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• Detect rotation angle and rotate final video using ffmpeg version 2.8

  3 février 2016, par Hemant Kumar

  I used to work on ffmpeg 2.2 until now and was detecting rotation angle of video uploaded from android / iPhone mobiles and rotate the resulting video so that it run perfectly on a correct angle.

  But since I have updated the ffmpeg to version 2.8 I am getting this rotation problem. My queries are not rotating the videos as they were earlier.

  Here’r the commands I was using :

  To check rotation angle :

  ffprobe -of json -show_streams {$input} | grep rotate

  below is my final command to convert a video to mp4

  "ffmpeg -i {$input} -strict -2 -vcodec libx264 -preset slow -vb 500k -maxrate 500k -bufsize 1000k -vf 'scale=-1:480 ".fix_video_orientation($input)."' -threads 0 -ab 64k -s {$resolution}  -movflags faststart -metadata:s:v:0 rotate=0 {$output}";

  "fix_video_orientation" function is given below. It detect the angle of rotation of the initial video and output optimal option for rotating the final video.

  function fix_video_orientation($input){
  
  
  
  $return= ", transpose=1 ";
  
  
  
  $dd= exec("ffprobe -of json -show_streams  {$input}   | grep rotate");
  
  
  
  if(!empty($dd)){
  
  
  
  $dd=explode(":",$dd);
  
  $rotate=str_replace(",","",str_replace('"',"",$dd[1]));
  
  
  
  if($rotate=="90")return $return;
  
  
  
  else if ($rotate=="180") return ", transpose=2,transpose=2 ";
  
  
  
  else if($rotate == "270") return ", transpose=2 ";
  
  }

  Currently above script is supporting "flv","avi","mp4","mkv","mpg","wmv","asf","webm","mov","3gp","3gpp" extensions, also the script is supporting the resulting .mp4 file to play on all browsers and devices.

  Now the ffprobe command is not returning rotation angle and so a portrait video if uploaded from iphone is showing as landscape on the website.

  Output console of ffprobe command :

  ffprobe version N-77455-g4707497 Copyright (c) 2007-2015 the FFmpeg developers
  
  built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04)
  
  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-libdcadec --enable-libfreetype --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-libvo-aacenc --enable-libvidstab
  
  libavutil 55. 11.100 / 55. 11.100
  
  libavcodec 57. 20.100 / 57. 20.100
  
  libavformat 57. 20.100 / 57. 20.100
  
  libavdevice 57. 0.100 / 57. 0.100
  
  libavfilter 6. 21.101 / 6. 21.101
  
  libavresample 3. 0. 0 / 3. 0. 0
  
  libswscale 4. 0.100 / 4. 0.100
  
  libswresample 2. 0.101 / 2. 0.101
  
  libpostproc 54. 0.100 / 54. 0.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/standard/PORTRAIT.m4v':
  
  Metadata:
  
  major_brand : qt
  
  
  
  minor_version : 0
  
  compatible_brands: qt
  
  
  
  creation_time : 2016-02-03 05:25:18
  
  com.apple.quicktime.make: Apple
  
  com.apple.quicktime.model: iPhone 4S
  
  com.apple.quicktime.software: 9.2.1
  
  com.apple.quicktime.creationdate: 2016-02-03T10:52:11+0530
  
  Duration: 00:00:03.34, start: 0.000000, bitrate: 7910 kb/s
  
  Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 63 kb/s (default)
  
  Metadata:
  
  creation_time : 2016-02-03 05:25:18
  
  handler_name : Core Media Data Handler
  
  Stream #0:1(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709), 720x1280 [SAR 1:1 DAR 9:16], 7832 kb/s, 29.97 fps, 29.97 tbr, 600 tbn, 50 tbc (default)
  
  Metadata:
  
  creation_time : 2016-02-03 05:25:18
  
  handler_name : Core Media Data Handler
  
  encoder : H.264
  
  Stream #0:2(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
  
  Metadata:
  
  creation_time : 2016-02-03 05:25:18
  
  handler_name : Core Media Data Handler
  
  Stream #0:3(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
  
  Metadata:
  
  creation_time : 2016-02-03 05:25:18
  
  handler_name : Core Media Data Handler
  
  Unsupported codec with id 0 for input stream 2
  
  Unsupported codec with id 0 for input stream 3

  If latest version of ffmpeg (2.8) is used to auto rotate the video, can you please suggest me what option I need to add or remove from my final command.

• ffmpeg does not record audio exactly after setting duration with -t

  25 janvier 2016, par rudyshihhh

  I tried to record the audio of web page by ffmpeg and it worked well with the comment as below.

  ~$ ffmpeg -f alsa -ac 2 -i pulse output5.wav

  and could get the audio file which was saved in my local device. However, recording could not work properly after I added the parameter "-t" to limit the duration of recording. For example, if I set -t 20, the saved file only 0 or 20 KB but the comment without -t can get about 4MB. Is there any problem with my comment ? or Is there any other manner to record the audio by ffmpeg in limited time ?

  ~$ ffmpeg -f alsa -ac 2 -i pulse -t 20 output5.wav
  
  
  
  ffmpeg version 0.8.17-4:0.8.17-0ubuntu0.12.04.1, Copyright (c) 2000-2014 the Libav developers
  
  built on Mar 16 2015 13:26:50 with gcc 4.6.3
  
  The ffmpeg program is only provided for script compatibility and will be removed
  
  in a future release. It has been deprecated in the Libav project to allow for
  
  incompatible command line syntax improvements in its replacement called avconv
  
  (see Changelog for details). Please use avconv instead.
  
  [alsa @ 0x212c7a0] capture with some ALSA plugins, especially dsnoop, may hang.
  
  [alsa @ 0x212c7a0] Estimating duration from bitrate, this may be inaccurate 
  
  Input #0, alsa, from 'pulse':
  
    Duration: N/A, start: 1453692638.847782, bitrate: N/A
  
      Stream #0.0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
  
  Output #0, wav, to 'output5.wav':
  
    Metadata:
  
      encoder         : Lavf53.21.1
  
      Stream #0.0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
  
  Stream mapping:
  
    Stream #0.0 -> #0.0
  
  Press ctrl-c to stop encoding
  
  size=      28kB time=0.15 bitrate=1538.5kbits/s    
  
  video:0kB audio:28kB global headers:0kB muxing overhead 0.162636%

• iPhone video conversion to Android supported format using FFMPEG

  21 janvier 2016, par Muhammad Umar

  I have an iPhone video created as follow

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'vid.mp4':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 0
  
      compatible_brands: qt  
  
      creation_time   : 2016-01-20 09:21:08
  
      make            : Apple
  
      make-eng        : Apple
  
      encoder         : 8.2
  
      encoder-eng     : 8.2
  
      date            : 2016-01-20T14:20:57+0500
  
      date-eng        : 2016-01-20T14:20:57+0500
  
      model           : iPhone 5
  
      model-eng       : iPhone 5
  
    Duration: 00:00:10.80, start: 0.000000, bitrate: 765 kb/s
  
      Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 62 kb/s (default)
  
      Metadata:
  
        creation_time   : 2016-01-20 09:21:08
  
        handler_name    : Core Media Data Handler
  
      Stream #0:1(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709), 320x320, 696 kb/s, 30 fps, 30 tbr, 600 tbn, 1200 tbc (default)
  
      Metadata:
  
        creation_time   : 2016-01-20 09:21:08
  
        handler_name    : Core Media Data Handler
  
        encoder         : H.264

  I want to convert it into Android support format so that all iPhone and maximum androids can read it.

  However if i convert to mpeg4 format using

  ffmpeg -i vid.mp4 -s 320x320 -vcodec mpeg4 -acodec aac -strict -2 -ac 2 -ar 44100 -ab 128k output.mp4

  it really degrades the quality

  How can i set the ffmpeg to create atleast as close as possible quality which runs on both android and iPhone