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• SDL Audio - Plays only Static Noise

  30 avril 2016, par bcpermafrost

  Im having an issue with playing audio.

  Im new to the SDL World of things so im learning from a tutorial.

  http://dranger.com/ffmpeg/tutorial03.html

  As far as audio goes, i have exactly what he put down and didnt get the result he says I should get. In the end of the lesson he specifies that the audio should play normally. However all i get is excessively loud static noise. This leads me to believe that the packets arent being read correctly. However I have no idea how to debug or look for the issue.

  Here is my main loop for parsing the packets :

   while (av_read_frame(pFormatCtx, &packet) >= 0) {
  
  
  
           if (packet.stream_index == videoStream) {
  
               avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);
  
  
  
               if (frameFinished){
  
  
  
                   AVPicture pict;
  
  
  
                   pict.data[0] = yPlane;
  
                   pict.data[1] = uPlane;
  
                   pict.data[2] = vPlane;
  
                   pict.linesize[0] = pCodecCtx->width;
  
                   pict.linesize[1] = uvPitch;
  
                   pict.linesize[2] = uvPitch;
  
  
  
                   sws_scale(sws_ctx,
  
                       pFrame->data, pFrame->linesize,
  
                       0, pCodecCtx->height,
  
                       pict.data, pict.linesize);
  
  
  
                   //SDL_UnlockTexture(bmp);
  
  
  
                   SDL_UpdateYUVTexture(bmp, 0, 
  
                       yPlane, pCodecCtx->width, 
  
                       uPlane, uvPitch, 
  
                       vPlane, uvPitch);
  
  
  
  
  
                   SDL_RenderClear(renderer);
  
                   SDL_RenderCopy(renderer, bmp, NULL, NULL);
  
                   SDL_RenderPresent(renderer);
  
  
  
  
  
                   av_free_packet(&packet);
  
  
  
  
  
               }
  
  
  
           }
  
           else if (packet.stream_index == audioStream) { 
  
               packet_queue_put(&audioq, &packet);
  
  
  
           }
  
           else
  
               av_free_packet(&packet);
  
  
  
  
  
  
  
           SDL_PollEvent(&event);
  
  
  
           switch (event.type) {
  
           case SDL_QUIT:
  
               quit = 1;
  
               SDL_DestroyTexture(bmp);
  
               SDL_DestroyRenderer(renderer);
  
               SDL_DestroyWindow(screen);
  
               SDL_Quit();
  
               exit(0);
  
               break;
  
           default:
  
               break;
  
  
  
           }
  
  
  
       }

  this is my initialization of the audio device :

  aCodecCtxOrig = pFormatCtx->streams[audioStream]->codec;
  
      aCodec = avcodec_find_decoder(aCodecCtxOrig->codec_id);
  
      if (!aCodec) {
  
          fprintf(stderr, "Unsupported codec!\n");
  
          return -1;
  
      }
  
  
  
      // Copy context
  
      aCodecCtx = avcodec_alloc_context3(aCodec);
  
      if (avcodec_copy_context(aCodecCtx, aCodecCtxOrig) != 0) {
  
          fprintf(stderr, "Couldn't copy codec context");
  
          return -1; // Error copying codec context
  
      }
  
  
  
  
  
      wanted_spec.freq = aCodecCtx->sample_rate;
  
      wanted_spec.format = AUDIO_U16SYS;
  
      wanted_spec.channels = aCodecCtx->channels;
  
      wanted_spec.silence = 0;
  
      wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
  
      wanted_spec.callback = audio_callback;
  
      wanted_spec.userdata = aCodecCtx;
  
  
  
  
  
      if (SDL_OpenAudio( &wanted_spec, &spec) < 0) {
  
          fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError());
  
          return -1;
  
      }
  
  
  
      avcodec_open2(aCodecCtx, aCodec, NULL);
  
  
  
      // audio_st = pFormatCtx->streams[index]
  
      packet_queue_init(&audioq);
  
      SDL_PauseAudio(0);

  The Call back (same as the tutorial) :|

  void audio_callback(void *userdata, Uint8 *stream, int len) {
  
  
  
      AVCodecContext *aCodecCtx = (AVCodecContext *)userdata;
  
      int len1, audio_size;
  
  
  
      static uint8_t audio_buf[(MAX_AUDIO_FRAME_SIZE * 3) / 2];
  
      static unsigned int audio_buf_size = 0;
  
      static unsigned int audio_buf_index = 0;
  
  
  
      while (len > 0) {
  
          if (audio_buf_index >= audio_buf_size) {
  
              /* We have already sent all our data; get more */
  
              audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf));
  
              if (audio_size < 0) {
  
                  /* If error, output silence */
  
                  audio_buf_size = 1024; // arbitrary?
  
                  memset(audio_buf, 0, audio_buf_size);
  
              }
  
              else {
  
                  audio_buf_size = audio_size;
  
              }
  
              audio_buf_index = 0;
  
          }
  
          len1 = audio_buf_size - audio_buf_index;
  
          if (len1 > len)
  
              len1 = len;
  
          memcpy(stream, (uint8_t *)audio_buf + audio_buf_index, len1);
  
          len -= len1;
  
          stream += len1;
  
          audio_buf_index += len1;
  
      }
  
  }

• SDL Audio - Plays only Static Noise

  19 août 2019, par bcpermafrost

  Im having an issue with playing audio.

  Im new to the SDL World of things so im learning from a tutorial.

  http://dranger.com/ffmpeg/tutorial03.html

  As far as audio goes, i have exactly what he put down and didnt get the result he says I should get. In the end of the lesson he specifies that the audio should play normally. However all i get is excessively loud static noise. This leads me to believe that the packets arent being read correctly. However I have no idea how to debug or look for the issue.

  Here is my main loop for parsing the packets :

   while (av_read_frame(pFormatCtx, &packet) >= 0) {
  
  
  
           if (packet.stream_index == videoStream) {
  
               avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);
  
  
  
               if (frameFinished){
  
  
  
                   AVPicture pict;
  
  
  
                   pict.data[0] = yPlane;
  
                   pict.data[1] = uPlane;
  
                   pict.data[2] = vPlane;
  
                   pict.linesize[0] = pCodecCtx->width;
  
                   pict.linesize[1] = uvPitch;
  
                   pict.linesize[2] = uvPitch;
  
  
  
                   sws_scale(sws_ctx,
  
                       pFrame->data, pFrame->linesize,
  
                       0, pCodecCtx->height,
  
                       pict.data, pict.linesize);
  
  
  
                   //SDL_UnlockTexture(bmp);
  
  
  
                   SDL_UpdateYUVTexture(bmp, 0, 
  
                       yPlane, pCodecCtx->width, 
  
                       uPlane, uvPitch, 
  
                       vPlane, uvPitch);
  
  
  
  
  
                   SDL_RenderClear(renderer);
  
                   SDL_RenderCopy(renderer, bmp, NULL, NULL);
  
                   SDL_RenderPresent(renderer);
  
  
  
  
  
                   av_free_packet(&packet);
  
  
  
  
  
               }
  
  
  
           }
  
           else if (packet.stream_index == audioStream) { 
  
               packet_queue_put(&audioq, &packet);
  
  
  
           }
  
           else
  
               av_free_packet(&packet);
  
  
  
  
  
  
  
           SDL_PollEvent(&event);
  
  
  
           switch (event.type) {
  
           case SDL_QUIT:
  
               quit = 1;
  
               SDL_DestroyTexture(bmp);
  
               SDL_DestroyRenderer(renderer);
  
               SDL_DestroyWindow(screen);
  
               SDL_Quit();
  
               exit(0);
  
               break;
  
           default:
  
               break;
  
  
  
           }
  
  
  
       }

  this is my initialization of the audio device :

  aCodecCtxOrig = pFormatCtx->streams[audioStream]->codec;
  
      aCodec = avcodec_find_decoder(aCodecCtxOrig->codec_id);
  
      if (!aCodec) {
  
          fprintf(stderr, "Unsupported codec!\n");
  
          return -1;
  
      }
  
  
  
      // Copy context
  
      aCodecCtx = avcodec_alloc_context3(aCodec);
  
      if (avcodec_copy_context(aCodecCtx, aCodecCtxOrig) != 0) {
  
          fprintf(stderr, "Couldn't copy codec context");
  
          return -1; // Error copying codec context
  
      }
  
  
  
  
  
      wanted_spec.freq = aCodecCtx->sample_rate;
  
      wanted_spec.format = AUDIO_U16SYS;
  
      wanted_spec.channels = aCodecCtx->channels;
  
      wanted_spec.silence = 0;
  
      wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
  
      wanted_spec.callback = audio_callback;
  
      wanted_spec.userdata = aCodecCtx;
  
  
  
  
  
      if (SDL_OpenAudio( &wanted_spec, &spec) < 0) {
  
          fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError());
  
          return -1;
  
      }
  
  
  
      avcodec_open2(aCodecCtx, aCodec, NULL);
  
  
  
      // audio_st = pFormatCtx->streams[index]
  
      packet_queue_init(&audioq);
  
      SDL_PauseAudio(0);

  The Call back (same as the tutorial) :|

  void audio_callback(void *userdata, Uint8 *stream, int len) {
  
  
  
      AVCodecContext *aCodecCtx = (AVCodecContext *)userdata;
  
      int len1, audio_size;
  
  
  
      static uint8_t audio_buf[(MAX_AUDIO_FRAME_SIZE * 3) / 2];
  
      static unsigned int audio_buf_size = 0;
  
      static unsigned int audio_buf_index = 0;
  
  
  
      while (len > 0) {
  
          if (audio_buf_index >= audio_buf_size) {
  
              /* We have already sent all our data; get more */
  
              audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf));
  
              if (audio_size < 0) {
  
                  /* If error, output silence */
  
                  audio_buf_size = 1024; // arbitrary?
  
                  memset(audio_buf, 0, audio_buf_size);
  
              }
  
              else {
  
                  audio_buf_size = audio_size;
  
              }
  
              audio_buf_index = 0;
  
          }
  
          len1 = audio_buf_size - audio_buf_index;
  
          if (len1 > len)
  
              len1 = len;
  
          memcpy(stream, (uint8_t *)audio_buf + audio_buf_index, len1);
  
          len -= len1;
  
          stream += len1;
  
          audio_buf_index += len1;
  
      }
  
  }

• Senior Software Engineer for Enterprise Analytics Platform

  28 janvier 2016, par Matthieu Aubry — Uncategorized

  We’re looking for a lead developer to work on Piwik Enterprise Analytics core platform software. We have some exciting challenges to solve and need you !

  You’ll be working with both fellow employees and our open-source community. Piwik staff lives in New Zealand, Europe (Poland, Germany) and in the U.S. We do the vast majority of our collaboration online.

  We are a small, flexible team, so when you come aboard, you will play an integral part in engineering. As a leader you’ll help us to prioritise work and grow our community. You’ll help to create a welcoming environment for new contributors and set an example with your development practices and communications skills. You will be working closely with our CTO to build a future for Piwik.

  Key Responsibilities

  • Strong competency coding in PHP and JavaScript.
  • Scaling existing backend system to handle ever increasing amounts of traffic and new product requirements.
  • Outstanding communication and collaboration skills.
  • Drive development and documentation of internal and external APIs (Piwik is an open platform).
  • Help make our development practices better and reduce friction from idea to deployment.
  • Mentor junior engineers and set the stage for personal growth.

  Minimum qualifications

  • 5+ years of experience in product development, security, usable interface design.
  • 5+ years experience building successful production software systems.
  • Strong competency in PHP5 and JavaScript application development.
  • Skill at writing tests and reviewing code.
  • Strong analytical skills.

  Location

  • Remote work position !
  • or you can join us in our office based in Wellington, New Zealand or in Wrocław, Poland.

  Benefits

  • Competitive salary.
  • Remote work is possible.
  • Yearly meetup with the whole team abroad.
  • Be part of a successful open source company and community.
  • In our Wellington (NZ) and Wroclaw (PL) offices : snacks, coffee, nap room, Table football, Ping pong…
  • Regular events.
  • Great team of people.
  • Exciting projects.

  Learn more

  Learn more what it’s like to work on Piwik in our blog post

  About Piwik

  At Piwik we develop the leading open source web analytics platform, used by more than one million websites worldwide. Our vision is to help the world liberate their analytics data by building the best open alternative to Google Analytics.

  The Piwik platform collects, stores and processes a lot of information : hundreds of millions of data points each month. We create intuitive, simple and beautiful reports that delight our users.

  Apply online

  To apply for this position, please Apply online here. We look forward to receiving your applications !