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• Batch statement to convert mp3 to aac

  20 décembre 2011, par Soham Dasgupta

  My question is straight forward. I have tow commands to convert a single mp3 file to aac in tow pass. Here are the commands -

  ffmpeg -i input.mp3 -f wav - | neroAacEnc -ignorelength -q 0.5 -if - -of output.m4a
  
  
  
  ffmpeg -i output.m4a -y -vn -acodec libvo_aacenc -ab 128k -ar 48000 -ac 2 final.aac

  Please guide me to some script where I'll be able to convert a folder full to mp3 files in one shot. Suppose if its a VBScript then would it ask for the folders where mp3 are kept.

  Also a question about libvo_aacenc codec, is it the best codec to convert to aac if not then what codec should I use for the second pass for converting m4a to aac with highest compression but good quality. The above settings does not produce too good compression. Please help. Am very new to audio encoding.

• Getting either incorrect output resolution or FPS from ffmpeg

  5 novembre 2011, par Adam

  I am capturing an RTSP stream from a security camera, and transcoding it for (live streaming) to iphone, using OSX as the encoding platform.
  I have it working correctly, and Im tuning it.
  However, it seems that it is not outputting the requested resolution. This is my script

  /Applications/SecurityCamera/openRTSP -v -c -t rtsp://10.0.1.118/ch1-s1 | \
  
      /Applications/SecurityCamera/ffmpeg \
  
      -r 10 -i - \
  
      -y -an -ab 64000 -f mpegts -vcodec copy -s 960x640 \
  
      -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 \
  
      -subq 5 -trellis 1 -refs 1 -coder 0 -me_range 16  -keyint_min 25 \
  
      -sc_threshold 40 -i_qfactor 0.71 -bt 400k -maxrate 524288 -bufsize 524288 \
  
      -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -level 30 \
  
      -aspect 960:640 -r 10 -g 10 -async 2 -\
  
      |/Applications/SecurityCamera/mediastreamsegmenter -b http://localhost:8080/\
  
        -f /Library/WebServer/Documents/ -i stream.m3u8 -t 10 -s 4 -D

  This is the status report :

  Input #0, h264, from 'pipe:':
  
  
  
    Duration: N/A, bitrate: N/A
  
    Stream #0.0: Video: h264, yuv420p, 1600x1200, 10 fps, 10 tbr, 1200k tbn, 20 tbc
  
    [mpegts @ 0x10100c200] muxrate VBR, pcr every 1 pkts, sdt every 200, pat/pmt every 40 pkts
  
    Output #0, mpegts, to 'pipe:':
  
    Metadata:
  
      encoder         : Lavf52.93.0
  
      Stream #0.0: Video: libx264, yuv420p, 1600x1200 [PAR 1:1 DAR 4:3], q=2-31, 90k tbn, 10 tbc
  
  Stream mapping:
  
    Stream #0.0 -> #0.0

  You can see that its working, but it is outputting 1600x1200 for some reason. (possibly -vcodec copy copies all codec parameters, not just the codec type ?)

  If I change the -vcodec copy to -vcodec libx264 then I get the correct status report (stating 960x640, correct), but the streaming switches to 2 FPS (why ? Im forcing both input and output !) and it halts after 54 frames (see output below)

  Seems stream 0 codec frame rate differs from container frame rate: 20.00 (20/1) -> 10.00 (20/2)
  
  Input #0, h264, from 'pipe:':
  
    Duration: N/A, bitrate: N/A
  
      Stream #0.0: Video: h264, yuv420p, 1600x1200, 10 fps, 10 tbr, 1200k tbn, 20 tbc
  
  [buffer @ 0x100d02420] w:1600 h:1200 pixfmt:yuv420p
  
  [scale @ 0x100d026f0] w:1600 h:1200 fmt:yuv420p -> w:960 h:640 fmt:yuv420p flags:0x4
  
  [libx264 @ 0x10100d400] using SAR=1/1
  
  [libx264 @ 0x10100d400] frame MB size (60x40) > level limit (1620)
  
  [libx264 @ 0x10100d400] using cpu capabilities: MMX2 SSE2Fast SSSE3 Cache64 SlowCTZ SlowAtom
  
  [libx264 @ 0x10100d400] profile Constrained Baseline, level 3.0
  
  [mpegts @ 0x10100c200] muxrate VBR, pcr every 1 pkts, sdt every 200, pat/pmt every 40 pkts
  
  Output #0, mpegts, to 'pipe:':
  
    Metadata:
  
      encoder         : Lavf52.93.0
  
      Stream #0.0: Video: libx264, yuv420p, 960x640 [PAR 1:1 DAR 3:2], q=10-51, 200 kb/s, 90k tbn, 10 tbc
  
  Stream mapping:
  
    Stream #0.0 -> #0.0
  
  read pmap fffps=  3 q=37.0 size=      37kB time=0.10 bitrate=3008.0kbits/s    bits/s    
  
  video pid set at 100
  
  found sequence start
  
    next segment value 1026000
  
  written bytes 376 skipped 0
  
  frame=   54 fps=  2 q=-1.0 Lsize=     160kB time=5.40 bitrate= 242.0kbits/s    
  
  video:141kB audio:0kB global headers:0kB muxing overhead 12.872737%
  
  frame I:6     Avg QP:34.68  size: 23524
  
  [libx264 @ 0x10100d400] frame P:48    Avg QP:41.53  size:    75
  
  [libx264 @ 0x10100d400] mb I  I16..4: 63.9%  0.0% 36.1%
  
  [libx264 @ 0x10100d400] mb P  I16..4:  0.1%  0.0%  0.0%  P16..4:  0.8%  0.1%  0.0%  0.0%  0.0%    skip:99.0%
  
  [libx264 @ 0x10100d400] final ratefactor: 38.54
  
  [libx264 @ 0x10100d400] coded y,uvDC,uvAC intra: 57.7% 22.3% 2.0% inter: 0.0% 0.1% 0.0%
  
  [libx264 @ 0x10100d400] i16 v,h,dc,p: 23% 35% 27% 15%
  
  [libx264 @ 0x10100d400] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 23% 32% 16%  4%  3%  3%  7%  4%  8%
  
  [libx264 @ 0x10100d400] i8c dc,h,v,p: 83% 11%  5%  0%
  
  [libx264 @ 0x10100d400] kb/s:214.43

• AVCodecContext settings for H264 (1080i)

  23 septembre 2013, par moose

  I'm trying to configure x264 for 1080i capturing. Most of these settings below are found in different examples. However, compiled together they don't work. ffmpeg API reports no error, but avcodec_encode_video() always returns zero.

  Some of the numbers are strange to me... for example, gop_size. Isn't 250 too high ?

  Event you can't offer the final answer, I'm still interested in any kind of comment on this subject.

  pCodecContext->codec_type              = AVMEDIA_TYPE_VIDEO;
  
  pCodecContext->codec_id                = CODEC_ID_H264;
  
  
  
  pCodecContext->coder_type              = FF_CODER_TYPE_AC;
  
  pCodecContext->flags                  |= CODEC_FLAG_LOOP_FILTER | CODEC_FLAG_INTERLACED_ME | CODEC_FLAG_INTERLACED_DCT;
  
  pCodecContext->me_cmp                 |= 1;
  
  pCodecContext->partitions             |= X264_PART_I8X8 | X264_PART_I4X4 | X264_PART_P8X8 | X264_PART_B8X8;
  
  pCodecContext->me_method               = ME_UMH;
  
  pCodecContext->me_subpel_quality       = 8;
  
  pCodecContext->me_range                = 16;
  
  
  
  pCodecContext->bit_rate                = 10 * 1024 * 1024; // 10 Mbps??
  
  pCodecContext->width                   = 1920;
  
  pCodecContext->height                  = 1080;
  
  
  
  pCodecContext->time_base.num           = 1;    // 25 fps
  
  pCodecContext->time_base.den           = 25;   // 25 fps
  
  
  
  pCodecContext->gop_size                = 250; // 250
  
  pCodecContext->keyint_min              = 25;
  
  pCodecContext->scenechange_threshold   = 40;
  
  pCodecContext->i_quant_factor          = 0.71f;
  
  pCodecContext->b_frame_strategy        = 1;
  
  pCodecContext->qcompress               = 0.6f;
  
  pCodecContext->qmin                    = 10;
  
  pCodecContext->qmax                    = 51;
  
  pCodecContext->max_qdiff               = 4;
  
  pCodecContext->max_b_frames            = 3;
  
  pCodecContext->refs                    = 4;
  
  pCodecContext->directpred              = 3;
  
  pCodecContext->trellis                 = 1;
  
  pCodecContext->flags2                 |= CODEC_FLAG2_WPRED | CODEC_FLAG2_MIXED_REFS | CODEC_FLAG2_8X8DCT | CODEC_FLAG2_FASTPSKIP;  // wpred+mixed_refs+dct8x8+fastpskip
  
  pCodecContext->weighted_p_pred         = 2; // not implemented with interlaced ??
  
  pCodecContext->crf                     = 22;
  
  
  
  pCodecContext->pix_fmt                 = PIX_FMT_YUV420P;
  
  
  
  pCodecContext->thread_count            = 0;