KR20110025367A - Multimedia transcoding client device and method - Google Patents

Abstract

PURPOSE: A high speed transcoding device is provided to connect a host system having a low calculation processing ability by enabling transcoding through a universal host interface using hardware and firmware inside a device. CONSTITUTION: A portable transcoding device transcodes a first video/audio data which is stored in a host system by using universal host interface. An universal host interface is used in transceiving a host system and data. A transcoding is for transcoding a first video/audio data into a second video/audio data. A first memory stores a total or some part of a first video/audio data. A second memory stores total or some part of a second video/audio data.

Description

Multimedia transcoding client device and method {METHOD AND DEVICE FOR MULTIMEDIA TRANSCODING CLIENT}

The present invention relates to a transcoding device for coded data streams, and more particularly, to a portable transcoder client device and method having a universal host interface such as USB, IEEE1394, and the like. By using a portable transcoder device, for example, the transcoding of the data stream from the MPEG-2 video stream to the H.264 video stream can be converted at high speed without using the resources of the host system.

High-capacity multimedia data such as video / audio are increasingly being used due to the development of efficient compression technology, improved PC performance for individuals, and the spread of the Internet.

Video / audio compression technology is widely used through standardization. However, compression codecs continue to evolve, and streams generated by various codecs coexist. This is because an identical codec must use an appropriate codec according to the playback environment. Sometimes, a stream encoded in the first standard is converted into a second standard and played back. In this case, a technique for efficiently transcoding multimedia streams between different standards is required.

In recent years, the quality of video / audio streams has been improved day by day, and the general demand for high-quality data streams has become universal. However, transcoding two hours of high-definition data streams such as movies can be a time-consuming task unless you have a high-performance computer.

Recently, the multimedia compression standard widely used, the terrestrial digital broadcasting and high-definition video content storage media such as DVD and Blueray uses a bit stream encoded in the MPEG-2 standard. Most current digital broadcast receivers or Personal Video Recorders (PVRs) for digital broadcast recording include audio / video splitters and MPEG-2 video decoders that can decode MPEG-2 compliant bit streams. It has a built-in Dolby AC3 audio decoder.

In addition, services using video content of relatively lower quality than MPEG-2 are also actively provided, and mainly use H.264 standard encoded video bit stream. The IPTV service receiver has made it possible to receive broadcasts through the Internet, where H.264 is also used.

Meanwhile, with the development of computer technology and low power technology, portable multimedia player (PMP) has been spread in various forms. Portable multimedia players have a small amount of storage, a small display screen, low computing power, low network connection bandwidth, limited battery capacity, and the like, and there are limitations on the type and quality of contents that can be utilized.

Existing main multimedia information sources are MPEG-2 and H.264 standards such as digital broadcasting, IPTV service, DVD / Blueray, etc., and H.264 standard has been proven to have better compression efficiency than MPEG-2 standard. It is expected that support for the H.264 standard will be generalized in mobile terminals such as media players. Accordingly, there is a need for a transcoding apparatus and method for converting multimedia contents of the MPEG-2 standard into H.264.

A basic operation of a conventional multimedia device is to decode a video bit string existing in a storage device of a host system using a decoder in a host system and to display it on a screen. Alternatively, the video bit stream received from the remote system through the network channel is decoded by the client system using a decoder and the video bit string is displayed on the screen.

If a video bit string standard encoded and stored is different from a bit string standard that can be decoded by a decoder, a transcoding technique for converting the standard is required.

Transcoding techniques decode video or audio bitstreams that have been compressed to a specific specification, and then re-encode them into other specifications to produce a compressed bitstream. In the process, control functions such as enlarge / reduce the screen size of the video, increase / decrease the screen rate, increase / decrease the bit rate, increase / decrease the sampling rate of the audio, increase / decrease the frame size, increase / decrease the frame rate, filter the sound field, etc. Can be added.

For example, Korean Patent Laid-Open No. 2008-12753 discloses a specific method for an efficient conversion technique of an encoded image. In more detail, the present invention improves image quality by optimizing bit allocation using signal dispersion for each video coding unit.

However, this does not have a separate transcoding system, but is limited to an efficient conversion technique of video that is transcoded inside the transcoder.

Meanwhile, Efficient Video Transcoding Technique for QoS-Based Home Gateway Service (J.-W.Kim, G.-R.Kwon, N.-H.Kim, A. Morales, S.-J.Ko, IEEE Trans.Consumer Electronics, Vol. 52, No. 1, pp. 129-137, Feb. 2006) reads video data from video server in home network and converts bit rate according to bandwidth of transmission channel and screen size and screen. It suggests a way to control the rate.

On the other hand, personal PCs can be connected to a variety of peripherals, traditionally connected devices such as printers using a parallel bus interface. However, such a parallel port is inconvenient to use, and the size of the cable is also a burden, and various methods have recently been used to replace it.

In particular, there are various interface standards using a serial bus. For example, universal serial bus (USB) and IEEE 1394 are widely used.

In addition, the latest short-range wireless communication technology provides a more convenient and high speed interface. For example, WiFi, RFID, Bluetooth, ZigBee, or IEEE 802.11 series wireless communication protocols may be used.

These universal host interfaces make it easy for PC users to connect peripherals and PCs, reducing the inconvenience of using PC peripherals, and connecting more multimedia devices to PCs.

It is difficult to reproduce a multimedia data stream encoded with a codec for a high definition video such as MPEG-2 in a small multimedia player such as a PMP or a mobile phone. There is a limit to the memory capacity of small devices, and there is a limit to the CPU performance of small devices. In addition, small devices have a small screen size, so it is possible to sufficiently reduce the resolution.

As mentioned earlier, H.264 will be widely used in small portable multimedia devices for the time being. As a result, individual users will need MPEG-2 to H.264 transcoding to play MPEG-2 data streams that can be played on a regular PC on portable multimedia devices.

Conventional transcoding devices are implemented in hardware or software embedded in a host system.

Software embedded transcoding devices are widely used and can be mounted and operated in host systems having various types of hardware and operating systems. However, since the transcoding conversion speed may vary according to the hardware arithmetic processing capability of the host system, high cost hardware is required for high speed conversion.

The hardware embedded transcoding device is capable of high speed conversion regardless of the host system's processing power. However, the transcoding hardware module should be designed to meet the specific bus specification and control structure inside the host system. In other words, the hardware built-in transcoding module is limited to the host system of other standard, and there is a limit that it should be manufactured only for a specific device including a transcoding function, not a general digital device.

The popularity of portable multimedia players is increasing rapidly, and the demand for videos to be played using the device is also rapidly increasing. However, in order to have a conventional software or hardware-embedded transcoding device, a user who owns a host system owned by a user, i.e., a device that enhances the performance of a personal PC or performs a high-speed transcoding function separately, that is, a card for transcoding There is a problem of high cost.

In order to solve the above-mentioned issue, the present invention uses the structure described below. In addition, reference signs, supplementary descriptions, and the like in parentheses indicate conformity with the embodiments described hereinafter to aid the understanding of the present invention, and do not impose any limitation on the present invention.

The present invention proposes a portable transcoding client device and method using a general-purpose host interface, and an internal operation structure, which are combined with a low specification host system to enable high-speed multimedia transcoding. The present invention relates to an apparatus and method for reading a video content stored in a host system through a universal host interface, converting the video content into another standard video content, and then storing the video content again in the host system through the same interface.

According to an aspect of the present invention, a portable transcoder device for transcoding first video / audio data stored in a host system using a universal host interface, comprising: a universal host interface, first video, used for transmitting and receiving data with a host system / Transcoder for transcoding audio data into second video / audio data, a first memory storing all or part of the first video / audio data, a second storing all or part of the second video / audio data Receive and store all or a portion of the first video / audio data stored in a host system using the memory and the general-purpose host interface, store in the first memory, and control the transcoder to transcode the data stored in the first memory; Of transcoded second video / audio data Or storing portion to the second memory, the second memory using the general purpose host interface the data stored in the portable transcoding device comprises a control unit for transmission to the host system is provided.

The transcoder is a demultiplexer that separates the first video / audio data into a video signal of the first standard and an audio signal of the second standard, and a video signal transformer that transcodes the video signal of the first standard into a video signal of the third standard. A coder, an audio signal transcoder for transcoding an audio signal of a second standard into an audio signal of a fourth standard, and a video signal of one of the first and third standards and an audio signal of one of the second and fourth standards It may include a multiplexer for multiplexing.

According to another aspect of the invention, the first video / audio data stored in the host system is transmitted to the transcoder device via a universal host interface; Storing the transmitted first video / audio data in the first memory, transcoding the data in the first memory into the second video / audio data, storing the second video / audio data in the second memory, And transmitting data from the second memory to the host system via the general purpose host interface.

The transcoding step may include: demultiplexing first video / audio data into a video signal of a first standard and an audio signal of a second standard, and transcoding a video signal of a first standard into a video signal of a third standard Transcoding an audio signal of a second standard into an audio signal of a fourth standard, and multiplexing a video signal of one of the first and third standards and an audio signal of one of the second and fourth standards It may include.

The above and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings.

The present invention enables transcoding using only hardware and firmware inside the apparatus irrespective of the processing capability of the host system, thereby enabling high-speed transcoding even when connected to a host system having low processing capability. Can be. As a result, individual PC users don't have to buy expensive PC equipment or hardware dedicated to PC-based transcoding just for transcoding.

In addition, the apparatus can be configured as an independent transcoder client apparatus having a general-purpose host interface without any dependency on any host system. Therefore, it can be applied to any host system having the same general-purpose interface, thereby enabling transcoding regardless of the bus specification and control structure inside the host system. Therefore, it is applicable to a host system having a general-purpose interface.

1 shows a configuration of a transcoder device of the present invention.

The transcoder device may have a universal host interface and may be physically or logically connected to a host system that supports the same universal host interface specification. Device drivers and firmware may be provided as needed for use of the transcoder device. The firmware may be embedded in the transcoder device and the device driver may be preinstalled in the host system.

For the operation of the transcoder device, the host system supplies the device with a transcoding input video bit string, provides a user interface for setting the video and audio transcoding control coefficients, sets the control registers inside the device, A transcoded video bit string is received and stored in a storage medium in the host system.

These operations are simple control functions that do not require high-speed computational processing and can be performed in real time even on low-performance host systems. The processing load required for transcoding is placed on the transcoder device of the present invention, which will be external to the host system.

The transcoding host unit resides in the memory of the host system to control transcoding through a general-purpose host interface. Such control can be realized through a user interface or the like. The installation of the user interface can be executed automatically at the same time as the transcoder device is connected, or can be pre-installed.

In the host system, for example, first video / audio data according to a first coding standard such as MPEG-2 is stored, and the transcoder device stores the first video / audio data in a second such as H.264. Transcode into second video / audio data according to the coding standard.

The first video / audio data input bitstream is transmitted to the transcoder device via a universal host interface and stored in an input bitstream storage, which is a temporary memory. The temporary memory may serve as a buffer before the data bit string is input to the transcoder. Alternatively, a large memory may be stored in advance to store files that require transcoding, and the transcoding may be reserved.

2 shows a detailed configuration of the transcoder.

The transcoding apparatus includes a video / audio demultiplexer to extract a video signal encoded with a first standard and an audio signal encoded with a second standard from a data bit string. This is to satisfy the various needs of the user by allowing the user to specify the target of transcoding in detail. For example, in the case of a video for a language course, video signals can be transcoded with low quality and audio signals can be transcoded with high quality.

The transcoding controller receives the transcoding control coefficients from the host system and adjusts the aspect ratio, the screen size, and the image quality (or target bit rate) of the video signal to generate the transcoded video signal. It is possible to enlarge / reduce the screen size, increase / decrease the screen rate, or increase / decrease the bit rate based on the video coding rate control coefficient set by the host system.

The aspect ratio / screen size adjusting unit adjusts the aspect ratio and the screen size of the video signal of the first standard extracted according to the control coefficient received from the transcoding controller. In addition, the bit rate controller adjusts the bit rate according to the control coefficient received from the transcoding controller.

The transcoding controller also controls the bit rate while transcoding the audio signal to the value specified in the transcoding control coefficients. That is, based on the audio coding rate control coefficient set by the host system, the sampling rate is increased / decreased, the audio frame size is increased / decreased, the bit rate is increased / decreased, or the sound field filtering is executed. It is possible to do The audio encoding rate control unit adjusts the encoding rate of the audio signal to be transcoded according to the control coefficient received from the transcoding control unit.

That is, the extracted video signal of the first standard is adjusted to a screen ratio, screen size, bit rate, and the like, and is transcoded from the third standard video encoder into a third standard video signal and then transmitted to the audio / video multiplexer. The audio signal of the second standard is transcoded from the fourth standard audio encoder unit to the fourth standard audio signal by adjusting the coding rate and transmitted to the audio / video multiplexer. Both the audio and video signals may be transcoded, and only one of the two signals may be transcoded.

The bit strings of the encoded audio and video signals are multiplexed and temporarily stored in the output bit string storage, which is a temporary memory, and transmitted back to the host system.

This allows the host system to store transcoded video / audio data without using resources such as the CPU of the host system.

While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be apparent to those skilled in the art that various modifications are possible within the spirit and scope of the appended claims in form and detail without departing from the spirit and scope of the invention. Should be understood.

According to the present invention, since high-speed conversion of MPEG-2 video to H.264 video from a general low-spec desktop / laptop computer is possible, a user with a low-spec PC can be included as a service target of high-definition video.

In addition, by applying to a digital broadcast receiver, a personal video recorder (PVR), etc., it is possible to reduce the digital broadcast storage cost received in the MPEG-2 standard.

As it can be an essential device for securing contents to be played in a portable multimedia player (PMP), the market is expected to expand rapidly in the world along with the expansion of the PMP market.

1 is a view showing a preferred configuration of a transcoder device of the present invention,

2 is a diagram showing an embodiment of a detailed configuration of a transcoder device of the present invention.

Claims (4)

A portable transcoder device for transcoding first video / audio data stored in a host system using a universal host interface, comprising: A universal host interface used to send and receive data with the host system, A transcoder for transcoding the first video / audio data into the second video / audio data, A first memory for storing all or part of the first video / audio data, A second memory for storing all or part of the second video / audio data, and Receives and stores all or part of first video / audio data stored in a host system using the general-purpose host interface in a first memory, controls the transcoder to transcode data stored in a first memory, and transcodes And a transcoding controller configured to store all or a portion of the second video / audio data in a second memory, and to transmit the data stored in the second memory to a host system using the universal host interface. The method of claim 1, The transcoder, A demultiplexer for separating first video / audio data into a video signal of a first standard and an audio signal of a second standard, A video signal transcoder for transcoding a video signal of a first standard into a video signal of a third standard, An audio signal transcoder for transcoding an audio signal of a second standard into an audio signal of a fourth standard, and A portable transcoding device comprising a multiplexer for multiplexing a video signal of one of the first and third standards and an audio signal of one of the second and fourth standards. A method of transcoding first video / audio data stored in a host system using a portable transcoder device having a universal host interface, the method comprising: Transmitting the first video / audio data stored in the host system to the transcoder device via the universal host interface; Storing the transmitted first video / audio data in a first memory, Transcoding the data in the first memory into the second video / audio data, Storing second video / audio data in a second memory, and And transmitting data from the second memory to the host system via the general purpose host interface. The method of claim 3, The transcoding step, Demultiplexing the first video / audio data into a video signal of a first standard and an audio signal of a second standard, Transcoding a video signal of a first standard into a video signal of a third standard, Transcoding an audio signal of a second standard into an audio signal of a fourth standard, and Multiplexing a video signal of one of the first and third specifications and an audio signal of one of the second and fourth specifications.

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