Recherche avancée

Sur d’autres sites (5825)

• Converting from FLV to MP4 using ffmpeg

  14 juillet 2016, par Brad

  I have a library of several thousand flv files which I need to convert to mp4. I’m trying to use ffmpeg to do so but I’m running into some issues.

  Primarily :

  1) I can’t switch from FLV to MP4 without re-encoding. If I do I get a message from ffmpeg saying "Could not find tag for codec flv1 in stream #0, codec not currently supported in container"

  2) If I re-encode the videos, the resultant videos are lower quality (I see artifacting in VLC) AND larger. For example one video went from 2.5MB to 4.3MB (almost double in size)

  Given number two you may be asking yourself - why convert then ?

  The answer is I need to stream these to mobile devices (phones/tablets etc) and flv isn’t supported. So I need to convert the files but I can’t tolerate more than a minimum change in quality, and preferably zero to no increase in size.

  Here’s the ffmpeg command I’m running :

  ffmpeg -i $_.FullName -movflags faststart -profile:v baseline -level 3.0 "$($_.BaseName).mp4"

  (Note that I’m running ffmpeg from powershell so :

  $_.FullName = the original file name 
  
  "$($_.BaseName).mp4" = the original file name with mp4 extension)

  Can any FFMPEG guru’s help me to understand what I’m doing wrong ? Is there some set of parameters I can use to make this conversion result in less loss of quality and similar size ?

  Note I’ve also tried "-c:v libx264 -preset veryslow -crf 23 -c:a copy". Using present "veryslow" doesn’t result in any appreciable difference.

  UPDATE
  I’m using the following options :

  ffmpeg -i $_.FullName -c:v libx264 -preset veryslow -crf 19 -c:a copy "$($_.BaseName).mp4"

  Here’s the full output :

      ffmpeg version 2.8.4 Copyright (c) 2000-2015 the FFmpeg developers
  
        built with gcc 5.2.0 (GCC)
  
        configuration : —enable-gpl —enable-version3 —disable-w32threads —enable-avisynth —enable-bzlib —enable-fontconfi
  
      g —enable-frei0r —enable-gnutls —enable-iconv —enable-libass —enable-libbluray —enable-libbs2b —enable-libcaca —
  
      enable-libdcadec —enable-libfreetype —enable-libgme —enable-libgsm —enable-libilbc —enable-libmodplug —enable-libm
  
      p3lame —enable-libopencore-amrnb —enable-libopencore-amrwb —enable-libopenjpeg —enable-libopus —enable-librtmp —en
  
      able-libschroedinger —enable-libsoxr —enable-libspeex —enable-libtheora —enable-libtwolame —enable-libvidstab —ena
  
      ble-libvo-aacenc —enable-libvo-amrwbenc —enable-libvorbis —enable-libvpx —enable-libwavpack —enable-libwebp —enabl
  
      e-libx264 —enable-libx265 —enable-libxavs —enable-libxvid —enable-lzma —enable-decklink —enable-zlib
  
        libavutil      54. 31.100 / 54. 31.100
  
        libavcodec     56. 60.100 / 56. 60.100
  
        libavformat    56. 40.101 / 56. 40.101
  
        libavdevice    56.  4.100 / 56.  4.100
  
        libavfilter     5. 40.101 /  5. 40.101
  
        libswscale      3.  1.101 /  3.  1.101
  
        libswresample   1.  2.101 /  1.  2.101
  
        libpostproc    53.  3.100 / 53.  3.100
  
      Input #0, flv, from ’C :\Users\brad\Desktop\ffmpeg\Originals\1019800-1278575542468.flv’ :
  
        Metadata :
  
          canSeekToEnd : false
  
          createdby : FMS 3.5
  
          creationdate : Thu Jul 08 03:52:25 2010
  
        Duration : 00:00:56.94, start : 0.000000, bitrate : 360 kb/s
  
          Stream #0:0 : Video : flv1, yuv420p, 320x240, 1k tbr, 1k tbn, 1k tbc
  
          [libx264 @ 02cf7300] using cpu capabilities : MMX2 SSE2Fast SSSE3 SSE4.2
  
          [libx264 @ 02cf7300] profile High, level 4.2
  
          [libx264 @ 02cf7300] 264 - core 148 r2638 7599210 - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - http://www.videolan.or
  
      g/x264.html - options : cabac=1 ref=16 deblock=1:0:0 analyse=0x3:0x133 me=umh subme=10 psy=1 psy_rd=1.00:0.00 mixed_ref=1
  
       me_range=24 chroma_me=1 trellis=2 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=7 lookahead_th
  
      reads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=8 b_pyramid=2 b_adapt=
  
      2 b_bias=0 direct=3 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=60
  
      rc=crf mbtree=1 crf=19.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
  
      Output #0, mp4, to ’1019800-1278575542468.mp4’ :
  
        Metadata :
  
          canSeekToEnd : false
  
          createdby : FMS 3.5
  
          creationdate : Thu Jul 08 03:52:25 2010
  
          encoder : Lavf56.40.101
  
          Stream #0:0 : Video : h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 320x240, q=-1—1, 1k fps, 16k tbn, 1k tbc
  
          Metadata :
  
            encoder : Lavc56.60.100 libx264
  
      Stream mapping :
  
        Stream #0:0 -> #0:0 (flv1 (flv) -> h264 (libx264))
  
      Press [q] to stop, [?] for help
  
      frame=57117 fps=199 q=-1.0 Lsize=    5611kB time=00:00:57.11 bitrate= 804.8kbits/s dup=56685 drop=0
  
      video:5184kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead : 8.229259%
  
      [libx264 @ 02cf7300] frame I:230   Avg QP:15.92  size :  8828
  
      [libx264 @ 02cf7300] frame P:6399  Avg QP:17.19  size :   385
  
      [libx264 @ 02cf7300] frame B:50488 Avg QP:27.13  size :    16
  
      [libx264 @ 02cf7300] consecutive B-frames :  0.4%  0.0%  0.0%  0.0%  0.0%  2.3%  0.0%  0.0% 97.2%
  
      [libx264 @ 02cf7300] mb I  I16..4 :  2.9% 92.6%  4.5%
  
      [libx264 @ 02cf7300] mb P  I16..4 :  0.1%  2.0%  0.2%  P16..4 :  2.4%  1.2%  1.1%  0.1%  0.0%    skip:92.9%
  
      [libx264 @ 02cf7300] mb B  I16..4 :  0.0%  0.0%  0.0%  B16..8 :  2.6%  0.0%  0.0%  direct : 0.0%  skip:97.3%  L0:45.0% L1:5
  
  4.9% BI : 0.0%
  
      [libx264 @ 02cf7300] 8x8 transform intra:90.7% inter:76.5%
  
      [libx264 @ 02cf7300] direct mvs  spatial:75.2% temporal:24.8%
  
      [libx264 @ 02cf7300] coded y,uvDC,uvAC intra : 94.4% 96.8% 64.8% inter : 0.3% 0.4% 0.1%
  
      [libx264 @ 02cf7300] i16 v,h,dc,p : 16% 25% 18% 41%
  
      [libx264 @ 02cf7300] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu : 19% 28% 30%  4%  3%  3%  4%  4%  5%
  
      [libx264 @ 02cf7300] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu : 18% 22%  9% 11%  8%  7% 10%  8%  7%
  
      [libx264 @ 02cf7300] i8c dc,h,v,p : 30% 34% 23% 13%
  
      [libx264 @ 02cf7300] Weighted P-Frames : Y:0.1% UV:0.1%
  
      [libx264 @ 02cf7300] ref P L0 : 74.1% 19.7%  4.5%  0.6%  0.1%  0.2%  0.0%  0.1%  0.0%  0.1%  0.0%  0.2%  0.0%  0.2%  0.0%
  
    0.1%
  
      [libx264 @ 02cf7300] ref B L0 : 95.5%  1.6%  0.7%  0.5%  0.4%  0.3%  0.3%  0.2%  0.1%  0.1%  0.1%  0.1%  0.1%  0.0%  0.0%
      [libx264 @ 02cf7300] ref B L1 : 84.5% 15.5%
  
      [libx264 @ 02cf7300] kb/s:743.46
  

  Original Video Size: 2.44 MB
  
  New Video Size: 5.6 MB

• Revision 32737 : habillage par defaut de Zpip utilise les conventions documentees

  8 novembre 2009, par cedric@… — Log

  habillage par defaut de Zpip utilise les conventions documentees

• MAINTAINERS : Split project server admin list

  6 août 2022, par Michael Niedermayer

  MAINTAINERS : Split project server admin list
  This updates the list closer to reality.
  
  Iam not a professional server admin, iam happy to help maintain the box as i have
  
  done in the past. But iam not qualified nor volunteering to fix sudden problems
  
  nor do i do major upgrades (i lack the experience to recover the box remotely if
  
  something goes wrong) and also iam not maintaining backups ATM (our backup system
  
  had a RAID-5 failure, raz is working on setting a new one up)
  Maybe this should be signaled in a different way than spliting the lines but ATM
  
  people ping me if something is wrong and what i do is mainly mail/ping raz
  
  and try to find another root admin so raz is not the only active & professional
  
  admin on the team. It would be more efficient if people contact raz and others
  
  directly instead of depending on my waking up and forwarding a "ffmpeg.org" is down note
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] MAINTAINERS