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• FFMPEG convert flv to mp4 without losing quality [closed]

  9 juillet 2013, par Chad Whitaker

  Currently I'm converting .flv flash files to .webm and .mp4 files to be used with an HTML5 video player.

  _

  I use this ffmpeg command for WEBM : ffmpeg -i filename.flv -vcodec libvpx -acodec libvorbis filename.webm
  which works great and the file size stays relatively the same (imporatant).

  _

  For MP4 I'm using the following : ffmpeg -i filename.flv -sameq -ar 22050 filename.mp4

  It converts to .mp4 fine and prevents any quality loss but the file size almost triples in size.

  What ffmpeg formula could be used to convert to MP4 without losing too much quality and preventing a much higher file size ?

• av_read_frame return -32 before EOF in case of gsm_ms/gsm wav files

  8 septembre 2011, par user924702

  av_read_frame function is returning -32 after 5/6 frames but I have very large file. This behaviour of the code is only for libgsm wav files only. If I play .mp3 or other wav files there is no error.

  Can some one help me why av_read_frame return -32 before EOF in case of libgsm_ms file on android platfrom.

  Below id my source code :

  while (mCurrentState != MEDIA_PLAYER_DECODED 
  
      && mCurrentState != MEDIA_PLAYER_STOPPED 
  
      && mCurrentState != MEDIA_PLAYER_STATE_ERROR )
  
  {
  
      __android_log_print(ANDROID_LOG_INFO, TAG, "Inside Decoder Run Loop.");
  
      if (mDecoderAudio->packets() > FFMPEG_PLAYER_MAX_QUEUE_SIZE) {
  
          __android_log_print(ANDROID_LOG_INFO, TAG, "mDecoderAudio->packets()  > FFMPEG_PLAYER_MAX_QUEUE_SIZE, lets sleep for 2mili sec.");
  
          usleep(200);
  
          continue;
  
      }
  
      __android_log_print(ANDROID_LOG_INFO, TAG, "Lets read frame using av_read_frame: %u",mMovieFile);
  
      int nResult = av_read_frame(mMovieFile, &pPacket);
  
      __android_log_print(ANDROID_LOG_INFO, TAG, "Read frameresult: %d",nResult);
  
      if(nResult < 0) {
  
          mCurrentState = MEDIA_PLAYER_DECODED;
  
          __android_log_print(ANDROID_LOG_INFO, TAG, "No more frame to decode.");
  
          continue;
  
      }
  
      if(mCurrentState == MEDIA_PLAYER_PAUSED){
  
          __android_log_print(ANDROID_LOG_INFO, TAG,"Player state is MEDIA_PLAYER_PAUSED.");
  
          continue;
  
      }
  
      if (pPacket.stream_index == mAudioStreamIndex) {
  
          __android_log_print(ANDROID_LOG_INFO, TAG,"Lets Enqueue Packet");
  
          mDecoderAudio->enqueue(&pPacket);
  
      }
  
      else {
  
           __android_log_print(ANDROID_LOG_INFO, TAG,"Lets Free Packet");
  
          av_free_packet(&pPacket);
  
      }
  
  }

• ffmpeg Sound going out of sync with -concat or -ss

  6 août 2012, par Jared Glass

  I have a tool that spits out video from a 3D application and then concats the individual videos to make a sequence. But the sound seems to go out of sync in the sequence (the inividual files are fine) and it stutters in VLC and Quicktime. Windows media player seems to handle it bes to my supprise, yet it still goes out of sync. I have two senarios, one works and one doesn't but i need both working :

  Working :
  get already created out movs...

  convert to avi :
  os.system( ffmpeg + " -i C:\clip.mov -sameq -r 24 -y C:\clip.avi")

  concat to avi sequence :
  os.system( ffmpeg + ''' -i concat: C:\clip.avi|C:\clip1.avi|C:\clip2.avi -sameq -r 24 -y C:\sequence.avi''' )

  convert sequence to mov :
  os.system( ffmpeg + " -i C:\sequence.avi -sameq -r 24 -y C:\sequence.mov")

  Not Working :
  create individual avi's from 3D program...

  cut down to correct length :
  os.system(ffmpeg + " -i C:\clip.avi -sameq -r 24 -ss " + startTime + " -vframes " + totalFrames + " -y C:\clip.avi" )

  concat to avi sequence :
  os.system( ffmpeg + ''' -i concat: C:\clip.avi|C:\clip1.avi|C:\clip2.avi -sameq -r 24 -y C:\sequence.avi''' )

  convert sequence to mov :
  os.system( ffmpeg + " -i C:\sequence.avi -sameq -r 24 -y C:\sequence.mov")

  convert individual avi's to mov :
  os.system( ffmpeg + " -i C:\clip.avi-sameq -r 24 -y C:\clip.mov")

  Please let me know where I've gone wrong ?