【Python】寫視訊的2種常用方法:write_videofile和videoWrite
阿新 • • 發佈:2018-12-28
一、使用Python自帶的write_videofile
1、函式說明如下:
def write_videofile(self, filename, fps=None, codec=None, bitrate=None, audio=True, audio_fps=44100, preset="medium", audio_nbytes=4, audio_codec=None, audio_bitrate=None, audio_bufsize=2000, temp_audiofile=None, rewrite_audio=True, remove_temp=True, write_logfile=False, verbose=True, threads=None, ffmpeg_params=None, progress_bar=True): """Write the clip to a videofile. Parameters ----------- filename Name of the video file to write in. The extension must correspond to the "codec" used (see below), or simply be '.avi' (which will work with any codec). fps Number of frames per second in the resulting video file. If None is provided, and the clip has an fps attribute, this fps will be used. codec Codec to use for image encoding. Can be any codec supported by ffmpeg. If the filename is has extension '.mp4', '.ogv', '.webm', the codec will be set accordingly, but you can still set it if you don't like the default. For other extensions, the output filename must be set accordingly. Some examples of codecs are: ``'libx264'`` (default codec for file extension ``.mp4``) makes well-compressed videos (quality tunable using 'bitrate'). ``'mpeg4'`` (other codec for extension ``.mp4``) can be an alternative to ``'libx264'``, and produces higher quality videos by default. ``'rawvideo'`` (use file extension ``.avi``) will produce a video of perfect quality, of possibly very huge size. ``png`` (use file extension ``.avi``) will produce a video of perfect quality, of smaller size than with ``rawvideo``. ``'libvorbis'`` (use file extension ``.ogv``) is a nice video format, which is completely free/ open source. However not everyone has the codecs installed by default on their machine. ``'libvpx'`` (use file extension ``.webm``) is tiny a video format well indicated for web videos (with HTML5). Open source. audio Either ``True``, ``False``, or a file name. If ``True`` and the clip has an audio clip attached, this audio clip will be incorporated as a soundtrack in the movie. If ``audio`` is the name of an audio file, this audio file will be incorporated as a soundtrack in the movie. audiofps frame rate to use when generating the sound. temp_audiofile the name of the temporary audiofile to be generated and incorporated in the the movie, if any. audio_codec Which audio codec should be used. Examples are 'libmp3lame' for '.mp3', 'libvorbis' for 'ogg', 'libfdk_aac':'m4a', 'pcm_s16le' for 16-bit wav and 'pcm_s32le' for 32-bit wav. Default is 'libmp3lame', unless the video extension is 'ogv' or 'webm', at which case the default is 'libvorbis'. audio_bitrate Audio bitrate, given as a string like '50k', '500k', '3000k'. Will determine the size/quality of audio in the output file. Note that it mainly an indicative goal, the bitrate won't necessarily be the this in the final file. preset Sets the time that FFMPEG will spend optimizing the compression. Choices are: ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, veryslow, placebo. Note that this does not impact the quality of the video, only the size of the video file. So choose ultrafast when you are in a hurry and file size does not matter. threads Number of threads to use for ffmpeg. Can speed up the writing of the video on multicore computers. ffmpeg_params Any additional ffmpeg parameters you would like to pass, as a list of terms, like ['-option1', 'value1', '-option2', 'value2']. write_logfile If true, will write log files for the audio and the video. These will be files ending with '.log' with the name of the output file in them. verbose Boolean indicating whether to print infomation. progress_bar Boolean indicating whether to show the progress bar.
2、使用程式碼如下:
from moviepy.editor import VideoFileClip
clip = VideoFileClip("myvideo.mp4").subclip(100,120)
clip.write_videofile("my_new_video.mp4")
clip.close()
二、載入opencv的videoWriter
1、函式說明如下:
videoWriter = cv.videoWriter(video_name, file_format, fps, isColor)
引數說明:
video_name:視訊名稱
file_format:檔案格式
fps:幀率
isColor:輸出格式,等於0時輸出灰度視訊,不等於0時輸出彩色視訊
2、使用程式碼如下:
import cv2 as cv # 呼叫攝像頭 videoCapture = cv.VideoCapture(0) # 設定幀率 fps = 30 # 獲取視窗大小 size = (int(videoCapture.get(cv.CAP_PROP_FRAME_WIDTH)), int(videoCapture.get(cv.CAP_PROP_FRAME_HEIGHT))) # 設定VideoWrite的資訊 videoWrite = cv.VideoWriter('MySaveVideo.avi', cv.VideoWriter_fourcc('I', '4', '2', '0'), fps, size) # 先獲取一幀,用來判斷是否成功呼叫攝像頭 success, frame = videoCapture.read() # 通過設定幀數來設定時間,減一是因為上面已經獲取過一幀了 numFrameRemainling = fps * 5 - 1 # 通過迴圈儲存幀 while success and numFrameRemainling > 0: videoWrite.write(frame) success, frame = videoCapture.read() numFrameRemainling -= 1 # 釋放攝像頭 videoCapture.release()