查找进度条的下载速度

Question

我正在编写脚本以从网站下载视频。我添加了一个报告挂钩来获取下载进度。所以，到目前为止，它显示了下载数据的百分比和大小。我认为添加下载速度和 eta 会很有趣。
问题是，如果我使用简单的 speed = chunk_size/time，显示的速度足够准确，但会疯狂地跳来跳去。所以，我使用了下载单个块所花费的时间的历史记录。比如，speed = chunk_size*n/sum(n_time_history).
现在它显示下载速度稳定，但它肯定是错误的，因为它的值是几bits/s，而下载的文件明显增长得更快。
有人可以告诉我哪里出错了吗？

这是我的代码。

def dlProgress(count, blockSize, totalSize):
    global init_count
    global time_history
    try:
        time_history.append(time.monotonic())
    except NameError:
        time_history = [time.monotonic()]
    try:
        init_count
    except NameError:
        init_count = count
    percent = count*blockSize*100/totalSize
    dl, dlu = unitsize(count*blockSize)             #returns size in kB, MB, GB, etc.
    tdl, tdlu = unitsize(totalSize)
    count -= init_count                             #because continuation of partial downloads is supported
    if count > 0:
        n = 5                                       #length of time history to consider
        _count = n if count > n else count
        time_history = time_history[-_count:]
        time_diff = [i-j for i,j in zip(time_history[1:],time_history[:-1])]
        speed = blockSize*_count / sum(time_diff)
    else: speed = 0
    n = int(percent//4)
    try:
        eta = format_time((totalSize-blockSize*(count+1))//speed)
    except:
        eta = '>1 day'
    speed, speedu = unitsize(speed, True)           #returns speed in B/s, kB/s, MB/s, etc.
    sys.stdout.write("\r" + percent + "% |" + "#"*n + " "*(25-n) + "| " + dl + dlu  + "/" + tdl + tdlu + speed + speedu + eta)
    sys.stdout.flush()

Edit:
Corrected the logic. Download speed shown is now much better.
As I increase the length of history used to calculate the speed, the stability increases but sudden changes in speed (if download stops, etc.) aren't shown.
How do I make it stable, yet sensitive to large changes?

我意识到这个问题现在更偏向于数学，但如果有人能帮助我或指出正确的方向，那就太好了。
另外，请告诉我是否有更有效的方法来完成此操作。

Answer 1

_count = n if count > n else count
time_history = time_history[-_count:]
time_weights = list(range(1,len(time_history))) #just a simple linear weights
time_diff = [(i-j)*k for i,j in zip(time_history[1:], time_history[:-1],time_weights)]
speed = blockSize*(sum(time_weights)) / sum(time_diff)

为了使其更稳定并且不会在下载高峰或下降时做出反应，您也可以添加以下内容：

_count = n if count > n else count
time_history = time_history[-_count:]
time_history.remove(min(time_history))
time_history.remove(max(time_history))
time_weights = list(range(1, len(time_history))) #just a simple linear weights
time_diff = [(i-j)*k for i,j in zip(time_history[1:], time_history[:-1],time_weights)]
speed = blockSize*(sum(time_weights)) / sum(time_diff)

这将消除 time_history 中的最高和最低峰值，这将使显示的数字更加稳定。如果你想挑剔，你可能可以在删除之前生成权重，然后使用 time_diff.index(min(time_diff)).

过滤映射值

同时使用非线性函数（如 sqrt()）生成权重会给您带来更好的结果。哦，正如我在评论中所说：将统计方法添加到过滤时间应该稍微好一些，但我怀疑它不值得增加开销。

查找进度条的下载速度

Find the speed of download for a progressbar

python

performance

python-3.x

download

urllib