利用python讀取YUV檔案 轉RGB 8bit/10bit通用
阿新 • • 發佈:2020-01-09
注:本文所指的YUV均為YUV420中的I420格式(最常見的一種),其他格式不能用以下的程式碼。
位深為8bit時,每個畫素佔用1位元組,對應檔案指標的fp.read(1);
位深為10bit時,每個畫素佔用2位元組,對應檔案指標的fp.read(2);
然後使用 int.from_bytes() 方法將二進位制轉換為int型數字。
以下程式可以讀8bit或10bit位深的YUV,需要指定從第幾幀開始讀、一共讀多少幀。
它返回三個陣列,其shape分別為:Y [frame,W,H] U [frame,W/2,H/2] V [frame,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,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,W),np.uint8) U = np.zeros((totalframe,uv_H,uv_W),np.uint8) V = np.zeros((totalframe,np.uint8) elif bitdepth == 10: Y = np.zeros((totalframe,np.uint16) U = np.zeros((totalframe,np.uint16) V = np.zeros((totalframe,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,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,n] = np.uint8(pel) elif bitdepth == 10: pel = bytes2num(fp.read(2)) U[i,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,n] = np.uint8(pel) elif bitdepth == 10: pel = bytes2num(fp.read(2)) V[i,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,v = readyuv420(r'F:\_commondata\video\1920x1080 B\RitualDance_1920x1080_60fps_10bit_420.yuv',10,1920,1080,True) print(y.shape,u.shape,v.shape)
以下程式將YUV轉為RGB(只能讀8bit位深的YUV),返回1個數組,其shape為: [frame,3]
# -*- coding: utf-8 -*- import cv2 import numpy as np import matplotlib.pyplot as plt def yuv2rgb(yuvfilename,show=False,out=False): # 從第startframe(含)開始讀(0-based),共讀totalframe幀 arr = np.zeros((totalframe,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,np.uint8) for j in range(H*3//2): for k in range(W): oneframe_I420[j,k] = int.from_bytes(fp.read(1),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',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
以上這篇利用python讀取YUV檔案 轉RGB 8bit/10bit通用就是小編分享給大家的全部內容了,希望能給大家一個參考,也希望大家多多支援我們。