Method of implementing source control rate of AMR speech sound coding
A technology of AMR voice and implementation method, which is applied in the field of voice coding, and can solve the problems of voice coding transmission coding redundancy, background noise discontinuity, disappearance, etc., and achieve the effects of saving calculation, reducing coding calculation, and saving bandwidth
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Embodiment 1
[0057] In the standard encoding method of the prior art, when in silent mode (that is, VAD flag="0"), after the first SID_FIRST frame is transmitted to the network, the SCR controller at the sending end will calculate and transmit a SID_UPDATE frame at regular intervals (ie comfort background noise) to the network. The SID_UPDATE frame is generated and transmitted every 8 frames, that is, 7 consecutive NO_DATA frames and then 1 SID_UPDATE frame is transmitted.
[0058] In this example, illustrate the N L = 24 cases.
[0059] For example figure 1 As shown, at the sending end, for 32 frames of comfort noise, in the coding of the prior art, these 32 frames contain 4 SID_UPDATE frames and 28 NO_DATA frames, and after adopting the method of the present invention, only 1 SID_UPDATE frame and 31 NO_DATA frames. Since the SID_UPDATE frame contains information and the NO_DATA frame does not contain information, after adopting the method of the present invention, it is at the sendin...
Embodiment 2
[0063] In this embodiment, taking the average reduction of 3 frames as an example, the average number of frames to be analyzed is shown in Table 3:
[0064] Condition Corresponding N L value The average number of frames required to reduce 3 frames F 0 24 32 1 48 28 2 72 26.67 3 96 26
[0065] table 3
[0066] After analysis, it can be found that the average required number of frames F for each reduction of 3 frames satisfies:
[0067] F = 4 + 3 * Mode Mode + 1 · 8 or: F = 24 ( N L + 8 ) N L ...
Embodiment 3
[0074]The method of the present invention can work under two working modes: original mode and enhanced mode. The original mode is consistent with the standard encoding method of the prior art, and the enhancement method adopts the method of the present invention. In the embodiment, the mode is expressed as a bit, wherein "0" indicates the original mode of system operation, that is, the standard encoding of the prior art is adopted, and "1" indicates that the system is in the enhanced mode, that is, encoding is performed by the method of the present invention; Define 2 bits x and y to represent the adopted N L the value of N 0 =24,N 1 =48,N 2 =72,N 3 =96, the corresponding values of x and y are 00, 01, 10, 11 respectively. Put the information of these three bits into the frame type representation field of SID_FIRST. Specific value definitions are shown in Table 4 and Table 5
[0075] pattern type Operating mode 0 original mode 1 enhanced mode ...
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