Patent Application
20090077606
1. Field of the Invention
The present invention relates to an audio/video transmission apparatus and an audio/video transmission method including a high-speed interface for transmitting audio and video information.
2. Description of the Related Art
A serial transmission interface called a High Definition Multimedia Interface (HDMI) for transmitting audio/video information is well known.
In
On the other hand, 611 indicates an EDID reading/determining section for reading out EDID information from the storage element 640 and determining a content of the EDID information, 612 indicates a hot plug detecting section for detecting a hot plug signal from the hot plug output section 652, 613 indicates a TMDS output section for outputting a TMDS signal to the TMDS input section 651, 610 indicates an HDMI processing section including the EDID reading/determining section 611, the hot plug detecting section 612, and the TMDS output section 613, and 620 indicates an audio/video processing section for performing various audio/video processes. The audio/video transmission apparatus 600 has an input section (not shown) for receiving a desired control item, a tuner (not shown), and an audio/video recording/reproducing section (not shown) for recording audio and video received via the tuner or reproducing recorded audio and video, as well as the HDMI processing section 610 and the audio/video processing section 620. Note that signal lines of the HDMI cable 680 that are not herein described are not shown.
The EDID reading/determining section 611 reads out EDID information from the storage element 640, and based on a content of the EDID information, determines whether the audio/video reception apparatus 630 is an HDMI apparatus, a Digital Visual Interface (DVI) apparatus, or other unknown apparatuses. When determining that the audio/video reception apparatus 630 is an HDMI apparatus, the EDID reading/determining section 611 instructs the TMDS output section 613 to output a TMDS signal.
As shown in
Note that the time periods t1, t2 and t3 each have a fixed value, so that only a single TMDS signal output scheme is available irrespective of the type, manufacturer, model and the like of the connected audio/video reception apparatus 630.
The audio/video reception apparatus 630 processes the received audio/video information into audio and video that can be listened and viewed using the audio/video processing section 660, and outputs the resultant data to the audio/video output section 670. Stages following the audio/video output section 670 vary depending on whether the audio/video reception apparatus 630 is a television set, a projector, or an AV amplifier, and will not be described. Also, a case where it is determined that the audio/video reception apparatus 630 is a DVI apparatus or other unknown apparatuses, will not be described.
Incidentally, in the configuration described above, the TMDS signal output scheme and the InfoFrame packet output timing are fixed. Therefore, a mismatch in process timing may occur between the sender and the receiver, depending on the connected audio/video reception apparatus, so that a defective phenomenon may occur, e.g., the authentication process may fail, audio may not be output or a discomfort sound may be generated, video may not be output or may be disturbed, or the like.
To avoid this, an audio/video transmission apparatus according to a conventional technique determines the type of a reception apparatus connected thereto based on EDID information including product information, manufacturer information, and video format information, and switches a control program only for a specific type. Thereby, even if the reception apparatus causes a hot plug signal to go from High to Low without holding the hot plug signal (without fixing the hot plug signal to High) while an authentication process is being performed, the transition is ignored and the authentication process is continued, so that a defective phenomenon is prevented (see Japanese Unexamined Patent Application Publication No. 2006-203725).
The defective phenomena described above may often be reduced by adjusting the TMDS signal output scheme and the InfoFrame packet output timings (t1, t2 and t3 of
Also, in order to secure the quality of a conventional apparatus every time the timings t1, t2 and t3 are adjusted, connection to the audio/video reception apparatus that would otherwise be conventionally free of the problem needs to be verified again so as to confirm that there is not the side effect. This process requires a vast time that is proportional to the number of apparatuses to be verified and the number of items to be evaluated.
In view of the problems described above, the present invention has been achieved. An object of the present invention is to provide an audio/video transmission apparatus having a plurality of output schemes in which the type of a reception apparatus is determined based on EDID information read out from an audio/video reception apparatus connected thereto, and a TMDS signal and an InfoFrame packet corresponding to the type can be output.
To achieve the object, the present invention provides an audio/video transmission apparatus connectable to an audio/video reception apparatus via a serial transmission interface, including a section for determining a type of the audio/video reception apparatus based on apparatus information about the connected audio/video reception apparatus, and a section for selecting an information transmission signal output scheme corresponding to the type of the connected audio/video reception apparatus from a plurality of output schemes for an information transmission signal, and outputting the information transmission signal.
More specifically, the present invention provides an audio/video transmission apparatus connectable to an audio/video reception apparatus via an HDMI interface, including a hot plug detecting section for detecting a hot plug signal output from the connected audio/video reception apparatus, an EDID reading/determining section for reading EDID information of the connected audio/video reception apparatus, and determining a content of the EDID information, a type determining section for determining a type of the connected audio/video reception apparatus based on a result of the determination of the EDID information, a TMDS switching section for designating an output scheme corresponding to the type of the connected audio/video reception apparatus of a plurality of TMDS signal output schemes, and a TMDS output section for outputting a TMDS signal in accordance with the output scheme designated by the TMDS switching section.
According to the present invention, as compared to the conventional single-output scheme, a mismatch in process timing between the sender and the receiver can be reduced, thereby making it possible to reduce a phenomenon due to the mismatch, such as a failure in authentication, the absence or disturbance of audio or video output, or the like.
In
On the other hand, 111 indicates an EDID reading/determining section for reading out EDID information form the storage element 140 and determines a content of the EDID information, 112 indicates a hot plug detecting section for determining a hot plug signal from the hot plug output section 152, 113 indicates a TMDS output section for outputting a TMDS signal to the TMDS input section 151, 114 indicates a type determining section for determining the type of the audio/video reception apparatus 130, 115 indicates a TMDS switching section that includes a plurality of output schemes and a plurality of InfoFrame packet output timings for the TMDS signal output from the TMDS output section 113, and switches the output schemes and the InfoFrame packet output timings, 110 indicates an HDMI processing section including the EDID reading/determining section 111, the hot plug detecting section 112, the TMDS output section 113, the type determining section 114, and the TMDS switching section 115, 120 indicates an audio/video processing section for performing various audio/video processes, 121 indicates an input section for providing a desired setting, 122 indicates a tuner, 123 indicates an audio/video recording/reproducing section including a hard disk drive (hereinafter referred to as an HDD), a CD/DVD drive or the like that records audio and video received by the tuner 122 or reproduces recorded audio and video, and 124 indicates a rewrite section for rewriting the TMDS signal output schemes and the InfoFrame packet output timings possessed by the TMDS switching section 115. The audio/video transmission apparatus 100 includes the HDMI processing section 110, the audio/video processing section 120, the input section 121, the tuner 122, the audio/video recording/reproducing section 123, and the rewrite section 124. 190 indicates a communications network, such as the Internet or the like. Note that signal lines of the HDMI cable 180 that are not herein described are not shown.
When the audio/video transmission apparatus 100 and the audio/video reception apparatus 130 are connected to each other via the HDMI cable 180 and both the apparatuses 100 and 130 are powered ON, the hot plug output section 152 causes a hot plug signal to go from Low to High. The hot plug detecting section 112, when detecting the transition of the hot plug signal from Low to High, determines that the audio/video transmission apparatus 100 and the audio/video reception apparatus 130 are physically connected to each other, so that EDID information can be read out, and then instructs the EDID reading/determining section 111 to read out EDID information from the storage element 140.
It will be described how the EDID reading/determining section 111 and the type determining section 114 determine the type of the audio/video reception apparatus 130, with reference to
The EDID reading/determining section 111, after reading out EDID information from the storage element 140, determines whether or not the structure of the EDID information includes an extension block (step 1). If an extension block is included, the EDID reading/determining section 111 determines that the audio/video reception apparatus 130 is an HDMI apparatus, and the process goes to step 2. If an extension block is not included, the EDID reading/determining section 111 determines that the audio/video reception apparatus 130 is a DVI apparatus, and the process goes to step 4-5.
In step 2, audio information belonging to the audio tag and the speaker tag included in the extension block is read out.
In step 3, the type of the audio/video reception apparatus 130 is determined based on the information read out in step 2. If the number of audio channels is two and the supported audio frequency is 48 kHz, the type of the audio/video reception apparatus 130 is determined to be a television set, and the process goes to step 4-1. If audio input is not permitted (not required), the type of the audio/video reception apparatus 130 is determined to be a projector, and the process goes to step 4-2. If the number of audio channels is up to eight and the supported audio frequency is up to 192 kHz, the type of the audio/video reception apparatus 130 is determined to be an AV amplifier, and the process goes to step 4-3. If the type of the audio/video reception apparatus 130 is determined to correspond to none of these types (i.e., determined to be unknown), the process goes to step 4-4.
In step 4-i (i=1 to 5), information for transmitting the type of the audio/video reception apparatus 130 determined in step 3 to the TMDS switching section 115 is set.
In step 5, the information set in step 4-i (i=1 to 5) is transmitted to the TMDS switching section 115.
The TMDS switching section 115 selects a TMDS signal output scheme and an InfoFrame packet output timing suitable for the audio/video reception apparatus 130 based on the information transmitted from the type determining section 114. For example, if the information indicates “television set”, a scheme A in
The TMDS output section 113 outputs a TMDS signal in accordance with the instruction from the TMDS switching section 115 in the following procedure. As in schemes of
The output audio/video information is either one that has been received by the tuner 122 or one that has been reproduced by the audio/video recording/reproducing section 123. The input section 121 selects either one of the pieces of audio/video information, and also selects the type of audio, the resolution of output video and the like. The audio/video processing section 120 processes the audio/video information into a desired audio type and video resolution and outputs the resultant data to the TMDS output section 113.
The audio/video reception apparatus 130 processes the received audio/video information into audio and video that can be listened and viewed using the audio/video processing section 160, and outputs the resultant data to the audio/video output section 170. Stages following the audio/video output section 170 vary depending on whether the audio/video reception apparatus 130 is a television set, a projector, or an AV amplifier, and will not be described.
If the audio/video reception apparatus 130 is, for example, newly designed or slightly changed, then when the TMDS signal output scheme and the InfoFrame packet output timing of
For example, if a newly designed television set is connected to the audio/video transmission apparatus 100, the TMDS signal output scheme and the InfoFrame packet output timing for the scheme A are selected. In this case, it is assumed that the process flow, process time or the like of the television set is changed, and therefore, a mismatch in process timing occurs between the television set and the audio/video transmission apparatus 100, so that neither audio nor video is output. It is also assumed that, as a result of adjustment, an improvement is achieved by elongating the time period TA3 by ΔT from the current state and delaying the InfoFrame packet output timing (hereinafter referred to as a “scheme A′” (not shown)). Although the scheme A′ is effective for the newly designed television set, it is not known at this time whether or not the scheme A′ is effective for a television set that conventionally does not have a problem. Therefore, the scheme A′ is used to verify connectivity with respect to the conventional television set, and if a problem does not arise, the scheme A′ is formally adopted and set as the scheme A. If a problem arises, additional measures, such as time adjustment or the like, are taken so as to find out a scheme suitable for both the television set that conventionally does not have a problem and the newly designed television set. This time adjustment is only for television sets, so that none of the scheme B for a projector, the scheme C for an AV amplifier, and the scheme D for others or a DVI apparatus is affected. Also, reverification of connectivity may be performed only with respect to the television set, i.e., reverification of connectivity is not required for the other types of apparatuses that have not been adjusted.
As described above, with the configuration of
Further, a TMDS signal output scheme and an InfoFrame packet output timing are set and adjusted only for a scheme corresponding to the type of the audio/video reception apparatus, and none of the other schemes (other types) is affected.
Further, connectivity reverification may be performed only for a scheme that has been set and adjusted, so that a verification time can be significantly reduced as compared to that in the conventional art, leading to a reduction in development cost.
Note that the TMDS signal output schemes and InfoFrame packet output timings selected by the TMDS switching section 115 are not limited to those shown in
Also, the method for determining the type of an audio/video reception apparatus that is performed by the type determining section 114 is not limited to that shown in
The TMDS switching section 115, when receiving information about the type of the audio/video reception apparatus 130 from the type determining section 114, selects a TMDS signal output scheme and an InfoFrame packet output timing suitable for the audio/video reception apparatus 130. For example, if the information indicates “television set”, the scheme storing device 1 of
The scheme storing devices 5 and 6 prepared as spares store output schemes suitable for types other than a television set, a projector, an AV amplifier and others (including a DVI apparatus) stored in the scheme storing devices 1 to 4. Alternatively, the scheme storing devices 5 and 6 store output schemes for a peculiar television set, projector, AV amplifier and others (including a DVI apparatus) that cannot be supported by the output schemes stored in the scheme storing devices 1 to 4.
For example, there are assumed to be television sets manufactured by companies X, Y and Z. It is also here assumed that the television sets of the company X and Y can be supported by the scheme A stored in the scheme storing device 1, and the television set of the company Z is supported by none of the schemes. In this case, information about a TMDS signal output scheme and an InfoFrame packet output timing dedicated to the television set of the company Z is stored in the scheme storing device 5. In addition, the type determining section 114 is provided with an additional process of determining whether the type of the audio/video reception apparatus 130 is the television set of the company Z.
Instead of time adjustment of the scheme A for the type “television set”, the information about the TMDS signal output scheme and the InfoFrame packet output timing dedicated to the television set of the company Z is additionally provided, so that reverification is not required for television sets that conventionally do not have a problem.
As described above, a spare scheme storing device for storing a TMDS signal output scheme and an InfoFrame packet output timing is additionally provided, so that a peculiar apparatus, type or the like can be flexibly supported, thereby making it possible to improve the quality of connectivity of the audio/video transmission apparatus.
Further, connectivity reverification may be performed only with respect to an additional scheme, so that a time required for connectivity verification does not significantly increases and therefore development cost is reduced.
Note that the number of scheme storing devices is not limited to that of
Incidentally, as shown in
When the communications network 190 is used, the audio/video transmission apparatus 100 needs to be previously connected to the communications network 190. The input section 121 instructs the rewrite section 124 to access a designated web site, download latest information about a TMDS signal output scheme and an InfoFrame packet output timing, and write the information to a designated scheme storing device i (i=1 to 6). The rewrite section 124 operates in accordance with the instruction.
When a CD or DVD medium is used, the input section 121 instructs the audio/video recording/reproducing section 123 to read update information written on the CD or DVD medium and transmit the information to the rewrite section 124, and instructs the rewrite section 124 to write update information from the audio/video recording/reproducing section 123 to a designated scheme storing device i (i=1 to 6). The rewrite section 124 operates in accordance with the instruction.
As described above, with the configuration of
Note that when the audio/video transmission apparatus 100 supports reading and writing of a compact storage medium, such as an SD card or the like, the audio/video transmission apparatus 100 can cause the rewrite section 124 to perform a rewrite operation using information stored in the compact storage medium, as is similar to the case of a CD or DVD medium.
Further, a remote controller or the like accompanying the audio/video transmission apparatus 100 may be used to adjust a TMDS signal output scheme and an InfoFrame packet output timing. Thus, the rewrite section 124 is not limited to that described above.
As described above, the audio/video transmission apparatus of the present invention is useful for home-use audio/video apparatuses, such as a DVD player, a DVD recorder, a hard disk recording/reproducing apparatus, an AV amplifier, and the like.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-237890 | Sep 2007 | JP | national |
