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• 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.

• Improve ffmpeg x11grab screen capture performance

  10 janvier 2020, par Toby Eggitt

  I have been doing screen-only (no sound) capture using ffmpeg with libx264 for the encoding quite successfully on an old machine built around a Core2 Quad Q6600 processor. I now need to include audio in this, but the fans on this ancient machine are too loud. So, I found a fanless motherboard (https://www.asrock.com/mb/Intel/J5005-ITX/index.asp) that has an Intel Pentium Silver J5005 processor and decided to use this instead. The CPU’s benchmarks put it in a similar bracket to the Q6600, and the general performance seems to be significantly better, presumably at least in part because it’s now using DDR4 memory that’s faster access.

  However, the machine fails horribly at the screen capture. It’s missing frames all over the place ; I actually end up with video that’s missing almost half the frames, and plays back at about double speed. Also, any audio is just messed up so badly I can hardly think how to describe it, best I can come up with is that I get perhaps a quarter second of sound then a few seconds pause (the video meanwhile is actually still playing back, albeit with no sense of time).

  Some things occur to me that might be the cause, or cure, of my troubles, some of which I might be able to fix, others not so much. What other things should I try ? (I’d prefer to avoid simply throwing money at the issue with random ideas that are baseless !)

  1) perhaps the CPU lacks some "extensions" to the instruction set (I recall years ago some CPUs gaining MMX extensions") so that the CPU is fast at mundane computing but sucks at video encoding.

  2) perhaps the fact that the old machine had a dedicated graphics card, while this new one is sharing main memory with the graphics system means that reading the screen pixels is much slower.

  3) perhaps the fact that this new machine has a single DDR4 memory stick in it means that I’m forcing all the memory reads and writes for the computations through the same memory as is holding the screen, and that’s too much (implying that adding an additional memory stick might jus possibly help ?)

  4) perhaps there’s some bios setting that would allow more efficient sharing of video memory ?

  5) my favorite, perhaps there’s a better compression library that I could use to get decent quality screen capture with much less CPU usage.

  I should also note that I have tried this with -threads 0, and the CPU usage hovers between 100% and 200% ; around 100% when the screen is static, and rising as I move windows around and otherwise create more output.

  6) the motherboard claims to have some kind of hardware video encoder built into it. I haven’t paid this any attention to this point, as I assumed it was for the purpose of taking HDMI input and encoding it, but maybe there’s a way to use this, if so, what libraries might I need to get ffmpeg to do this.

  Edits :

  • This is an off the shelf ffmpeg. I’m certainly willing to try building it myself if I have some idea what I should do different.
  • The motherboard claims to have hardware encoders, but I’m struggling to find out what they are (seems like it’s an Intel chip called "UHD Graphics 605" but nothing I can find suggests ffmpeg can work with that)

  • command line right now has been (without audio) :

    ffmpeg  -video_size 1280x720   -f x11grab  -i ${DISPLAY}+100,100  -vcodec libx264  -f alsa -i pulse -acodec ac3 -threads 0  ./video$(date +%F-%H-%M-%S).mp4

  Log from a short recording session is :

  ffmpeg version 3.4.6-0ubuntu0.18.04.1 Copyright (c) 2000-2019 the FFmpeg developers
  
    built with gcc 7 (Ubuntu 7.3.0-16ubuntu3)
  
    configuration: --prefix=/usr --extra-version=0ubuntu0.18.04.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  
    libavutil      55. 78.100 / 55. 78.100
  
    libavcodec     57.107.100 / 57.107.100
  
    libavformat    57. 83.100 / 57. 83.100
  
    libavdevice    57. 10.100 / 57. 10.100
  
    libavfilter     6.107.100 /  6.107.100
  
    libavresample   3.  7.  0 /  3.  7.  0
  
    libswscale      4.  8.100 /  4.  8.100
  
    libswresample   2.  9.100 /  2.  9.100
  
    libpostproc    54.  7.100 / 54.  7.100
  
  [x11grab @ 0x561a723e5ac0] Stream #0: not enough frames to estimate rate; consider increasing probesize
  
  Input #0, x11grab, from ':0+100,100':
  
    Duration: N/A, start: 1578693116.465807, bitrate: N/A
  
      Stream #0:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 1280x720, 29.97 fps, 1000k tbr, 1000k tbn, 1000k tbc
  
  Unknown decoder 'libx264'
  
  simon@studio:~$ ffmpeg  -video_size 1280x720   -f x11grab  -i ${DISPLAY}+100,100  -vcodec libx264 -threads 0  ./video$(date +%F-%H-%M-%S).mp4
  
  ffmpeg version 3.4.6-0ubuntu0.18.04.1 Copyright (c) 2000-2019 the FFmpeg developers
  
    built with gcc 7 (Ubuntu 7.3.0-16ubuntu3)
  
    configuration: --prefix=/usr --extra-version=0ubuntu0.18.04.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  
    libavutil      55. 78.100 / 55. 78.100
  
    libavcodec     57.107.100 / 57.107.100
  
    libavformat    57. 83.100 / 57. 83.100
  
    libavdevice    57. 10.100 / 57. 10.100
  
    libavfilter     6.107.100 /  6.107.100
  
    libavresample   3.  7.  0 /  3.  7.  0
  
    libswscale      4.  8.100 /  4.  8.100
  
    libswresample   2.  9.100 /  2.  9.100
  
    libpostproc    54.  7.100 / 54.  7.100
  
  [x11grab @ 0x558225bc29a0] Stream #0: not enough frames to estimate rate; consider increasing probesize
  
  Input #0, x11grab, from ':0+100,100':
  
    Duration: N/A, start: 1578693132.513351, bitrate: N/A
  
      Stream #0:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 1280x720, 29.97 fps, 1000k tbr, 1000k tbn, 1000k tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
  
  Press [q] to stop, [?] for help
  
  [libx264 @ 0x558225bcd360] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2
  
  [libx264 @ 0x558225bcd360] profile High 4:4:4 Predictive, level 3.1, 4:4:4 8-bit
  
  [libx264 @ 0x558225bcd360] 264 - core 152 r2854 e9a5903 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x1:0x111 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=4 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
  
  Output #0, mp4, to './video2020-01-10-14-52-12.mp4':
  
    Metadata:
  
      encoder         : Lavf57.83.100
  
      Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv444p, 1280x720, q=-1--1, 29.97 fps, 30k tbn, 29.97 tbc
  
      Metadata:
  
        encoder         : Lavc57.107.100 libx264
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
  
  Past duration 0.806847 too large     256kB time=00:00:00.43 bitrate=4835.3kbits/s dup=16 drop=0 speed=0.207x    
  
  frame=  371 fps= 29 q=-1.0 Lsize=     639kB time=00:00:12.27 bitrate= 426.6kbits/s dup=16 drop=14 speed=0.971x    
  
  video:634kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.813096%
  
  [libx264 @ 0x558225bcd360] frame I:2     Avg QP:18.16  size:221502
  
  [libx264 @ 0x558225bcd360] frame P:93    Avg QP:14.97  size:  2007
  
  [libx264 @ 0x558225bcd360] frame B:276   Avg QP:20.13  size:    69
  
  [libx264 @ 0x558225bcd360] consecutive B-frames:  0.8%  0.0%  0.0% 99.2%
  
  [libx264 @ 0x558225bcd360] mb I  I16..4: 44.6%  0.0% 55.4%
  
  [libx264 @ 0x558225bcd360] mb P  I16..4:  0.2%  0.0%  0.3%  P16..4:  0.7%  0.1%  0.1%  0.0%  0.0%    skip:98.5%
  
  [libx264 @ 0x558225bcd360] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  1.0%  0.0%  0.0%  direct: 0.0%  skip:99.0%  L0:50.9% L1:49.0% BI: 0.1%
  
  [libx264 @ 0x558225bcd360] coded y,u,v intra: 41.3% 37.5% 37.4% inter: 0.1% 0.0% 0.0%
  
  [libx264 @ 0x558225bcd360] i16 v,h,dc,p: 58% 41%  1%  0%
  
  [libx264 @ 0x558225bcd360] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 33% 30% 14%  2%  4%  4%  5%  3%  5%
  
  [libx264 @ 0x558225bcd360] Weighted P-Frames: Y:0.0% UV:0.0%
  
  [libx264 @ 0x558225bcd360] ref P L0: 59.2%  8.8% 25.5%  6.5%
  
  [libx264 @ 0x558225bcd360] ref B L0: 59.4% 39.0%  1.6%
  
  [libx264 @ 0x558225bcd360] ref B L1: 96.5%  3.5%
  
  [libx264 @ 0x558225bcd360] kb/s:419.29
  
  Exiting normally, received signal 2.