TW201404156A - Wireless video/audio data transmission systems and methods, and computer products thereof - Google Patents

Abstract

A wireless video/audio data transmission method for a wireless video/audio data transmission system is provided. First, a type of an application that is currently operating and a system resource usage amount are detected. Then, an encoding condition of an image is dynamically adjusted based on the type of the application and the system resource usage amount detected and the image is encoded using the adjusted encoding condition to generate an encoded image for transmission so as to transmit the encoded image wirelessly through a wireless transmission unit to perform a wireless video/audio data transmission, wherein the encoding condition is used for determining a compress ratio, a resolution and a data transmission amount corresponding to the image during the encoding operation.

Description

Wireless video transmission system and method thereof, and computer program product thereof

The invention relates to a wireless video transmission system and related audio and video coding method, in particular to a wireless video transmission system capable of dynamically adjusting coding conditions for wireless video transmission and related audio and video coding methods.

In recent years, due to the rapid development of wireless network applications, the demand for wireless audio and video transmission has also increased. The general wireless video transmission system may include a transmitting end device and a receiving end device, wherein the transmitting end device may first capture the currently executed screen image, then perform image compression and encoding on the captured image, and then pass through the wireless transmission unit. The encoded image is transmitted wirelessly. The receiving device receives the image sent by the transmitting device by using a receiving module, then performs image decoding, then enlarges or reduces the image, and finally sends it to the display end for display. In general, in order to maintain smooth wireless video playback, at least a fixed number of images per second need to be transmitted, for example, at least 24 images per second need to be transmitted.

At present, the existing wireless transmission technologies include Wi-Fi, Wi-Di and WiHD, etc., which are technologies for transmitting wireless video and audio by using a fixed wireless frequency band, and the number of audio and video transmissions per second is fixed, each The compression ratio of audio and video is fixed, and the resolution of each video is fixed. Such a non-elastic design, in the process of wireless audio and video transmission, if the current computer system specifications are not strong enough, the central processing unit (CPU) is too large or the memory space is not enough, it will lead to bad wireless video and audio. pass If the result of the loss, for example, the number of video sheets that cannot be specified is transmitted, the problem of unsmooth video playback (lag), frame loss, and A/V non-sync will be caused.

In view of this, the present invention provides a wireless video transmission system and related wireless video transmission method to solve the above problems.

Embodiments of the present invention provide a wireless video and audio transmission method, which is applicable to a wireless video and audio transmission system. First, detect one of the categories of applications currently in execution and a system resource usage. Then, according to the detected type of the application and the usage of the system resources, one of the encoding conditions of the image is dynamically adjusted and the image is encoded by the encoding condition to generate a coded image for transmission, and then transmitted through a wireless transmission. The unit transmits the encoded image for performing a wireless video and audio transmission, wherein the encoding condition is used to determine a compression ratio, a resolution, and a transmission data amount corresponding to the image at the time of encoding.

The embodiment of the invention further provides a wireless video and audio transmission system, which comprises at least a picture buffer, an encoding unit and a wireless transmission unit. The picture buffer provides an image. The coding unit is coupled to the picture buffer for detecting one of the currently-executed applications, detecting the system resource usage of the wireless video transmission system, and depending on the type of the detected application and The system resource usage dynamically adjusts one of the image encoding conditions in the picture buffer, and encodes the image according to the encoding condition to generate a coded image for transmission. The wireless transmission unit is coupled to the coding unit for transmitting the encoded image for a wireless video transmission. The coding condition is used to determine a compression ratio and an analysis corresponding to the image at the time of encoding. Degree and the amount of data transferred.

The above method of the present invention can be recorded in physical media through code. When the code is loaded and executed by the machine, the machine becomes the means for practicing the invention.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

1 shows a schematic diagram of a wireless video transmission system 100 in accordance with an embodiment of the present invention. The wireless video transmission system 100 can be used in an electronic device such as a personal computer and a portable device such as a personal digital assistant, a smart phone, a mobile phone, a mobile Internet device (MID), a notebook computer or a mini note. A computer (Netbook), etc., but not limited to this. The wireless video transmission system 100 includes at least a frame buffer 110, an encoding unit 120, and a wireless transmission unit 130. The picture buffer 110 is connected to the encoding unit 120, and the encoding unit 120 and the wireless transmission unit 130 are connected. Connect as a signal. The picture buffer 110 can store the image data displayed on the current screen, that is, the related picture data of one of the currently open/executed applications. The wireless transmission unit 130 can provide a wireless communication function to receive signals from the wireless network or transmit signals to the wireless network. The wireless transmission unit 130 can include any wireless communication module, such as a radio frequency module, a blue-tooth communication module, a WiFi or an IEEE 802.1X-compliant wireless network (WLAN) communication module, or each Can support 2G (GSM), 2.5G (GPRS/CDMA1x), 3G (CDMA2000, WCDMA, TD-SCDMA, WiMAX), 3.5G (HSDPA) to 4G (LTE) and other wireless technology communication systems, etc., can be connected to the corresponding wireless network, so that the wireless video transmission system 100 can pass through The wireless network and the receiving device perform wireless video and audio transmission.

The encoding unit 120 can be used to capture the image in the picture buffer 110, detect the system resource usage, detect the application type, and determine the encoding condition at the time of encoding, and use the determined encoding condition to generate one of the encoded data to be transmitted. Then, it is sent to a receiving device (not shown) through the wireless network technology of the wireless transmission unit 130. After receiving the encoded data sent by the wireless transmission unit 130, the receiving device may decode the received encoded data by using a decoding unit to restore the encoded data to an audio and video signal conforming to the specifications of the display unit, and output the image to a display. The unit is played to realize the function of wireless video transmission.

The encoding unit 120 can be used to execute the wireless video transmission method of the present invention when detecting that an application is started, and the details thereof will be described later.

2 is a flow chart showing a method for transmitting wireless video and audio according to an embodiment of the present invention. Please refer to both Figure 1 and Figure 2. The wireless video and audio transmission method according to the embodiment of the present invention can be applied to the wireless video and audio transmission system 100 for dynamically determining an encoding condition during encoding, and then using the determined encoding condition to generate an image to be transmitted for wireless video transmission. In this embodiment, it is assumed that an application has been opened and its corresponding picture image is stored in the picture buffer 110.

First, in step S202, the encoding unit 120 detects the category of the currently open application and the current system resource usage. In one embodiment, detecting an application category is detected by one of the applications corresponding to the application. A keyword or a file name, such as the keyword generated by the application during execution or the file extension of the file being executed. In this embodiment, the application may be first divided into several categories, for example, a word processing class, a photo browsing class, a web application class, a video playback class, and a game execution class, but the present invention is not limited thereto. The encoding unit 120 can detect a keyword or a file name corresponding to the application to determine whether the currently open application belongs to the category of the application. For example, the word processing application usually has the keyword "office" or the file name of the file it executes is the name of the text file such as *.doc, *.txt, *.pdf, etc., photo The browsing class usually has a keyword such as "Photo" or the file name of the file to be executed is called the photo file extension file name such as *.bmp, *.jpg, etc., the video playback application usually has "player" The keyword such as "the key file of the file or the file to be executed is called the image file extension file name such as *.wmv, *.avi, *.mpg, etc., but is not limited thereto.

In addition, the encoding unit 120 also detects the current system resource usage. The encoding unit 120 detecting the current system resource usage may include detecting a load status of the central processing unit (CPU), a usage status of the memory space, a current wireless network bandwidth, and a hardware specification of the system itself.

After detecting the category of the application and the system resource usage, then, in step S204, the encoding unit 120 dynamically adjusts an encoding condition according to the detected type of the application and the system resource usage. In this step, the encoding unit 120 may encode different encoding conditions according to the keyword generated by each application during execution or the file name of the executed file and the current system resource status. The best wireless audio and video transmission. The coding condition is used to determine coding parameters corresponding to the image to be transmitted, such as image resolution, compression ratio, and transmission. The amount of data lost, and so on. The image system to be transmitted is taken from the picture buffer 110. Adjusting the encoding conditions may include adjusting the image resolution, adjusting the compression ratio, and adjusting the amount of transmitted data. The image resolution is adjusted by up scaling or down scaling (for example, adjusting the resolution of the encoded image from 1024+768 to 1280*968 or 640*480), and adjusting the compression ratio. By increasing or decreasing the image compression ratio (for example, adjusting the compression ratio of the encoded image from 30 percent to 50 percent or not compressing), adjusting the amount of transmitted data by increasing or decreasing the number of images to be transmitted per second The number (for example, the amount of transmitted data of the encoded image is adjusted from 24 images per second to 30 images per second or 10 images per second).

The encoding unit 120 may further evaluate whether the system resource usage amount meets a predetermined condition according to the foregoing detection result, such as whether the central processing unit (CPU) is overloaded, whether the memory space is insufficient, whether the current wireless network bandwidth is too small, or the system 100 itself. Whether the hardware specifications are too bad and so on. When it is detected that the central processing unit is overloaded, the memory space is insufficient, the current wireless network bandwidth is too small, or the hardware specifications of the system 100 itself are too poor, it is determined that the system resource usage meets the established conditions. When it is found that the system resource usage does not meet the predetermined condition, it indicates that the system resource is sufficient, and then the encoding unit 120 decides not to adjust the encoding condition. Therefore, the encoding unit 120 may determine that the encoding condition at the time of encoding is not adjusting the image resolution and not adjusting the compression ratio. And does not change the amount of data transferred. That is to say, the encoding unit 120 will encode the image according to the original image resolution, compression ratio, and transmission data amount setting.

When it is found that the system resource usage meets the established conditions (for example, the central processing unit is overloaded, the memory space is insufficient, the current wireless network bandwidth is too small, or the hardware specifications of the system 100 itself are too poor), indicating that the system resources are insufficient. In order to maintain the execution of the current application and good wireless video transmission, the encoding unit 120 needs to actively perform the dynamic adjustment action to adjust the encoding conditions. For example, in an embodiment, when the wireless transmission bandwidth is insufficient or interfered, the user still wants to play high-definition video and audio through the wireless video transmission technology, in order to maintain the smoothness of the video playback, limited Under the wireless video transmission bandwidth, the encoding unit 120 can adjust the encoding condition to increase the compression ratio (sacrifice video quality) in exchange for a smooth playback effect. In another embodiment, if the user needs to transmit the game screen through the wireless transmission technology during the execution of the game, the burden on the processing unit by the execution of the game is originally large. To maintain the smoothness of the game screen, the encoding unit 120 can adjust The encoding condition is to reduce the resolution in exchange for smooth playback.

After the encoding condition is adjusted, in step S206, the encoding unit 120 encodes the captured image in the picture buffer 110 by using the adjusted encoding condition to generate an encoded image, and then transmits the transmitted image through the wireless transmission unit 130 as in step S208. Encode the image to the receiving device for a wireless video transmission. In this step, the encoding unit 120 may compress and encode the image according to the image resolution, the compression ratio, and the amount of data transmitted in the encoding condition (for example, the number of frames transmitted per second), and then generate the encoded image, and then transmit the wireless image. The transmission unit 130 wirelessly transmits the encoded image to the receiving device in the amount of transmission data specified in the encoding condition. For example, if the original encoding condition is 1920*1080, the compression ratio is 30%, and the data volume is 30 frames per second, the adjusted encoding conditions are to reduce the image resolution, increase the compression ratio, and increase the transmission data. When the quantity is used, the encoding unit 120 may adjust the image resolution to 1024*768, the compression ratio to be 50%, and the transmission data amount to be 20 frames per second to generate the encoded image.

Therefore, the encoding unit 120 can encode different encoding conditions according to the keyword generated by each application during execution or the file name of the executed file and the current system resource to achieve the best. Wireless video transmission. In an embodiment, when the category of the application is a game execution class (for example, the file name of the executed file is *.exe), when the system resource usage amount meets the predetermined condition, the encoding unit 120 adjusts/determines the code. The condition is to reduce the image resolution, increase the compression ratio and transmit at least 30 images per second, so that although some details are sacrificed, the picture can be kept smooth. When the application category is an audio-visual playback class (for example, an application with a keyword such as "player" or an extension of the file it executes is called an image file extension such as *.wmv, *.avi, *. In the case of mpg), when the system resource usage meets the predetermined conditions, the encoding unit 120 adjusts/determines the encoding condition to reduce the image resolution, increase the compression ratio, and transmit at least 24 images per second, thus, while sacrificing some details, Can keep the audio and video smooth.

When the type of the application is a document processing class or a photo browsing class, when the system resource usage amount meets the predetermined condition, the encoding unit 120 adjusts/determines the encoding condition to not reduce the image resolution, reduce the compression ratio, and transmit at least 10 per second. Image, so you can maintain text or image details.

When the application category is web browsing, when the system resource usage exceeds the threshold, the video encoder will determine the encoding condition to not reduce the image resolution, reduce the compression ratio and transmit at least 30 images to maintain the text details. The mouse is smooth.

The receiving device can decode the encoded encoded data wirelessly to obtain a decoded audio and video data, and then upscale the decoded audio and video data into original or higher resolution video data for display in the display. On the display unit.

Note that when the system resource usage does not meet the established conditions, indicating that the current system resources are sufficient, the encoding unit 120 may determine that the coding conditions of all types of application coding are not reducing the image resolution, and not reducing the compression ratio and each. Transfer at least 30 images in seconds, allowing audio and video transmission and playback without sacrificing any detail and smoothness.

In some embodiments, the user can simultaneously open multiple applications and switch execution images of multiple applications, and the wireless video transmission system of the present invention can detect the category switching of the application. The measured application category and system resource usage are used to adjust the encoding conditions.

FIG. 3 is a flow chart showing a method for transmitting wireless video and audio according to another embodiment of the present invention. Please refer to both Figure 1 and Figure 3. The wireless video transmission method according to the embodiment of the present invention can be applied to the wireless video transmission system 100 for dynamically determining an encoding condition at the time of encoding according to an application category. In this embodiment, it is assumed that the first application and the second application are enabled and the user selects to execute the first application (in the job), wherein the first application has a first category, and the second application has Different from a second category of the first category. The screen image corresponding to the first application of the first category is stored in the screen buffer 110.

First, in step S302, the encoding unit 120 detects that the system resource usage amount meets a predetermined condition. As described above, the encoding unit 120 can evaluate whether the system resource usage meets a predetermined condition according to the detection result, such as whether the central processing unit (CPU) is overloaded, whether the memory space is insufficient, whether the current wireless network bandwidth is too small, or the system itself. Whether the hardware specifications are too bad, etc. Wait. When it is detected that the central processing unit is overloaded, the memory space is insufficient, the current wireless network bandwidth is too small, or the hardware specifications of the computer itself are too poor, it is determined that the system resource usage meets the established conditions. When it is found that the system resource usage does not meet the predetermined condition, it indicates that the system resource is sufficient, and then the encoding unit 120 decides not to adjust the encoding condition. Therefore, the encoding unit 120 may determine that the encoding condition at the time of encoding is not adjusting the image resolution and not adjusting the compression ratio. And does not change the amount of data transferred.

When it is found that the system resource usage meets the established conditions (for example, the central processing unit is overloaded, the memory space is insufficient, the current wireless network bandwidth is too small, or the hardware specifications of the system itself are too poor), indicating that the system resources are insufficient, so the coding The unit 120 decides to adjust the encoding condition, and encodes the image by a first encoding condition to generate the encoded image to be transmitted (step S304). For example, in an embodiment, when detecting that the system resource usage quantity meets the predetermined condition, the coding unit 120 may set the first coding condition to reduce the compression ratio, resolution, and The amount of data transferred. After determining the first encoding condition, the encoding unit 120 encodes the image by using the first encoding condition to generate an encoded image, and then transmits the encoded image to the receiving device through the wireless transmission unit 130 to perform a wireless video transmission.

After the user switches to the second application of the second category, the encoding unit 120 converts the category of the detection application from the first category to the second category (step S306), and then detects according to the detected The type of the application to be used and the system resource usage, and the encoding condition of the adjusted image is a second encoding condition, wherein the first encoding condition and the second encoding condition have different compression ratios, resolutions, and/or transmission data amounts (steps) S308). For example, the first encoding condition may be reducing the image resolution, increasing the compression ratio, and transmitting at least 30 images per second, and the second encoding condition may be reducing the image resolution, increasing the compression ratio, and transmitting at least 24 images per second. Or it can be used to reduce image resolution, reduce compression ratio and transmit at least 30 images per second.

After determining the second encoding condition, the encoding unit 120 encodes the image by using the adjusted encoding condition (second encoding condition) to generate an encoded image (step S308), and then transmits the encoded image to the receiving end device through the wireless transmission unit 130. For wireless audio and video transmission.

For example, if the encoding unit 120 detects the system resource usage and finds that the system resource usage meets a predetermined condition, for example, the central processing unit is overloaded or the memory space is insufficient, the encoding unit 120 can detect one of the current applications. A keyword or a file name to determine which application is currently open for that category. When the category of the first application is the game execution class (the first category), when the system resource usage amount meets the predetermined condition, the encoding unit 120 adjusts/determines the first encoding condition to reduce the image resolution, increase the compression ratio, and each Transfer at least 30 images in seconds. After that, when the user switches the executed application so that the category of the application is switched from the game execution class to the word processing class or the photo browsing class (second category), when the system resource usage amount meets the predetermined condition, the encoding unit 120 The adjustment/decision coding conditions are such that the image resolution is not reduced, the compression ratio is reduced, and at least 10 images per second (second encoding condition) are transmitted. After that, when the user switches back to the original application, so that the category of the application is switched back to the game execution class by the word processing class or the photo browsing class (the second category), when the system resource usage amount meets the predetermined condition, the coding unit 120 will be re-edited The code condition returns to the first encoding condition, that is, the image resolution is reduced, the compression ratio is increased, and at least 30 images are transmitted per second; or when the user opens a third application, the encoding unit 120 adjusts the encoding condition to correspond to the first A third encoding condition of the three applications for subsequent encoding.

In summary, according to the wireless video transmission system and the wireless video transmission method thereof, when the wireless video transmission and playback are performed, the coding unit can be based on the type of the application currently executed and the system resource usage status, for example, the system is hard. The size of the body, the amount of use of the central processing unit, and the amount of idle memory, etc., dynamically adjust the image compression ratio, resolution, and number of images to be transmitted when the image encoding is to be transmitted, so as to achieve wireless video transmission and playback. The good effect can effectively reduce the probability that the audio and video playback is not smooth, the number of audio and video is missing, and the audio and video are not synchronized.

The method of the present invention, or a specific type or part thereof, may be included in a physical medium such as a floppy disk, a compact disc, a hard disk, or any other machine (for example, a computer readable computer). A storage medium in which, when the code is loaded and executed by a machine, such as a computer, the machine becomes a device for participating in the present invention. The method and apparatus of the present invention can also be transmitted in a code format through some transmission medium such as a wire or cable, an optical fiber, or any transmission type, wherein the code is received, loaded, and executed by a machine such as a computer. At this time, the machine becomes a device for participating in the present invention. When implemented in a general purpose processor, the code in conjunction with the processor provides a unique means of operation similar to application specific logic.

While the present invention has been described in its preferred embodiments, the present invention is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. Protection The scope is subject to the definition of the scope of the patent application attached.

100‧‧‧Wireless audio and video transmission system

110‧‧‧ Picture buffer

120‧‧‧ coding unit

130‧‧‧Wireless transmission unit

S202, S204, S206, S208‧‧‧ execution steps

S302, S304, S306, S308‧‧‧ execution steps

1 is a schematic diagram showing a wireless video transmission system according to an embodiment of the present invention.

2 is a flow chart showing a method for transmitting wireless video and audio according to an embodiment of the present invention.

3 is a flow chart showing a wireless video transmission method according to another embodiment of the present invention.

S202, S204, S206, S208‧‧‧ execution steps

Claims (18)

A wireless audio and video transmission method, applicable to a wireless video transmission system, comprising the steps of: detecting one of an application type currently in execution and a system resource usage; and determining the category of the application according to the detected application And the system resource usage, dynamically adjusting an encoding condition of an image and encoding the image according to the encoding condition, generating a coded image for transmission, and transmitting the encoded image through a wireless transmission unit to perform a wireless video and audio Transmission; wherein the coding condition is used to determine a compression ratio, a resolution, and a transmission data amount corresponding to the image at the time of encoding. The wireless video transmission method according to claim 1, wherein the dynamically adjusting the coding condition of the image according to the detected category of the application and the resource usage of the system further comprises: determining the Detector The system resource usage is determined to meet a predetermined condition; when the system resource usage does not meet the predetermined condition, the decoding condition is not adjusted; and when the system resource usage meets the predetermined condition, the decoding condition is adjusted. The wireless video transmission method according to claim 2, wherein when the system resource usage amount satisfies at least one of the following conditions, determining that the system resource usage amount meets the predetermined condition: the wireless video transmission system A central processing unit is overloaded; the wireless audio and video transmission system has insufficient memory space; one of the wireless video transmission systems currently has a wireless network bandwidth that is too small; And the hardware specifications of the wireless video transmission system are too bad. The wireless video transmission method of claim 2, wherein the step of adjusting the decoding condition comprises adjusting the compression ratio corresponding to the image when encoding. The wireless video transmission method of claim 2, wherein the step of adjusting the decoding condition comprises adjusting the resolution corresponding to the image when encoding. The wireless video transmission method of claim 2, wherein the step of adjusting the decoding condition comprises adjusting the amount of the transmission data corresponding to the image at the time of encoding. The wireless video transmission method according to claim 2, wherein the dynamically adjusting the coding condition of the image further comprises: determining the system resource according to the measured category of the application and the resource usage of the system. The usage amount meets the predetermined condition; when the category of the application is detected as a first category, the encoding condition of the image is adjusted to be a first encoding condition; and the category of the application is detected by the first When a category is converted into a second category, the encoding condition for adjusting the image is a second encoding condition; wherein the first encoding condition and the second encoding condition have different compression ratios, the resolution, and/or the The amount of data transferred. The wireless video transmission method of claim 1, wherein the detecting the currently running category of the application is by detecting a keyword and a file name corresponding to the application. For example, the wireless video transmission method described in claim 1 is The encoding condition for adjusting the image includes reducing the compression ratio, reducing the resolution, and reducing the amount of transmitted data. The wireless video transmission method of claim 1, wherein the encoding condition for adjusting the image comprises increasing the compression ratio, amplifying the resolution, and increasing the amount of transmission data. The wireless video transmission method of claim 1, wherein the image system is extracted from a frame buffer. A wireless video transmission system includes: a picture buffer for providing an image; and an encoding unit coupled to the picture buffer for detecting one of the currently executing applications and detecting the wireless video transmission a system resource usage of the system, and dynamically adjusting one of the image encoding conditions in the picture buffer according to the detected category of the application and the system resource usage, and using the encoding condition The image is encoded to generate a coded image for transmission; and a wireless transmission unit is coupled to the code unit for transmitting the coded image for wireless video transmission; wherein the coding condition is used to determine the code The image corresponds to a compression ratio, a resolution, and a data volume. The wireless video transmission system according to claim 12, wherein the coding unit further determines whether the detection of the system resource usage amount meets a predetermined condition, and determines that the system resource usage amount does not meet the predetermined condition. The decoding condition is adjusted, and when the system resource usage amount meets the predetermined condition, it is decided to adjust the decoding condition. The wireless video transmission system described in claim 13 The system, when the system resource usage quantity meets at least one of the following conditions, the coding unit determines that the system resource usage amount meets the predetermined condition: one central processing unit of the wireless video transmission system is overloaded; the wireless video and audio The memory space of the transmission system is insufficient; one of the wireless video transmission systems is currently too small in wireless network bandwidth; and the hardware specifications of the wireless video transmission system are too poor. The wireless video transmission system of claim 13, wherein the adjusting the decoding condition comprises adjusting the compression ratio, the resolution, and/or the amount of transmission data corresponding to the image when encoding. The wireless video transmission system according to claim 13, wherein the encoder further determines that the system resource usage amount meets the predetermined condition, and when the category of the application is detected as a first category, adjusting the The encoding condition of the image is a first encoding condition, and when the category of the application is detected to be converted from the first category to the second category, the encoding condition of the image is adjusted to a second encoding condition, wherein The first encoding condition and the second encoding condition have different compression ratios, the resolution, and/or the amount of transmitted data. The wireless video transmission system of claim 12, wherein the encoder detects the category of the application currently being executed by detecting a keyword and a file name corresponding to the application. A computer program product that is loaded by a machine to perform a wireless video and audio transmission method for performing a wireless video transmission. The computer program product includes: a first code for detecting one of the currently active applications and a system resource usage; and a second code for determining the category of the application and the System resource usage, dynamically adjusting an encoding condition of an image and encoding the image according to the encoding condition, generating a coded image for transmission, and transmitting the encoded image through a wireless transmission unit to perform the wireless video transmission; The coding condition is used to determine a compression ratio, a resolution, and a transmission data amount corresponding to the image at the time of encoding.