Delta压缩，端口matlab代码到python

Question

以下matlab函数解码信号delta编码：

% Method      : DeltaCompression
% Description : Decode delta compressed signal
%
function data = DeltaCompression(file, data)

if ftell(file) == -1
    data.Time = [];
    data.Signal = [];
    return;
else
    fseek(file, 0, 'eof');
    stop = ftell(file);

    fseek(file, data.DataOffset, 'bof');
    start = ftell(file);
end

signal = zeros(round((stop-start)/2), 1);
buffer = zeros(4, 1);
index = 1;

while ftell(file) < stop

    buffer(1) = fread(file, 1, 'int16', 'b');
    buffer(2) = buffer(4);

    if bitshift(buffer(1), 12, 'int16') == 0
        signal(index:end) = [];
        break
    end

    for i = 1:bitand(buffer(1), 4095, 'int16');

        buffer(3) = fread(file, 1, 'int16', 'b');

        if buffer(3) ~= -32768
            buffer(2) = buffer(2) + buffer(3);
        else
            buffer(2) = fread(file, 1, 'int32', 'b');
        end

        signal(index) = buffer(2);
        index = index + 1;
    end

    buffer(4) = buffer(2);
end

我正在尝试将该代码移植到python。这是一个有效的例子：

import numpy as np
import matplotlib.pyplot as plt

# The start position of the data
data_offset = 6144


def parse_data(file_):

    # Go to the end of the file and calculate how many points 8 byte floats
    # there are
    file_.seek(0, 2)
    n_points = (file_.tell() - data_offset) // 8

    # Read the data into a numpy array
    file_.seek(data_offset)
    values = np.fromfile(file_, dtype=np.int8, count=n_points)

    values = values.tolist()

    decoded_vals = []

    last = 0

    for index, val in enumerate(values):

        delta = val
        val = delta + last
        last = val

        decoded_vals.append(val)

    return decoded_vals


if __name__ == '__main__':
    with open("VWD1A.ch", 'rb') as file_:
        values = parse_data(file_)

    fig = plt.figure(1)
    ax = plt.subplot(111)

    plt.plot(values)

    plt.show()

我正在尝试解码delta编码的数据。我几乎可以肯定delta解压缩应该可以工作，但我不确定我是否正确解析了二进制文件。 以下是二进制文件的链接：https://www.dropbox.com/s/b7p3l2wn2iaen5z/VWD1A.ch?dl=0

matlab函数做了一些我不理解的奇怪事情。你能否向我解释一下matlab函数在做什么以及我应该在哪里开始将它移植到python（我对matlab一无所知）？

这是预期结果的图片（我现在不介意轴的值，我只想看到这一个峰值）：