CN109785849B

CN109785849B - Method for inserting unidirectional control information into pcm audio stream based on iis transmission

Info

Publication number: CN109785849B
Application number: CN201910043795.7A
Authority: CN
Inventors: 帅文; 高尔登; 王光灿
Original assignee: Fujian Electronic Information Technology Co ltd Song Airlines
Current assignee: Fujian Electronic Information Technology Co ltd Song Airlines
Priority date: 2019-01-17
Filing date: 2019-01-17
Publication date: 2020-11-27
Anticipated expiration: 2039-01-17
Also published as: CN109785849A

Abstract

The invention relates to a method for inserting unidirectional control information into a pcm audio stream based on iis transmission. And according to the characteristic that at least one intermediate point introduced by linear interpolation exists between inflection points of the audio pcm data subjected to linear interpolation, converting the next bit of data of the interpolation data subjected to the inflection points, so that the interpolation data is changed into a new inflection point serving as an identification point of a separation control command, and further realizing mixed transmission of the audio and the data. The method realizes the mixed transmission of small data and audio by only using the iis physical channel without influencing the tone quality obviously.

Description

Method for inserting unidirectional control information into pcm audio stream based on iis transmission

Technical Field

The invention relates to a method for inserting unidirectional control information into a pcm audio stream based on iis transmission.

Background

In the conventional digital audio playing process, pcm data stream is transmitted to the DAC chip through iis for audio playing, and control information is separately transmitted through iic or spi. The invention provides a method for completing mixed transmission of small data and audio by only using an iis physical channel on the premise of not influencing the sound quality significantly.

Disclosure of Invention

The invention aims to provide a method for inserting unidirectional control information into a pcm audio stream based on the iis transmission, which realizes the mixed transmission of small data and audio by only using the iis physical path without influencing the sound quality significantly.

In order to achieve the purpose, the technical scheme of the invention is as follows: according to the characteristic that at least one intermediate point for linear interpolation introduction exists between inflection points of audio pcm data after linear interpolation, the next bit data of the interpolation data after the inflection points are transformed, so that the interpolation data become a new inflection point serving as an identification point of a separation control command, and the mixed sending of audio and data is realized by taking the abnormality of two adjacent inflection points as an identification of insertion control information.

In an embodiment of the present invention, the method specifically includes the following steps:

step S1, firstly, carrying out interpolation frequency raising on the transmitted audio data to ensure that the interpolated data does not have two adjacent inflection points, when the transmitting end needs to transmit a command, finding the nearest inflection point, and transforming the next bit data of the interpolated data after the inflection point to change the interpolated data into a new inflection point, so that the two adjacent inflection points appear in the data, and simultaneously replacing the corresponding audio data of the right channel with the command needing to be transmitted;

step S2, after the receiving end receives the data, judging that two adjacent inflection points are found, knowing that the sending end has a command to send, receiving the command according to an agreed format, and calculating the original audio data through a linear interpolation algorithm; and mixed transmission of audio and data is realized.

Compared with the prior art, the invention has the following beneficial effects: the method realizes the mixed transmission of small data and audio by only using the iis physical channel without influencing the tone quality obviously.

Drawings

FIG. 1 shows 5 trends in audio pcm data variation; where circles represent raw data and asterisks represent interpolated data.

FIG. 2 is a schematic diagram illustrating a method for inserting unidirectional control information into a pcm audio stream based on the iis transmission according to the present invention.

FIG. 3 is a schematic diagram of an embodiment of the present invention.

Detailed Description

The technical scheme of the invention is specifically explained below with reference to the accompanying drawings.

The invention provides a method for inserting unidirectional control information into pcm audio stream based on iis transmission, which comprises the steps of converting the next bit of data of interpolation data after an inflection point according to the characteristic that at least one intermediate point of linear interpolation introduced between the inflection points exists in the audio pcm data after linear interpolation, changing the interpolation data into a new inflection point as an identification point of a separation control command, and using the abnormality of two adjacent inflection points as identification of insertion control information to further realize mixed transmission of audio and data. The method comprises the following concrete implementation steps:

step S1, firstly, interpolation frequency boosting is carried out on original data, so that two adjacent inflection points do not appear on the interpolated data, when a sending end needs to send a command, the sending end finds the nearest inflection point, the next bit data of the interpolated data after the inflection point is transformed, so that the interpolated data is changed into a new inflection point, the two adjacent inflection points appear in the data, and meanwhile, the corresponding audio data of the right channel is replaced by the command needing to be sent;

The following is a specific implementation of the present invention.

The technical principle of the method for inserting the unidirectional control information into the pcm audio stream based on the iis transmission is as follows:

as shown in fig. 1, the following 5 variations of standard audio data are possible: the star is a point inserted by a linear interpolation method for frequency multiplication upsampling, and as can be seen from the figure, the linear interpolation point does not change the variation trend of the original audio data, except for straight data, inflection points exist in 'peak' and 'valley', and the inflection points are inevitably generated under the maximum and minimum influences of the ascending and descending. The ordinary quantized audio pcm data has inflection points (highest point and lowest point in a local range) necessarily, and a large number of such inflection points exist in the actually quantized audio pcm data, the inflection points of the original audio pcm data can be adjacent to or spaced by a few slowly-varying data points, but the interpolated data has no two immediately-connected inflection points necessarily, namely, at least one intermediate point introduced by linear interpolation exists between the inflection points, and the characteristic is a key characteristic for realizing the insertion of the control command.

As shown in FIG. 2, the method of the present invention is implemented as follows: when a sending end needs to transmit a word command, a subsequent datum of the interpolation datum can be modified, a new inflection point is artificially formed, meanwhile, an original datum after the interpolation datum on a subsequent other pcm data channel is changed into a command word, when a receiving end finds two adjacent inflection points, the original datum can be restored according to a linear interpolation method, meanwhile, a datum after the inflection point of another sound channel is read as the command word, and meanwhile, the normal audio datum is restored according to the linear interpolation method.

As shown in fig. 3, taking stereo transmission as an example: the original left and right channel data are interpolated, the interpolated data are adjusted to form two adjacent inflection points, and the data corresponding to the other channel are modified into a command. And the receiving end judges that the two adjacent inflection points can analyze the corresponding channel data as command data.

The above are preferred embodiments of the present invention, and all changes made according to the technical scheme of the present invention that produce functional effects do not exceed the scope of the technical scheme of the present invention belong to the protection scope of the present invention.

Claims

1. A method for inserting unidirectional control information into pcm audio stream based on iis transmission is characterized in that according to the characteristic that at least one intermediate point of linear interpolation import exists between inflection points of audio pcm data after linear interpolation, the next bit of data of the interpolation data after the inflection points is transformed, so that the interpolation data becomes a new inflection point serving as an identification point of a separation control command, and further mixed transmission of audio and data is realized, and the next bit of data of the interpolation data is the value of the next voice sampling point; the method comprises the following concrete implementation steps:

step S1, firstly, interpolation frequency raising is carried out on original data, when a sending end needs to send a command, the sending end finds a nearest inflection point, and the next bit data of the interpolation data after the inflection point is transformed, so that the interpolation data is changed into a new inflection point, and meanwhile, the corresponding audio data of the right channel is replaced by the command needing to be sent;