Recherche avancée

Sur d’autres sites (8588)

• Does Audio queue support 12.8kbps LPCM data playback ?

  21 décembre 2012, par brook.yang

  I use ffmpeg to decode a local 3gp file just for audio in IOS Simulator environments.

  The audio format information of this file is as follows :

  aCodec name: AMR-NB (Adaptive Multi-Rate NarrowBand) 
  
  audio sample_rate: 8000 
  
  audio channels : 1 
  
  audio bit_rate : 12800 
  
  sample_fmt : flt

  But I only hear the voice of continuous "d ".

  The basic configuration of the audio queue as follow :

   audioStreamBasicDesc_.mFormatID = kAudioFormatLinearPCM;
  
   audioStreamBasicDesc_.mSampleRate = ffmpegDecoder.aCodecCtx->sample_rate;     
  
   audioStreamBasicDesc_.mChannelsPerFrame = ffmpegDecoder.aCodecCtx->channels;
  
   int bitsPerChannel ＝ 32;
  
  
  
   audioStreamBasicDesc_.mFormatFlags = kLinearPCMFormatFlagIsFloat | kAudioFormatFlagIsPacked; audioStreamBasicDesc_.mBitsPerChannel = bitsPerChannel;      
  
   audioStreamBasicDesc_.mFramesPerPacket = 1; audioStreamBasicDesc_.mBytesPerFrame = audioStreamBasicDesc_.mBitsPerChannel / 8 * audioStreamBasicDesc_.mChannelsPerFrame; 
  
   audioStreamBasicDesc_.mBytesPerPacket = audioStreamBasicDesc_.mBytesPerFrame * audioStreamBasicDesc_.mFramesPerPacket; 
  
   audioStreamBasicDesc_.mReserved = 0;

  I tried to just reduce the bit_rate to 5200bps by some software, then it played OK. So I am very confused and I don't known why.

• ffmpeg complied for ios, mp3 decoding bug

  23 juin 2014, par Sergey92zp

  i compiled ffmpeg for ios via this script https://github.com/kewlbear/FFmpeg-iOS-build-script and when i try to play decoded MP3 i got sound with distortions on device.

  As i understand problem only on real devices(ARM arch). On Simulator all works fine(i386 arch).

  I found bug in ffmpeg mail list http://ffmpeg.org/pipermail/libav-user/2013-April/004357.html but even when i try to compile with flags from last link and with gas-preprocessor that they offer, but i got distortion even with that.

  I tried many versions 1.0 , 1.1 , 2.0 , 2.1 , 2.2. but always got same result.

  do anyone solve that problem ? or maybe someone have compiled library without that bug.

• ffmpeg won't build in my project, works fine in example app

  28 février 2015, par Joseph Toronto

  I’ve tried for hours but I can’t figure this out. I’m using KXMOVIE in my project. I’ve downloaded and compiled the ffmpeg binaries as instructed. The example app actually works just fine, but I can’t get it to build in my own project. All the .a files are there, exactly how it is in the example app. I’m getting this error when I try and build for the simulator.

  Undefined symbols for architecture i386:
  
    "_iconv", referenced from:
  
        _avcodec_decode_subtitle2 in libavcodec.a(utils.o)
  
    "_iconv_close", referenced from:
  
        _avcodec_open2 in libavcodec.a(utils.o)
  
        _avcodec_decode_subtitle2 in libavcodec.a(utils.o)
  
    "_iconv_open", referenced from:
  
        _avcodec_open2 in libavcodec.a(utils.o)
  
        _avcodec_decode_subtitle2 in libavcodec.a(utils.o)
  
  ld: symbol(s) not found for architecture i386
  
  clang: error: linker command failed with exit code 1 (use -v to see invocation)

  What am I doing wrong ? I don’t even know where to begin.