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• Using libav-tools versus libav built from source - video quality much worse

  17 juin 2015, par kislo

  We are trying to create a video from still images, running on Ubuntu 14.04.

  If we have installed libav-tools then the output video is much higher quality than if we have installed libav manually. Unfortunately, we need to run a solution where libav is built from source, so we want to find out how to improve the quality.

  Here is the console output for the libav-tools (higher quality) :

  avconv version 9.18-6:9.18-0ubuntu0.14.04.1, Copyright (c) 2000-2014 the Libav developers
  
    built on Mar 16 2015 13:19:10 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
  
  [image2 @ 0x22ae120] max_analyze_duration reached
  
  Input #0, image2, from 'frame.%04d.jpg':
  
    Duration: 00:00:10.00, start: 0.000000, bitrate: N/A
  
      Stream #0.0: Video: mjpeg, yuvj420p, 1280x720 [PAR 1:1 DAR 16:9], 8 fps, 8 tbr, 8 tbn
  
  [libx264 @ 0x22afac0] using SAR=1/1
  
  [libx264 @ 0x22afac0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX AVX2 FMA3 LZCNT BMI2
  
  [libx264 @ 0x22afac0] profile High, level 3.1
  
  [libx264 @ 0x22afac0] 264 - core 142 r2389 956c8d8 - H.264/MPEG-4 AVC codec - Copyleft 2003-2014 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=8 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.25 aq=1:1.00
  
  Output #0, mp4, to 'a1.mp4':
  
    Metadata:
  
      encoder         : Lavf54.20.4
  
      Stream #0.0: Video: libx264, yuvj420p, 1280x720 [PAR 1:1 DAR 16:9], q=-1--1, 8 tbn, 8 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (mjpeg -> libx264)
  
  Press ctrl-c to stop encoding
  
  frame=  159 fps= 43 q=32766.0 Lsize=    1580kB time=19.62 bitrate= 659.3kbits/s    
  
  video:607kB audio:0kB global headers:0kB muxing overhead 160.388953%
  
  [libx264 @ 0x22afac0] frame I:21    Avg QP:14.32  size: 21142
  
  [libx264 @ 0x22afac0] frame P:132   Avg QP:16.12  size:  8691
  
  [libx264 @ 0x22afac0] frame B:6     Avg QP:13.61  size:  3874
  
  [libx264 @ 0x22afac0] consecutive B-frames: 95.0%  0.0%  0.0%  5.0%
  
  [libx264 @ 0x22afac0] mb I  I16..4: 37.4% 61.4%  1.2%
  
  [libx264 @ 0x22afac0] mb P  I16..4:  9.1% 19.2%  0.3%  P16..4:  6.2%  2.8%  1.3%  0.0%  0.0%    skip:61.1%
  
  [libx264 @ 0x22afac0] mb B  I16..4:  1.8%  2.0%  0.0%  B16..8: 31.9%  7.1%  0.7%  direct: 9.2%  skip:47.3%  L0:69.8% L1:29.5% BI: 0.8%
  
  [libx264 @ 0x22afac0] 8x8 transform intra:65.0% inter:92.8%
  
  [libx264 @ 0x22afac0] coded y,uvDC,uvAC intra: 36.3% 31.8% 7.1% inter: 3.6% 6.0% 0.7%
  
  [libx264 @ 0x22afac0] i16 v,h,dc,p: 74% 14%  6%  6%
  
  [libx264 @ 0x22afac0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 29% 24% 32%  5%  2%  3%  2%  1%  3%
  
  [libx264 @ 0x22afac0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 51% 23%  9%  2%  3%  6%  3%  1%  2%
  
  [libx264 @ 0x22afac0] i8c dc,h,v,p: 52% 20% 25%  2%
  
  [libx264 @ 0x22afac0] Weighted P-Frames: Y:6.8% UV:6.1%
  
  [libx264 @ 0x22afac0] ref P L0: 58.1%  6.2% 12.1% 22.6%  0.9%
  
  [libx264 @ 0x22afac0] ref B L0: 83.0% 16.3%  0.7%
  
  [libx264 @ 0x22afac0] ref B L1: 93.5%  6.5%
  
  [libx264 @ 0x22afac0] kb/s:649.85

  Here is the console output for libav built manually (lower quality) :

  avconv version 11.4, Copyright (c) 2000-2014 the Libav developers
  
    built on Jun 17 2015 02:19:28 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
  
  [image2 @ 0x329f140] max_analyze_duration 5000000 reached
  
  Input #0, image2, from 'frame.%04d.jpg':
  
    Duration: 00:00:10.00, start: 0.000000, bitrate: N/A
  
      Stream #0.0: Video: mjpeg, yuvj420p, 1280x720 [PAR 1:1 DAR 16:9], 8 fps, 8 tbn
  
  Output #0, mp4, to 'a2.mp4':
  
    Metadata:
  
      encoder         : Lavf56.1.0
  
      Stream #0.0: Video: mpeg4, yuv420p, 1280x720 [PAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 8 fps, 8 tbn, 8 tbc
  
      Metadata:
  
        encoder         : Lavc56.1.0 mpeg4
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (mjpeg (native) -> mpeg4 (native))
  
  Press ctrl-c to stop encoding
  
  frame=  159 fps=  0 q=31.0 Lsize=     902kB time=19.75 bitrate= 374.2kbits/s    
  
  video:900kB audio:0kB other streams:0kB global headers:0kB muxing overhead: 0.239928%

  In case it helps : the images are named frame.0000.jpg, frame.0001.jpg, etc., so our command is :
  avconv -y -f image2 -r 8 -i frame.%04d.jpg -vf "setpts=2*PTS" videofile.mp4 for both runs shown above. Any help would be hugely appreciated !

• FFMPEG Scale video without filtering

  24 juin 2015, par honi

  I am interested in scaling a video to a larger size without applying any filter or anything. The output video should look very pixelated. How do I do this in FFMPEG ?

  On the suggestion of Ronald S. Bultje, I am using the neighbor flag. I have also decided to use the rawvideo codec to avoid compression.

  The current command I am running is

  ffmpeg -i vid.avi -s 800x800 -sws_flags neighbor -sws_dither none -vcodec rawvideo vid2.avi

  The command line output of that command is

  ffmpeg version 2.7 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn)
  
    configuration: --prefix=/opt/local --enable-swscale --enable-avfilter --enable-avresample --enable-libmp3lame --enable-libvorbis --enable-libopus --enable-libtheora --enable-libschroedinger --enable-libopenjpeg --enable-libmodplug --enable-libvpx --enable-libspeex --enable-libass --enable-libbluray --enable-lzma --enable-gnutls --enable-fontconfig --enable-libfreetype --enable-libfribidi --disable-indev=jack --disable-outdev=xv --mandir=/opt/local/share/man --enable-shared --enable-pthreads --cc=/usr/bin/clang --enable-vda --arch=x86_64 --enable-yasm --enable-gpl --enable-postproc --enable-libx264 --enable-libxvid
  
    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
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  2.100 /  1.  2.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Input #0, avi, from 'vid.avi':
  
    Duration: 00:00:25.00, start: 0.000000, bitrate: 226 kb/s
  
      Stream #0:0: Video: rawvideo, pal8, 80x80, 206 kb/s, 4 fps, 4 tbr, 4 tbn, 4 tbc
  
  File 'vid2.avi' already exists. Overwrite ? [y/N] y
  
  Output #0, avi, to 'vid2.avi':
  
    Metadata:
  
      ISFT            : Lavf56.36.100
  
      Stream #0:0: Video: rawvideo, pal8, 800x800, q=2-31, 200 kb/s, 4 fps, 4 tbn, 4 tbc
  
      Metadata:
  
        encoder         : Lavc56.41.100 rawvideo
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (rawvideo (native) -> rawvideo (native))
  
  Press [q] to stop, [?] for help
  
  frame=  100 fps=0.0 q=0.0 Lsize=   62608kB time=00:00:25.00 bitrate=20515.4kbits/s    
  
  video:62600kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.012614%

• ffmpeg mov to vp9 webm with transparency (alpha channel) issue

  17 juin 2015, par kambythet

  Using ffmpeg (command below) to convert an mov that has an alpha channel to a webm with alpha channel is proving to be problematic. The resulting webm does not have the alpha channel.

  Any help would be appreciated !

  /Applications/ffmpeg -i trex-01.mov -c:v libvpx-vp9 -b:v 1000K -threads 8 -speed 1 -tile-columns 6 -frame-parallel 1 -auto-alt-ref 1 -lag-in-frames 25 -c:a libopus -b:a 64k -f webm trex-01.webm

  Full input and output from ffmpeg :

  /Applications/ffmpeg -i trex-01.mov -c:v libvpx-vp9 -b:v 1000K -threads 8 -speed 1 -tile-columns 6 -frame-parallel 1 -auto-alt-ref 1 -lag-in-frames 25 -c:a libopus -b:a 64k -f webm trex-01.webm
  
  ffmpeg version 2.6.2-tessus Copyright (c) 2000-2015 the FFmpeg developers
  
    built with Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn)
  
    configuration: --cc=/usr/bin/clang --prefix=/Users/helmutt/data/ext/ffmpeg/sw --as=yasm --extra-version=tessus --disable-shared --enable-static --disable-ffplay --enable-gpl --enable-pthreads --enable-postproc --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libx265 --enable-libxvid --enable-libspeex --enable-bzlib --enable-zlib --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libxavs --enable-libsoxr --enable-libwavpack --enable-version3 --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvpx --enable-libgsm --enable-libopus --enable-libmodplug --enable-fontconfig --enable-libfreetype --enable-libass --enable-libbluray --enable-filters --disable-indev=qtkit --disable-indev=x11grab_xcb --enable-runtime-cpudetect
  
    libavutil      54. 20.100 / 54. 20.100
  
    libavcodec     56. 26.100 / 56. 26.100
  
    libavformat    56. 25.101 / 56. 25.101
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 11.102 /  5. 11.102
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Guessed Channel Layout for  Input Stream #0.1 : mono
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'trex-01.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 537199360
  
      compatible_brands: qt  
  
      creation_time   : 2013-01-28 20:07:34
  
    Duration: 00:00:07.97, start: 0.000000, bitrate: 26594 kb/s
  
      Stream #0:0(eng): Video: png (png  / 0x20676E70), rgba, 640x360 [SAR 2834:2834 DAR 16:9], 25842 kb/s, 30 fps, 30 tbr, 30 tbn, 30 tbc (default)
  
      Metadata:
  
        creation_time   : 2013-01-28 20:07:34
  
        handler_name    : Apple Alias Data Handler
  
        encoder         : PNG
  
        timecode        : 00:00:00:00
  
      Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 44100 Hz, 1 channels, s16, 705 kb/s (default)
  
      Metadata:
  
        creation_time   : 2013-01-28 20:07:34
  
        handler_name    : Apple Alias Data Handler
  
        timecode        : 00:00:00:00
  
      Stream #0:2(eng): Data: none (tmcd / 0x64636D74), 0 kb/s (default)
  
      Metadata:
  
        creation_time   : 2013-01-28 20:07:54
  
        handler_name    : Apple Alias Data Handler
  
        timecode        : 00:00:00:00
  
  File 'trex-01.webm' already exists. Overwrite ? [y/N] y
  
  [libvpx-vp9 @ 0x7ffb7d00b400] v1.3.0
  
  Output #0, webm, to 'trex-01.webm':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 537199360
  
      compatible_brands: qt  
  
      encoder         : Lavf56.25.101
  
      Stream #0:0(eng): Video: vp9 (libvpx-vp9), yuv420p, 640x360 [SAR 1:1 DAR 16:9], q=-1--1, 1000 kb/s, 30 fps, 1k tbn, 30 tbc (default)
  
      Metadata:
  
        creation_time   : 2013-01-28 20:07:34
  
        handler_name    : Apple Alias Data Handler
  
        timecode        : 00:00:00:00
  
        encoder         : Lavc56.26.100 libvpx-vp9
  
      Stream #0:1(eng): Audio: opus (libopus), 48000 Hz, mono, s16, 64 kb/s (default)
  
      Metadata:
  
        creation_time   : 2013-01-28 20:07:34
  
        handler_name    : Apple Alias Data Handler
  
        timecode        : 00:00:00:00
  
        encoder         : Lavc56.26.100 libopus
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (png (native) -> vp9 (libvpx-vp9))
  
    Stream #0:1 -> #0:1 (pcm_s16le (native) -> opus (libopus))