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• avformat/internal : Move ff_read_line_to_bprint_overwrite to avio_internal.h

  23 juillet 2021, par Andreas Rheinhardt

  avformat/internal : Move ff_read_line_to_bprint_overwrite to avio_internal.h
  It only uses an AVIOContext and an AVBPrint.
  When doing so, it turned out that several non-users of
  
  ff_read_line_to_bprint_overwrite() and ff_bprint_to_codecpar_extradata()
  
  relied on libavformat/internal.h to include bprint.h or avstring.h
  
  for them. In order to avoid a repeat of this and in order to reduce
  
  unnecessary dependencies, a forward declaration of struct AVBPrint is
  
  used instead of including bprint.h.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavdevice/v4l2.c
  • [DH] libavformat/aadec.c
  • [DH] libavformat/argo_asf.c
  • [DH] libavformat/argo_cvg.c
  • [DH] libavformat/au.c
  • [DH] libavformat/avio_internal.h
  • [DH] libavformat/concatdec.c
  • [DH] libavformat/dashdec.c
  • [DH] libavformat/dashenc.c
  • [DH] libavformat/flacenc.c
  • [DH] libavformat/framecrcenc.c
  • [DH] libavformat/hlsenc.c
  • [DH] libavformat/internal.h
  • [DH] libavformat/librist.c
  • [DH] libavformat/mxfdec.c
  • [DH] libavformat/ttmlenc.c
  • [DH] libavformat/utils.c

• How to use ffmpeg in flask server to convert between audio formats without writing files to disk ?

  14 avril 2020, par Athwulf

  I have successfully managed to use ffmpeg in python to convert the format of some audio files like this :

  



  command = "ffmpeg -i audio.wav -vn -acodec pcm_s16le output.wav"
subprocess.call(command, shell=True)


  



  However I want to do this in memory and avoid saving the input and output files to disk.

  



  I have found the follwing code to do such a thing (Passing python’s file like object to ffmpeg via subprocess) :

  



  command = ['ffmpeg', '-y', '-i', '-', '-f', 'wav', '-']
process = subprocess.Popen(command, stdin=subprocess.PIPE)
wav, errordata = process.communicate(file)


  



  But I am struggeling to use this in my context.

  



  I am receiving the file on a server as part of a multipart/form-data request.

  



  @server.route("/api/getText", methods=["POST"])
def api():
    if "multipart/form-data" not in request.content_type:
        return Response("invalid content type: {}".format(request.content_type))
    # check file format
    file = request.files['file']
    if file:
        print('**found file', file.filename)


  



  Now I have the file as a FileStorage Object (https://tedboy.github.io/flask/generated/generated/werkzeug.FileStorage.html). This object has a stream, which can be accessed by using the read method. So I thought I might be able to use this as input for ffmpeg like so :

  



  f = file.read()
command = ['ffmpeg', '-y', '-i', '-', '-f', 'wav', '-']
process = subprocess.Popen(command, stdin=subprocess.PIPE)
wav, errordata = process.communicate(f)


  



  However this yields the the following error :

  



  AssertionError: Given audio file must be a filename string or a file-like object


  



  I have also tried another approach which I found online, using io.BytesIO, to which I can't find the source anymore :

  



  memfile = io.BytesIO()  # create file-object
memfile.write(file.read())  # write in file-object
memfile.seek(0)  # move to beginning so it will read from beginning


  



  And then trying this again :

  



  command = ['ffmpeg', '-y', '-i', '-', '-f', 'wav', '-']
process = subprocess.Popen(command, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
wav, errordata = process.communicate(memfile)


  



  This gets me the following error :

  



  TypeError: a bytes-like object is required, not '_io.BytesIO'


  



  Does anyone have an idea of how to do this ?

  



  Update

  



  The first error message is actually not a error message thrown by ffmpeg. As v25 pointed out correctly in his answer the first approach also returns a bytes object and is also a valid solution.

  



  The error message got thrown by a library (speech_recognition) when trying to work with the modified file. In the unlikely case of someone coming across the same problem here the solution :

  



  The bytes objected returned by ffmpeg (variable wav) has to be turned into a file-like object as the error message implies. This can easily be done like this :

  



  memfileOutput = io.BytesIO(wav)

  


• Video encoder & segmenter for HLS VoD poor quality

  10 juillet 2017, par Murilo

  I am trying to encode and segment video for HLS on demand(VoD).
  I am using the following code for such :

  ffmpeg -i 20170706_174314.mp4 -c 24 \
  
          -vcodec libx264 -acodec aac -ac 1 -strict -2 -b:v 128k \
  
          -profile:v baseline -maxrate 400k -bufsize 1835k \
  
          -hls_time 10 -hls_playlist_type vod -vsync 1 \
  
          video_chunks/index1.m3u8 \
  
          -c 24 -vcodec libx264 -acodec aac -ac 1 -strict -2 -b:v 128k \
  
          -profile:v baseline -maxrate 700k -bufsize 1835k \
  
          -hls_time 10 -hls_playlist_type vod -vsync 1 \
  
          video_chunks/index2.m3u8

  I tried this other code also just for segmenting but had the same exactly problem :

  ffmpeg -i 20170706_174314.mp4 \
  
  -c:a libmp3lame -ar 48000 -ab 64k  -c:v libx264 -b:v 128k -flags \ 
  
  -global_header -map 0 -f segment \
  
  -segment_list video_chunks/test.m3u8 -segment_time 10 -segment_format mpegts \
  
  video_chunks/segment_%05d.ts

  Later on I create another playlist with bandwidth separators to call on the two other playlists generated with the code above.

  This code was working great on some videos but yesterday I recorded a video with my Samsung J7 Prime phone to test since the videos will be generated by phone and this video was poorly encoded. The quality sucks and some parts of the video turned Black&White.

  Another thing I noticed on this video is that the following message kept appearing in loop until the end of the encoding&segmenting process.

  Past duration X too large

  Where X is a decimal really close to

  0.675316

  The link to the video is below :

  Dropbox Link

  My FFmpeg version :

  ffmpeg --version
  
  ffmpeg version N-86482-gbc40674 Copyright (c) 2000-2017 the FFmpeg developers
  
    built with gcc 7.1.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
  
    libavutil      55. 66.100 / 55. 66.100
  
    libavcodec     57. 99.100 / 57. 99.100
  
    libavformat    57. 73.100 / 57. 73.100
  
    libavdevice    57.  7.100 / 57.  7.100
  
    libavfilter     6. 92.100 /  6. 92.100
  
    libswscale      4.  7.101 /  4.  7.101
  
    libswresample   2.  8.100 /  2.  8.100
  
    libpostproc    54.  6.100 / 54.  6.100

  SO : Windows 10

  EDIT1 : Link to the output
  If you see the output it might be worth saying I am also seeing the message

  VBV underflow(Frame X, -Y bits)