Recherche avancée

Sur d’autres sites (11779)

• ffmpeg produced .wav reads only zeros with scipy.io.wavfile

  8 janvier 2015, par question_mark

  Hi everyone and thanks for reading.

  I wanted to do some analysis on a song using Python’s scipy.io.wavfile. Since I only have the song as .mp3 I converted the file to .wav using ffmpeg the following way :

  ffmpeg -i test.mp3 test.wav

  The .wav file plays perfectly well with vlc player, but wavfile shows only zeroes when reading it :

  from scipy.io import wavfile as wf
  
  
  
  data = wf.read("test.wav")
  
  C:\Program Files\Anaconda\lib\site-packages\scipy\io\wavfile.py:42: WavFileWarning: Unknown wave file format
  
    warnings.warn("Unknown wave file format", WavFileWarning)
  
  
  
  data
  
  (44100, array([[0, 0],
  
          [0, 0],
  
          [0, 0],
  
          ..., 
  
          [0, 0],
  
          [0, 0],
  
          [0, 0]], dtype=int16))

  I tried getting the data with Python’s built-in wave module before to the same effect (only zeros).
  I am using the 64bit version of ffmpeg (ffmpeg-20140218-git-61d5970-win64-static).

  Any help is appreciated :-)

  Edit : Included .wav header and tried forcing ffmpeg output format

  I guess the header information of the .wav file is included here :

  ffmpeg -i .\test.wav
  
  Guessed Channel Layout for  Input Stream #0.0 : stereo
  
  Input #0, wav, from '.\test.wav':
  
    Metadata:
  
      artist          : Joe Cocker
  
      copyright       : (C) 1987 Capitol Records, Inc.
  
      date            : 1987
  
      genre           : Pop
  
      title           : Unchain My Heart
  
      album           : Unchain My Heart
  
      track           : 1/10
  
      encoder         : Lavf55.33.100
  
    Duration: 00:05:04.33, bitrate: 1411 kb/s
  
    Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, s16, 1411 kb/s

  If I try to specify the ffmpeg output format explicitly for the .mp3 conversion :

  ffmpeg -i .\test.mp3 -f s16le -ar 44100 -ac 2 test.wav
  
  Input #0, mp3, from '.\test.mp3':
  
    Metadata:
  
      title           : Unchain My Heart
  
      artist          : Joe Cocker
  
      album           : Unchain My Heart
  
      genre           : Pop
  
      composer        : Bobby Sharp
  
      track           : 1/10
  
      disc            : 1/1
  
      album_artist    : Joe Cocker
  
      copyright       : (C) 1987 Capitol Records, Inc.
  
      date            : 1987
  
    Duration: 00:05:04.35, start: 0.025056, bitrate: 240 kb/s
  
      Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 235 kb/s
  
      Stream #0:1: Video: mjpeg, yuvj420p(pc), 600x600 [SAR 1:1 DAR 1:1], 90k tbr, 90k tbn, 90k tbc
  
      Metadata:
  
        title           :
  
        comment         : Cover (front)
  
  Output #0, s16le, to 'test.wav':
  
    Metadata:
  
      title           : Unchain My Heart
  
      artist          : Joe Cocker
  
      album           : Unchain My Heart
  
      genre           : Pop
  
      composer        : Bobby Sharp
  
      track           : 1/10
  
      disc            : 1/1
  
      album_artist    : Joe Cocker
  
      copyright       : (C) 1987 Capitol Records, Inc.
  
      date            : 1987
  
      encoder         : Lavf55.33.100
  
      Stream #0:0: Audio: pcm_s16le, 44100 Hz, stereo, s16, 1411 kb/s
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (mp3 -> pcm_s16le)
  
  Press [q] to stop, [?] for help
  
  video:0kB audio:52425kB subtitle:0 data:0 global headers:0kB muxing overhead 0.000000%
  
  size=   52425kB time=00:05:04.32 bitrate=1411.2kbits/s

  But in this case (forced format), both ffmpeg and wavfile are not able to read the file :

  ffmpeg -i .\test.wav
  
  .\test.wav: Invalid data found when processing input

  and

  data = wf.read("test2.wav")
  
  ---------------------------------------------------------------------------
  
  ValueError                                Traceback (most recent call last)
  
   in <module>()
  
  ----> 1 data = wf.read("test2.wav")
  
  
  
  C:\Program Files\Anaconda\lib\site-packages\scipy\io\wavfile.pyc in read(filename, mmap)
  
      152 
  
      153     try:
  
  --> 154         fsize = _read_riff_chunk(fid)
  
      155         noc = 1
  
      156         bits = 8
  
  
  
  C:\Program Files\Anaconda\lib\site-packages\scipy\io\wavfile.pyc in _read_riff_chunk(fid)
  
       98         _big_endian = True
  
       99     elif str1 != b'RIFF':
  
  --> 100         raise ValueError("Not a WAV file.")
  
      101     if _big_endian:
  
      102         fmt = '>I'
  
  
  
  ValueError: Not a WAV file.
  
  </module>

• Is it possible to stream MJPEG content over MPEG-DASH ?

  26 juillet 2021, par Eloy Schultz

  I am trying to re-stream an MJPEG stream over dash using ffmpeg.

  


  I have an ESP32 camera module that outputs an MJPEG livestream at 192.168.2.128:81/stream (Arduino code here).
I can open this stream directly in the browser and see the video in realtime, but the camera will only allow for a single client at a time while I am in need of a multi client solution.

  


  What doesn't work

  
A solution I am currently trying to implement is to use a seperate server (Raspberry Pi) running apache and ffmpeg to re-stream the MJPEG content using DASH :


  ffmpeg -re -i http://192.168.2.128:81/stream -strict -2 -an -c:v copy -b:v 2000k -f dash -window_size 4 -extra_window_size 0 -min_seg_duration 2000000 -remove_at_exit 1 /var/www/html/out.mpd


  


  I get no errors when executing this command on the server.
I then use this ffmpeg-dash.html to display the video in the browser.
This code unfortunately fails, in Firefox the console reports the error :

  


  [72][Stream] No streams to play.


  


  followed by :

  


  Cannot play media. No decoders for requested formats: video/mp4;codecs="mp4v.6c";width="640";height="480"


  


  What does work

  
What is puzzling me is that the above code works fine if I replace the MJPEG livestream url with a sample .mkv file, so if I use


  ffmpeg -re -i /var/www/html/video.mkv -strict -2 -an -c:v copy -b:v 2000k -f dash -window_size 4 -extra_window_size 0 -min_seg_duration 2000000 -remove_at_exit 1 /var/www/html/out.mpd


  


  I can view the livestreamed sample video (video.mkv) without problems using the previously mentioned ffmpeg-dash.html file.
Furthermore, it seems that ffmpeg can read the MJPEG livestream without problems, since

  


  ffmpeg -t 10 -i http://192.168.2.128:81/stream -filter:v fps=15 -c:v flv test.flv


  


  returns a 10 second clip of the livestream succesfully.

  


  So to me it seems that the problem lies in how I combine the two. What am I missing ? Is it even possible to stream MJPEG content over MPEG-DASH ?
(I am new to this, sorry in advance for my ignorance)

  


• A/V out of sync when using ffmpeg from mpeg-ts to dash

  17 mai 2018, par user3540646

  I’m using ffmpeg in order to convert MPEG-TS stream to MPEG-DASH.
  The mpeg-ts is h264 and aac_latm.
  Therefore I don’t need to reencode the video.
  The command I use :

  ffmpeg -i http://10.0.0.211:55555/Ch%2011%20Kan -strict -2 -c:v copy -window_size 10 -extra_window_size 10 -use_template 1 -use_timeline 1 -f dash kan.mpd

  I’m copying the video codec by using -c:v copy and the audio codec is default to aac.

  That way I get DASH stream BUT the audio/video is out of sync !

  How can I fix it ?

  Notes :

  1. If I reencode both audio and video like :

     ffmpeg -i http://10.0.0.211:55555/Ch%2011%20Kan -strict -2 -window_size 10 -extra_window_size 10 -use_template 1 -use_timeline 1 -f dash kan.mpd

  Then the audio/video is synced perfectly.
  But I do not want to reencode the video for nothing as I mentioned the video is already h264. (directly impact to performance)

  2. If I convert the MPEG-TS stream to mp4 file like :

     ffmpeg -i http://10.0.0.211:55555/Ch%2011%20Kan -strict -2 -c:v copy kan.mp4

  Then the audio/video is synced perfectly.