Newest 'ffmpeg' Questions - Stack Overflow

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• JavaCv and FFMpeg

  19 mai 2018, par Karthik Veenam

  I was given a task to merge an Image and Audio to make a video file out of them in android. I successfully finished the task by using javacv ffmpeg but after so much of compression my app size is still around 15mb. After analysing the apk, I've found that libavcodec.so is occupying 64% of the size. Since my app relies on that, I can't exclude the file. So my question is "Is it feasible to complete this task with very less apk size? Like around < 5Mb?"

• How to fix this FFMPEG command to record audio as well ?

  19 mai 2018, par James Kowalski

  I am trying to fix this FFMPEG command to record audio.

  I have tried using the parts recommended on the official stackoverflow site but they didn't work

  Orignal Command

  ffmpeg_stream = '/usr/bin/ffmpeg -f x11grab -s 1280x720 -r 24 -i :%d+nomouse -c:v libx264 -preset superfast -pix_fmt yuv420p -s 1280x720 -threads 0 -f flv "%s"' % (xvfb.new_display, info['destination'])

  Command with attempted audio

  ffmpeg_stream = '/usr/bin/ffmpeg -f x11grab -s 1280x720 -r 24 -i :%d+nomouse -c:v libx264 -preset superfast -pix_fmt yuv420p -s 1280x720 -threads 0 -f alsa -ac 2 -i hw:0 -f flv "%s"' % (xvfb.new_display, info['destination'])

• FFMPEG not extracting all the frames from a video

  19 mai 2018, par Jonathan Huang

  I am trying to extract all the frames from a video in order to get some training data for a tensor flow project. However whenever I run

  ffmpeg -i one.mp4 -r 1/1 "$filename%03d.jpeg"
  

  I only get 15 pictures. My phone films in 30fps, and the video was 13 seconds long, so shouldn't I get roughly 490 pictures?

  Is there an error in my understanding or am I using the wrong function?

• Use ffmpeg to time-dilate and resample audio without changing frequencies

  18 mai 2018, par Adisak

  I have some audio (wave file) that is sampled at a rate of 48000 samples per second.

  This audio was created to match a 30 FPS video. However, the video actually plays back on the target at the NTSC framerate of 29.97 (30 X 1000/1001).

  This means that I need to time-dilate the audio so that there are 48048 samples where there were previously 48000 samples (it plays back 1.001 times slower) but still maintains that the final audio file's rate is 48000 samples per second.

  Ideally, also, I'd like to do this resample using the sox library option for FFMPEG since I hear it has much higher quality.

  Can anyone help me with the command line necessary to process a file in this manner?

• Downloading a specific segment of a YouTube video

  18 mai 2018, par BlueStone

  I normally download files or parts of them using ffmepg command.

  ffmpeg -ss 00:05:00 -i "video url here "   -t 100 -c copy   -avoid_negative_ts 1 out.mkv  
  

  Now, downloading a YouTube video is not problem using youtube-dl, but I want to download specific part of a video (1080p+), I thought I could use youtube-dl to grab the link of the video and pass it to ffmpeg to do the cutting with the previous code, but could not figure how to do this.

  Searched and tried many commands and stuff here and there, but nothing worked.