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• Can you "stream" images to ffmpeg to construct a video, instead of saving them to disk ?

  8 juillet 2016, par Brandon

  My work recently involves programmatically making videos. In python, the typical workflow looks something like this :

  import subprocess, Image, ImageDraw
  
  
  
  for i in range(frames_per_second * video_duration_seconds):
  
      img = createFrame(i)
  
      img.save("%07d.png" % i)
  
  
  
  subprocess.call(["ffmpeg","-y","-r",str(frames_per_second),"-i", "%07d.png","-vcodec","mpeg4", "-qscale","5", "-r", str(frames_per_second), "video.avi"])

  This workflow creates an image for each frame in the video and saves it to disk. After all images have been saved, ffmpeg is called to construct a video from all of the images.

  Saving the images to disk (not the creation of the images in memory) consumes the majority of the cycles here, and does not appear to be necessary. Is there some way to perform the same function, but without saving the images to disk ? So, ffmpeg would be called and the images would be constructed and fed to ffmpeg immediately after being constructed.

• Android : mp4 file plays when downloaded but when choosing "Video" player gets "Cannot play video"

  14 janvier 2014, par gview

  I've converted the video to an mp4 with ffmpeg using the h264 codec and AAC, and used the baseline profile.

  Videos are 540x360x250kbps

  I then ran qt-faststart on the file to move the atoms into the right order.

  I've stuck the file up on a wiki we use and created a link to it.

  My test phone is a Samsung Galaxy S3.

  When I browse to the page that has links to the mp4's on it, and I click on them, I get a popup window with 2 options : Internet and Video.

  If I download the videos using the "Internet" option, I can play them on the phone without issue.

  I've done other encodings with the main profile as well, and these also play fine. I thought that a powerful phone like the s3 would be able to handle the more advanced compression schemes available in h264, however I've also browsed the Android docs in regards to supported video formats, and it seems to state that only the "baseline" compression profile is supported.

  Regardless, what doesn't work is trying to use the "Video" option which I assume tries to stream the video.

  For the wiki in question, clicking on the link reveals that the content-type and content-length headers are being set :

  Content-Length  6175996
  
  Content-Type    video/mp4;charset=UTF-8

  Clicking on the link with a browser invokes a player (Quicktime in most cases) that can play the mp4's.

  Is there more to having the file HTTP streamable beyond making a link to it ? Why won't my Android 4 play these files ?

  UPDATE :
  I decided to make a quick HTML5 page using the video tag, and the videos do play on both my Galaxy S3 and the latest IOS.

• Android FFmpeg reports "file protocol not found"

  27 avril 2017, par Abdul Mateen

  I am trying to convert sequence images to video using ffmpeg command in android.
  I have build ffmpeg for android and put ffmpeg binary file in /data/local folder.
  I am running ffmpeg command using Runtime.getruntime.execute("mycommand") in Android.

  Stucture of mycommand is like this

  "/data/local/ffmpeg -r 40 qscale 2 -i /mnt/sdcard/images/img%d.jpg /mnt/sdcard/images/finalvideo.mp4" 

  mycommand contains the path of a folder where I placed all my sequence images. Running this command gives me error "protocol not found".

  Also I read that file protocol is default in ffmpeg documentation.

  How can I run such commands ?

  The Error I am getting after running simple command like ffmpeg -i /mnt/sdcard/vid.mp4

  ffmpeg version 0.11.1.git Copyright (c) 2000-2012 the FFmpeg developers
  
  built on Sep 26 2012 11:58:35 with gcc 4.4.3 (GCC)
  
  configuration: --target-os=linux --prefix=/home/esteves/android-ffmpeg --enable-cross-compile --enable-runtime-cpudetect --disable-asm --arch=arm --cc=/home/esteves/android-ndk/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc --cross-prefix=/home/esteves/android-ndk/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi- --disable-stripping --nm=/home/esteves/android-ndk/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-nm --sysroot=/home/esteves/android-ndk/platforms/android-8/arch-arm --enable-nonfree --enable-version3 --disable-everything --enable-gpl --disable-doc --enable-avresample --enable-demuxer=amr --enable-demuxer=aac --enable-demuxer=rawvideo --enable-demuxer=rtsp --enable-muxer=rtsp --enable-muxer=flv --enable-muxer=mpegts --enable-muxer=mp4 --enable-demuxer=rtp --enable-demuxer=rtp --disable-ffplay --disable-ffserver --enable-ffmpeg --disable-ffprobe --enable-libx264 --enable-encoder=libx264   libavutil      51. 72.100 / 51. 72.100
  
  libavcodec     54. 55.100 / 54. 55.100
  
  libavformat    54. 25.105 / 54. 25.105
  
  libswscale      2.  1.101 /  2.  1.101
  
  error of main   libswresample   0. 15.100 /  0. 15.100
  
  error of main   libpostproc    52.  0.100 / 52.  0.100
  
  /mnt/sdcard/vid.mp4: Protocol not found