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gstreamer从缓冲区读取分贝(gstreamer read decibel from buffer)

 我试图获得传入音频样本的dB级别。 在每个视频帧上，我更新dB级别并绘制一个代表0 - 100％值的条形（0％是任意的，例如-20.0dB，100％是0dB）。  
gdouble sum, rms;
sum = 0.0;
guint16 *data_16 = (guint16 *)amap.data;
for (gint i = 0; i < amap.size; i = i + 2)
{
    gdouble sample = ((guint16)data_16[i]) / 32768.0;
    sum += (sample * sample);
}
rms = sqrt(sum / (amap.size / 2));
dB = 10 * log10(rms);
 
 这是从代码示例中修改为C，标记为答案，从这里开始 。 我想知道我从这个非常简单的等式中遗漏了什么。  
 回答 ：夹克是关于失去标志的代码是正确的，所以一切都结果是积极的。 代码10 * log(rms)也不正确。 它应该是20 * log(rms)因为我将幅度转换为分贝（作为输出功率的度量）。 

I am trying to get the dB level of incoming audio samples. On every video frame, I update the dB level and draw a bar representing a 0 - 100% value (0% being something arbitrary such as -20.0dB and 100% being 0dB.) 
gdouble sum, rms;
sum = 0.0;
guint16 *data_16 = (guint16 *)amap.data;
for (gint i = 0; i < amap.size; i = i + 2)
{
    gdouble sample = ((guint16)data_16[i]) / 32768.0;
    sum += (sample * sample);
}
rms = sqrt(sum / (amap.size / 2));
dB = 10 * log10(rms);
 
This was adapted to C from a code sample, marked as the answer, from here. I am wondering what it is that I am missing from this very simple equation.  
Answered: jacket was correct about the code loosing the sign, so everything ended up being positive. Also the code 10 * log(rms) is incorrect. It should be 20 * log(rms) as I am converting amplitude to decibels (as a measure of outputted power). 

原文：https://stackoverflow.com/questions/32792308

更新时间：2023-07-01 10:07

最满意答案

 在按钮的方法中，创建新视图并将其添加为子视图。 将frame.origin.x设置为0减去视图的宽度（如果您希望它从左侧推动），使其不可见并将该值更改为您希望它在内部的位置[UIView animateWithDuration:animations:] 。  
[UIView animateWithDuration:1.0 animations:^(void){
    [newView setFrame:({
        CGRect frame = newView.frame;
        frame.origin.x = 150; // If you want it to start at x = 150
        frame;
    })];

    // If you want to move other views too, just add them in this block
}];
 
 如果你没有得到我正在做的设置框架，请查看本文中的第一个提示。 

In the method of the button create the new view and add it as a subview. Set the frame.origin.x to 0 minus the width of the view (if you want it to push from the left) so it is not visible and change that value to where you want it to be inside [UIView animateWithDuration:animations:]. 
[UIView animateWithDuration:1.0 animations:^(void){
    [newView setFrame:({
        CGRect frame = newView.frame;
        frame.origin.x = 150; // If you want it to start at x = 150
        frame;
    })];

    // If you want to move other views too, just add them in this block
}];
 
If you don't get what I'm doing to set the frame, check out the first tip in this post.

gstreamer从缓冲区读取分贝(gstreamer read decibel from buffer)

最满意答案

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