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• Official Piwik Training in Berlin – 2014, June 6th

  6 mai 2014, par Piwik Core Team — Community

  This event will focus on providing training to users of the Piwik analytics platform. The training will provide attendees with the necessary skills and knowledge that they will need to be able to take their website to the next level with Piwik.

  Language : English

  Register to Piwik Training now.

  Location : The 25hours Hotel Bikini Berlin is as diverse as the big city it is located in and as wild as a jungle. The hotel showcases cosmopolitan Berlin at its location in the listed Bikini-Haus building between the Tiergarten park and Breitscheidplatz with Kaiser Wilhelm Memorial Church.

  

  Why do you need training ?

  If you have just started using Piwik and are finding it a bit overwhelming, this training event will benefit you immensely. You will be able to learn all the necessary skills that will allow you move forward with Piwik.

  For users who have been using Piwik for a short time and have a bit of experience in using Piwik, you will be able to learn how to advance your skills and extend your knowledge of the Piwik platform.

  Advanced users will be able to gain more knowledge about the complex features and functions that Piwik incorporates, allowing you to customise different areas of the platform and learn about advanced topics.

  How can you benefit from this training event ?

  By understanding how Piwik works and how to use and operate Piwik more effectively, you will be able to make sound changes to your website that will allow you to achieve your business goals.

  Everyone, from ecommerce businesses to government organisations can benefit from this training event and learn the essential skills and gain the relevant knowledge to meet their goals and requirements.

  Some of the skills that you will learn during the training include :

  • How to install and get started with the Piwik platform
  • How Piwik will add value to your website
  • How to analyse and make sense of the data and information that you collect
  • How to create custom segments that will allow you to report on certain data and information
  • Advance exercises – Piwik settings, tweaking and basic diagnostics

  What equipment do I need in order to participate in the event ?

  You will need a computer that is able to connect to a Wifi network

  Are the tickets transferable ?

  Yes, the tickets are transferable.

  What is the refund policy on the tickets ?

  You are entitled to a refund up to 1 week before the commencement of the training.

  Training details

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  Contact us : contact@piwik.pro

  Registrations

  Register to Piwik Training now !

• use ffmpeg api to convert audio files. crash on avcodec_encode_audio2

  17 février 2014, par fabian

  From the examples I got the basic idea of this code.
  However I am not sure, what I am missing, as muxing.c demuxing.c and decoding_encoding.c
  all use different approaches.

  The process of converting an audio file to another file should go roughly like this :
  inputfile -demux-> audiostream -read-> inPackets -decode2frames->
  frames
   encode2packets-> outPackets -write-> audiostream -mux-> outputfile

  However I found the following comment in demuxing.c :
  /* Write the raw audio data samples of the first plane. This works
  * fine for packed formats (e.g. AV_SAMPLE_FMT_S16). However,
  * most audio decoders output planar audio, which uses a separate
  * plane of audio samples for each channel (e.g. AV_SAMPLE_FMT_S16P).
  * In other words, this code will write only the first audio channel
  * in these cases.
  * You should use libswresample or libavfilter to convert the frame
  * to packed data. */

  My questions about this are :

  1. Can I expect a frame that was retrieved by calling one of the decoder functions, f.e.
     avcodec_decode_audio4 to hold suitable values to directly put it into an encoder or is
     the resampling step mentioned in the comment mandatory ?

  2. Am I taking the right approach ? ffmpeg is very asymmetric, i.e. if there is a function
     open_file_for_input there might not be a function open_file_for_output. Also there are different versions of many functions (avcodec_decode_audio[1-4]) and different naming
     schemes, so it's very hard to tell, if the general approach is right, or actually an
     ugly mixture of techniques that where used at different version bumps of ffmpeg.

  3. ffmpeg uses a lot of specific terms, like 'planar sampling' or 'packed format' and I am having a hard time, finding definitions for these terms. Is it possible to write working code, without deep knowledge of audio ?

  Here is my code so far that right now crashes at avcodec_encode_audio2
  and I don't know why.

  int Java_com_fscz_ffmpeg_Audio_convert(JNIEnv * env, jobject this, jstring jformat, jstring jcodec, jstring jsource, jstring jdest) {
  
      jboolean isCopy;
  
      jclass configClass = (*env)->FindClass(env, "com.fscz.ffmpeg.Config");
  
      jfieldID fid = (*env)->GetStaticFieldID(env, configClass, "ffmpeg_logging", "I");
  
      logging = (*env)->GetStaticIntField(env, configClass, fid);
  
  
  
      /// open input
  
      const char* sourceFile = (*env)->GetStringUTFChars(env, jsource, &isCopy);
  
      AVFormatContext* pInputCtx;
  
      AVStream* pInputStream;
  
      open_input(sourceFile, &pInputCtx, &pInputStream);
  
  
  
      // open output
  
      const char* destFile = (*env)->GetStringUTFChars(env, jdest, &isCopy);
  
      const char* cformat = (*env)->GetStringUTFChars(env, jformat, &isCopy);
  
      const char* ccodec = (*env)->GetStringUTFChars(env, jcodec, &isCopy);
  
      AVFormatContext* pOutputCtx;
  
      AVOutputFormat* pOutputFmt;
  
      AVStream* pOutputStream;
  
      open_output(cformat, ccodec, destFile, &pOutputCtx, &pOutputFmt, &pOutputStream);
  
  
  
      /// decode/encode
  
      error = avformat_write_header(pOutputCtx, NULL);
  
      DIE_IF_LESS_ZERO(error, "error writing output stream header to file: %s, error: %s", destFile, e2s(error));
  
  
  
      AVFrame* frame = avcodec_alloc_frame();
  
      DIE_IF_UNDEFINED(frame, "Could not allocate audio frame");
  
      frame->pts = 0;
  
  
  
      LOGI("allocate packet");
  
      AVPacket pktIn;
  
      AVPacket pktOut;
  
      LOGI("done");
  
      int got_frame, got_packet, len, frame_count = 0;
  
      int64_t processed_time = 0, duration = pInputStream->duration;
  
      while (av_read_frame(pInputCtx, &pktIn) >= 0) {
  
          do {
  
              len = avcodec_decode_audio4(pInputStream->codec, frame, &got_frame, &pktIn);
  
              DIE_IF_LESS_ZERO(len, "Error decoding frame: %s", e2s(len));
  
              if (len < 0) break;
  
              len = FFMIN(len, pktIn.size);
  
              size_t unpadded_linesize = frame->nb_samples * av_get_bytes_per_sample(frame->format);
  
              LOGI("audio_frame n:%d nb_samples:%d pts:%s\n", frame_count++, frame->nb_samples, av_ts2timestr(frame->pts, &(pInputStream->codec->time_base)));
  
              if (got_frame) {
  
                  do {
  
                      av_init_packet(&pktOut);
  
                      pktOut.data = NULL;
  
                      pktOut.size = 0;
  
                      LOGI("encode frame");
  
                      DIE_IF_UNDEFINED(pOutputStream->codec, "no output codec");
  
                      DIE_IF_UNDEFINED(frame->nb_samples, "no nb samples");
  
                      DIE_IF_UNDEFINED(pOutputStream->codec->internal, "no internal");
  
                      LOGI("tests done");
  
                      len = avcodec_encode_audio2(pOutputStream->codec, &pktOut, frame, &got_packet);
  
                      LOGI("encode done");
  
                      DIE_IF_LESS_ZERO(len, "Error (re)encoding frame: %s", e2s(len));
  
                  } while (!got_packet);
  
                  // write packet;
  
                  LOGI("write packet");
  
                  /* Write the compressed frame to the media file. */
  
                  error = av_interleaved_write_frame(pOutputCtx, &pktOut);
  
                  DIE_IF_LESS_ZERO(error, "Error while writing audio frame: %s", e2s(error));
  
                  av_free_packet(&pktOut);
  
              }
  
              pktIn.data += len;
  
              pktIn.size -= len;
  
          } while (pktIn.size > 0);
  
          av_free_packet(&pktIn);
  
      }
  
  
  
      LOGI("write trailer");
  
      av_write_trailer(pOutputCtx);
  
      LOGI("end");
  
  
  
      /// close resources
  
      avcodec_free_frame(&frame);
  
      avcodec_close(pInputStream->codec);
  
      av_free(pInputStream->codec);
  
      avcodec_close(pOutputStream->codec);
  
      av_free(pOutputStream->codec);
  
      avformat_close_input(&pInputCtx);
  
      avformat_free_context(pOutputCtx);
  
  
  
      return 0;
  
  }

• How do you compile Winff ?

  3 mai 2015, par Richard

  I downloaded the WinFF source code in the hopes the new version would solve a segfault.

  It’s sitting, extracted, in its folder. But I see no ./configure, nothing make would know what to do with, no binaries, and no compilation instructions :

  $ ls
  
  AUTHORS        COPYING           README-Presets.txt  unit2.lfm  unit4.pas  winff.1      winff.rc
  
  changelog.txt  docs              README.txt          unit2.pas  unit5.lfm  winff.ico
  
  clean.bat      languages         RESOURCES.RC        unit3.lfm  unit5.pas  winff-icons
  
  clean.sh       potranslator.pas  unit1.lfm           unit3.pas  unit6.lfm  winff.lpi
  
  COMPILE.TXT    presets.xml       unit1.pas           unit4.lfm  unit6.pas  winff.lpr

  Does anyone know how I can try to actually compile the code ?

  All we get is a README.txt :

  Winff - graphical video and audio batch converter using ffmpeg or
  avconv Copyright © 2006-2012 Matthew Weatherford
  http://www.winff.org

  This program is free software : you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or (at
  your option) any later version.

  This program is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY ; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program. If not, see http://www.gnu.org/licenses/.

  WinFF is a GUI for the command line video converter FFmpeg or avconv.

  Get the latest ffmpeg builds and source from http://ffmpeg.org/