Patent Application
20090040287
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2007-091658, filed Mar. 30, 2007, the entire contents of which are incorporated herein by reference.
1. Field
One embodiment of the present invention relates to a video communication device having a communication function for transmitting and receiving data at a plurality of transfer rates, and in particular to a video communication device and a video communication method having a function of displaying the communication situation.
2. Description of the Related Art
Recent years have seen a remarkable extension of the ownership and use of digital devices having mutual communication functions capable of collaborative operation. These digital communication functions, however, operate not necessarily in stable fashion constantly, and the communication is desirably continued by taking an appropriate action in case of a communication error.
Patent Document 1 (Jpn. Pat. Appln. KOKAI Publication No. 2000-101605) discloses a technique relating to an infrared ray video communication device having the function of calculating the communication quality and the function of changing the communication speed in accordance with the result of communication quality calculation.
According to the conventional technique described in Patent Document 1, however, the communication is changed in speed or suspended automatically in accordance with the communication quality. In the digital video communication such as HDMI, on the other hand, even though somewhat low in communication quality, the video signal format of the same type may be used as it is. In many cases, therefore, the communication situation should be better indicated to the user thereby to allow the user to take an appropriate action rather than to change the communication speed or suspend the communication.
A general architecture that implements the various feature of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention.
Various embodiments according to the invention will be described hereinafter with reference to the accompanying drawings. In general, according to one embodiment of the invention, there are provided a video communication device and a video communication method for displaying the communication situation in the digital video communication such as HDMI.
One embodiment for achieving the object is a video communication device comprising:
a first communication unit (17) which conducts communication of management information with an external device through a cable at a first communication speed;
a second communication unit (16) which conducts communication of a video signal with the external device through the cable at a second communication speed higher than the first communication speed;
a detector (11, 12) which detects an error signal by observing a communication situation with the external device; and
a generating unit (13) which generates an image signal indicating the communication situation based on the error signal detected by the detector.
The communication quality of the communication cable used is displayed on the digital TV screen, for example, linked to each video signal format such as 480p, 1080i or 1080p, and therefore, the user can conduct the communication with the optimum video signal in the range available for the particular communication cable.
Embodiments of this invention will be explained in detail below with reference to the drawings.
(Example of Digital Video Communication Having Plural Communication Speeds)
First, the digital video communication having a plurality of communication speeds used by a video communication device according to an embodiment of this invention will be explained below.
In the case where a communication error occurs in the digital data communication typically conducted by the computer, the communication quality is secured normally by recognizing the communication error at the transmitting and receiving ends and executing the retransmission process. In the digital video communication typically using HDMI, however, an error, if any, developed in a part of the video data, though a cause of a noise on the screen, has no such an effect as to destroy the entire video service and the data is not retransmitted.
Typical methods of digital video signal transmission include HDMI (high-definition multimedia interface) and DVI (digital visual interface), and a new transmission method such as DP (display port) has been proposed as a method which is expected to become a reality in the near future. Generally, a new method is standardized to transmit an image with a higher resolution and requires a correspondingly higher quality of the cable as well as the transmitter/receiver.
In HDMI, the cable quality can be set arbitrarily in design stage. By employing the quality test for authentication, however, the trouble which otherwise might occur at the time of user operation is avoided. Actually, however, it is unrealistic to test all the cables. Further, with the progress toward a higher definition of the digital video format, a plurality of types of data transfer rate are specified to such an extent that the communication quality now depends also on the transmission video format (data transfer rate).
For example, a cable capable of communication for 1080i without any problem may develop an error at 1080p. According to HDMI Ver1.3 recently standardized, a method of transmitting the more finely detailed digital signal called DeepColor has been defined. In this method, though having the same resolution as the conventional HDMI Ver1.2a, the fine video data transfer requires the definition of the actual transfer rate of the digital signal up to 3.4 Gbps or about twice as large as in the prior art.
In the world of the digital video communication typically using HDMI, the video format capable of being received at the receiving end can be read at the transmitting end using a low-speed communication path different from the digital video signal. This communication path is low in speed, and the requirement for communication quality is met by the cable quality lower than for the high-speed digital video communication.
In the ordinary video communication device, however, the communication quality is not measured for both the transmitter and the receiver, and consequently, the transmitter selectively transmits data of a high image quality based on the receivable format information obtained on the low-speed communication path. Depending on the cable quality, therefore, a screen anomaly may develop and the proper transmission situation cannot be recognized by the user.
In the video communication device according to an embodiment of the invention, the communication situation of the communication cable, etc. is displayed in the state linked to, for example, the video signal format, and therefore, the user can conduct the optimum video signal communication in the range usable with the particular communication cable.
<Video Communication Device According to an Embodiment of the Invention>
Next, an example of the video communication device according to an embodiment of the invention will be explained in detail with reference to the drawings. The embodiment described below discloses an example of the video communication device and the video communication method having the function of detecting and displaying the communication situation of the communication path for the digital video communication with HDMI as an example. This embodiment of the invention, however, is not limited to HDMI but may use other digital communication standards as well as a display port and widely applicable to digital communication.
(Configuration)
First, as shown in
The video communication device D1 according to an embodiment of the invention, as shown in
On the other hand, the video communication device D2 according to an embodiment of the invention, which is, for example, a digital TV having the HDMI communication function like a broadcast receiver 100 for displaying the broadcast signal described in
(HDMI Terminal and Display Port Terminal)
Next, the HDMI terminal and the display port terminal will be briefly explained with reference to
The HDMI terminal handled by the video communication device according to an embodiment of the invention includes first to 12th terminals for the high-speed audio-visual transmission line, and 13th, 15th, 16th and 19th terminals for the low-speed communication line.
Similarly, as shown in
(Other Configuration:
Next, as shown in
The video communication device D1 according to an embodiment of the invention has the same configuration as the corresponding device shown in
(Other Configuration:
Next, as shown in
The video communication device D1′ having no communication situation display function, as shown in
Incidentally, the video communication device D2 according to an embodiment of the invention has the same configuration as the corresponding device shown in
<Example of Communication Situation Display Process of Video Communication Device According to an Embodiment of the Invention>
Next, an example of the communication situation display process of the video communication device according to an embodiment of the invention will be explained in detail with reference to the drawings.
Also, the embodiment described below represents a case in which the control unit is in charge of the steps of each operation. Nevertheless, the embodiments of the invention are not necessarily configured in such a manner, but an equivalent operation and effect can be achieved by each circuit configuration exhibiting the respective function without the control unit.
(Source-Side Communication Situation Display Process)
First, an example of the communication situation display process executed by the source-side video communication device D1 shown in
In the case where the party at the other end of communication is a control unit 22 having the error detector 26 or an error reporting function as shown in
In similar fashion, the control unit 12 tries to acquire a signal indicating the degree of a jitter error from the video communication device D2, for example, through the DDC communication unit 17 and the communication line (step S13). In the case where the other party of communication is the control unit 22 having the error detector 26 or the error reporting function as shown in
Next, the error detector 11 detects the degree of an Ri error under the control of the control unit 12. Now, the packet error, the jitter error and the Ri error will be explained.
The packet error is given by an error correction code or the like in an HDMI data island packet. This code can be monitored by the HDMI receiver (sink side), and based on this value, the error can be checked.
The error correction code for the high-speed data line is available and the communication error of the high-speed line (digital audio-visual transfer) can be monitored also according to the DP standard equipped with the high-speed data line and the low-speed data line as in the HDMI.
Now, the jitter error will be explained. According to HDMI or DP, the digital video signal is coded and transferred, and therefore, several data exist which are required to be transmitted at a specified timing. In each frame, a period exists, for example, during which the HDMI encryption is prohibited, and the limit of the start timing is specified. Also, the timing to transmit the information indicating the presence or absence of encryption is specified for each frame. These timings are not specified strictly for each Ck but with some degree of design freedom, and therefore, have some freedom. The normal transmission timing is often designed the same way for each frame, and in the case where the communication path poses a quality problem, the timing is not necessarily constant but may be somewhat shifted. By monitoring this shift, the jitter error can be observed.
Next, the random number Ri will be described. In the HDMI encryption process, when the HDCP encryption is used, the random number called Ri is required to be matched between transmission and receiving ends, and can be periodically observed at the transmission end (source side). The random number Ri is dependent on the TMDS line Ck and the encrypted pixel count, and in the case where the TMDS signal cannot be correctly received, the count is shifted and the received Ri is mismatched. Specifically, the communication situation can be confirmed by checking whether Ri is matched or not at the transmitting end (source side). At the receiving end (sink side), on the other hand, the Ri matching cannot be directly monitored. Upon occurrence of an Ri mismatch, however, the HDMI is rechecked. In this way, the error state can also be monitored.
As described above, the control unit 12 collects the packet error, the jitter error and the Ri error. More preferably, however, the control unit 12 collects still other indexes of the communication situation. The control unit 12 compares the degree of each error signal with a preset threshold value (step S15), and in accordance with the comparison result, quantitatively evaluates the communication situation. As a result, the control unit 12 and the image message generating unit 13 generate an image signal indicating the communication situation as shown in
Specifically, in
The figure “480p” is one of the video signal formats for the digital TV broadcasting and represents an image of progressive scan type having 480 effective scanning lines and the frame frequency of 59.94 Hz. The number of pixels is 720×480 with the aspect ratio of 16:9. This is a kind of the SDTV video format having the same number of scanning lines as the current analog TV broadcasting.
The figure “1080i” is one of the video signal formats for the digital TV broadcasting and represents an image of interlace scan type having 1080 effective scanning lines and the frame frequency of 29.97 Hz. The number of pixels is 1920×1080 with the aspect ratio of 16:9. This is a kind of the HDTV video format.
The figure “1080p” is one of the video signal formats for the digital TV broadcasting and represents an image of progressive scan type having 1080 effective scanning lines and the frame frequency of 59.94 Hz. The number of pixels is 1920×1080 with the aspect ratio of 16:9. This is a kind of the HDTV video format.
In
In a similar fashion, in
Further, in the display example of the communication situation shown in
(Sink-Side Communication Situation Display Process)
Next, with reference to the flowchart of
Further, as shown in
Once the Ri mismatch occurs, however, the HDMI is authenticated again, and therefore, the error state can be suitably monitored.
As described above, the control unit 22, though adapted to collect the packet error, jitter error and Ri error, more preferably collects other indexes of the communication situation. The control unit 22 compares the degree of each error signal with a preset threshold value (step S25), and in accordance with the comparison result, quantitatively evaluates the communication situation. As a result, the control unit 22 and the image message generating unit 27 generate an image signal indicating the communication situation as shown in
In this way, the error signal indicating the error state is collected at the receiving end (sink side) as well as at the transmitting end (source side), so that the communication situation is displayed in a form easily understandable to the user as shown in
<Broadcast Receiver Using Video Communication Device According to an Embodiment of the Invention>
Next, an example of the broadcast receiver using the video communication device according to an embodiment of the invention will be explained with reference to the drawings.
Although the broadcast receiver is explained here taking the digital TV as an example, the video communication device according to an embodiment of the invention includes various forms all of which should be interpreted to be included in the scope of the embodiments of the invention.
In the broadcast receiver 100 shown in
Now, the broadcast receiver 100 shown in
Further, the broadcast receiver 100 is connected to the control unit 130 through a data bus, and has an operating unit 132 for user operation and the operation of a remote controller R. The remote controller R can operate substantially the same way as the operating unit 132 of the broadcast receiver 100 proper, and is capable of various setting operations including tuner operation and recording reservation.
As described above, the video communication device according to an embodiment of the invention is applicable as a communication unit of the broadcast receiver (digital TV or the like) having the aforementioned configuration. According to this embodiment, the communication quality of the communication cable used for HDMI or the like is displayed on the screen of a digital TV, for example, in correspondence with the video signal formats of 480p, 1080i, 1080p. etc. As a result, the user can conduct the communication with the optimum video signal within the range operable through the communication cable.
With the various embodiments described above, those skilled in the art can implement the present invention. Further, it is easy for those skilled in the art to conceive various modifications of these embodiments, and without any special inventive ability, applications to various embodiments are possible. This invention, therefore, covers a wide scope not in conflict with the disclosed principle and the novel features and is not limited to the embodiments described above.
While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-091658 | Mar 2007 | JP | national |
