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• convert WAV to TETRA format

  14 juin 2020, par Ashish Arora

  I am trying to convert a wav file into TETRA encoded file (https://en.wikipedia.org/wiki/Terrestrial_Trunked_Radio). Tetra is used by fire-fighters, it provides a radio-like voice.

  



  I am trying to use the official tetra codec codes available at (https://www.etsi.org/deliver/etsi_en/300300_300399/30039502/01.03.01_60/) and we can easily compile it using the scripts available at https://github.com/sq5bpf/install-tetra-codec.

  



  However, I am not able to figure out how to convert a wav file into tetra codec files using these files. I tried going through the documentation of the compiled files (ccoder, cdecoder, scoder, sdecoder).

  



  I tried the following command -

  



  


  tetra/bin/scoder input.wav serial_file synth_file

  


  



  here serial_file and synth_file are the output files and have following documentation in the scoder.c file :

  



      INPUT   :   - Description : speech file to be analyzed
                - Format : binary file 16 bit-samples
                  240 samples per frame

serial_file :   - Description : serial stream output file 
            - Format : binary file 16 bit-samples
              each 16 bit-sample represents one encoded bit
              138 (= 1 + 137) bits per frame

synth_file  :   - Description : local synthesis output file 
            - Format : binary file 16 bit-samples


  



  For an input file of size 13M, I obtained serial_file and synth_file of size 8.0M and 16M. However, I thought since the wav file is getting converted into a walkie-talkie type signal the output file size will be alot smaller.

  



  I want to clarify if :

  



  

  • I used the correct code to convert an input wav file into a tetra format output file.

  


  • can you please help me understand, what is serial_file and synth_file.

  


  



  Thanks,
Ashish

  


• ffplay cannot play more than one song

  5 février 2020, par Bernie gach

  i have taken ffplay.c file from http://ffmpeg.org/doxygen/trunk/ffplay_8c-source.html and re edited it to a cpp file to embed in my win32 gui application . i have made the following changes to it.

  1. made the int main function into a local function as follows, i can pass the HWND to embedd the player

  void Ffplay::play_song(string file, HWND parent, bool* successfull)
  
  {
  
      int flags;
  
      VideoState* is;
  
      input_filename = file; 
  
      /* register all codecs, demux and protocols */
  
  #if CONFIG_AVDEVICE
  
      avdevice_register_all();
  
  #endif
  
      //avformat_network_init();
  
      //check whether the filename is valid
  
      if (input_filename.empty())
  
      {
  
          logger.log(logger.LEVEL_ERROR, "filename %s is not valid\n", file);
  
          return;
  
      }
  
      if (display_disable)
  
      {
  
          video_disable = 1;
  
      }
  
      flags = SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER;
  
      if (audio_disable)
  
          flags &= ~SDL_INIT_AUDIO;
  
      else
  
      {
  
          /* Try to work around an occasional ALSA buffer underflow issue when the
  
           * period size is NPOT due to ALSA resampling by forcing the buffer size. */
  
          if (!SDL_getenv("SDL_AUDIO_ALSA_SET_BUFFER_SIZE"))
  
              SDL_setenv("SDL_AUDIO_ALSA_SET_BUFFER_SIZE", "1", 1);
  
      }
  
      if (display_disable)
  
          flags &= ~SDL_INIT_VIDEO;
  
      SDL_SetMainReady();
  
      if (SDL_Init(flags))
  
      {
  
          logger.log(logger.LEVEL_ERROR, "Could not initialize SDL - %s\n", SDL_GetError());
  
          logger.log(logger.LEVEL_ERROR, "(Did you set the DISPLAY variable?)\n");
  
          return;
  
      }
  
      //Initialize optional fields of a packet with default values.
  
      //Note, this does not touch the data and size members, which have to be initialized separately.
  
      av_init_packet(&flush_pkt);
  
      flush_pkt.data = (uint8_t*)&flush_pkt;
  
  
  
      if (!display_disable)
  
      {
  
          int flags = SDL_WINDOW_HIDDEN;
  
          if (alwaysontop)
  
  #if SDL_VERSION_ATLEAST(2,0,5)
  
              flags |= SDL_WINDOW_ALWAYS_ON_TOP;
  
  #else
  
              logger.log(logger.LEVEL_INFO, "SDL version doesn't support SDL_WINDOW_ALWAYS_ON_TOP. Feature will be inactive.\n");
  
  #endif
  
          if (borderless)
  
              flags |= SDL_WINDOW_BORDERLESS;
  
          else
  
              flags |= SDL_WINDOW_RESIZABLE;
  
          SDL_InitSubSystem(flags);
  
          ShowWindow(parent, true);
  
          //window = SDL_CreateWindow(program_name, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, default_width, default_height, flags);
  
          window = SDL_CreateWindowFrom(parent);
  
          SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "linear");
  
          if (window) {
  
              renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
  
              if (!renderer)
  
              {
  
                  logger.log(logger.LEVEL_ERROR, "Failed to initialize a hardware accelerated renderer: %s\n", SDL_GetError());
  
                  renderer = SDL_CreateRenderer(window, -1, 0);
  
              }
  
              if (renderer)
  
              {
  
                  if (!SDL_GetRendererInfo(renderer, &renderer_info))
  
                  {
  
                      logger.log(logger.LEVEL_INFO, "Initialized %s renderer.\n", renderer_info.name);
  
                  }
  
              }
  
          }
  
          if (!window || !renderer || !renderer_info.num_texture_formats)
  
          {
  
              logger.log(logger.LEVEL_ERROR, "Failed to create window or renderer: %s\n", SDL_GetError());
  
              return;
  
          }
  
      }
  
  
  
      is = stream_open(input_filename.c_str(), file_iformat);
  
      if (!is)
  
      {
  
          logger.log(logger.LEVEL_ERROR, "Failed to initialize VideoState!\n");
  
          return;
  
      }
  
      //the song is playing now
  
      *successfull = true;
  
      event_loop(is);
  
      //the song has quit;
  
      *successfull = false;
  
  }

  2. changed the callback functions as the static ones couldn’t be used by c++ eg,

  void Ffplay::static_sdl_audio_callback(void* opaque, Uint8* stream, int len)
  
  {
  
      static_cast(opaque)->sdl_audio_callback(opaque, stream, len);
  
  }

  closing doesn’t change from the main file to close the audio and sdl framework

  void Ffplay::do_exit(VideoState* is)
  
  {
  
      abort = true;
  
      if(is)
  
      {
  
          stream_close(is);
  
      }
  
      if (renderer)
  
          SDL_DestroyRenderer(renderer);
  
      if (window)
  
           SDL_DestroyWindow(window);
  
  #if CONFIG_AVFILTER
  
      av_freep(&vfilters_list);
  
  #endif
  
      avformat_network_deinit();
  
      SDL_Quit();
  
  
  
  }

  i call the functions as follows from main gui

  ft=std::async(launch::async, &Menu::play_song, this, songs_to_play.at(0));

  the menu::play_song function is :

  void Menu::play_song(wstring song_path)
  
  {
  
      ready_to_play_song = false;
  
      OutputDebugString(L"\nbefore song\n");
  
      using std::future;
  
      using std::async;
  
      using std::launch;
  
  
  
      string input{ song_path.begin(),song_path.end() };
  
      Ffplay ffplay;
  
      ffplay.play_song(input, h_sdl_window, &song_opened);
  
  
  
      OutputDebugString(L"\nafter song\n");
  
      ready_to_play_song = true;
  
  }

  THE PROBLEM is i can only play one song . if i call the menu::play_song function again the sound is missing and the video/art cover is occasionally missing also. it seems some resources are not been released or something like that.

  i have localised the proble to this function

  int Ffplay::packet_queue_get(PacketQueue* q, AVPacket* pkt, int block, int* serial)
  
  {
  
  
  
      MyAVPacketList* pkt1;
  
      int ret;
  
      int count=0;
  
      SDL_LockMutex(q->mutex);
  
  
  
      for (;;) 
  
      {
  
  
  
  
  
          if (q->abort_request)
  
          {
  
              ret = -1;
  
              break;
  
          }
  
  
  
          pkt1 = q->first_pkt;
  
          if (pkt1) {
  
              q->first_pkt = pkt1->next;
  
              if (!q->first_pkt)
  
                  q->last_pkt = NULL;
  
              q->nb_packets--;
  
              q->size -= pkt1->pkt.size + sizeof(*pkt1);
  
              q->duration -= pkt1->pkt.duration;
  
              *pkt = pkt1->pkt;
  
              if (serial)
  
                  *serial = pkt1->serial;
  
              av_free(pkt1);
  
              ret = 1;
  
              break;
  
          }
  
          else if (!block) {
  
              ret = 0;
  
              break;
  
          }
  
          else 
  
          {
  
              logger.log(logger.LEVEL_INFO, "packet_queue before");
  
              SDL_CondWait(q->cond, q->mutex);
  
              logger.log(logger.LEVEL_INFO, "packet_queue after");
  
  
  
          }
  
      }
  
      SDL_UnlockMutex(q->mutex);
  
      return ret;
  
  }

  the call to SDL_CondWait(q->cond, q->mutex); never returns

• Start of video is not labeled as "0" in QuickTime Video from GoPro

  26 mars 2020, par John Terragnoli

  I’m trying to combine four GoPro videos into a single video, and then rotate it 90 degrees. However, the time scales on the bottom of the videos are all wrong. The videos are 17 minutes and 42 second. But the beginning time is labeled as 5:15:20:32 and the ending time is 5:33:01:32. It just looks really weird and I’d like to fix it. After I use ffmpeg to rotate and concatenate the videos, the problem persists. Could it possibly be fixed with Exiftool ?

  ffmpeg -safe 0 -f concat -i list.txt -vcodec copy -acodec copy merged_videos.MP4

  ffmpeg -i input.mov -vf "transpose=1" output.mov

  Here is the exiftool information on one of the videos :

  File Name                       : GOPR3023.MP4
  
  Directory                       : .
  
  File Size                       : 3.7 GB
  
  File Modification Date/Time     : 2018:04:12 14:56:16-05:00
  
  File Access Date/Time           : 2020:03:25 12:17:18-05:00
  
  File Inode Change Date/Time     : 2020:03:25 17:57:04-05:00
  
  File Permissions                : rwxrwxrwx
  
  File Type                       : MP4
  
  File Type Extension             : mp4
  
  MIME Type                       : video/mp4
  
  Major Brand                     : MP4 v1 [ISO 14496-1:ch13]
  
  Minor Version                   : 2013.10.18
  
  Compatible Brands               : mp41
  
  Movie Data Size                 : 4001979951
  
  Movie Data Offset               : 28
  
  Movie Header Version            : 0
  
  Create Date                     : 2018:04:12 14:38:32
  
  Modify Date                     : 2018:04:12 14:38:32
  
  Time Scale                      : 60000
  
  Duration                        : 0:17:42
  
  Preferred Rate                  : 1
  
  Preferred Volume                : 100.00%
  
  Preview Time                    : 0 s
  
  Preview Duration                : 0 s
  
  Poster Time                     : 0 s
  
  Selection Time                  : 0 s
  
  Selection Duration              : 0 s
  
  Current Time                    : 0 s
  
  Next Track ID                   : 6
  
  Firmware Version                : HD5.03.02.51.00
  
  Lens Serial Number              : NAH6092300301117
  
  Camera Serial Number Hash       : 34676f2cdf49b86a1514817a93377bf7
  
  Track Header Version            : 0
  
  Track Create Date               : 2018:04:12 14:38:32
  
  Track Modify Date               : 2018:04:12 14:38:32
  
  Track ID                        : 1
  
  Track Duration                  : 0:17:42
  
  Track Layer                     : 0
  
  Track Volume                    : 0.00%
  
  Image Width                     : 1920
  
  Image Height                    : 1080
  
  Graphics Mode                   : srcCopy
  
  Op Color                        : 0 0 0
  
  Compressor ID                   : avc1
  
  Source Image Width              : 1920
  
  Source Image Height             : 1080
  
  X Resolution                    : 72
  
  Y Resolution                    : 72
  
  Compressor Name                 : GoPro AVC encoder
  
  Bit Depth                       : 24
  
  Color Representation            : nclx 1 1 1
  
  Video Frame Rate                : 59.94
  
  Time Code                       : 3
  
  Balance                         : 0
  
  Audio Format                    : mp4a
  
  Audio Channels                  : 2
  
  Audio Bits Per Sample           : 16
  
  Audio Sample Rate               : 48000
  
  Text Font                       : Unknown (21)
  
  Text Face                       : Plain
  
  Text Size                       : 10
  
  Text Color                      : 0 0 0
  
  Background Color                : 65535 65535 65535
  
  Font Name                       : Helvetica
  
  Other Format                    : tmcd
  
  Warning                         : [minor] The ExtractEmbedded option may find more tags in the movie data
  
  Matrix Structure                : 1 0 0 0 1 0 0 0 1
  
  Media Header Version            : 0
  
  Media Create Date               : 2018:04:12 14:38:32
  
  Media Modify Date               : 2018:04:12 14:38:32
  
  Media Time Scale                : 60000
  
  Media Duration                  : 0:17:42
  
  Handler Class                   : Media Handler
  
  Handler Type                    : NRT Metadata
  
  Handler Description             : GoPro SOS
  
  Gen Media Version               : 0
  
  Gen Flags                       : 0 0 0
  
  Gen Graphics Mode               : srcCopy
  
  Gen Op Color                    : 0 0 0
  
  Gen Balance                     : 0
  
  Meta Format                     : fdsc
  
  Image Size                      : 1920x1080
  
  Megapixels                      : 2.1
  
  Avg Bitrate                     : 30.1 Mbps
  
  Rotation                        : 0

  Part 2
  There is a pretty obvious "stutter" at the 17:42 mark where the two clips are combined. I’ve tried using ffmpeg and iMovie, but both give the same results. The GoPro broke up the event into multiple clips on it’s own so it seems weird that there would be any information missing. Is there any way to get rid of this stutter ?

  Thanks !