CN1960498A - Method for realizing multiple audio tracks in mobile multimedia broadcast system - Google Patents

Abstract

A multi-track implementation method of a mobile multimedia broadcasting system. When a mobile multimedia broadcasting system sends audio data containing one or more audio tracks in a channel, the audio data is divided into audio packet headers and N audio units. The audio packet header contains the track number of each audio unit, which is then sent on one or more data channels assigned to that channel. A sync header can also be added between each audio unit for isolation. The invention is suitable for use in a mobile multimedia broadcasting system, can transmit audio data containing one or more audio tracks in one channel, and has higher transmission efficiency.

Description

A multi-track implementation method of a mobile multimedia broadcasting system

technical field

The present invention relates to a mobile multimedia broadcasting system, more specifically, to a method for realizing multi-audio tracks of a mobile multimedia broadcasting system.

Background technique

Mobile multimedia broadcasting is a multimedia playback technology that has emerged in recent years. Through the mobile terminal, in the case of high-speed movement, you can watch TV. The mobile terminal can receive the program list through the wireless protocol, and can select the program it is interested in, so as to receive the multimedia data stream and realize watching TV on the mobile terminal.

The air data transmitted by the mobile multimedia broadcasting system is divided into different channels and transmitted through the multiplexing technology. The mobile terminal can receive the relevant data, and realize the normal broadcasting of the TV through the player on the terminal.

For the same channel, the mobile multimedia broadcasting system can send the audio stream of one audio track or the audio stream of multiple audio tracks.

There are two methods for realizing multi-track in the prior art:

First, TS (Transport Stream, Transport Stream) mode, TS protocol is one of the MPEG (Moving Picture Expert Group, Motion Picture Experts Group) standards, it puts video, audio and control information in a fixed 188-byte size It is transmitted in the data packet, and different audio tracks are distinguished through the PID (Program Identifier, program number) field, so that the playback of multiple audio tracks can be supported.

Second, the ISMA (Internet Streaming Media Alliance, Internet Streaming Media Alliance) method, the ISMA specification uses RTP (Real Time Transport Protocol, Real Time Transport Protocol) to transmit multimedia information, and multiple RTP channels can be opened to transmit different audio tracks. This method is suitable for use on IP networks.

However, the method for realizing multiple audio tracks in the prior art has the following problems: each packet of the TS method is small, and the efficiency is relatively low, while the ISMA method has a small application range and can only be used on an IP network.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for implementing multi-audio tracks suitable for use in a mobile multimedia broadcasting system, which can transmit audio data containing one or more audio tracks in one channel.

In order to solve the above problems, the present invention provides a multi-track implementation method of a mobile multimedia broadcasting system. The data is divided into an audio packet header and N audio units. The audio packet header contains the track number of each audio unit, and then it is sent on one or more data channels allocated to the channel.

Furthermore, the above multi-track implementation method may also have the following characteristics: a synchronization header is added between each audio unit for isolation.

Furthermore, the above multi-track implementation method may also have the following characteristics: the audio packet header also includes length information of audio units, which is used to locate and divide each audio unit data, and the length can be flexibly set.

Furthermore, the above-mentioned method for implementing multiple audio tracks may also have the following feature: the audio packet header also includes time stamp information, which is used to indicate the playing time.

Further, the above multi-track implementation method can also have the following characteristics: the mobile multimedia broadcasting system sends a full frame of data at a fixed time interval, and the full frame data is composed of one control channel with a fixed size and M-1 described consists of data channels, and M is fixed.

Furthermore, the above multi-track implementation method may also have the following characteristics: the bandwidth of each data channel is a fixed value, and multiple data channels jointly transmit the data of one channel.

Furthermore, the above multi-track implementation method may also have the following characteristics: the audio packet header also includes the unit number of each audio unit, which is numbered sequentially according to the audio unit.

The present invention encapsulates multiple audio tracks in one channel, divides the audio data in one channel into multiple audio units, and transmits them through one or more channels, so that one audio track, two audio tracks or More than 2 audio tracks are transmitted in one channel at the same time, and have high transmission efficiency.

Description of drawings

Fig. 1 is a schematic diagram of the channel data packet encapsulation structure of the multi-track implementation method of the mobile multimedia broadcasting system of the present invention;

Fig. 2 is a schematic diagram of realizing two audio tracks by using the multi-audio track implementation method of the mobile multimedia broadcasting system of the present invention.

Detailed ways

The multi-track implementation method of the mobile multimedia broadcasting system of the present invention will be further described below in conjunction with the accompanying drawings.

The mobile multimedia broadcasting system sends a full frame of data at a fixed time interval, and the fixed time interval can be 1 second or other time values. The full-frame data consists of M channels, which are divided into 1 control channel and M-1 data channels. The number of channels M is fixed.

Among them, channel 0 is a control channel, which is used to transmit control information and program lists. Channel 1 to channel M-1 are data channels for transmitting channel data.

As shown in Figure 1, the channel data includes: packet header, video data, audio data and synchronization data. The data of one channel can be transmitted in one data channel, or can be transmitted in multiple data channels.

The audio data is divided into audio packet headers and N audio units, and each audio unit is isolated by a synchronization header to achieve the function of error isolation.

The audio packet header contains description information for N audio units, including: the length of each audio unit, the track number of the audio unit, time stamp and other information, where the length of the audio unit can be used to locate and divide each audio unit data , can be set flexibly. The time stamp refers to the playback time, and the track number is used to identify which track this audio unit belongs to. In addition, audio units can also be sequentially numbered as unit numbers.

Fig. 2 is a schematic diagram of realizing two audio tracks by using the multi-audio track implementation method of the mobile multimedia broadcasting system of the present invention. The audio packet header and synchronization header are omitted in the figure. Assuming that the first audio track has 15 audio units, and the second audio track has 10 audio units, as shown in Figure 2, the first audio track includes: audio units 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 22, 23, 24, 25, the second track includes: Audio Unit 2, 4, 6, 8, 10, 12, 14, 16, 18, 20. In the figure, there is a sync header between each audio unit to divide each audio unit.

The audio units of the two audio tracks may not be arranged in the above sequence, but the sequence can be adjusted flexibly.

According to the above principles, one audio track, two audio tracks or more than two audio tracks can be simultaneously transmitted in one or more data channels allocated by one channel.

For example, in the case of 1 channel containing 2 audio tracks, each data channel has a rate of 128Kbit/s, and 1 channel uses 2 data channels for transmission, which can have a rate of 256Kbit/s.

Among them: the packet header is 122 bytes long, the video data is 22.5K bytes in total, the audio data is 8K bytes long, and the synchronous data is 1K bytes. For the part less than 32K bytes, it can be filled with all 0s. Audio data includes 2 audio tracks, each with 32Kbit/s. Compared with the TS method, the transmission efficiency is greatly improved.

Such a channel can satisfy the transmission of 1 QVGA resolution, 25 frames of H264 or AVS-M video data, and the transmission of 2 32Kbit/s AAC audio track data, and can provide users with quite satisfactory high quality Audio streaming of mobile broadcast TV programs.

Claims (7)

1. A multi-track implementation method of a mobile multimedia broadcasting system, characterized in that: the mobile multimedia broadcasting system divides these audio data into audio packet headers and N audio unit, the audio packet header contains the track number of each audio unit, and then send it on one or more data channels allocated for the channel. 2. The multi-track implementation method of the mobile multimedia broadcasting system according to claim 1, characterized in that a synchronization header is added between each audio unit for isolation. 3. The multi-track implementation method of the mobile multimedia broadcasting system according to claim 1, wherein the audio packet header also includes length information of the audio unit, which is used to locate and divide each audio unit data, and the length It can be set flexibly. 4. The method for implementing multi-audio tracks in a mobile multimedia broadcasting system according to claim 1, wherein the audio packet header further includes timestamp information for indicating the playing time. 5. The multi-track implementation method of the mobile multimedia broadcasting system as claimed in claim 1, wherein the mobile multimedia broadcasting system sends a full-frame data at a fixed time interval, and the full-frame data consists of a fixed-size one The control channel is composed of M-1 data channels, and M is fixed. 6. The multi-track implementation method of the mobile multimedia broadcasting system according to claim 5, wherein the bandwidth of each data channel is a fixed value, and multiple data channels jointly transmit the data of one channel. 7. The multi-track implementation method of the mobile multimedia broadcasting system according to claim 1, characterized in that, the audio packet header also includes the unit number of each audio unit, which is numbered sequentially according to the audio unit.

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