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• Realtime output from ffmpeg and livestreamer using subprocess.Popen

  6 mars 2016, par Roger B

  In ffmpeg and livestreamer i only get a few lines in realtime then i get the rest of them when the process is done...

  I have tried two codes :

  from subprocess import *
  
  p = Popen('ffmpeg -i infile.mp4 outfile.mp4', stderr=STDOUT, stdout=PIPE)
  
  for line in iter(p.stdout.readline(), b'')
  
     print line.rstrip()

  and

  from subprocess import *
  
  p = Popen('ffmpeg -i infile.mp4 outfile.mp4', stderr=STDOUT, stdout=PIPE)
  
  while p.poll is None:
  
     line = p.stdout.readline()
  
     print line.rstrip()

  Both of them prints first :

  ffmpeg version N-72805-g913685f Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 4.9.2 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
  
  isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
  
  le-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --
  
  enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-l
  
  ibilbc --enable-libmodplug --enable-libmfx --enable-libmp3lame --enable-libopenc
  
  ore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --ena
  
  ble-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable
  
  -libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enabl
  
  e-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable
  
  -libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --e
  
  nable-lzma --enable-decklink --enable-zlib
  
    libavutil      54. 27.100 / 54. 27.100
  
    libavcodec     56. 41.100 / 56. 41.100
  
    libavformat    56. 36.100 / 56. 36.100
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 16.101 /  5. 16.101
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  2.100 /  1.  2.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'a.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf56.10.100
  
    Duration: 01:34:36.14, start: 0.021333, bitrate: 6205 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720,
  
   5938 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, flt
  
  p, 256 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  [mp4 @ 05013ce0] Codec for stream 0 does not use global headers but container fo
  
  rmat requires global headers
  
  [mp4 @ 05013ce0] Codec for stream 1 does not use global headers but container fo
  
  rmat requires global headers
  
  Output #0, mp4, to 'b.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf56.36.100
  
      Stream #0:0(und): Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 1280x720, q
  
  =2-31, 5938 kb/s, 30 fps, 30 tbr, 15360 tbn, 15360 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac ([64][0][0][0] / 0x0040), 48000 Hz, stereo, 256
  
   kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
    Stream #0:1 -> #0:1 (copy)
  
  Press [q] to stop, [?] for help

  Then when the convert process is done the rest of the log turns up...

  How can i get all stdout in realtime ??

  EDIT :

  If i use a text file to write to it get all in realtime.

  from subprocess import *
  
  out_file = open('stdout.txt','a')
  
  Popen('ffmpeg -i infile.mp4 outfile.mp4', stderr=STDOUT, stdout=out_file)

  But i want it print out stdout in realtime..

  Why does it work in realtime to a file but not direct print ?

• Creating exact replica of video file[ffmpeg]

  13 octobre 2015, par gaurav

  I have written some code using ffmpeg’s library which decodes every frame of video file, does some manipulation on it and finally encode and mux the frame to new container.this all works.
  The problem i am trying to solve here is how to make the output file have exact stream settings as input file.

  if i run ffmpeg -i on my files i get following -
  1)Input File -
  Duration : 00:00:30.95, start : 0.000000, bitrate : 1195 kb/s
  Stream #0:0(eng) : Video : h264 (Main) (avc1 / 0x31637661), yuv420p(tv), 1280x720 [SAR 1:1 DAR 16:9], 996 kb/s, 25 fps, 25 tbr, 25k tbn, 50 tbc (default)
  
  Metadata :
  creation_time : 2015-09-30 06:33:24
  handler_name : Mainconcept MP4 Video Media Handler
  encoder : AVC Coding

  2)Output file -
  Duration : 00:00:30.96, start : 0.000000, bitrate : 1225 kb/s
  Stream #0:0(und) : Video : h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 1032 kb/s, 25.03 fps, 25 tbr, 25k tbn, 100 tbc (default)
  Metadata :
  handler_name : VideoHandler

  3)If i run my code again on above output file to generate another output file then that file looks like this-

  Duration : 00:00:30.96, start : 0.000000, bitrate : 1264 kb/s
  Stream #0:0(und) : Video : h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 1071 kb/s, 25.03 fps, 25 tbr, 25k tbn, 200 tbc (default)

  Notice the bitrate and TBC is changing everytime i run my code.
  How should i configure my encoder to make the output file identical to input file ? the current code for configuring encoder looks like this -

          c = out_stream->codec;
  
          c->codec_id                = inputStream->codec->codec_id;
  
          c->bit_rate                = inputStream->codec->bit_rate;
  
  
  
          /* Resolution must be a multiple of two. */
  
          c->width                   = inputStream->codec->width;
  
          c->height                  = inputStream->codec->height;
  
          c->gop_size                = inputStream->codec->gop_size;
  
  
  
          c->time_base               = inputStream->codec->time_base;
  
          out_stream->time_base      = inputStream->time_base;
  
  
  
          av_stream_set_r_frame_rate(out_stream,av_stream_get_r_frame_rate(inputStream));
  
          out_stream->avg_frame_rate = inputStream->avg_frame_rate;
  
  
  
          c->pix_fmt                 = AV_PIX_FMT_YUV420P;
  
          c->sample_aspect_ratio.num = inputStream->codec->sample_aspect_ratio.num;
  
          c->sample_aspect_ratio.den = inputStream->codec->sample_aspect_ratio.den;
  
          c->ticks_per_frame         = inputStream->codec->ticks_per_frame;
  
          c->profile                 = inputStream->codec->profile;
  
          out_stream->duration       = inputStream->duration;

• Q.For encoding error of ffmpeg

  21 mars 2016, par 社畜根性

  I ran the following command.

  ffmpeg -i test.mp4 -threads 2 -codec:v libx264 -s:v 1280x720 -aspect:v 16:9 -b:v 256k -map 0 -f segment -segment_format mpegts -segment_time 10 -segment_list stream.m3u8 streamfiles/stream%03d.ts

  Execution result

  ffmpeg version N-75926-gce0834b Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 4.6 (Debian 4.6.3-14+rpi1)
  
    configuration: --arch=armel --target-os=linux --enable-shared --enable-gpl --enable-libx264 --enable-nonfree
  
    libavutil      55.  3.100 / 55.  3.100
  
    libavcodec     57.  5.100 / 57.  5.100
  
    libavformat    57.  3.100 / 57.  3.100
  
    libavdevice    57.  0.100 / 57.  0.100
  
    libavfilter     6. 11.100 /  6. 11.100
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.100 /  2.  0.100
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf56.40.100
  
    Duration: 00:00:03.28, start: 0.000000, bitrate: 10159 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080, 10156 kb/s, 25 fps, 25 tbr, 1200k tbn, 2400k tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
  Illegal instruction

  The result is that an error occurred.
  Someone told me that it’s an error if you do not put the option to ./configure of libx264. That option is the --extra-cflags='-march=armv6' --extra-ldflags='-march=armv6'. Otherwise it would use the instruction of unsupported.

  So I ran ./configure with the option, then I ran the make and now I’m getting an error message :

  common/arm/quant-a.S: Assembler messages:
  
  common/arm/quant-a.S:362: Error: selected processor does not support ARM mode `rbit r1,r1'
  
  common/arm/quant-a.S:363: Error: selected processor does not support ARM mode `rbit r1,r1'
  
  Makefile:217: recipe for target 'common/arm/quant-a.o' failed
  
  make: *** [common/arm/quant-a.o] Error 1

  I do not know the meaning of this error. How should you deal me this error ?

  I use the machine is Raspberry PI B+ and my OS is Raspbian. I want to use ffmpeg and libx264.

  Any advice and suggestions will be greatly appreciated.