video-processing

I tried to answer this in the original thread however SO would not let me. Hopefully someone with more authority can merge this into the original question. OK here is a more complete answer. First, setup the capture: // Create capture session self.captureSession = [[AVCaptureSession alloc] init]; [self.captureSession setSessionPreset:AVCaptureSessionPresetPhoto]; // Setup capture input self.inputDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; AVCaptureDeviceInput *captureInput = [AVCaptureDeviceInput deviceInputWithDevice:self.inputDevice error:nil]; [self

I'm using this command to crop,scale, and then add subtitles as overlay ffmpeg -i input.avi -vf "[in]crop=in_w:in_h-20:0:0 [crop]; [crop]scale=320:240 [scale];[scale]subtitles=srt.srt" -aspect 16:9 -vcodec libx264 -crf 23 oq.mp4 how can we set font size/color of subtitle ? There are two methods to use subtitles: hardsubs and softsubs. Hardsubs The subtitles video filter can be used to hardsub, or burn-in, the subtitles. This requires re-encoding and the subtitles become part of the video itself. force_style option To customize the subtitles you can use the force_style option in the subtitles

I have a need to burn in a time code to a video and am wondering if this is something that ffmpeg is capable of? Short answer, no. Long answer, yes, but not without using a separate library to create the frames with the rendered time code on them, with transparency filling the rest of the frame, then using FFmpeg to overlay the frames on the existing video. Off the top of my head I don't know how to do this, but I'm sure if you're creative you can figure it out. Edit: I've been working on this problem because it is an interesting question/project for me. I have come a little further in the

I'm trying to render frames grabbed and converted from a video using ffmpeg to an OpenGL texture to be put on a quad. I've pretty much exhausted google and not found an answer, well I've found answers but none of them seem to have worked. Basically, I am using avcodec_decode_video2() to decode the frame and then sws_scale() to convert the frame to RGB and then glTexSubImage2D() to create an openGL texture from it but can't seem to get anything to work. I've made sure the "destination" AVFrame has power of 2 dimensions in the SWS Context setup. Here is my code: SwsContext *img_convert_ctx = sws

From here I know a way to write a file and be accessible to other app and other intent, but now that the Context.MODE_WORLD_READABLE is deprecated how can I safely accomplish this? FileOutputStream out = myActivity.openFileOutput(fileTo, Context.MODE_WORLD_READABLE); Okay more info: I'm using this: intent = new Intent(Intent.ACTION_VIEW); intent.setDataAndType(uri, "video/*"); And the uri will be the one that I will write to a sdcard location. And the video will come from the application so problem is, if this is now not allowed, how can I write the file and view it. And the uri will be the

How to read a frame from YUV file in OpenCV? I wrote a very simple python code to read YUV NV21 stream from binary file. import cv2 import numpy as np class VideoCaptureYUV: def __init__(self, filename, size): self.height, self.width = size self.frame_len = self.width * self.height * 3 / 2 self.f = open(filename, 'rb') self.shape = (int(self.height*1.5), self.width) def read_raw(self): try: raw = self.f.read(self.frame_len) yuv = np.frombuffer(raw, dtype=np.uint8) yuv = yuv.reshape(self.shape) except Exception as e: print str(e) return False, None return True, yuv def read(self): ret, yuv =

I am planning to use ffmpeg to ensure all video files uploaded to my website are encoded as mp4 h264. Rather than automatically processing every file I would like to minimise the processing overhead by only processing those files that are not already mp4 h264. Is there an easy way to do this either with ffmpeg or with another command line utility? If you pass an input file to ffmpeg, without other parameters, it will give you information about the video source: ffmpeg -i myfile.avi Another way would be the -identify option of mplayer, which might be slightly easier to parse. There is a wrapper