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• ffmpeg amerge prefer longest audio track

  4 décembre 2013, par Adam Chance

  I'm trying to combine two audio tracks in ffmpeg with amerge, but it is only as long as the shortest feature. The ffmpeg wiki says that this is the behaviour of the amerge filter, but I need the output to be as long as the longest audio track. The code I'm using is

  ffmpeg -i audio.flac -i song.flac -filter_complex amerge -acodec mp2 -b:a 128k audiotrack.mp2
  

  Console output:

      ffmpeg version N-58688-gc46ab34 Copyright (c) 2000-2013 the FFmpeg developers
      built on Dec  1 2013 14:39:22 with gcc 4.7 (Ubuntu/Linaro 4.7.3-1ubuntu1)
      configuration: --enable-outdev=alsa --enable-indev=alsa --enable-gpl --enable-x11grab --enable-libpulse --enable-libopus --enable-libvorbis --enable-libtheora --enable-pthreads
      libavutil      52. 56.100 / 52. 56.100
      libavcodec     55. 44.100 / 55. 44.100
      libavformat    55. 22.100 / 55. 22.100
      libavdevice    55.  5.102 / 55.  5.102
      libavfilter     3. 91.100 /  3. 91.100
      libswscale      2.  5.101 /  2.  5.101
      libswresample   0. 17.104 /  0. 17.104
      libpostproc    52.  3.100 / 52.  3.100
      Input #0, flac, from 'audio.flac':
      Metadata:
      ENCODER         : Lavf55.22.100
      Duration: 00:00:04.14, bitrate: 172 kb/s
      Stream #0:0: Audio: flac, 16000 Hz, mono, s16
      Input #1, flac, from 'song.flac':
      Duration: 00:07:38.04, bitrate: 676 kb/s
      Stream #1:0: Audio: flac, 44100 Hz, stereo, s16
      Stream #1:1: Video: mjpeg, yuvj444p(pc), 500x500 [SAR 28:28 DAR 1:1], 90k tbr, 90k tbn, 90k tbc
      Metadata:
      comment         : Cover (front)
      File 'audiotrack.mp2' already exists. Overwrite ? [y/N] y
      [Parsed_amerge_0 @ 0x317f580] No channel layout for input 1
      Output #0, mp2, to 'audiotrack.mp2':
      Metadata:
      encoder         : Lavf55.22.100
      Stream #0:0: Audio: mp2, 16000 Hz, stereo, s16, 128 kb/s (default)
      Stream mapping:
      Stream #0:0 (flac) -> amerge:in0
      Stream #1:0 (flac) -> amerge:in1
      amerge -> Stream #0:0 (mp2)
      Press [q] to stop, [?] for help
      size=      65kB time=00:00:04.14 bitrate= 128.9kbits/s
  

• Joining h264 MP4 with ffmpeg Concat without re-encoding

  4 décembre 2013, par Lisa Jacobs

  I am trying to write a batch file to stitch 3 MP4 videos together without having to re-encode them, using a text file mylist.txt:

  file 'video1.mp4'
  file 'video2.mp4'
  file 'video3.mp4'
  

  I am stitching with: ffmpeg -f concat -i input.txt -c copy output.mp4 but for some reason the second video remains with a blackscreen and/or like if the stream was corrupted. It's like there was no keyframe at the beginning of video2.mp4 ? Video2.mp4 plays fine and does not seem to be corrupted.

• Get keyframes of video ffmpeg

  4 décembre 2013, par akash777.sharma

  I had a task of getting keyframes information of a video i.e. getting time duration of all keyframes(seeking video via rtmp url). To get information of all the frames of video use following command:

  ffprobe -show_frames testVideo.mp4 > data.txt
  

  The information I get from data.txt file :

  “keyframe=1” signifies that it tried to make keyframe
  “pict_type=I” signifies a keyframe or I-frame
  here I get exact time duration of keyframe.
  

  actual fps of video

  fps = coded_picture_number(last frame that contains coded_picture_number) / pkt_pts_time
  

  Above information worked well for most of the videos.But for some videos that were created by Red5 were showing abnormal results. List of urls I have searched
  http://sinclairmediatech.com/using-ffprobe-to-evaluate-keyframes/
  http://ffmpeg-users.933282.n4.nabble.com/How-can-I-find-the-keyframe-information-for-a-mp4-video-td4349687.html

  please help if I am wrong or need any other command. Thanks in advance.

• Conflicting types error using linphone ios sdk

  4 décembre 2013, par VinZ

  I downloaded the linphone sdk for iphone sourcecode and compiled it on my machine. The SDK build was successful after few fixes. But while building the app in Xcode, it is throwing the following error:

  Error 1:

  /linphone-iphone/submodules/linphone/mediastreamer2/src/utils/ffmpeg-priv.h:78:17: Conflicting types for 'avcodec_alloc_context3'
  

  Error 2:

  /linphone-iphone/submodules/linphone/mediastreamer2/src/utils/ffmpeg-priv.h:82:5: Conflicting types for 'avcodec_open2'
  

  It is coming from mediastreamer2/ffmpeg source code. Any help on how to fix this is highly appreciated.

• ffmpeg : using the returned data in php

  4 décembre 2013, par user1503606

  I have started using ffmpeg and I am very new to it, so please bear with me.

  I have installed ffmpeg on my server and it works great; I can run certain commands and get output data when logged in via ssh

  For example I can run

  ffmpeg -i Sleep\ Away.mp3 
  

  Which returns the following:

  ffmpeg version 0.8.5, Copyright (c) 2000-2011 the FFmpeg developers
    built on Aug 20 2012 09:28:43 with clang 3.1 (tags/Apple/clang-318.0.61)
    configuration: --enable-nonfree --enable-gpl --enable-version3 --enable-postproc --enable-swscale --enable-avfilter --enable-libmp3lame --enable-libvorbis --enable-libtheora --enable-libfaac --enable-libxvid --enable-libx264 --enable-libvpx --enable-hardcoded-tables --enable-shared --enable-pthreads --disable-indevs --cc=clang
    libavutil    51.  9. 1 / 51.  9. 1
    libavcodec   53.  7. 0 / 53.  7. 0
    libavformat  53.  4. 0 / 53.  4. 0
    libavdevice  53.  1. 1 / 53.  1. 1
    libavfilter   2. 23. 0 /  2. 23. 0
    libswscale    2.  0. 0 /  2.  0. 0
    libpostproc  51.  2. 0 / 51.  2. 0
  [mp3 @ 0x7f9694011a00] Header missing
      Last message repeated 13 times
  [mp3 @ 0x7f9694007c00] max_analyze_duration 5000000 reached at 5007020
  [mp3 @ 0x7f9694007c00] Estimating duration from bitrate, this may be inaccurate
  Input #0, mp3, from 'Sleep Away.mp3':
    Metadata:
      track           : 3
      album           : Bob Acri
      artist          : Bob Acri
      title           : Sleep Away
      genre           : Jazz
      album_artist    : Bob Acri
      composer        : Robert R. Acri
      date            : 2004
    Duration: 00:03:21.77, start: 0.000000, bitrate: 192 kb/s
      Stream #0.0: Audio: mp3, 44100 Hz, stereo, s16, 192 kb/s
  At least one output file must be specified
  

  The question I am asking is, how can I use the output data above? I am developiong a music website; say I want to loop through all the MP3 files and save the info about them into a database, so that the above would result in:

  Sleep Away.mp3    mp3    3:21    Jazz    2004     Bob Acri ...
  

  obviously in a table

  I have tried to use the php backtick operator with no success so far. I just thought I would put a question up here to get some advice from people that have done something similar.

  Thanks

  Update: I have tried the following

  <?php $output = `ffmpeg -i Sleep\ Away.mp3`; echo "
  $output
  "; ?>
  <?php $output = shell_exec('ffmpeg -i Sleep\ Away.mp3'); echo "
  $output
  "; ?>
  

  both don't appear to return anything.