Recherche avancée

Sur d’autres sites (8005)

• How can I split an mp4 video with ffmpeg every time the volume is zero ?

  14 mars 2019, par Juan Pablo Fernandez

  I need to split a video into many smaller videos.
  I have tried PySceneDetect and its 2 scene detection methods don’t fit my need.

  The idea is to trigger a scene cut/break every time the volume is very low, every time audio level is less than a given parameter. I think overall RMS dB volume level is what I mean.

  The purpose is to split an mp4 video into many short videos, each smaller video with short dialog phrases.

  So far I have a command to get the overall RMS audio volume level.

  ffprobe -f lavfi -i amovie=01x01TheStrongestMan.mp4,astats=metadata=1:reset=1 -show_entries frame=pkt_pts_time:frame_tags=lavfi.astats.Overall.RMS_level,lavfi.astats.1.RMS_level,lavfi.astats.2.RMS_level -of csv=p=0

  How can I get only the minimum values for RMS level and its corresponding frame or time ?

  And then how can I use ffmpeg to split the video in many videos on every frame that corresponds to a minimum RMS ?

  Thanks.

• lame mp3 change bitrate cpp

  23 mai 2019, par user2018761

  I need to change mp3 bitrate, I’m using lame for cpp project under Windows and Linux. I think I need to convert mp3 to wav and then wav to mp3 with desired bitrate.

  For wav to mp3 I already have the code (using lame) it works.
  For mp3 to wav there is problem with app crashing on hip_decode.
  Probably due to ID3 tags at the beginning of the file.
  How to skip the ID3 tags or is this a different problem ?

  This is code I’m using

  bool Helper::convert2Wav(QString fromFile, QString toFile) {
  
      int read, write;
  
      int ctn = 0;
  
  
  
      FILE *mp3_in =fopen(fromFile.toLocal8Bit().data(),"rb");
  
      //this should be WAV
  
      FILE *pcm_out =fopen(toFile.toLocal8Bit().data(),"wb");
  
  
  
      const int PCM_SIZE = 4096;
  
      const int MP3_SIZE = 4096;
  
  
  
      short int pcm_buffer[PCM_SIZE*2];
  
      short int pcm_buffer1[PCM_SIZE];
  
      short int pcm_buffer2[PCM_SIZE];
  
      unsigned char mp3_buffer[MP3_SIZE];
  
  
  
  
  
      memset(pcm_buffer, 0, sizeof(pcm_buffer));
  
      memset(pcm_buffer1, 0, sizeof(pcm_buffer1));
  
      memset(pcm_buffer2, 0, sizeof(pcm_buffer2));
  
      memset(mp3_buffer, 0, sizeof(mp3_buffer));
  
  
  
      lame_t lame = lame_init();
  
      hip_t l = hip_decode_init();
  
      lame_set_in_samplerate(lame, 44100);
  
      //lame_set_VBR(lame, vbr_default);
  
      //lame_set_mode(lame, MONO);
  
      lame_init_params(lame);
  
  
  
      qDebug()<<"start decoding";
  
  
  
      do {
  
          ctn += 4096;
  
          qDebug()<<"a message:"</read = hip_decode(l, mp3_buffer, MP3_SIZE, pcm_buffer1,pcm_buffer2);
  
  
  
          //memcpy(pcm_buffer, pcm_buffer1, sizeof(pcm_buffer1));
  
          //memcpy(&pcm_buffer[PCM_SIZE], pcm_buffer2, sizeof(pcm_buffer2));
  
          //write = lame_encode_buffer_interleaved(lame, pcm_buffer, read,mp3_buffer, MP3_SIZE);
  
          //fwrite(pcm_buffer, 1, sizeof(pcm_buffer), pcm_out);
  
  
  
      } while (read != 0);
  
  
  
      hip_decode_exit(l);
  
      lame_close(lame);
  
      fclose(pcm_out);
  
      fclose(mp3_in);
  
  
  
      return true;
  
  }

  It is crashing with an output :

  start decoding
  
  a message: 4096
  
  a message: 8192
  
  a message: 12288
  
  1   ??                                 0x7ffff7b8f0b5     
  
  2   hip_decode1_headers                0x7ffff7b8f34b     
  
  3   hip_decode1_headers                0x7ffff7b8f385     
  
  4   hip_decode_headers                 0x7ffff7b8f42d     
  
  5   hip_decode                         0x7ffff7b8f47c     
  
  6   Helper::convert2Wav helper.cpp 498 0x5555555b0fe7     
  
  7   ??                                 0x4490551063006a0  
  
  
  
          MP3_SIZE    258346945   int
  
          PCM_SIZE    234884892   int
  
          ctn 189860957   int
  
          l   1050198802094820962 hip_t
  
          lame    1165886731226582744 lame_t
  
          mp3_buffer  "\005\0029lM^J\035�xo�R����(����Rj\172175r�V�����ԡCb٥���0a�ע�r�4�A��7Xj�Q0u�\033Os��L5�S$D2\002\016� UxCp\014s��08\004+7��@"�r"... (4096)   unsigned char[4096]
  
          mp3_in  0xe0b0e1e0e060d4a   FILE*
  
          pcm_buffer  @0x7fffffff89a0 short[8192]
  
          pcm_buffer1 @0x7fffffff69a0 short[4096]
  
          pcm_buffer2 @0x7fffffff49a0 short[4096]
  
          pcm_out 0xc460bb00bb40c82   FILE*
  
          read    229772669   int
  
          write   <optimized out="out"> 
  
  </optimized>

  it seems this is not ID3 issue, I have used this code https://searchcode.com/file/31230698/ID3.cpp to read ID3 and it shows there is no ID3 tags
  But still crashing at the same point :

  Has ID3v2 Tag: No
  
    Tag size: 0
  
  start decoding skip tag_size: 0
  
  a message: 4096
  
  a message: 8192
  
  a message: 12288

• lame mp3 to wav crashing (need to skip ID3 tag ?)

  18 janvier 2018, par user2018761

  I need to change mp3 bitrate, I’m using lame for cpp project under Windows and Linux. I think I need to convert mp3 to wav and then wav to mp3 with desired bitrate.
  For wav to mp3 I already have the code (using lame) it works.
  For mp3 to wav there is problem with app crashing on hip_decode.
  Probably due to ID3 tags at the beginning of the file.
  How to skip the ID3 tags or is this a different problem ?

  This is code I’m using

  bool Helper::convert2Wav(QString fromFile, QString toFile) {
  
      int read, write;
  
      int ctn = 0;
  
  
  
      FILE *mp3_in =fopen(fromFile.toLocal8Bit().data(),"rb");
  
      //this should be WAV
  
      FILE *pcm_out =fopen(toFile.toLocal8Bit().data(),"wb");
  
  
  
      const int PCM_SIZE = 4096;
  
      const int MP3_SIZE = 4096;
  
  
  
      short int pcm_buffer[PCM_SIZE*2];
  
      short int pcm_buffer1[PCM_SIZE];
  
      short int pcm_buffer2[PCM_SIZE];
  
      unsigned char mp3_buffer[MP3_SIZE];
  
  
  
  
  
      memset(pcm_buffer, 0, sizeof(pcm_buffer));
  
      memset(pcm_buffer1, 0, sizeof(pcm_buffer1));
  
      memset(pcm_buffer2, 0, sizeof(pcm_buffer2));
  
      memset(mp3_buffer, 0, sizeof(mp3_buffer));
  
  
  
      lame_t lame = lame_init();
  
      hip_t l = hip_decode_init();
  
      lame_set_in_samplerate(lame, 44100);
  
      //lame_set_VBR(lame, vbr_default);
  
      //lame_set_mode(lame, MONO);
  
      lame_init_params(lame);
  
  
  
      qDebug()<<"start decoding";
  
  
  
      do {
  
          ctn += 4096;
  
          qDebug()<<"a message:"</read = hip_decode(l, mp3_buffer, MP3_SIZE, pcm_buffer1,pcm_buffer2);
  
  
  
          //memcpy(pcm_buffer, pcm_buffer1, sizeof(pcm_buffer1));
  
          //memcpy(&pcm_buffer[PCM_SIZE], pcm_buffer2, sizeof(pcm_buffer2));
  
          //write = lame_encode_buffer_interleaved(lame, pcm_buffer, read,mp3_buffer, MP3_SIZE);
  
          //fwrite(pcm_buffer, 1, sizeof(pcm_buffer), pcm_out);
  
  
  
      } while (read != 0);
  
  
  
      hip_decode_exit(l);
  
      lame_close(lame);
  
      fclose(pcm_out);
  
      fclose(mp3_in);
  
  
  
      return true;
  
  }

  It is crashing with an output :

  start decoding
  
  a message: 4096
  
  a message: 8192
  
  a message: 12288
  
  1   ??                                 0x7ffff7b8f0b5     
  
  2   hip_decode1_headers                0x7ffff7b8f34b     
  
  3   hip_decode1_headers                0x7ffff7b8f385     
  
  4   hip_decode_headers                 0x7ffff7b8f42d     
  
  5   hip_decode                         0x7ffff7b8f47c     
  
  6   Helper::convert2Wav helper.cpp 498 0x5555555b0fe7     
  
  7   ??                                 0x4490551063006a0  
  
  
  
          MP3_SIZE    258346945   int
  
          PCM_SIZE    234884892   int
  
          ctn 189860957   int
  
          l   1050198802094820962 hip_t
  
          lame    1165886731226582744 lame_t
  
          mp3_buffer  "\005\0029lM^J\035�xo�R����(����Rj\172175r�V�����ԡCb٥���0a�ע�r�4�A��7Xj�Q0u�\033Os��L5�S$D2\002\016� UxCp\014s��08\004+7��@"�r"... (4096)   unsigned char[4096]
  
          mp3_in  0xe0b0e1e0e060d4a   FILE*
  
          pcm_buffer  @0x7fffffff89a0 short[8192]
  
          pcm_buffer1 @0x7fffffff69a0 short[4096]
  
          pcm_buffer2 @0x7fffffff49a0 short[4096]
  
          pcm_out 0xc460bb00bb40c82   FILE*
  
          read    229772669   int
  
          write   <optimized out="out"> 
  
  </optimized>

  it seems this is not ID3 issue, I have used this code https://searchcode.com/file/31230698/ID3.cpp to read ID3 and it shows there is no ID3 tags
  But still crashing at the same point :

  Has ID3v2 Tag: No
  
    Tag size: 0
  
  start decoding skip tag_size: 0
  
  a message: 4096
  
  a message: 8192
  
  a message: 12288

  Best Regards

  Marek