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• Evolution #2100 : Nom de répertoire de lib externe

  30 mai 2011, par cedric -

  Il faudrait améliorer cela, en effet. Mais le stockage en base me parait peut possible. Il faut éviter que le dezippage de deux archives differentes ne tombe dans le même dossier. A ce titre le md5 devrait porter sur toute l’url du zip plutot que sur le basename, et on pourrait fournir une (...)

• VLC libx264 streaming muxed as FLV

  24 mars 2012, par Jan Novák

  I have a question on streaming output of libx264. My scenario is that Iam capturing video from webcam, encoding with x264 and then streaming data to flash, muxed as FLV. For muxing, Im using output/flv_bitstream.h, included in libx264 budle. The only modification of muxer, that I made, is that instead of fwrite() im usig send() to transfer data via socket... Encoding library is working fine. If I save output (even muxed), vlc player is able to play it. But, when it goes to data transfer via socket, vlc and flash are not cooperating. The weird thig is, that if Im sending data to vlc player thru socket, it waits till transmission end and then plays video from buffer. But what I need is to play live stream.

  I also tryed to read flv file and send it to vlc of flash tag by tag and it is working fine.

  Any suggestions ?

• Big difference in wav file created from mp3 using ffmpeg versus Audacity

  16 octobre 2020, par MJLerxst

  I need to convert mp3 to wav files that will then be used by Python script. (The script analyzes the wav file data in the form of numpy arrays for each channel.) That all works fine. To get the wav, I first used Audacity "by hand" and opened the mp3, then used "Export as WAV". All good, but, I now need to automate this and avoid using Audacity. So I modified my Python script to first run ffmpeg to do the conversion, using :

  


  subprocess.call(["ffmpeg -i", mp3filename, wavfilename])


  


  Looking at the resulting wavfilename.wav data, I find it is totally different from what is in the Audacity-produced file. I verified that both approaches are using PCM 16-bit unsigned little endian, same sample rate, etc.

  


  Now, if I take that ffmpeg-produced wav file, open it with Audacity, and then "export as WAV", it will produce a 3rd wav that works just fine, and looks identical to the one that I created with Audacity in the first place - and when I say identical, I mean that I compare the numpy arrays element by element, and they line right up, whereas the ffmpeg data does not correlate to the Audacity data at all.

  


  I am using the very latest ffmpeg, ffmpeg version N-99557-g6bdfea8d4b with Lavf58.62.100. Audacity is 2.3.2. I have tried using pydub also but that gives the same results as ffmpeg.

  


  Clearly, Audacity is doing something differently when it exports the wav, and even though the ffmpeg data looks very different in Python, Audacity plays it just fine - so it is also able to correctly account for whatever it is that ffmpeg did when it made the wav file. I would simply like to get ffmpeg to emulate what Audacity does. Any advice or insight is greatly appreciated.