to a position of a macroblock lost by the video unit in a video unit adjacent to the video unit as error compensation information of the lost macroblock.
When the device is located in an access network or a core network, the device may further include a decoding module, configured to decode a source video unit sent by a video server, so that the encoding module encodes the decoded video unit by using the first application layer encoding parameter.
Taking the DCT coefficient as the QP as an example, the calculation formula of the resource occupation situation when obtaining different MCSs and different DCT coefficients is:
wherein N isjkNumber of resource blocks occupied for one video unit, l (q)j) For using QP of qjNumber of bits occupied, theta (c)k) For the adopted MCS to be ckSpectral efficiency of time, N0The number of bits occupied for a single resource block.
In the embodiment, the DCT coefficient and the MCS which satisfy the requirement of the distortion degree and occupy the minimum resource are calculated, the DCT coefficient is used for final application layer processing, and the video transmission requirement corresponding to the MCS is used for the access network to calculate the physical layer transmission parameter, so that a cross-layer optimal scheme can be realized, and the system capacity is maximized on the basis of satisfying the user experience.
Fig. 7 is a schematic structural diagram of another embodiment of a video transmission device in a wireless network according to the present invention, which may be embodied as the second device described above, and which may be located in an access network, and which includes a channel information collection module 71, a selection module 72, and a transmission module 73; the channel information collection module 71 is configured to send average wireless channel information to a first device, so that the first device determines, according to the average wireless channel information, a first physical layer transmission parameter and a first application layer coding parameter when a distortion degree is smaller than a set threshold and occupies a minimum resource; the fine selection module 72 is configured to receive the video stream information sent by the first device and the video stream transmission requirement information corresponding to the first physical layer transmission parameter, and determine a second physical layer transmission parameter according to the real-time wireless channel information and the video stream transmission requirement information; the transmission module 73 is configured to receive the video unit encoded by the first device using the first application layer encoding parameter, perform physical layer processing on the video unit using the second physical layer transmission parameter, and send the video unit.
In one embodiment, the real-time wireless channel information is a real-time SNR, the video stream information is a packet length L, the video stream transmission requirement information is a PLR, the physical layer transmission parameter is an MCS, and the refining module 72 is specifically configured to: according to the real-time SNR and different MCS, obtaining the block error rate of the physical layer when the MCS is different through table look-up; obtaining packet loss rates of different MCS according to the physical layer block error rate and the packet length of the different MCS; and determining the MCS with the highest modulation level as the transmission parameter of the second physical layer, wherein the corresponding packet loss rate is smaller than the PLR.
In one embodiment, the channel information collecting module 71 is further configured to: and receiving wireless channel information reported by a video terminal in real time, or actively detecting to obtain the real-time wireless channel information, and performing statistical averaging on the real-time channel information to obtain average wireless channel information.
In the embodiment, the DCT coefficient and the MCS which satisfy the requirement of the distortion degree and occupy the minimum resource are calculated, the DCT coefficient is used for final application layer processing, and the video transmission requirement corresponding to the MCS is used for the access network to calculate the physical layer transmission parameter, so that a cross-layer optimal scheme can be realized, and the system capacity is maximized on the basis of satisfying the user experience.
Fig. 8 is a schematic structural diagram of an embodiment of a video transmission system in a wireless network according to the present invention, where the system includes a first device 81 and a second device 82, the first device 81 may be as shown in fig. 6, and the second device 82 may be as shown in fig. 7. In addition, the first device 81 may be located in a video server, a core network, or an access network, and the second device 82 may be located in the access network.
In the embodiment, the first device processes the video transmission requirement corresponding to the MCS when the first device uses the DCT coefficient satisfying the distortion requirement and occupying the minimum resource in the application layer, and the second device processes the video transmission requirement corresponding to the MCS when the second device uses the above optimization condition in the real-time corresponding MCS, so that a cross-layer optimal scheme can be realized, and the system capacity is maximized on the basis of satisfying the user experience.
It will be appreciated that the relevant features of the method and apparatus described above are referred to one another. In addition, "first", "second", and the like in the above embodiments are for distinguishing the embodiments, and do not represent merits of the embodiments.
Those of ordinary skill in the art will understand that: all or part of the steps for realizing the method embodiments can be completed by hardware related to program instructions, the program can be stored in a computer readable storage medium, and the program executes the steps comprising the method embodiments when executed; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (18)
1. A method for video transmission in a wireless network, comprising:
the first equipment determines distortion degrees and resource occupation conditions corresponding to different application layer coding parameters and different physical layer transmission parameters according to coding information corresponding to the different application layer coding parameters, different physical layer transmission parameters, average wireless channel information sent by an access network and error compensation information;
the method comprises the steps that first equipment determines a physical layer transmission parameter and an application layer coding parameter when distortion degree is smaller than a set threshold value and minimum resources are occupied as a first physical layer transmission parameter and a first application layer coding parameter, and sends video stream information determined according to coding information and video stream transmission requirement information corresponding to the first physical layer transmission parameter to an access network, so that the access network determines a second physical layer transmission parameter according to the video stream information and the video stream transmission requirement information;
and the first equipment adopts the first application layer coding parameter to code the video unit sent by the video server and sends the coded video unit to the access network, so that the access network adopts the second physical layer transmission parameter to carry out physical layer processing on the received video unit and then sends the processed video unit.
2. The method of claim 1, wherein before determining the distortion and the resource occupation of the different application layer coding parameters and the different physical layer transmission parameters according to the coding information corresponding to the different application layer coding parameters, the different physical layer transmission parameters, the average radio channel information sent by the access network, and the error compensation information, the first device further comprises:
and the first equipment adopts different application layer coding parameters to code the video unit to obtain coding information corresponding to the different application layer coding parameters.
3. The method according to claim 1, wherein the average radio channel information is an average signal-to-noise ratio (SNR), the physical layer transmission parameter is a Modulation Coding Scheme (MCS), the application layer coding parameter is a Discrete Cosine Transform (DCT) coefficient, the DCT coefficient is a DCT Quantization Parameter (QP) and/or a DCT truncation, the coding information includes a code rate, a pixel value and offset information, and the determining the distortion and the resource occupation status corresponding to the different application layer coding parameters and the different physical layer transmission parameters according to the coding information corresponding to the different application layer coding parameters, the different physical layer transmission parameters, the average radio channel information sent by the access network, and the error compensation information comprises:
according to the average SNR and the MCS, obtaining the block error rate of the physical layer when different MCS are obtained through table look-up;
obtaining the packet length of a data packet according to the code rate;
obtaining packet loss rates of different MCS according to the physical layer block error rate and the packet length of the different MCS;
and obtaining the distortion degree and the resource occupation condition when the MCS and the DCT coefficient are different according to the packet loss rate when the MCS is different, the DCT coefficient, the corresponding pixel value and the offset information thereof and the error compensation information.
4. The method of claim 1, further comprising:
the first equipment receives error compensation information reported by a video terminal; or,
the first device determines macroblock information corresponding to a position of a macroblock lost by the video unit in a video unit adjacent to the video unit as error compensation information of the lost macroblock.
5. The method of claim 1, wherein prior to encoding the video unit sent by the video server using the first application layer encoding parameters, the method further comprises:
the first device decodes a source video unit sent by a video server so as to encode the decoded video unit by using the first application layer encoding parameter.
6. The method of any one of claims 1-5, further comprising:
the second equipment sends average wireless channel information to the first equipment, so that the first equipment determines a first physical layer transmission parameter and a first application layer coding parameter when the distortion degree is smaller than a set threshold value and occupies a minimum resource according to the average wireless channel information;
the second equipment receives the video stream information sent by the first equipment and the video stream transmission requirement information corresponding to the first physical layer transmission parameter, and determines a second physical layer transmission parameter according to the real-time wireless channel information, the video stream information and the video stream transmission requirement information;
the second device receives the video unit coded by the first device by adopting the first application layer coding parameter, and sends the video unit after the physical layer processing is carried out on the video unit by adopting the second physical layer transmission parameter;
wherein the second device is located in the access network.
7. A method for video transmission in a wireless network, comprising:
the second equipment sends the average wireless channel information to the first equipment, so that the first equipment determines a first physical layer transmission parameter and a first application layer coding parameter when the distortion degree is smaller than a set threshold value and occupies the minimum resource according to the average wireless channel information;
the second equipment receives the video stream information sent by the first equipment and the video stream transmission requirement information corresponding to the first physical layer transmission parameter, and determines a second physical layer transmission parameter according to the real-time wireless channel information, the video stream information and the video stream transmission requirement information;
and the second equipment receives the video unit coded by the first equipment by adopting the first application layer coding parameter, and sends the video unit after the second physical layer transmission parameter is adopted to carry out physical layer processing on the video unit.
8. The method of claim 7, wherein the real-time wireless channel information is a real-time signal-to-noise ratio (SNR), the video stream information is a packet length (L), the video stream transmission requirement information is a Packet Loss Ratio (PLR), the physical layer transmission parameter is a Modulation and Coding Scheme (MCS), and the determining the second physical layer transmission parameter comprises:
according to the real-time SNR and different MCS, obtaining the block error rate of the physical layer when the MCS is different through table look-up;
obtaining packet loss rates of different MCS according to the physical layer block error rate and the packet length of the different MCS;
and determining the MCS with the highest modulation level as the transmission parameter of the second physical layer, wherein the corresponding packet loss rate is smaller than the PLR.
9. The method of claim 7 or 8, wherein before the second device sends the average radio channel information to the first device, further comprising:
the second equipment receives real-time wireless channel information reported by a video terminal, and average wireless channel information is obtained after the real-time wireless channel information is subjected to statistical averaging;
or,
the second device actively detects to obtain real-time wireless channel information, and obtains average wireless channel information after performing statistical averaging on the real-time wireless channel information.
10. A video transmission device in a wireless network, comprising:
the distortion degree evaluation and occupied resource block calculation module is used for determining the distortion degrees and resource occupation conditions corresponding to different application layer coding parameters and different physical layer transmission parameters according to coding information corresponding to different application layer coding parameters, different physical layer transmission parameters, average wireless channel information sent by an access network and error compensation information;
an optimal parameter combination selection module, configured to determine a physical layer transmission parameter and an application layer coding parameter when the distortion obtained by the distortion evaluation and resource block occupation calculation module is smaller than a set threshold and occupies a minimum resource, as a first physical layer transmission parameter and a first application layer coding parameter, and send video stream information determined according to the coding information and video stream transmission requirement information corresponding to the first physical layer transmission parameter to an access network, so that the access network determines a second physical layer transmission parameter according to the video stream information and the video stream transmission requirement information;
and the coding module is used for coding the video unit sent by the video server by adopting the first application layer coding parameter obtained by the optimal parameter combination selection module and sending the coded video unit to the access network, so that the access network performs physical layer processing on the received video unit by adopting the second physical layer transmission parameter and then sends the processed video unit.
11. The apparatus of claim 10, wherein the encoding module is further configured to:
and coding the video unit by adopting different application layer coding parameters to obtain coding information corresponding to the different application layer coding parameters.
12. The device according to claim 10 or 11, wherein the average radio channel information is an average signal-to-noise ratio SNR, the physical layer transmission parameter is a modulation coding scheme MCS, the application layer coding parameter is a discrete cosine transform DCT coefficient, the DCT coefficient is a DCT quantization parameter QP and/or a DCT truncation, the coding information includes a code rate, a pixel value and offset information, and the distortion estimation and occupied resource block calculation module is specifically configured to:
according to the average SNR and the MCS, obtaining the block error rate of the physical layer when different MCS are obtained through table look-up;
obtaining the packet length of a data packet according to the code rate;
obtaining packet loss rates of different MCS according to the physical layer block error rate and the packet length of the different MCS;
and obtaining the distortion degree and the resource occupation condition when the MCS and the DCT coefficient are different according to the packet loss rate when the MCS is different, the DCT coefficient, the corresponding pixel value and the offset information thereof and the error compensation information.
13. The apparatus of claim 10 or 11, wherein the distortion estimation and occupied resource block calculation module is further configured to:
receiving error compensation information reported by a video terminal; or,
determining macroblock information corresponding to a position of a macroblock lost by the video unit in a video unit adjacent to the video unit as error compensation information of the lost macroblock.
14. The apparatus of claim 10 or 11, further comprising:
and the decoding module is used for decoding the source video unit sent by the video server so that the coding module adopts the first application layer coding parameter to code the decoded video unit.
15. A video transmission device in a wireless network, comprising:
the channel information collection module is used for sending average wireless channel information to first equipment, so that the first equipment determines a first physical layer transmission parameter and a first application layer coding parameter when the distortion degree is smaller than a set threshold value and the minimum resource is occupied according to the average wireless channel information;
the selection module is used for receiving the video stream information sent by the first equipment and the video stream transmission requirement information corresponding to the first physical layer transmission parameter, and determining a second physical layer transmission parameter according to the real-time wireless channel information, the video stream information and the video stream transmission requirement information;
and the transmission module is used for receiving the video unit coded by the first device by adopting the first application layer coding parameter, and sending the video unit after the video unit is subjected to physical layer processing by adopting the second physical layer transmission parameter.
16. The device according to claim 15, wherein the real-time wireless channel information is a real-time SNR, the video stream information is a packet length L, the video stream transmission requirement information is a packet loss ratio PLR, the physical layer transmission parameter is a modulation and coding scheme MCS, and the refining module is specifically configured to:
according to the real-time SNR and different MCS, obtaining the block error rate of the physical layer when the MCS is different through table look-up;
obtaining packet loss rates of different MCS according to the physical layer block error rate and the packet length of the different MCS;
and determining the MCS with the highest modulation level as the transmission parameter of the second physical layer, wherein the corresponding packet loss rate is smaller than the PLR.
17. The apparatus of claim 15 or 16, wherein the channel information collecting module is further configured to:
receiving real-time wireless channel information reported by a video terminal, and carrying out statistical averaging on the real-time wireless channel information to obtain average wireless channel information;
or,
and actively detecting to obtain real-time wireless channel information, and performing statistical averaging on the real-time wireless channel information to obtain average wireless channel information.
18. A system for video transmission in a wireless network, comprising:
the apparatus of any one of claims 10-14; and the number of the first and second groups,
the apparatus of any one of claims 15-17.
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