METHOD FOR PROCESSING MULTI-MEDIA SIGNALS AND ASSOCIATED MULTI-MEDIA DEVICE

A method for processing a multi-media signal and an associated multi-media device are provided. The method includes: receiving a first audio signal within the multi-media signal from a display device through a first transmission interface of a multi-media device; converting the first audio signal into a second audio signal applicable to a second transmission interface of the multi-media device; and outputting the second audio signal to an audio device through the second transmission interface for playback.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to multi-media signals, and more particularly, to a method for processing a multi-media signal, and an associated multi-media device.

2. Description of the Prior Art

High Definition Multimedia Interface (HDMI) Licensing Administrator, Inc. (HDMI LA) specifies an Audio Return Channel (ARC) which allows audio signals to be transmitted indifferent directions. As transmission speed of signals reaches 12 Giga bits per second in the HDMI 2.1 specification, a length of HDMI cable is severely limited (e.g. 2-3 meters at most) under a condition of not introducing signal errors, which greatly limits locations of a projector (or TV) and an amplifier. Thus, there is a need for a novel multi-media signal processing method and associated multi-media device to solve the problem of limited cable length.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a method for processing a multi-media signal and an associated multi-media device, which can prevent locations of a projector (or TV) and an amplifier from being limited by the length of an HDMI cable in order to improve user experience.

At least one embodiment of the present invention provides a method for processing a multi-media signal. The method comprises: receiving a first audio signal within the multi-media signal from a display device through a first transmission interface of a multi-media device; converting the first audio signal into a second audio signal applicable to a second transmission interface of the multi-media device; and outputting the second audio signal to an audio device through the second transmission interface for playback.

At least one embodiment of the present invention provides a multi-media device. The multi-media device comprises a first transmission interface, a second transmission interface and a system chip, wherein the system chip comprises a conversion circuit coupled between the first transmission interface and the second transmission interface. In operations of the multi-media device, the first transmission interface may be configured to receive a first audio signal within a multi-media signal from a display device, and the second transmission interface may be configured to output a second audio signal to an audio device for playback. In addition, the system chip may utilize the conversion circuit to convert the first audio signal into the second audio signal applicable to the second transmission interface.

The multi-media device of the present invention converts the first audio signal into the second audio signal, where a transmission length of the second audio signal is less likely to be limited by the length of HDMI cable. For example, the second transmission interface maybe implemented by a Universal Serial Bus (USB) interface in order to solve the related art problems of using HDMI cables. In addition, embodiments of the present invention will not greatly increase costs, so the present invention can solve the problem of the related art without introducing any side effect or in a way that is less likely to introduce side effects.

DETAILED DESCRIPTION

At least one embodiment of the present invention provides a multi-media device. The multi-media device may utilize a video decoding circuit therein to perform video decoding to generate video output signals, and transmit the aforementioned video output signals to at least one video output device (e.g. digital TV, projector, etc.) through at least one High Definition Multimedia Interface (HDMI) cable. General digital TV performance has undergone recent improvements. For example, smart TVs can execute some video application programs (e.g. YouTube, Google Play and Netflix) which support high level audio specifications (e.g. Dolby Digital and Digital Theater System (DTS)). The multi-media device can support signal processing during execution of these video application programs, in order to allow users to enjoy the experience of using audio output equipment coupled to the multi-media device (e.g. audio output of the audio output equipment).

FIG. 1is a diagram illustrating a video system10according to an embodiment of the present invention. The video system10may comprise a multi-media device100, a display device200and an audio device500, where examples of the display device200may include, but are not limited to: a display device without the function of executing the video application programs (such as a projector or a conventional TV), and a display device with the function of executing the video application programs (such as a smart TV); and examples of the audio device500may include, but are not limited to: an audio device integrating a speaker and an amplifier into a single device, and an audio system constituted by connecting a speaker and an amplifier. In some embodiments, the multi-media device100may be implemented in small sized multi-media devices such as an Over The Top (OTT) box and a TV stick.

In this embodiment, the multi-media device100may comprise a first transmission interface such as an HDMI interface120, a video decoding circuit130, a second transmission interface such as a Universal Serial Bus (USB) interface140, and a system chip such as a System on a Chip (SoC)160, where the SoC160may comprise a conversion circuit162coupled between the HDMI interface120and the USB interface140. The HDMI interface120may allow the multi-media device100to be coupled to the display device200through an HDMI cable, and the USB interface140may allow the multi-media100to be coupled to the audio device500through at least one USB cable (e.g. a USB type-C cable). In some embodiments, in addition to the conversion circuit162, the SoC160may further comprise one or more processing circuits (not shown) for executing various types of video application programs (e.g. YouTube, Google Play, Netflix, etc.), but the present invention is not limited thereto.

In this embodiment, the audio device500may comprise an audio amplifier520and a speaker540(e.g. a passive speaker) coupled to the audio amplifier, where the audio amplifier520may comprise an amplifier circuit522, a digital-to-analog converter (DAC)524coupled to the amplifier circuit522, and a power management circuit526respectively coupled to the amplifier circuit522and the DAC524. In this embodiment, the DAC524may obtain a digital audio signal from the multi-media device100through the aforementioned at least one USB cable, and perform digital-to-analog conversion on the digital audio signal to output an analog audio signal; and then the amplifier circuit522may amplify the analog audio signal to drive the speaker540with the analog audio signal for playback; but the present invention is not limited thereto. In this embodiment, the power management circuit526may provide the amplifier circuit522and the DAC524with power, and may also provide the multi-media device100(such as the HDMI interface120, the USB interface140and the SoC160therein) with power through the aforementioned at least one USB cable. Thus, the present invention provides a design of separated power sources, which makes the multi-media device100able to obtain power from the power management circuit526within the audio device500through at least one USB cable connecting the USB interface140to the audio device500, to thereby allow the multi-media device100to normally operate without any built-in power management circuit, and required hardware size can be reduced.

In this embodiment, both the multi-media device100and the display device200have a function of obtaining streaming data (e.g. streaming data comprising image data and audio data) from a data streaming source. For better comprehension, the following description takes a smart TV as an example of the display device200. When the display device200operates in an ordinary mode, the aforementioned streaming data is obtained from the data streaming source (e.g. a remote server or internet connected to the remote server) through the multi-media device100rather than through the display device200, where the SoC160may utilize the video decoding circuit130to perform video decoding. In addition, the multi-media device100may utilize the HDMI interface120to transmit the image data within the streaming data to the display device200for display and utilize the USB interface140to transmit the audio data within the streaming data to the audio device500for playback. When the display device200operates in an internet mode, the aforementioned streaming data is obtained from the data streaming source (e.g. a remote server or internet connected to the remote server) through the display device200rather than through the multi-media device100, where the SoC160may receive a first audio signal within a multi-media signal from the display device200through an Audio Return Channel (ARC) or an enhanced ARC (eARC) (e.g. the first audio signal may carry the audio data within the streaming data obtained by the display device200), and then the SoC160may utilize the conversion circuit162therein to convert the first audio signal into a second audio signal applicable to the USB interface140, and output the second audio signal to the audio device500through the USB interface140for playback.

In some embodiments, the conversion circuit162may comprise a decoder (not shown) to make the multi-media100able to process compressed audio data in addition to uncompressed audio data. For example, when the first audio signal (e.g. the audio data within the streaming data obtained by the display device200is audio data having Dolby Digital or Digital Theater System (DTS) format), the decoder within the conversion circuit162may decode (decompress) the audio data first, and then convert the decoded data into a USB signal format for being outputted by the USB interface140; in another example, when the first audio signal is uncompressed audio data, the conversion circuit162may skip the aforementioned decoding step and directly convert the uncompressed data into a USB signal format for being outputted by the USB interface140; but the present invention is not limited thereto.

FIG. 2is a diagram illustrating a video system20according to an embodiment of the present invention, where the USB interface140within the multi-media device100may comprise a USB type-C interface. A difference between this embodiment and the embodiment shown inFIG. 1is that the audio device600connected to the multi-media device100does not comprise the DAC524, and the audio device600is implemented by merely utilizing the power management circuit526, the amplifier circuit522(e.g. a class-D amplifier) and the speaker540. In comparison with the audio device500, an audio signal received by the audio device600is an analog audio signal rather than a digital signal. In this embodiment, the USB interface140may determine whether the audio device600is an audio device without any DAC (e.g. a passive audio device) by detecting a set of input resistors (e.g. a set of resistors of configuration channel (CC) pins) of the audio device600(amplifier circuit), e.g. by detecting voltage levels corresponding to resistances of the set of resistors; wherein when the audio device600is an audio device without any DAC, the USB interface140may operate in an audio adapter accessory mode, and output an analog audio signal to the audio device600for playback. For example, when the multi-media device100(such as the SoC160and the USB interface140therein) operates in the audio adapter accessory mode, the conversion circuit162may utilize a DAC therein (not shown) to convert the audio signal received from the display device200into an analog audio signal, and further transmit the analog audio signal to the audio device600through the USB interface140for playback.

In practice, based on the limitation of a length of HDMI cable, the multi-media device100is usually arranged at a position near the display device200. According to user experience, an audio device may need to be arranged at a position having a specific distance from the display device200(or the multi-media device100). In the related art, an audio signal from the display device200may be transmitted by optical fibers to overcome the limitation of the length of HDMI cable, but equipment for optical fiber transmission is usually expensive. In comparison with the related art, based on the USB interface140within the multi-media device100of the present invention, a plurality of cables can be connected in series to connect the USB interface140to the audio device (e.g. the audio device500shown inFIG. 1) through at least one hub to increase a transmission distance of an audio signal (such as the aforementioned second audio signal) between the multi-media device100and the audio device (e.g. the audio device500shown inFIG. 1). For example, when a single USB cable is not long enough to satisfy requirements of the video system established by a user, the user may utilize a hub to connect two USB cables (or utilize two or more hubs to connect three or more USB cables) to increase the transmission distance of the audio signal, but the present invention is not limited thereto.

FIG. 3is a flowchart illustrating a method for processing a multi-media signal (e.g. the streaming data obtained by the display device200from a data streaming source in the aforementioned embodiment) according to an embodiment of the present invention. For better comprehension, please refer toFIG. 3in conjunction withFIG. 1andFIG. 2.

In Step310, a first transmission interface such as the HDMI interface120of the multi-media device100receives a first audio signal within the multi-media signal from the display device200. More specifically, the HDNI interface120may utilize an ARC or an eARC to receive the first audio signal.

In Step320, the multi-media device100(more particularly, the conversion circuit162within the SoC160) converts the first audio signal into a second audio signal applicable to a second transmission interface such as the USB interface140of the multi-media device100.

In Step330, the multi-media device100may output the second audio signal to an audio device through the second transmission interface for playback. Note that, when the multi-media device100is coupled to the audio device500(as shown inFIG. 1), the second audio signal may comprise a digital audio signal; and when the multi-media device100is coupled to the audio device600(as shown inFIG. 2), the multi-media100(e.g. the USB interface140) may operate in an audio adapter accessory mode to make the second audio signal comprise an analog audio signal.

Briefly summarized, the method and the multi-media device of the present invention can solve the problems caused by insufficient length of an HDMI cable by converting an audio signal received by the HDMI interface120into another audio signal for being outputted by the USB interface140. In addition, the USB interface140is not only for transmitting audio signals, but also for obtaining power from the audio device. According to this power separated design, the size of the multi-media device can be reduced. As mentioned above, the present invention can improve user experience and solve the problem of the related art without introducing any side effect or in a way that is less likely to introduce side effects.