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• Extracting a clip from a video with low fps

  1er juin 2016, par superMind

  I want to extract a clip from a video( downloaded from [1]) (which has low frame rate) by specifying the start and end time. In order to do that, I use the following command :

  ffmpeg -i example.webm -ss 116.38 -to 126.38 clip.mpg

  however, I get the following error :

  ---

  ffmpeg version N-80026-g936751b Copyright (c) 2000-2016 the FFmpeg developers
  
  built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.3)
  
  configuration: --extra-libs=-ldl --prefix=/opt/ffmpeg --mandir=/usr/share/man --enable-avresample --disable-debug --enable-nonfree --enable-gpl --enable-version3 --enable-libopencore-amrnb --enable-libopencore-amrwb --disable-decoder=amrnb --disable-decoder=amrwb --enable-libpulse --enable-libfreetype --enable-gnutls --enable-libx264 --enable-libx265 --enable-libfdk-aac --enable-libvorbis --enable-libmp3lame --enable-libopus --enable-libvpx --enable-libspeex --enable-libass --enable-avisynth --enable-libsoxr --enable-libxvid --enable-libvidstab
  
  libavutil 55. 24.100 / 55. 24.100
  
  libavcodec 57. 42.100 / 57. 42.100
  
  libavformat 57. 36.100 / 57. 36.100
  
  libavdevice 57. 0.101 / 57. 0.101
  
  libavfilter 6. 45.100 / 6. 45.100
  
  libavresample 3. 0. 0 / 3. 0. 0
  
  libswscale 4. 1.100 / 4. 1.100
  
  libswresample 2. 0.101 / 2. 0.101
  
  libpostproc 54. 0.100 / 54. 0.100
  
  Input #0, matroska,webm, from 'example.webm':
  
  Metadata:
  
  encoder : Google
  
  Duration: 00:04:22.29, start: 0.000000, bitrate: 207 kb/s
  
  Stream #0:0: Video: vp8, yuv420p, 630x360, SAR 1:1 DAR 7:4, 6 fps, 6 tbr, 1k tbn (default)
  
  Stream #0:1: Audio: vorbis, 44100 Hz, stereo, fltp (default)
  
  [mpeg1video @ 0x252f200] MPEG1/2 does not support 5/1 fps
  
  Output #0, mpeg, to 'clip.mpg':
  
  Metadata:
  
  encoder : Google
  
  Stream #0:0: Unknown: none, SAR 1:1 DAR 0:0 (default)
  
  Metadata:
  
  encoder : Lavc57.42.100 mpeg1video
  
  Stream #0:1: Unknown: none (default)
  
  Metadata:
  
  encoder : Lavc57.42.100 mp2
  
  Stream mapping:
  
  Stream #0:0 -> #0:0 (vp8 (native) -> mpeg1video (native))
  
  Stream #0:1 -> #0:1 (vorbis (native) -> mp2 (native))
  
  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height
  
  -----------------------------------------------------

  I tried by adding -r 20 to the above command. It works in this case but not sure this is correct way to do it.
  I was wondering how can I extract the clip from this video given start time and endtime ? what are parameters should I use ? or what is correct way to do it ?

  Thanks.

  [1]https://www.youtube.com/watch?v=Yc52pGHr0xc

• where to save mpd file in raspberry pi so dash.js can access it remotely ?

  11 mai 2016, par Djm

  This is very high level question. I want to stream a live video from raspberry pi. I want to be able to watch live video in the browser remotely being streamed by the Raspberry pi.I want to use DASH stream protocol, and Dash.js as client to HTML5. I have looked through different tutorials but i am still puzzled about how this works.I understand that (assuming you have already prepared your videos with FFMPEG tool) from the client Dash.js
  you have to make a call/request and pass a url to your mpd file. My question is where would you save the file in raspberry pi especially if the Dash client is in a different web app(i want to make the call remotely) ?

• Android - Adding Effects to Videos like Instagram

  10 mai 2016, par San

  I am in need of a idea to apply filters to video like Instagram, video trimming and fetching images from the video. I have researched a lot and all I can come up with is the following ways to achieve what I want :

  1. FFMPEG
  2. Open CV
  3. Camera2 API

  FFMPEG :

  As far as FFMPEG is considered, majority of the average level droid devs feel that its a pain cause it involves NDK and compiling the FFMPEG commands.The above mentioned link is self-explanatory and it saves me the pain of setting up the NDK but the biggest drawback in this is that its not stable and its REALLY slow.
  My query on this topic is that how do I compile FFMPEG into my project. I have gone through several links to integrate FFMPEG as follows :

  One

  Two

  Three

  The third link seemed to make sense but ultimately I couldn’t understand completely and go where,do what after following those steps.

  Question 1 :

  Is there is a solid Android - FFMPEG Integration Document that can help a beginner like me ?

  Open CV

  Question 2 :

  I haven’t tried Open CV yet but will it be worth it ?

  Camera2 API

  Question 3 :

  As far as I researched, I can see that the Camera2 API can help us shoot videos and images with effects added to it but will it be useful for me to process the already existing videos and images ? I don’t have the requirement to add effects to the camera while its captured, its aftermath is where I want to add my effects.

  If someone is kind enough to accept my stupidity and help me out, I am thankful to them.

  Will going ahead with FFMPEG be good or OpenCV or Camera2 API will be better ?