Patent Application
20150139339
This application claims priority to and the benefit of Korean Patent Application No. 10-201 3-01 42390 filed in the Korean Intellectual Property Office on Nov. 21, 2013, the entire contents of which are incorporated herein by reference.
(a) Field of the Invention
The present invention relates to a broadcast transmitting apparatus and method, and more particularly, to a broadcast transmitting apparatus and method which take a user's viewing environment into consideration.
(b) Description of the Related Art
Nowadays, broadcasting and multicasting services have been popularized in such a way that they deliver multimedia applications to mobile equipment, as is the case with mobile TV services, as well as making stationary reception available.
However, current broadcasting services are disadvantageous in that video and audio signals are not properly received if the intensity of received signals is low, thus failing to receive the broadcasting services.
This leads to a demand for a method that enables a user to receive a broadcasting service even when the intensity of received signals is low.
The present invention has been made in an effort to provide a broadcast transmitting apparatus and method which provide broadcasting service by taking a user's viewing environment into consideration.
An exemplary embodiment of the present invention provides a broadcast transmitting method for a broadcast transmitting apparatus. The broadcast transmitting method includes: splitting a piece of broadcast content into an audio signal and a video signal; encoding the audio signal and the video signal to generate an audio bit string and a video bit string; multiplexing the video bit string and the audio bit string; and modulating the multiplexed bit strings into a symbol, wherein some bits of the symbol include the audio bit string, and the remaining bits of the symbol include the video bit string.
The some bits may include the most significant bit and at least one bit after the most significant bit.
A signal allocated to each bit in the symbol may be determined depending on the characteristics of the symbol.
The characteristics may include error probability.
The encoding may include encoding the audio bit string at a lower encoding rate than that of the video bit string.
Another exemplary embodiment of the present invention provides a broadcast transmitting apparatus. The broadcasting transmitting apparatus includes a splitter, an audio encoder, a video encoder, a multiplexer, and a modulator. The splitter splits a piece of broadcast content into an audio signal and a video signal. The audio encoder encodes the audio signal to generate an audio bit string. The video encoder encodes the video signal to generate a video bit string. The multiplexer multiplexes the audio bit string and the video bit string. The modulator modulates the multiplexed bit strings into a symbol. The modulator allocates the encoded audio bit string to some bits of the symbol and allocates the encoded audio bit string to the remaining bits of the symbol.
The some bits may include the most significant bit, and the remaining bits may include the least significant bit.
The some bits may have lower error probability than the remaining bits.
The audio encoder may encode the audio signal at a lower encoding rate than that for the video encoder.
In the following detailed description, only certain exemplary embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.
Throughout the specification and the claims, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.
Now, a broadcast transmitting apparatus and method according to an exemplary embodiment of the present invention will be described in detail with reference to the drawings.
Referring to
Referring to
The video encoder 120 encodes a video signal to generate a video bit string, and the audio encoder 130 encodes an audio signal to generate an audio bit string (S220). The video encoder 120 and the audio encoder 130 can encode a video signal and an audio signal in the same encoding mode. Also, the audio encoder 130 may be of a lower order than the video encoder 120. That is, the audio encoder 130 can encode an audio signal at a lower encoding rate than that of the video encoder 120.
The multiplexer 140 multiplexes the encoded video bit string and the encoded audio bit string to generate a single transmission stream (S230).
The modulator 150 modulates the transmission stream into a symbol by a set modulation scheme. The modulator 150 allocates the encoded video bit string and the encoded audio bit string to bits in the symbol. That is, the modulator 150 allocates the encoded audio signal to bits with low error probability within a symbol and the encoded video signal to the remaining bits, that is, bits with high error probability, within the symbol (S240). For example, in a 64 QAM (Quadrature Amplitude Modulation) scheme, one symbol consists of 6 bits. In this case, the encoded audio signal may be allocated to the two most significant bits with low error probability, and the encoded video signal may be allocated to the four least significant bits with high error probability. That is, in 64 QAM, a 6-bit value is mapped to each symbol. Accordingly, the modulator 150 performs symbol mapping on the encoded audio bit string by using a specific number of most significant bits in each symbol, and performs symbol mapping on the encoded video bit string by using a specific number of least significant bits in each symbol. For example, encoded audio bits 00 may be mapped to one of 16 symbols whose two most significant bits are 00, and encoded video bits 0000 may be mapped to a symbol whose four least significant bits are 0000.
In this way, the broadcast transmitting apparatus 100 according to an exemplary embodiment of the present invention allocates a video signal to bits with high error probability within one symbol and an audio signal to bits with low error probability within a symbol. By doing so, audio signals can be demodulated properly even if the reception environment of the broadcast transmitting apparatus is not good.
Referring to
If the QAM symbol consists of 4 bits, the error probability is the same, i.e., 16 QAM, within the decision boundary D1-D2 and the decision boundary D3-D4, both having the error probability of 4 QAM.
Likewise, if the QAM symbol consists of 6 bits, the error probability is the same, i.e., 64 QAM, within the decision boundary D1-D6 because the decision boundary D5-D6 of 4 QAM is added.
The error probability for 64 QAM is lower than the error probability for 16 QAM, and the error probability for 16 QAM is lower than the error probability for 4 QAM.
Assuming that a received signal is r and a 64 QAM symbol is transmitted, the 2 most significant bits of the 64 QAM symbol are determined according to bit information and
required for determination. Also, the third and fourth bits are determined according to bit information
and
required for determination, and the 2 least significant bits are determined according to
and
.
Here, =Real(r) and
=Imag(r), which represent the real and imaginary values of the received signal r. Also,
=|
|−4A,
=|
|−4A,
=|
|−2A, and
=|
|−2A.
In this way, a broadcast receiving apparatus demodulates a received signal.
For 64 QAM, one symbol consists of 6 bits. The 2 most significant bits of one symbol have a lower error probability than the 4 least significant bits. For 16 QAM, one symbol consists of 4 bits. The 2 most significant bits of one symbol likewise have a lower error probability than the 2 least significant bits.
Accordingly, the modulator 150 according to the exemplary embodiment of the present invention allows for proper demodulation of audio signals to make them robust to the reception environment by allocating an encoded audio signal to bits with low error probability within a symbol.
Referring to
If the intensity of a received signal is normal, the broadcast receiving apparatus can demodulate a video signal and an audio signal, thus enabling the user to properly view the broadcast. However, if the intensity of a received signal decreases and the signal is not properly received, bits with high error probability within a symbol cannot be properly demodulated and the video signal therefore may not be properly processed. On the other hand, bits with low error probability within the symbol are properly demodulated and the audio signal is therefore properly processed and received.
That is, audio signals can be properly received even when the reception environment of the broadcast receiving apparatus is not good.
Referring to
As shown in
The demultiplexer 520 demultiplexes the reception bit string into a video bit string and an audio bit string (S620). The video bit string and the audio bit string are respectively input into the video encoder 530 and the audio encoder 540.
The video decoder 530 decodes the video bit string and reproduces it (S630).
The audio decoder 540 decodes the audio bit string and reproduces it (S640.
According to an embodiment of the present invention, audio signals with low error probability can be properly received even when it is difficult to properly view the broadcast because the intensity of a received signal decreases while viewing the broadcast, thereby enabling continuous broadcast reception.
An exemplary embodiment of the present invention may not only be embodied through the above-described apparatus and method, but may also be embodied through a program that executes a function corresponding to a configuration of the exemplary embodiment of the present invention or through a recording medium on which the program is recorded, and can be easily embodied by a person of ordinary skill in the art from a description of the foregoing exemplary embodiment.
While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2013-0142390 | Nov 2013 | KR | national |
