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• ffmpeg encoded mp4 won't play in safari, works in chrome & ff

  16 avril 2017, par Mark Kahn

  like the title says, I’m encoding a video from ffmpeg and it plays fine in chrome & ff but not safari. Anyone know why, what to try, etc ?

  I followed the advice in this thread to no avail.

  ffmpeg command :

  ffmpeg -f lavfi -i color=$1 -i $2 -vcodec libx264 -pix_fmt yuv420p -filter_complex "[0:v][1:v]scale2ref[c][v];[c][v]overlay=shortest=1[j];[j]scale=134:80" $3_120-3x.mp4

  Most of that is just adding a background color to a video that has alpha transparency. The -vcodec libx264 -pix_fmt yuv420p piece seems to be what’s important (btw without that it doesn’t play in FF either).

  result of ffprobe :

  ffprobe version 3.2.4 Copyright (c) 2007-2017 the FFmpeg developers
  
    built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/3.2.4 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --disable-lzma --enable-vda
  
    libavutil      55. 34.101 / 55. 34.101
  
    libavcodec     57. 64.101 / 57. 64.101
  
    libavformat    57. 56.101 / 57. 56.101
  
    libavdevice    57.  1.100 / 57.  1.100
  
    libavfilter     6. 65.100 /  6. 65.100
  
    libavresample   3.  1.  0 /  3.  1.  0
  
    libswscale      4.  2.100 /  4.  2.100
  
    libswresample   2.  3.100 /  2.  3.100
  
    libpostproc    54.  1.100 / 54.  1.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'alarm_clock_120-3x.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.56.101
  
    Duration: 00:00:05.96, start: 0.000000, bitrate: 144 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 600x360 [SAR 1:1 DAR 5:3], 140 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler

  Also won’t play in mobile chrome/safari

• How do I configure ffmpeg & openh264 so that the video file can be opened in Windows Media Player 12

  10 mars 2017, par Sacha Guyer

  I have successfully created h264/mp4 movie files with ffmpeg and the x264 library.

  Now I would like to change the h264 library from x264 to openH264. I could replace the x264 library with openH264, recompile ffmpeg and produce movie files, without changing my sources that produce the movie. The resulting movie opens fine in Quicktime on Mac, but on Windows, Windows Media Player 12 cannot play it.

  The documentation about Windows Media Player support for h264 is unclear. File types supported by Windows Media Player states in the table that Windows Media Player 12 supports mp4, but the text below says :

  Windows Media Player does not support the playback of the .mp4 file format.

  From what I have observed, Windows Media Player 12 IS capable of playing h264/mp4 files, but only when created with x264.

  Does anyone know how I need to adjust the configuration of the codec/context so that the movie plays in Windows Media Player ? Does Windows Media Player only support certain h264 profiles ?

  I noticed the warning :

  [libopenh264 @ 0x...] [OpenH264] this = 0x..., Warning:bEnableFrameSkip = 0,bitrate can’t be controlled for RC_QUALITY_MODE,RC_BITRATE_MODE and RC_TIMESTAMP_MODE without enabling skip frame

  With the configuration :

  av_dict_set(&options, "allow_skip_frames", "1", 0);

  I could get rid of this warning, but the movie still does not play. Are there other options that need to be set so that the movie plays in Windows Media Player ?

  Thank you for your help

  ffprobe output of the file that does play fine in Windows Media Player :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test_x264.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      title           : retina
  
      encoder         : Lavf57.56.100
  
      comment         : Creation Date: 2017-03-10 07:47:39.601
  
    Duration: 00:00:04.17, start: 0.000000, bitrate: 17497 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661),
  
        yuv420p, 852x754, 17495 kb/s, 24 fps, 24 tbr, 24k tbn, 48 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler

  ffprobe output of the file that does not play in Windows Media Player :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test_openh264.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      title           : retina
  
      encoder         : Lavf57.56.100
  
      comment         : Creation Date: 2017-03-10 07:49:27.024
  
    Duration: 00:00:04.17, start: 0.000000, bitrate: 17781 kb/s
  
      Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661),
  
        yuv420p, 852x754, 17779 kb/s, 24 fps, 24 tbr, 24k tbn, 48k tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler

• Android : Recording audio in Android and then reading audio into python

  4 février 2017, par Hephaestus

  I need to record audio in an Android application that needs to be imported into Python (ndarray) for plotting and signal processing. It seemed like such a simple idea.
  I started with a simple bit of code for AAC/MPEG4 recording. Recording worked great. I can play it on the Android phone (Nexus 5X) and on a Mac (Quicktime). No problem ! Right ?!? But finding codec/formats that match between Android and Python seems to not be trivial. I’m wondering if the file/codec format written by Android is non-standard and FFMPEG can’t read it.
  If so, what is good audio format/codec that can be written simply in Android and read into an array in Python (2.7.x). Thanks.

  Details :
  Here is an abbreviated form of the android code :

  private final int AUDIO_SAMPLE_RATE = 16000;   
  
  private final String FILE_EXTENSION = "m4a";  // Audio file extension
  
  mAbsolutePathFile = workingDir + "/" + mFilename + FILE_EXTENSION;
  
  mMediaRecording = new MediaRecorder();
  
  mMediaRecording.setAudioSource (MediaRecorder.AudioSource.MIC);
  
  mMediaRecording.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
  
  mMediaRecording.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
  
  mMediaRecording.setAudioSamplingRate(AUDIO_SAMPLE_RATE);
  
  mMediaRecording.setOutputFile(mAbsolutePathFile);
  
  mMediaRecording.prepare();
  
  mMediaRecording.start();

  As I mentioned, the result audio plays nicely in both Android and MacOS, so all seemed well. I did a bit of searching to find a python package for AAC audio and pydub looked like the simplest (I tried audiotools, but couldn’t find sample code). To install pydub, I followed the instructions :

  pip install pydub

  and

  brew install libav --with-libvorbis --with-sdl --with-theora

  and

  brew install ffmpeg --with-libvorbis --with-ffplay --with-theora

  Following the discussions (here), i tested ffmpeg and it does execute from the command line :

    $ffmpeg
  
    ffmpeg version 3.2.2 Copyright (c) 2000-2016 the FFmpeg developers
  
    built with Apple LLVM version 8.0.0 (clang-800.0.42.1)

  But when I try to read the file using Python :

  import pydub
  
  pydub.AudioSegment.from_file("sensorlog_2017-02-03_12-50-25-345_Dev26c5_Loc27_TypeAUDIO.m4a", "aac")

  I get :

  Traceback (most recent call last):
  
    File "...anaconda2/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 2881, in run_code
  
      exec(code_obj, self.user_global_ns, self.user_ns)
  
    File "", line 1, in <module>
  
  pydub.AudioSegment.from_file("sensorlog_2017-02-03_12-50-25-345_Dev26c5_Loc27_TypeAUDIO.m4a", "aac")
  
  File ".../anaconda2/lib/python2.7/site-packages/pydub/audio_segment.py", line 472, in from_file
  
      raise CouldntDecodeError("Decoding failed. ffmpeg returned error code: {0}\n\nOutput from ffmpeg/avlib:\n\n{1}".format(p.returncode, p_err))
  
  CouldntDecodeError: Decoding failed. ffmpeg returned error code: 1
  
  Output from ffmpeg/avlib:
  
  avconv version 11.4, Copyright (c) 2000-2014 the Libav developers
  
    built on Feb  3 2017 12:09:15 with Apple LLVM version 8.0.0 (clang-800.0.42.1)
  
  [aac @ 0x7ff30001cc00] get_buffer() failed
  
  [aac @ 0x7ff30001cc00] channel element 3.14 is not allocated
  
  [aac @ 0x7ff30001cc00] Sample rate index in program config element does not match the sample rate index configured by the container.
  
  [aac @ 0x7ff30001cc00] Input buffer exhausted before END element found
  
  [aac @ 0x7ff30001cc00] More than one AAC RDB per ADTS frame is not implemented. Update your Libav version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
  
  [aac @ 0x7ff30001cc00] Error decoding AAC frame header.
  
  [aac @ 0x7ff300001000] Could not find codec parameters (Audio: aac, 4.0, fltp, 213 kb/s)
  
  [aac @ 0x7ff300001000] Estimating duration from bitrate, this may be inaccurate
  
  /var/folders/cm/1r6x6rbj7hn_51qvfjzj7nx80000gn/T/tmps7b8Gf: could not find codec parameters
  
  </module>

  In summary, is this a conflict between Android and FFMPEG ? Should I use a different codec/format ? Should I use a different Python Audio library ?
  Thanks.