用python讀取YUV文件 轉RGB 8bit/10bit通用

注：本文所指的YUV均爲YUV420中的I420格式（最常見的一種），其他格式不能用以下的代碼。

位深爲8bit時，每個像素佔用1字節，對應文件指針的fp.read(1)；

位深爲10bit時，每個像素佔用2字節，對應文件指針的fp.read(2)；

然後使用 int.from_bytes() 方法將二進制轉換爲int型數字。

 

以下程序可以讀8bit或10bit位深的YUV，需要指定從第幾幀開始讀、一共讀多少幀。

它返回三個數組，其shape分別爲：Y [frame,W,H]   U [frame,W/2,H/2]   V [frame,W/2,H/2]

當只讀1幀時它返回：Y [W,H]   U [W/2,H/2]   V [W/2,H/2]

# -*- coding: utf-8 -*-

import math
from functools import partial
import numpy as np
import matplotlib.pyplot as plt


def readyuv420(filename, bitdepth, W, H, startframe, totalframe, show=False):
    # 從第startframe（含）開始讀（0-based），共讀totalframe幀

    uv_H = H // 2
    uv_W = W // 2

    if bitdepth == 8:
        Y = np.zeros((totalframe, H, W), np.uint8)
        U = np.zeros((totalframe, uv_H, uv_W), np.uint8)
        V = np.zeros((totalframe, uv_H, uv_W), np.uint8)
    elif bitdepth == 10:
        Y = np.zeros((totalframe, H, W), np.uint16)
        U = np.zeros((totalframe, uv_H, uv_W), np.uint16)
        V = np.zeros((totalframe, uv_H, uv_W), np.uint16)

    plt.ion()

    bytes2num = partial(int.from_bytes, byteorder='little', signed=False)

    bytesPerPixel = math.ceil(bitdepth / 8)
    seekPixels = startframe * H * W * 3 // 2
    fp = open(filename, 'rb')
    fp.seek(bytesPerPixel * seekPixels)

    for i in range(totalframe):

        for m in range(H):
            for n in range(W):
                if bitdepth == 8:
                    pel = bytes2num(fp.read(1))
                    Y[i, m, n] = np.uint8(pel)
                elif bitdepth == 10:
                    pel = bytes2num(fp.read(2))
                    Y[i, m, n] = np.uint16(pel)

        for m in range(uv_H):
            for n in range(uv_W):
                if bitdepth == 8:
                    pel = bytes2num(fp.read(1))
                    U[i, m, n] = np.uint8(pel)
                elif bitdepth == 10:
                    pel = bytes2num(fp.read(2))
                    U[i, m, n] = np.uint16(pel)

        for m in range(uv_H):
            for n in range(uv_W):
                if bitdepth == 8:
                    pel = bytes2num(fp.read(1))
                    V[i, m, n] = np.uint8(pel)
                elif bitdepth == 10:
                    pel = bytes2num(fp.read(2))
                    V[i, m, n] = np.uint16(pel)

        if show:
            print(i)
            plt.subplot(131)
            plt.imshow(Y[i, :, :], cmap='gray')
            plt.subplot(132)
            plt.imshow(U[i, :, :], cmap='gray')
            plt.subplot(133)
            plt.imshow(V[i, :, :], cmap='gray')
            plt.show()
            plt.pause(1)
            #plt.pause(0.001)

    if totalframe==1:
        return Y[0], U[0], V[0]
    else:
        return Y,U,V


if __name__ == '__main__':
    #y, u, v = readyuv420(r'F:\_commondata\video\176x144 qcif\football_qcif.yuv', 8, 176, 144, 1, 5, True)
    y, u, v = readyuv420(r'F:\_commondata\video\1920x1080 B\RitualDance_1920x1080_60fps_10bit_420.yuv', 10, 1920, 1080, 0, 5, True)
    print(y.shape,u.shape,v.shape)

 

以下程序將YUV轉爲RGB（只能讀8bit位深的YUV），返回1個數組，其shape爲： [frame,W,H,3]

# -*- coding: utf-8 -*-
import cv2
import numpy as np
import matplotlib.pyplot as plt
 
 
def yuv2rgb(yuvfilename, W, H, startframe, totalframe, show=False, out=False):
    # 從第startframe（含）開始讀（0-based），共讀totalframe幀
    arr = np.zeros((totalframe,H,W,3), np.uint8)
    
    plt.ion()
    with open(yuvfilename, 'rb') as fp:
        seekPixels = startframe * H * W * 3 // 2
        fp.seek(8 * seekPixels) #跳過前startframe幀
        for i in range(totalframe):
            print(i)
            oneframe_I420 = np.zeros((H*3//2,W),np.uint8)
            for j in range(H*3//2):
                for k in range(W):
                    oneframe_I420[j,k] = int.from_bytes(fp.read(1), byteorder='little', signed=False)
            oneframe_RGB = cv2.cvtColor(oneframe_I420,cv2.COLOR_YUV2RGB_I420)
            if show:
                plt.imshow(oneframe_RGB)
                plt.show()
                plt.pause(0.001)
            if out:
                outname = yuvfilename[:-4]+'_'+str(startframe+i)+'.png'
                cv2.imwrite(outname,oneframe_RGB[:,:,::-1])
            arr[i] = oneframe_RGB
    return arr
 
if __name__ == '__main__':
    video = yuv2rgb(r'D:\_workspace\akiyo_qcif.yuv', 176, 144, 0, 10, False, True)

 

用ffmpeg也可以，比如你需要將yuv的第8幀輸出成一個png：

ffmpeg -s 176x144 -i akiyo_qcif.yuv -filter:v select="between(n\,8\,8)" out.png