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• Python librosa NoBackendError even though ffmpeg is installed

  11 avril 2020, par Slavko Kovačević

  I recently installed librosa (package I've been using for a while on different PC) on my new PC with Windows 10 running. After that I've downloaded latest static version of ffmpeg and copied it to C: and added it to the Path. Tested ffmpeg and it works like a charm ! For python I am using Anaconda environment and after starting Jupyter Notebook and running librosa.load(path, sr = None) I've got

  



   in <module>&#xA;----> 1 audio = librosa.load(pathToJson)&#xA;&#xA;~\anaconda3\envs\tf_gpu\lib\site-packages\librosa\core\audio.py in load(path, sr, mono, offset, duration, dtype, res_type)&#xA;    117 &#xA;    118     y = []&#xA;--> 119     with audioread.audio_open(os.path.realpath(path)) as input_file:&#xA;    120         sr_native = input_file.samplerate&#xA;    121         n_channels = input_file.channels&#xA;&#xA;~\anaconda3\envs\tf_gpu\lib\site-packages\audioread\__init__.py in audio_open(path, backends)&#xA;    114 &#xA;    115     # All backends failed!&#xA;--> 116     raise NoBackendError()&#xA;&#xA;NoBackendError:&#xA;</module>

  



  strange isn't it ? Then I went all over the internet, doing whatnot trying to fix it and then I've got an idea to run my line of code inside anaconda command interface and it WORKS ?? How is this possible ? It is the same environment.

  



  python
Python 3.7.7 (default, Mar 23 2020, 23:19:08) [MSC v.1916 64 bit (AMD64)] :: Anaconda, Inc. on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import librosa
>>> librosa.load('test.wav')
(array([-0.00027   , -0.00039953, -0.0003659 , ..., -0.16393574,
       -0.17814247,  0.        ], dtype=float32), 22050)


  



  I did a lot of testing and I really prefer my Jupyter so any help would be appreciated. I tried the following : I've added C:\ffmpeg\bin and C:\ffmpeg to my Path for both User and System Variables. After that I've made specific variables for ffmpeg and ffmpeg_bin for both User and System Variables. No luck. After that I've tried installing ffmpeg using conda, without success. The last thing I've tested is this :

  



  import audioread
audioread.ffdec.FFmpegAudioFile('test.wav')


  



  and that works. Thanks

  


• Why won't this encrypted HLS video play on iOS (but works on Windows Chrome via hls.js library) ?

  8 mai 2023, par Ryan

  I am trying to play an MP4 test video.

  


  My /home/vagrant/Code/example/public/hls_hls.keyInfo is :

  


  https://example.com/hls.key
/home/vagrant/Code/example/public/hls_hls.key
467216aae8a26fb699080812628031955e304a66e9e4480f9b70d31d8fe94e9a


  


  My /home/vagrant/Code/example/public/hls_hls.key was generated using PHP : hex2bin('467216aae8a26fb699080812628031955e304a66e9e4480f9b70d31d8fe94e9a')

  


  The ffmpeg command for encrypting the video as HLS playlist with "ts" files :

  


  '/usr/bin/ffmpeg' '-y' '-i' 'storage/app/sample_media2/2020-02-27/Sample_Videos_5.mp4' 
'-c:v' 'libx264' '-s:v' '1920x1080' '-crf' '20' '-sc_threshold' '0' '-g' '48' 
'-keyint_min' '48' '-hls_list_size' '0' 
'-hls_time' '10' '-hls_allow_cache' '0' '-b:v' '4889k' '-maxrate' '5866k' 
'-hls_segment_type' 'mpegts' '-hls_fmp4_init_filename' 'output_init.mp4' 
'-hls_segment_filename' 'storage/app/public/test/output_1080p_%04d.ts' 
'-hls_key_info_file' '/home/vagrant/Code/example/public/hls_hls.keyInfo' 
'-strict' '-2' '-threads' '12' 'storage/app/public/test/output_1080p.m3u8'


  


  Then, I know from https://caniuse.com/#search=hls that Windows Chrome won't be able to play the HLS video without a library, so I use https://github.com/video-dev/hls.js/, and Windows Chrome successfully plays the encrypted video !

  


  However, iOS Safari is unable to play it (with or without the hls.js library).

  


  On iOS Safari, when I try to play the video, I see just a quick glimpse (less than a second) where the screen shows 0:15, so it must be reading and decrypting enough to know the correct duration of the video.

  


  So, to debug, I log events :

  


  const nativeHlsEvents = ['play', 'playing', 'abort', 'error', 'canplaythrough', 'waiting', 'loadeddata', 'loadstart', 'progress', 'timeupdate', 'volumechange'];
$.each(nativeHlsEvents, function (i, eventType) {
    video.addEventListener(eventType, (event) => {//https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement
        console.log(eventType, event);
        if (eventType === 'error') {
            console.error(video.error);//https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement/error
        }
    });
});


  


  I see in the console log :

  


  loadstart, {"isTrusted":true}
progress, {"isTrusted":true}
play, {"isTrusted":true}
waiting, {"isTrusted":true}
error, {"isTrusted":true}
video.error, {}


  


  I don't know how to find more details about the error.

  


  Note that even though Windows Chrome successfully plays the video, it too shows warnings in the console log :

  


  {"type":"mediaError","details":"fragParsingError","fatal":false,"reason":"TS packet did not start with 0x47","frag":{"...
{"type":"mediaError","details":"fragParsingError","fatal":false,"reason":"no audio/video samples found","frag":{...


  


  Where is my problem ?

  


• Create animated gif from a set of png images

  12 avril 2020, par Zizi96

  I'm trying to use ffpmeg to convert a list of png to a gif.

  



  Running C:\Users\Me\Art\Animations\wubz\output> dir shows my files :

  



  12/04/2020  16:48    <dir>          ..&#xA;12/04/2020  16:45           136,706 wubz_0001.png&#xA;12/04/2020  16:45           136,180 wubz_0002.png&#xA;12/04/2020  16:45           136,413 wubz_0003.png&#xA;12/04/2020  16:45           136,099 wubz_0004.png&#xA;12/04/2020  16:45           136,309 wubz_0005.png&#xA;12/04/2020  16:45           137,172 wubz_0006.png&#xA;</dir>

  



  The code I'm running in command prompt from C:\Users\Me\Art\Animations\wubz\output> :

  



  ffmpeg-f image2 -framerate 30 -i wubz_%d.png video.flv


  



  gives the error message :
[image2 @ 000001efd6c4bac0] Could find no file with path 'wubz_%d.png' and index in the range 0-4
wubz_%d.png: No such file or directory

  



  Can someone explain what I'm doing wrong, I don't get why ffmpeg isn't seeing the png files in the output directory.