JP2012129712A - Coding method of screen frame, and electronic device applied with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coding method of a screen frame and an electronic device using it.SOLUTION: Related to the coding method of a screen frame and an electronic device using it, a fluctuation region and a still region are quickly detected from the screen frame of no loss which is captured by a software. After that, the fluctuation region is coded in low image quality and the still region is coded in high image quality, to smooth a video image at a reception end with no delay. Further, since the coding method requires no complex operation in video coding of known technology, such as motion discrimination and motion correction, the method can be executed with less system resource and delay.

Description

  The present invention relates to an encoding method of a screen frame and an electronic device to which the encoding method is applied, and more particularly, to an adaptively changing screen frame that adaptively changes image quality. The present invention relates to an encoding method and an electronic apparatus using the same.

  Screen frame sharing is one of the important applications of information technology. Examples of screen frame sharing are performing remote control with a remote desktop, or a computer connected to a projector in a wireless manner to perform a presentation, etc. Usually, the screen frame data is obtained through a software program by the operating system, so that the obtained screen data is lossless. However, due to communication bandwidth limitations, screen frame data must be compressed by encoding before transmission.

  The screen frame has many regular patterns, for example rectangular frames, curves or fonts, and any loss of image quality is easily observed by the user, so that the decoded and recovered screen frame The demand for image quality is high. In addition, when the screen frame is shared, the user mainly depends on other tasks such as remote control and presentation, so the screen encoder occupies a lot of system resources, and the main work progresses. Should be avoided. Further, when the delay from the screen frame transmitted from the transmission end to the screen frame displayed by the reception end is shortened, the remote user's immediate control feeling is improved.

  However, when known screen encoders use lossless or low loss encoding when processing screen frames that contain video regions, the amount of data can exceed the load on the network or receiving system. Insufficient frame rate at the receiving end causes discontinuity in the video. Conversely, when known screen encoders compress data due to high loss encoding, the still area of the screen frame also has high loss image quality. In addition, the regular pattern of screen frames is also lossy when processed by known video encoders. In addition, complicated calculation methods employed by known video encoders, such as motion estimation and motion compensation, occupy many system resources and have a long delay.

  Accordingly, there is a need for a screen frame encoding method that occupies less system resources and a shared screen frame simultaneously represents smooth video and high-quality still images within a short delay time.

  The present invention provides an encoding method for a screen frame and an electronic apparatus using the same, and is a method for adaptively changing image quality, and is shared within a short delay time under a situation where system resources are less occupied. It is an object of the present invention to enable a screen frame to be able to express a smooth video and a high-quality still image at the same time.

  According to an embodiment of the present invention, there is provided a screen frame encoding method for adaptively changing image quality, wherein at least one variable region and at least one stationary region are identified in the screen frame, and at least one of covering the variable region. Determining a variable coding region, determining a variable image quality, encoding a variable coding region, determining at least one static coding region covering the static region, and static Determining image quality and encoding a still coding region, the still image quality being better than the varying image quality.

  An electronic apparatus for transmitting a screen frame for adaptively changing image quality according to another embodiment of the present invention includes a processor unit that executes a screen frame transmission method and displays a screen frame at a receiving end. Identifying at least one variable region; determining at least one variable coding region covering the variable region; determining variable image quality; encoding the variable coding region; and Transmitting, identifying at least one still region in the variable coding region, determining at least one still coding region covering the still region, determining still image quality, and still coding Encoding and transmitting regions, and still image quality is better than variable image quality.

  Hereinafter, the present invention will be described in detail with reference to examples and drawings to facilitate understanding of the objects, technical contents, features, and effects achieved by the present invention.

  Less system resources and short delay.

FIG. 6 is a flowchart illustrating steps of a screen frame encoding method according to an embodiment of the present invention. FIG. 4 is a diagram illustrating steps of a screen frame encoding method according to an embodiment of the present invention. FIG. 4 is a diagram illustrating steps of a screen frame encoding method according to an embodiment of the present invention. FIG. 6 is a flowchart illustrating steps of a screen frame encoding method according to another embodiment of the present invention. FIG. 4 is a flowchart illustrating steps of a transmission method performed by an electronic device according to one embodiment of the present invention.

  Referring to FIGS. 1 and 2a, a screen frame encoding method for adaptively changing image quality according to an embodiment of the present invention includes the following steps. First, at least one variable region 21, 21 'in the screen frame 2 and at least one stationary region are identified (step 11). According to the embodiment, the static area is an area of the screen frame 2 other than the variable areas 21 and 21 ′. It should be noted that one screen frame may have a plurality of variable areas and stationary areas. According to the embodiment, the fluctuation regions 21 and 21 ′ are obtained by comparing the differences between the pixels of the screen frame in two specific periods. For example, after each corresponding pixel of two consecutive screen frames is subjected to an XOR operation, the variation region of the subsequent screen frame is identified.

  Thereafter, at least one variation coding region covering the variation region identified in step 11 is determined (step 12). As shown in FIG. 2 a, the fluctuation area 21 is covered with a fluctuation coding area 22. According to the embodiment, the variation coding area 22 is rectangular. It should be noted that a single variation coding region can cover a plurality of variation regions, but is not limited to this. A single variation region may be covered by a plurality of variation encoding regions. As shown in FIG. 2a, the variation region 21 ′ is covered by variation encoding regions 22a, 22b, 22c, 22d, and 22e. In other words, the variation coding region covers a part of the plurality of variation regions or the plurality of variation regions.

  Next, the variation image quality is determined, and the variation encoding regions 22 and 22a to 22e are encoded based on the variation image quality (step 13). According to the embodiment, the size of the variation coding area is one of the determinants of the variation image quality. For example, the variation image quality is inversely proportional to the size of the variation encoding region, that is, as the variation encoding region becomes larger, the variation image quality selected for encoding becomes lower. In addition, different image qualities are selected for multiple variable coding regions.

  Referring to FIG. 1 again, at least one stationary coding area covering the stationary area is determined (step 14). For the same reason as described above, the stationary coding area is rectangular and the single stationary coding area covers a plurality of stationary areas, or the single stationary area is covered by a plurality of stationary coding areas. be able to. Next, the still image quality is determined, and the still coding region is encoded based on the still image quality (step 15). It should be noted that “variable image quality” is the image quality of “variable coding region”, “still image quality” is the image quality of “still image coding region”, and still image quality is variable image quality. Better than that. Briefly, the screen frame encoding method of the present embodiment adaptively changes the image quality, the fluctuation region of the screen frame is encoded with a low image quality, and the static region of the screen frame has a high image quality. It is encoded with. According to the embodiment, the still image quality is a lossless image quality, and represents a regular pattern of a screen frame, but is not limited thereto.

  If the above steps are repeated and the screen frames are processed in sequence, the video area in the same screen frame is played smoothly, and the still area is displayed with the preferred image quality. The encoding method of the present embodiment does not use complicated calculation methods such as motion estimation and motion compensation, and therefore occupies less system resources and has a short delay.

  According to another embodiment shown in FIGS. 3 and 2b, the screen frame encoding method adaptively changes the image quality and has the following steps. First, at least one variable region 21 is identified in the screen frame 2 ′ (step 31). Thereafter, at least one variation coding region 22 covering the variation region 21 is determined (step 32). Thereafter, the variation image quality is determined, and the variation encoding region is encoded based on the variation image quality (step 33). Since the details of the steps have been described above, they are omitted here.

  Continuing the above description, the screen frame encoding method further includes the following steps. First, the variable coding region is added to the historical list (step 34). Thereafter, at least one stationary region is identified from the variation coding region in the history list (step 35). For example, the history list includes information such as the range and coordinates of the variation encoding region 22 and a time stamp corresponding to the variation encoding region 22. As a result, after the specific period, all or part of the variable coding area 22 that has not changed yet is identified as a static area. As shown in FIG. 2 b, the window 23 having the static contents partially overlaps with the variable coding area 22. After the specific period, the overlapped area of the hatched portion is regarded as a still area 24.

  Thereafter, at least one stationary coding area covering the stationary area 24 is determined (step 36). In this embodiment, the static coding area is equal to the static area 24. Thereafter, the still image quality is determined, and the still coding region is encoded based on the still image quality (step 37), and the still image quality is better than the varying image quality. Finally, the variation coding area corresponding to the stationary coding area is removed from the history list (step 38). As shown in FIG. 2b, according to the embodiment, the variation coding area 22 and the stationary coding area are non-overlapping areas, and avoid overlapping operations on the overlapping area.

  According to the embodiment of FIG. 4, the electronic device applies the screen frame encoding method to the transmission of a screen frame that adaptively changes the image quality. The electronic device has a processor unit that executes the screen frame transmission method, and the receiving end displays the screen frame transmitted by the electronic device. According to another embodiment, the electronic device can transmit the screen frame by wired or wireless communication. The transmission method includes the following steps. First, at least one variable region is identified (step 42). At least one variation coding region covering the variation region is determined (step 43). The variable image quality is determined, and the variable coding area is encoded and transmitted based on the variable image quality (step 44). At least one stationary region is identified in the variation coding region (step 46). At least one stationary coding area covering the stationary area is determined (step 47). The still image quality is determined, and the still coding region is encoded and transmitted based on the still image quality (step 48). Still image quality is better than variable image quality. Since the details of the steps have been described above, they are omitted here.

  According to an embodiment of the present invention, the transmission method further includes the following steps. After the variation coding region is transmitted, the variation coding region is added to the history list (step 45). Thereafter, the stationary region of step 46 is identified from the variable code region in the history list. In addition, after the stationary coding area is encoded and transmitted, the variable coding area corresponding to the stationary coding area is removed from the history list (step 49).

  According to the embodiment of FIG. 4, the electronic device can initially transmit a full screen frame (step 41). Accordingly, the electronic device can transmit only the variable coding area and the static coding area that need to be updated in steps 42 to 49. The receiving end receives the initial full screen frame, the subsequent variable coding area, and the stationary coding area, and reconstructs the screen frame. For example, it is assumed that the window 23 in FIG. 2B is initially in the lower layer of the variable coding area 22. Therefore, after the full screen frame 2 ′ is transmitted, it is necessary to transmit only the variable coding area 22 including the video. When the window 23 moves to the upper layer of the variable coding area, only the shaded still area 24 is an update area for the screen frame 2 '. As a result, the transmission end transmits only the static coding region and the variable coding region 22 not covered by the window 23 to the receiving end, and the receiving end reconstructs the screen frame.

  In summary, the encoding method of the screen frame and the electronic device using the same encode the fluctuation region of the screen frame with low image quality, and a smooth video is expressed at the receiving end. Encoding with high image quality, high quality still images are simultaneously represented at the receiving end. In addition, the screen frame encoding method according to the present embodiment does not use complicated calculation methods such as motion determination and motion correction, and thus requires less system resources, is suitable for background execution, It avoids affecting work and has low latency, making it more suitable for immediacy applications.

  In the present invention, preferred embodiments have been disclosed as described above. However, the present invention is not limited to the present invention, and any person who is familiar with the technology can use various methods within the spirit and scope of the present invention. Variations and moist colors can be added, so the protection scope of the present invention is based on what is specified in the claims.

2, 2 '... Screen frame 21, 21' ... Fluctuation area 22 ... Fluctuation coding area 22a-22e ... Fluctuation coding area 23 ... Window 24 ... Still area

Claims (24)

A screen frame encoding method for adaptively changing image quality,
Identifying at least one variable region and at least one stationary region in a screen frame;
Determining at least one variable coding region covering the variable region;
Determining variable image quality and encoding the variable coding region;
Determining at least one stationary coding region covering the stationary region;
Determining a still image quality and encoding the still coding region,
The screen frame encoding method for adaptively changing the image quality, wherein the still image quality is better than the varying image quality. Furthermore,
The method of claim 1, further comprising the step of adding the variable coding region to a history list.   3. The method of claim 2, wherein the history list includes a time stamp corresponding to the variable coding area.   The method according to claim 2 or 3, wherein the still area is identified from the variable coding area in the history list. Furthermore,
5. The method according to claim 4, further comprising the step of removing the variable coding area corresponding to the still area from the history list.   6. The image quality according to claim 1, wherein the fluctuation region is obtained by comparing a difference between each pixel of the screen frame in two specific periods. Coding method of a screen frame that is changed in a periodic manner.   The screen for adaptively changing the image quality according to claim 1, wherein the variation coding region covers a part of the variation region or a plurality of variation regions. Frame encoding method.   The screen for adaptively changing the image quality according to claim 1, wherein the still coding region covers a part of the still region or a plurality of still regions. Frame encoding method.   9. The method according to claim 1, wherein the variation image quality is inversely proportional to the size of the variation encoding area.   10. The method of encoding a screen frame for adaptively changing the image quality according to claim 1, wherein the still image quality is lossless or high quality.   The code of a screen frame for adaptively changing image quality according to any one of claims 1 to 10, wherein at least one of the variable coding region and the static coding region is a rectangle. Method. An electronic apparatus for transmitting a screen frame that adaptively changes image quality, comprising: a processor unit that executes the screen frame transmission method and displays the screen frame at a receiving end;
Identifying at least one variable region in the screen frame;
Determining at least one variable coding region covering the variable region;
Determining variable image quality, encoding and transmitting the variable coding region;
Identifying at least one stationary region in the variable coding region;
Determining at least one stationary coding region covering the stationary region;
Determining a still image quality, and encoding and transmitting the still coding region,
The electronic apparatus characterized in that the still image quality is better than the varying image quality. The transmission method further includes:
13. The electronic device according to claim 12, further comprising a step of transmitting a full screen frame. The transmission method further includes:
14. The electronic device according to claim 12, further comprising the step of joining the variable coding area to a history list.   15. The electronic device according to claim 14, wherein the history list includes a time stamp corresponding to the variable coding area.   16. The electronic device according to claim 14, wherein the static area is identified from the variable coding area in the history list. The transmission method further includes:
The electronic device according to claim 16, further comprising a step of removing the variable coding area corresponding to the stationary area from the history list.   18. The electronic device according to claim 12, wherein the variable region is obtained by comparing a difference between each pixel of the screen frame in two specific periods.   The electronic device according to claim 12, wherein the variation coding region covers a part of the variation region or a plurality of variation regions.   The electronic device according to claim 12, wherein the static coding area covers a part of the static area or a plurality of static areas.   21. The electronic device according to claim 12, wherein the variation image quality is inversely proportional to a size of the variation encoding area.   The electronic device according to any one of claims 12 to 21, wherein the still image quality is lossless or high quality.   23. The electronic device according to claim 12, wherein at least one of the variable coding area and the static coding area is a rectangle.   The electronic device according to any one of claims 12 to 23, wherein the screen frame is transmitted to the receiving end by wired or wireless communication.

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