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• Best way to extract all keyframes from a video in Java ?

  2 mars 2017, par JT J

  I have a Windows batch script that I’m currently trying to recreate in Java. The script runs an ffmpeg command that extracts all of the keyframes from a video and pastes them as .BMP images in a folder.

  This is what it the script looks like :

  ffmpeg -i input.mp4 -vf "select=eq(pict_type\,I)" -vsync 1 %%3d.bmp

  The end result of this is that it takes "input.mp4" and outputs each keyframe as 001.bmp, 002.bmp... and so on.

  I’m trying to avoid simply starting an ffmpeg runtime, because I want to be able to run this script on other platforms in the future. Also, I’ll be doing this for very long videos (multiple hours long sometimes) so performance is very important, and needs to be done as fast as possible. Is it possible to use multithreading ? That’s something I’m not familiar with in Java. What would be the best way to do this ?

• adding silent audio in ffmpeg

  10 février 2017, par jon

  I’m trying to use ffmpeg to add a silent audio track to a MOV file.

  I created a silent audio track longer than the video, and intend to use the -shortest option with ffmpeg.

  Using SoX v14.3.1, I run this to generate a wav file :

  sox -n -r 44100 -b 16 -c 2 -L silence.wav trim 0.0 60.000
  
  
  
  # -n  = Sox's null file
  
  # -r = sample rate 
  
  # -b = bits per sample
  
  # -c = num of channels
  
  # -L = little endian
  
  # filename
  
  # trim - is an effect, args start and length.

  My basic ffmpeg command looks like this :

  ffmpeg -shortest \
  
  -i silence.wav -acodec pcm_s16le \
  
  -i vid_no_sound.mov -vcodec copy vid_with_sound.mov

  The result of this is :

  ffmpeg version 0.11.1 Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Aug 27 2012 13:11:25 with gcc 4.4.5
  
    configuration: --extra-cflags=-static --prefix=/root/ffmpeg_build/src/ffmpeg-0.11.1 --enable-bzlib --enable-gnutls --enable-libfreetype --enable-libmp3lame --enable-libdc1394 --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-openssl --enable-zlib --enable-gpl --enable-nonfree --enable-version3
  
    libavutil      51. 54.100 / 51. 54.100
  
    libavcodec     54. 23.100 / 54. 23.100
  
    libavformat    54.  6.100 / 54.  6.100
  
    libavdevice    54.  0.100 / 54.  0.100
  
    libavfilter     2. 77.100 /  2. 77.100
  
    libswscale      2.  1.100 /  2.  1.100
  
    libswresample   0. 15.100 /  0. 15.100
  
    libpostproc    52.  0.100 / 52.  0.100
  
  [wav @ 0x29ab2e0] max_analyze_duration 5000000 reached at 5015510
  
  Guessed Channel Layout for  Input Stream #0.0 : stereo
  
  Input #0, wav, from 'silence.wav':
  
    Duration: 00:01:00.00, bitrate: 1411 kb/s
  
      Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, s16, 1411 kb/s
  
  Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'vid_no_sound.mov':
  
    Metadata:
  
      major_brand     : qt
  
      minor_version   : 537199360
  
      compatible_brands: qt
  
      creation_time   : 2012-07-25 13:41:44
  
    Duration: 00:00:14.50, start: 0.000000, bitrate: 27457 kb/s
  
      Stream #1:0(eng): Video: qtrle (rle  / 0x20656C72), rgb24, 1920x1080, 27450 kb/s, SAR 1920:1920 DAR 16:9, 24 fps, 24 tbr, 24 tbn, 24 tbc
  
      Metadata:
  
        creation_time   : 2012-07-25 13:41:44
  
        handler_name    : Apple Alias Data Handler
  
      Stream #1:1(eng): Data: none (tmcd / 0x64636D74)
  
      Metadata:
  
        creation_time   : 2012-07-25 13:42:06
  
        handler_name    : Apple Alias Data Handler
  
        timecode        : 00:00:00:00
  
  File 'vid_with_sound.mov' already exists. Overwrite ? [y/N] y
  
  auto-inserting filter 'auto-inserted resampler 0' between the filter 'src' and the filter 'aformat'
  
  [aresample @ 0x2ab3b00] chl:stereo fmt:s16 r:44100Hz -> chl:stereo fmt:flt r:44100Hz
  
  [NULL @ 0x2994320] Codec is experimental but experimental codecs are not enabled, try -strict -2
  
  Output #0, mov, to 'vid_with_sound.mov':
  
      Stream #0:0(eng): Video: qtrle (rle  / 0x20656C72), rgb24, 1920x1080 [SAR 1920:1920 DAR 16:9], q=2-31, 27450 kb/s, 24 fps, 90k tbn, 24 tbc
  
      Metadata:
  
        creation_time   : 2012-07-25 13:41:44
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:1: Audio: none, 44100 Hz, stereo, flt, 128 kb/s
  
  Stream mapping:
  
    Stream #1:0 -> #0:0 (copy)
  
    Stream #0:0 -> #0:1 (pcm_s16le -> aac)
  
  Error while opening encoder for output stream #0:1 - maybe incorrect parameters such as bit_rate, rate, width or height

  I have tried adding the -strict -2 as suggested, although I am not sure where to put it in the command line.

  I’ve spent two hours trying different things and reading ffmpeg documentation, but I’m still stuck.

  How do I add a silent audio track to a mov file ?

• Video and audio stretch calculations in ffmpeg

  30 janvier 2017, par garrettlynch

  I’m doing some extreme slow motion in ffmpeg on a video, both video and audio track, but can’t quite get my calculations correct.

  The input video is 00:06:41:00 at 24fps (9624 frames).
  I need the output video to be 34:00:00:00 at 24fps (2937600 frames).

  I tried these for the video and audio :

  setpts=305.237*PTS
  
  
  
  atempo=0.5, atempo=0.5, atempo=0.5, atempo=0.5, atempo=0.5, atempo=0.5, atempo=0.5, atempo=0.5, atempo=0.807668329177057

  However the video overshoots by 00:01:19:08 and the audio I’m unsure, on one player it stops somewhere around 8 hours but on another it just continues. What are the correct formulas ?

  Also on VLC the video has grey frames between video frames - do I need to interpolate to have continuous video frames ?

  ---

  Edit by @Mulvya :

  fred-macbookpro:~ srederiquefantune$ ffmpeg -i /Users/srederiquefantune/Desktop/test.mp4 -filter_complex "[0:v]setpts=305.237*PTS, scale=320:240[v];[0:a]atempo=0.5, atempo=0.5, atempo=0.5, atempo=0.5, atempo=0.5, atempo=0.5, atempo=0.5, atempo=0.5, atempo=0.807668329177057[a]" -map "[v]" -map "[a]" /Users/srederiquefantune/Desktop/output2.mp4
  
  ffmpeg version 3.2.2 Copyright (c) 2000-2016 the FFmpeg developers
  
    built with gcc 4.2.1 (GCC) (Apple Inc. build 5666) (dot 3)
  
    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-libsoxr --enable-libspeex --enable-libass --enable-libbluray --enable-lzma --enable-gnutls --enable-fontconfig --enable-libfreetype --enable-libfribidi --disable-libxcb --disable-libxcb-shm --disable-libxcb-xfixes --disable-indev=jack --disable-outdev=xv --disable-audiotoolbox --disable-videotoolbox --disable-sdl2 --mandir=/opt/local/share/man --enable-shared --enable-pthreads --cc=/usr/bin/gcc-4.2 --disable-filter=coreimage --disable-filter=coreimagesrc --enable-vda --disable-indev=avfoundation --arch=x86_64 --enable-yasm --enable-libx265 --enable-gpl --enable-postproc --enable-libx264 --enable-libxvid
  
    libavutil      55. 34.100 / 55. 34.100
  
    libavcodec     57. 64.101 / 57. 64.101
  
    libavformat    57. 56.100 / 57. 56.100
  
    libavdevice    57.  1.100 / 57.  1.100
  
    libavfilter     6. 65.100 /  6. 65.100
  
    libavresample   3.  1.  0 /  3.  1.  0
  
    libswscale      4.  2.100 /  4.  2.100
  
    libswresample   2.  3.100 /  2.  3.100
  
    libpostproc    54.  1.100 / 54.  1.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/Users/srederiquefantune/Desktop/test.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
    Duration: 00:06:41.25, start: 0.000000, bitrate: 2294 kb/s
  
      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 2172 kb/s, 24 fps, 120 tbr, 90k tbn, 48 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 112 kb/s (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
  [libx264 @ 0x104801200] using SAR=4/3
  
  [libx264 @ 0x104801200] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.1 Cache64
  
  [libx264 @ 0x104801200] profile High, level 1.3
  
  [libx264 @ 0x104801200] 264 - core 148 - H.264/MPEG-4 AVC codec - Copyleft 2003-2016 - 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=3 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=24 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=1.40 aq=1:1.00
  
  Output #0, mp4, to '/Users/srederiquefantune/Desktop/output2.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.56.100
  
      Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 320x240 [SAR 4:3 DAR 16:9], q=-1--1, 24 fps, 12288 tbn, 24 tbc (default)
  
      Metadata:
  
        encoder         : Lavc57.64.101 libx264
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
  
      Stream #0:1: Audio: aac (LC) ([64][0][0][0] / 0x0040), 44100 Hz, stereo, fltp, 128 kb/s (default)
  
      Metadata:
  
        encoder         : Lavc57.64.101 aac
  
  Stream mapping:
  
    Stream #0:0 (h264) -> setpts
  
    Stream #0:1 (aac) -> atempo
  
    scale -> Stream #0:0 (libx264)
  
    atempo -> Stream #0:1 (aac)
  
  Press [q] to stop, [?] for help
  
  [output stream 0:1 @ 0x104105420] 100 buffers queued in output stream 0:1, something may be wrong.
  
  frame=    1 fps=0.0 q=0.0 size=       3kB time=00:00:22.01 bitrate=   1.2kbits/s
  
  …
  
  frame=2938515 fps=281 q=-1.0 Lsize= 2439310kB time=35:19:08.66 bitrate= 157.2kbits/s dup=2928888 drop=1 speed=12.1x    
  
  video:389302kB audio:1994106kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.345466%
  
  [libx264 @ 0x104801200] frame I:15399 Avg QP:14.27  size: 20680
  
  [libx264 @ 0x104801200] frame P:740673 Avg QP:17.21  size:    68
  
  [libx264 @ 0x104801200] frame B:2182443 Avg QP:25.83  size:    14
  
  [libx264 @ 0x104801200] consecutive B-frames:  0.9%  0.2%  0.1% 98.8%
  
  [libx264 @ 0x104801200] mb I  I16..4:  7.9% 47.3% 44.8%
  
  [libx264 @ 0x104801200] mb P  I16..4:  0.0%  0.1%  0.1%  P16..4:  0.7%  0.1%  0.1%  0.0%  0.0%    skip:99.0%
  
  [libx264 @ 0x104801200] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  0.1%  0.0%  0.0%  direct: 0.0%  skip:99.9%  L0:14.0% L1:85.9% BI: 0.0%
  
  [libx264 @ 0x104801200] 8x8 transform intra:48.2% inter:52.8%
  
  [libx264 @ 0x104801200] coded y,uvDC,uvAC intra: 91.4% 90.7% 88.0% inter: 0.1% 0.1% 0.0%
  
  [libx264 @ 0x104801200] i16 v,h,dc,p: 78%  4% 11%  7%
  
  [libx264 @ 0x104801200] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 18% 13% 17%  7%  8% 10%  7% 10% 10%
  
  [libx264 @ 0x104801200] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 19% 13% 11%  8% 10% 11%  8% 10%  9%
  
  [libx264 @ 0x104801200] i8c dc,h,v,p: 62% 15% 16%  7%
  
  [libx264 @ 0x104801200] Weighted P-Frames: Y:0.0% UV:0.0%
  
  [libx264 @ 0x104801200] ref P L0: 87.6%  7.8%  4.0%  0.6%  0.0%
  
  [libx264 @ 0x104801200] ref B L0: 50.0% 49.6%  0.4%
  
  [libx264 @ 0x104801200] ref B L1: 91.3%  8.7%
  
  [libx264 @ 0x104801200] kb/s:26.05
  
  [aac @ 0x104802a00] Qavg: 632.499
  
  fred-macbookpro:~ srederiquefantune$