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• ffmpeg link errors when building on iPhone 4.3 SDK

  12 septembre 2011, par YuzaKen

  After a rather trying few days, I finally got ffmpeg to compile under Xcode 4 with SDK 4.3. The issue no is a series (39) link errors. They fall into at least two cases : assembly language routines and static arrays defined in header files. My believe is that it is generating C method names for the assembly routines while the .c files containing the reference to the routine is generating a different method name (munging).

  Undefined symbols for architecture armv7 :

    "_ff_vector_fmul_vfp", referenced from:
  
        _ff_dsputil_init_vfp in libavcodec.a(dsputil_init_vfp.o)
  
    "_main", referenced from:
  
        start in crt1.3.1.o
  
    "_av_solve_lls", referenced from:
  
        _ff_lpc_calc_coefs in libavcodec.a(lpc.o)
  
    "_ff_inv_aanscales", referenced from:
  
        _dct_quantize_trellis_c in libavcodec.a(mpegvideo_enc.o)
  
        _decode_frame in libavcodec.a(eamad.o)
  
        _tgq_decode_frame in libavcodec.a(eatgq.o)
  
        _tqi_decode_frame in libavcodec.a(eatqi.o)
  
    "_ff_add_pixels_clamped_armv6", referenced from:
  
        _ff_dsputil_init_armv6 in libavcodec.a(dsputil_init_armv6.o)
  
    "_ff_cga_palette", referenced from:
  
        _tmv_decode_frame in libavcodec.a(tmv.o)
  
    "_ff_svq1_inter_multistage_vlc", referenced from:
  
        _encode_block in libavcodec.a(svq1enc.o)
  
        _svq1_decode_init in libavcodec.a(svq1dec.o)
  
    "_ff_simple_idct_armv6", referenced from:
  
        _ff_dsputil_init_armv6 in libavcodec.a(dsputil_init_armv6.o)
  
    "_BZ2_bzDecompressInit", referenced from:
  
        _matroska_decode_buffer in libavformat.a(matroskadec.o)
  
    "_ff_put_pixels8_y2_arm", referenced from:
  
        _ff_put_pixels16_y2_arm in libavcodec.a(dsputil_init_arm.o)
  
        _dsputil_init_arm in libavcodec.a(dsputil_init_arm.o)
  
    "_ff_simple_idct_add_armv6", referenced from:

  ...and so on.

  Anyone with experience with ffmpeg on iPhone ? Successfully ?

• iPhone ffmpeg dev using libav to decode from AMR to ACC codec

  10 octobre 2011, par VictorT

  It seems to be that, the AMR support of AudioQueue has been disappeared since iOS 4.3 was released. I can't use audio frame received from RSTP server with old way :

  audioFormat.mFormatID = kAudioFormatAMR; 
  
  int err = AudioQueueNewOutput(&audioFormat, MyAudioQueueOutputCallback, self, NULL, kCFRunLoopCommonModes, 0, &audioQueue);

  As a result I received an error in last string.

  Maybe someone know how to decode AMR AVPacket into raw buffer and encode it with AAC or MP3 using LIBAV ?

  I've tried to use

  avcodec_decode_audio3

  It works and I can get raw buffer but when I'm trying to encode it with

  avcodec_encode_audio

  I get 0 as result

  This is my method to encode buffer :

  - (AVPacket) encodeRawFrame:(const short *) in_buffer withSize:(unsigned int) in_buf_byte_size
  
  {
  
      AVPacket res;
  
      AVCodec *codec;
  
      AVCodecContext *c= NULL;
  
      int count, out_size, outbuf_size, frame_byte_size;
  
      uint8_t *outbuf;
  
  
  
      avcodec_init();
  
      avcodec_register_all();
  
  
  
      printf("Audio encoding\n");
  
  
  
      codec = avcodec_find_encoder(CODEC_ID_AAC);
  
      if (!codec) {
  
          fprintf(stderr, "codec not found\n");
  
          return res;
  
      }
  
  
  
      c= avcodec_alloc_context();
  
  
  
      c->bit_rate = 64000;
  
      c->sample_rate = 24000;
  
      c->channels = 2;
  
  
  
      if (avcodec_open(c, codec) < 0) 
  
      {
  
          fprintf(stderr, "could not open codec\n");
  
      }
  
      else
  
      {
  
          frame_byte_size=c->frame_size*2*2;
  
          count = in_buf_byte_size/frame_byte_size;
  
  
  
          fprintf(stderr, "Number of frames: %d\n", count);
  
  
  
          outbuf_size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
  
          outbuf = (uint8_t*) malloc(outbuf_size);
  
  
  
          out_size = avcodec_encode_audio(c, outbuf, outbuf_size, &in_buffer[frame_byte_size*i]);
  
          if(out_size >= 0)
  
          {
  
              res.size = outbuf_size;
  
              res.data = malloc(outbuf_size);                
  
          }
  
  
  
          free(outbuf);
  
      }
  
  
  
  
  
      avcodec_close(c);
  
      av_free(c);
  
      return res;
  
  }

  After encoding "out_size" is always 0 and result buffer is empty.

  Thanks.

• How to play wma file in iphone ?

  3 octobre 2011, par Mohasin

  I want to build a radio app in iPhone for which wma streaming is necessary. So if u have any idea please help me.
  thanks in advance