codec

The opencv works fine when doing other things. It can open images and show images. But it can't open a video. The code I'm using to open a video is as below import cv2 cap = cv2.VideoCapture("MOV_0006.mp4") while True: ret, frame = cap.read() cv2.imshow('video', frame) if cv2.waitKey(1) & 0xff == ord('q'): break cap.release() cv2.destroyAllWindows() But when executing, it outputs error messages like below [h264 @ 0x1053ba0] AVC: nal size 554779904 [h264 @ 0x1053ba0] AVC: nal size 554779904 [h264 @ 0x1053ba0] no frame! My vlc and mplayer can play this video, but the opencv can't. I have

There are two ways to open a text file in Python: f = open(filename) And import codecs f = codecs.open(filename, encoding="utf-8") When is codecs.open preferable to open ? Luciano Ramalho Since Python 2.6, a good practice is to use io.open() , which also takes an encoding argument, like the now obsolete codecs.open() . In Python 3, io.open is an alias for the open() built-in. So io.open() works in Python 2.6 and all later versions, including Python 3.4. See docs: http://docs.python.org/3.4/library/io.html Now, for the original question: when reading text (including "plain text", HTML, XML and

I am trying to decode AAC audio to PCM audio in iOS, what the best way to do this?Any sample code would be very helpful...Is there any simple APIs to do this..? I have sample code to do it. At start you should configure in/out ASBD (AudioStreamBasicDescription) and create converter: - (void)setupAudioConverter{ AudioStreamBasicDescription outFormat; memset(&outFormat, 0, sizeof(outFormat)); outFormat.mSampleRate = 44100; outFormat.mFormatID = kAudioFormatLinearPCM; outFormat.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger; outFormat.mBytesPerPacket = 2; outFormat.mFramesPerPacket = 1;

There does not seem to be any explanation online as to what these are. People talk about them a lot. I just want to know what they are and why they are significant. Using -video_track_timescale, how would I determine a number for it? Is it random? Should it be 0? Modern containers govern the time component of presentation of video (and audio) frames using timestamps, rather than framerate. So, instead of recording a video as 25 fps, and thus implying that each frame should be drawn 0.04 seconds apart, they store a timestamp for each frame e.g. Frame pts_time 0 0.00 1 0.04 2 0.08 3 0.12 ... For