Recherche avancée

Sur d’autres sites (4136)

• FFmpeg converting image sequence to video results in blank video [closed]

  11 juillet 2019, par Brandon Durham

  I’ve got a series of 361 .png files that I’m trying to convert to video, and for whatever reason the resulting video is just black. Here is the FFmpeg code I’m using :

  ffmpeg -f image2 -i "FeatureTour_%05d.png" -r 30 -vcodec libx264 -b:v 9600k "FeatureTour.mp4"

  The files are formatted correctly (FeatureTour_00001.png) and no errors are thrown. It just results in a 160kb mp4 files that’s black.

  Any idea what I’m doing wrong ?

  EDIT

  Here is my output after using the above code :

  ffmpeg version N-46206-g0e4d34e Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Oct 30 2012 23:07:44 with llvm-gcc 4.2.1 (LLVM build 2336.11.00)
  
    configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable-libaacplus --enable-libass --enable-libcelt --enable-libfaac --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-openssl --enable-libopus --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvo-aacenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --prefix=/usr/local
  
    libavutil      52.  1.100 / 52.  1.100
  
    libavcodec     54. 70.100 / 54. 70.100
  
    libavformat    54. 35.100 / 54. 35.100
  
    libavdevice    54.  3.100 / 54.  3.100
  
    libavfilter     3. 20.113 /  3. 20.113
  
    libswscale      2.  1.101 /  2.  1.101
  
    libswresample   0. 16.100 /  0. 16.100
  
    libpostproc    52.  1.100 / 52.  1.100
  
  [image2 @ 0x7fa68381e200] max_analyze_duration 5000000 reached at 5000000
  
  Input #0, image2, from 'FeatureTour_%05d.png':
  
    Duration: 00:00:14.44, start: 0.000000, bitrate: N/A
  
      Stream #0:0: Video: png, rgb24, 114x151 [SAR 2835:2835 DAR 114:151], 25 fps, 25 tbr, 25 tbn, 25 tbc
  
  [libx264 @ 0x7fa683826c00] using SAR=1/1
  
  [libx264 @ 0x7fa683826c00] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.2 AVX
  
  [libx264 @ 0x7fa683826c00] profile High 4:4:4 Predictive, level 3.0, 4:4:4 8-bit
  
  [libx264 @ 0x7fa683826c00] 264 - core 125 - H.264/MPEG-4 AVC codec - Copyleft 2003-2012 - 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=4 threads=12 lookahead_threads=2 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=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=abr mbtree=1 bitrate=9600 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
  
  Output #0, mp4, to 'FeatureTour.mp4':
  
    Metadata:
  
      encoder         : Lavf54.35.100
  
      Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuv444p, 114x151 [SAR 1:1 DAR 114:151], q=-1--1, 9600 kb/s, 15360 tbn, 30 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (png -> libx264)
  
  Press [q] to stop, [?] for help
  
  frame=  432 fps=0.0 q=-2.0 Lsize=     152kB time=00:00:14.33 bitrate=  86.9kbits/s dup=71 drop=0    
  
  video:146kB audio:0kB subtitle:0 global headers:0kB muxing overhead 3.905020%
  
  [libx264 @ 0x7fa683826c00] frame I:3     Avg QP: 0.06  size:  8557
  
  [libx264 @ 0x7fa683826c00] frame P:135   Avg QP: 0.10  size:   653
  
  [libx264 @ 0x7fa683826c00] frame B:294   Avg QP: 0.43  size:   120
  
  [libx264 @ 0x7fa683826c00] consecutive B-frames:  8.8%  0.9%  1.4% 88.9%
  
  [libx264 @ 0x7fa683826c00] mb I  I16..4: 30.0%  0.4% 69.6%
  
  [libx264 @ 0x7fa683826c00] mb P  I16..4:  2.1%  0.0%  1.9%  P16..4:  7.5%  1.2%  0.8%  0.0%  0.0%    skip:86.5%
  
  [libx264 @ 0x7fa683826c00] mb B  I16..4:  0.2%  0.0%  0.1%  B16..8:  4.4%  0.3%  0.2%  direct: 0.9%  skip:93.8%  L0:46.5% L1:48.9% BI: 4.5%
  
  [libx264 @ 0x7fa683826c00] final ratefactor: -45.15
  
  [libx264 @ 0x7fa683826c00] 8x8 transform intra:0.7% inter:19.3%
  
  [libx264 @ 0x7fa683826c00] coded y,u,v intra: 44.4% 32.1% 31.5% inter: 2.3% 1.6% 1.4%
  
  [libx264 @ 0x7fa683826c00] i16 v,h,dc,p: 25% 75%  0%  0%
  
  [libx264 @ 0x7fa683826c00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 30% 40% 10%  0%  5%  0% 10%  0%  5%
  
  [libx264 @ 0x7fa683826c00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 16% 71%  5%  1%  1%  1%  2%  1%  2%
  
  [libx264 @ 0x7fa683826c00] Weighted P-Frames: Y:0.0% UV:0.0%
  
  [libx264 @ 0x7fa683826c00] ref P L0: 88.0%  3.9%  5.0%  3.1%
  
  [libx264 @ 0x7fa683826c00] ref B L0: 85.4% 12.4%  2.1%
  
  [libx264 @ 0x7fa683826c00] ref B L1: 98.1%  1.9%
  
  [libx264 @ 0x7fa683826c00] kb/s:82.86

• Revision 3606b78108 : Modified test for auto key frame detection. The existing test was triggering a

  16 avril 2015, par paulwilkins

  Changed Paths :
   Modify /vp9/encoder/vp9_firstpass.c

  
  
  Modified test for auto key frame detection.

  The existing test was triggering a lot of false positives on some types
  of animated material with very plain backgrounds. These were triggering
  code designed to catch key frames in letter box format clips.

  This patch tightens up the criteria and imposes a minimum requirement
  on the % blocks coded intra in the first pass and the ratio between the
  % coded intra and the modified inter % after discounting neutral (flat)
  blocks that are coded equally well either way.

  On a particular problem animation clip this change eliminated a large
  number of false positives including some cases where the old code
  selected kf several times in a row. Marginal false negatives are less
  damaging typically to compression and in the problem clip there are now
  a couple of cases where "visual" scene cuts are ignored because of well
  correlated content across the scene cut.

  Replaced some magic numbers related to this with #defines and added
  explanatory comments.

  Change-Id : Ia3d304ac60eb7e4323e3817eaf83b4752cd63ecf

• Get frames from a video into a matrix

  19 juin 2019, par Nephilim

  I’m currently trying to implement a compression algorithm(frame prediction) for an assignment. I am not looking for thumbnail files, or even just a shell command to generate something for me. My problem is specifically integrating it with a golang program.

  I just started and I’m already stuck. I’m supposed to get each frame out of a video,divide it into I P and B frames and perform inter-coding(compress the frame itself), then perform intra-coding(between the frames).

  Right now I cannot even get started on the above problems, because I have no idea how to read the video as something I could use in code. Apparently, the only library I can think of is ffmpeg. FFMPEG can get separate frames, apparently even i p and b frames.

  ffmpeg -i <inputfile> -vf '[in]select=eq(pict_type\,B)[out]' b.frames.mp4
</inputfile>

  But this is just another video output, that I do not know how to open.
  What I was thinking of was outputting frames into bitmaps(?), then reading each bitmap separately, to reconstruct three 3D matrixes, of i frames, p frames and b frames. However this seems like quite a feat. Someone, somewhere has definitely tried to parse a video into a 3D matrix and has found a better solution than what I’m thinking of.

  To be concise, I have a video, I need a 3D matrix. The 3D matrix is a matrix of 2D matrixes, which represent a frame in the video. Each point in a 3D matrix is a pixel(or whatever the equivalent is in videos).