For a future myself, here is what I ended up with: def generate_video(img): for i in xrange(len(img)): plt.imshow(img[i], cmap=cm.Greys_r) plt.savefig(folder + “/file%02d.png” % i) os.chdir(“your_folder”) subprocess.call([ ‘ffmpeg’, ‘-framerate’, ‘8’, ‘-i’, ‘file%02d.png’, ‘-r’, ’30’, ‘-pix_fmt’, ‘yuv420p’, ‘video_name.mp4’ ]) for file_name in glob.glob(“*.png”): os.remove(file_name)
If you just want a ffmpeg command, try ffmpeg -i input.mov -i overlay.mov \ -filter_complex “[1:v]setpts=PTS-10/TB[a]; \ [0:v][a]overlay=enable=gte(t\,5):shortest=1[out]” \ -map [out] -map 0:a \ -c:v libx264 -crf 18 -pix_fmt yuv420p \ -c:a copy \ output.mov This starts the overlay at 5 seconds with the overlaid video start point being 00:15. setpts=PTS-10/TB is setpts=PTS+(overlay_delay-video_trim_in)/TB overlay=enable=gte(t\,5) is … Read more
This is an update to my initial answer after I had a chance to play with this myself. Yes, it is possible to use CvVideoCamera with a view controller written in Swift. If you just want to use it to display video from the camera in your app, it’s really easy. #import <opencv2/highgui/cap_ios.h> via the … Read more
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 … Read more
I assume your video is in an Mp4 container. The mp4 file format contains a hierarchical structure of ‘boxes’. One of these boxes is the Time-To-Sample (stts) box. This box contains the time of every frame (in a compact fashion). From here you can find the ‘chunk’ that contains the frame using the Sample-to-Chunk (stsc) … Read more
I ended up rolling my own stand alone class (with the single method I described), the source can be viewed here. Media browser is GPL but I am happy for the code I wrote for that file to be Public Domain. Keep in mind it uses interop from the directshow.net project so you will have … Read more
Of course you could code up some C/C++ and link to -lav*, basically creating a simplified version of ffmpeg just for extracting frames, and maybe even do it as a php extension (also I wouldn’t run it as the same user, let alone in the same process). But the result is very unlikely to be … Read more
presetName use “AVAssetExportPresetPassthrough” instead “AVAssetExportPresetLowQuality” AVAssetExportSession *exportSession = [[AVAssetExportSession alloc]initWithAsset:avAsset presetName:AVAssetExportPresetPassthrough];
Use ffprobe Example command $ ffprobe -v error -select_streams v:0 -show_entries stream=codec_name -of default=nokey=1:noprint_wrappers=1 input.mp4 Result h264 Option descriptions -v error Omit extra information except for fatal errors. -select_streams v:0 Select only the first video stream. Otherwise the codec_name for all other streams in the file, such as audio, will be shown as well. -show_entries … Read more
Android do not support for AWT’s BufferedBitmap nor AWTUtil, that is for Java SE. Currently the solution with SequenceEncoder has been integrated into jcodec’s Android version. You can use it from package org.jcodec.api.SequenceEncoder. Here is the solution for generating MP4 file from series of Bitmaps using jcodec: try { File file = this.GetSDPathToFile(“”, “output.mp4”); SequenceEncoder … Read more