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• Can I make calls to APIs such as youtube-dl and ffmpeg from a chrome-app ?

  8 janvier 2015, par ErickR

  First of all, I haven’t started the implementation of the system I’m about to describe, as I didn’t want to commit on implementing something I did not know if was possible.

  So, what I’m trying to achieve is to build a chrome-app to download the audio from certain websites (e.g. youtube and soundcloud) using youtube-dl, post process it using ffmpeg and then upload it to a cloud service via some api. The reason I want to do it via a chrome-app is because I could do all the work on the client side (no need for servers) and I’d have the ability to insert javascript into the pages using content scripts, which would make the app pretty simple to use (I could create buttons such as ’download song’ and stuff like that).

  Although I have already read the documentation explaining the NaCl Technical Overview and some of the Application Structure, I still am not sure as to whether I would be able to make these calls via some C/C++ module or if I would get denied due to security reasons.

  To summarize : considering that the user has the needed dependencies in his system (youtube-dl, python, ffmpeg and etc.), is it possible to make calls to third party APIs such as the ones described before via a chrome-app using NaCl ?

  Thank you all in advance,

• How to read short (16bits) integers from an unsigned char (8bits) buffer

  28 août 2013, par Alba Malaga

  As in the title I need to read short integers from a char buffer

  The buffer

  uint8_t *data[AV_NUM_DATA_POINTERS]

  which is a field of the AVFrame frame structure, is filled by a call to the ffmpeg function

  avcodec_decode_audio4(avctx,frame,got_frame_ptr,avpkt)

  But, I need to read this buffer as a buffer of signed 16 bits integers because this is the sample format indicated by the codec context
  avctx->sample_fmt==AV_SAMPLE_FMT_S16

  I tried to do this using a memcpy but I have not succeeded to get reasonable values so then I tried to use a union struct as suggested on some related questions here in StackOverflow. My code is as follows :
  union CharToStruct
  uint8_t myCharArray[2] ;
  short value ;
  presentSound ;

   audioRet=avcodec_decode_audio4(avctx,frame,got_frame_ptr,avpkt);
  
   if(got_frame_ptr){
  
       audioRet=audioRet/2;
  
       int b=0;
  
       for(int i=0;idata[0][2*i+1];
  
           presentSound.myCharArray[1]=frame->data[0][2*i]
  
           dbuf[((i-b)/2)*8+inc-è>mLeft+b]=info->presentSound.value;//the reason of the offset by 8 here is because I will be writing the result to a multichannel device
  
   }

  With this, the values are reasonable, but when I write this to a device using portaudio, I get just clicking noise. Am I doing the conversion in a wrong way ? Can you help me maybe with some better way to do this reading ?

  Thank you very much for your help

  Alba

• Still on Piwik 2 ? Update now to Piwik 3, the most efficient and secure Piwik version

  5 avril 2017, par Piwik Core Team — Community

  It has been almost four months since we released Piwik 3. The major new release came with a new UI, performance and security improvements. If you are still on Piwik 2, the security improvements alone should be worth updating your Piwik now to Piwik 3. We cannot recommend this enough.

  Since the Piwik 3.0 release we have released three new versions that fix over 250 issues including more performance and security issues. And new features : the Life Time Revenue, or the Cross Domain linking feature to track visitors across different domains accurately. Also, most plugins from the Piwik Marketplace are now compatible with Piwik 3 so there is no reason to wait anymore.

  The update to Piwik 3 should be smooth, but may take a while depending on the amount of data you have. If you have any problem with the update, feel free to get in touch with us. At Piwik and at InnoCraft, the company of the makers of Piwik, we have successfully updated many Piwik installations.

  

  Wondering what’s changed ?

  • Piwik 3.0.0 Changelog
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