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• OpenCV Reporting TBR instead of FPS when using capture.get(CV_CAP_PROP_FPS)

  22 février 2012, par Malife

  I have several videos that I am trying to process using OpenCV and Qt 4.7.4 on Mac OS 10.6.8 (Snow Leopard). If I create a cv::VideoCapture object and then query for the frame rate related to such video, what I get back is the TBR and not FPS.

  For instance if use ffprobe Video1.mp4 what I get is :

  >> ffprobe Video1.mp4      
  
  ffprobe version 0.7.8, Copyright (c) 2007-2011 the FFmpeg developers
  
  built on Nov 24 2011 14:31:00 with gcc 4.2.1 (Apple Inc. build 5666) (dot 3)
  
  configuration: --prefix=/opt/local --enable-gpl --enable-postproc --enable-swscale --   
  
  enable-avfilter --enable-libmp3lame --enable-libvorbis --enable-libtheora --enable-
  
  libdirac --enable-libschroedinger --enable-libopenjpeg --enable-libxvid --enable-libx264 
  
  --enable-libvpx --enable-libspeex --mandir=/opt/local/share/man --enable-shared --
  
  enable-pthreads --cc=/usr/bin/gcc-4.2 --arch=x86_64 --enable-yasm
  
  libavutil    50. 43. 0 / 50. 43. 0
  
  libavcodec   52.123. 0 / 52.123. 0
  
  libavformat  52.111. 0 / 52.111. 0
  
  libavdevice  52.  5. 0 / 52.  5. 0
  
  libavfilter   1. 80. 0 /  1. 80. 0
  
  libswscale    0. 14. 1 /  0. 14. 1
  
  libpostproc  51.  2. 0 / 51.  2. 0
  
  
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Video1.mp4':
  
  Metadata:
  
  major_brand     : isom
  
  minor_version   : 0
  
  compatible_brands: mp41avc1qt  
  
  creation_time   : 2012-01-09 23:09:43
  
  encoder         : vlc 1.1.3 stream output
  
  encoder-eng     : vlc 1.1.3 stream output
  
  Duration: 00:10:10.22, start: 0.000000, bitrate: 800 kb/s
  
  Stream #0.0(eng): Video: h264 (Baseline), yuvj420p, 704x480 [PAR 10:11 DAR 4:3], 798 
  
  kb/s, 27.71 fps, 1001 tbr, 1001 tbn, 2002 tbc
  
  Metadata:
  
    creation_time   : 2012-01-09 23:09:43

  Which correctly reports FPS = 27.71 and TBR = 1001. Nevertheless if I use the following OpenCV code to query for the FPS :

  QString filename = QFileDialog::getOpenFileName(this,
  
                                          "Open Video",
  
                                          "Video Files (*.mp4, *.mpg)");
  
  
  
  capture.release();
  
  capture.open(filename.toAscii().data());
  
  
  
  if (!capture.isOpened()){
  
      qDebug() <<"Error when opening the video!";
  
      return;
  
  }
  
  
  
  
  
  qDebug() << "Frame Rate:" << capture.get(CV_CAP_PROP_FPS);
  
  qDebug() << "Num of Frames:" << capture.get(CV_CAP_PROP_FRAME_COUNT);
  
  qDebug() << "OpenCV Version" << CV_VERSION;

  The output I get is :

  Frame Rate: 1001 
  
  Num of Frames: 610832 
  
  OpenCV Version 2.3.1 

  Which reports the TBR instead of the FPS. This behavior is consistent when I try to open different videos.

  I checked OpenCV's bug tracker and I also found this stack overflow question to be a similar but not quite the same problem, so I am at a loss to what to do next. Any hint or idea is most welcome since I've tried lots of things and seem to be getting nowhere.

• ffmpeg - operation not permitted error while conversion

  20 février 2012, par Jomoos

  I am developing an android app. My requirement is that to implement an rtsp streaming server on android. It has to live stream video and audio captured using MediaRecorder. Another requirement is that I have to use live555 as the streaming server. What I get from MediaRecorder is in MP4 or 3GP format. live555 cannot able to stream both. But it can stream audio if I recorded it only in 'RAW_AMR' format. Since live555 support 'mpg' format for streaming, I decided to put someone in middle who can convert 'mp4' or '3gp' to 'mpg', and I chose ffmpeg.

  I have ported live555 and ffmpeg to android. ffmpeg is able to convert the file recorded by MediaRecorder once it is finished. But the problem is that ffmpeg cannot be able to do it concurrently. That is, ffmpeg is not able to convert the file while recording. It shows an Operation not permitted error. I tried the same on my linux machine, using VLC to record instead of MediaRecorder on android. The result is same. ffmpeg is able to convert once the recording is finished, and not able to do the same while recording.

  Here is the ffmpeg command I issued on my linux box :

  ffmpeg -v 9 -loglevel 99 -i test.mp4 test.mpg

  Where test.mp4 is the file to which VLC is recording in mp4 format. and test.mpg is my destination file. The following is the output by ffmpeg on terminal.

  ffmpeg version 0.8.9, Copyright (c) 2000-2011 the FFmpeg developers
  
    built on Feb  1 2012 18:29:27 with gcc 4.6.2 20111027 (Red Hat 4.6.2-1)
  
    configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --extra-cflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic' --enable-bzlib --enable-libcelt --enable-libdc1394 --enable-libdirac --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-x11grab --enable-avfilter --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-runtime-cpudetect
  
    libavutil    51.  9. 1 / 51.  9. 1
  
    libavcodec   53.  8. 0 / 53.  8. 0
  
    libavformat  53.  5. 0 / 53.  5. 0
  
    libavdevice  53.  1. 1 / 53.  1. 1
  
    libavfilter   2. 23. 0 /  2. 23. 0
  
    libswscale    2.  0. 0 /  2.  0. 0
  
    libpostproc  51.  2. 0 / 51.  2. 0
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x1672600] Format mov,mp4,m4a,3gp,3g2,mj2 probed with size=2048 and score=100
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x1672600] ISO: File Type Major Brand: isom
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x1672600] moov atom not found
  
  test.mp4: Operation not permitted

  Would anyone please tell me what is causing the problem ? Or is the scenario above is possible by ffmpeg. That is, is ffmpeg is able to do the conversion at the same time as that of recording ? If it is not possible by ffmpeg, would you please suggest any alternative solutions ?

  NOTE : I am putting a C tag because if it possible by some tweaking in C on ffmpeg, I am ready to do that(I want the solution that badly). But please provide some pointers to the right direction.

• Convert .mov to .mp4 and keep alpha channel using FFMPEG

  5 mai 2015, par Mark S.

  I am trying to convert a .mov file that is Quicktime with Alpha Channel to a .mp4 movie. I am using FFMPEG and I can successfully convert the video to a .mp4 video, but I loose the alpha channel.

  Here is the command I am running :
  ffmpeg -i BLUE_LOWER_THIRD.mov -vcodec libx264 -vpre medium blue_lower_third.mp4

  I am running this on Ubuntu 11.10. Here is the information about my install of ffmpeg.

  ffmpeg version 0.7.3-4:0.7.3-0ubuntu0.11.10.1, Copyright (c) 2000-2011 the Libav developers
  
    built on Jan  4 2012 16:08:51 with gcc 4.6.1
  
    configuration: --extra-version='4:0.7.3-0ubuntu0.11.10.1' --arch=amd64 --prefix=/usr --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --enable-shared --disable-static
  
    avutil      configuration: --extra-version='4:0.7.3ubuntu0.11.10.1' --arch=amd64 --prefix=/usr --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --enable-runtime-cpudetect --enable-vaapi --enable-libopenjpeg --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdirac --enable-libmp3lame --enable-librtmp --enable-libx264 --enable-libxvid --enable-libvo-aacenc --enable-version3 --enable-libvo-amrwbenc --enable-version3 --enable-libdc1394 --enable-shared --disable-static
  
    avcodec     configuration: --extra-version='4:0.7.3ubuntu0.11.10.1' --arch=amd64 --prefix=/usr --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --enable-runtime-cpudetect --enable-vaapi --enable-libopenjpeg --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdirac --enable-libmp3lame --enable-librtmp --enable-libx264 --enable-libxvid --enable-libvo-aacenc --enable-version3 --enable-libvo-amrwbenc --enable-version3 --enable-libdc1394 --enable-shared --disable-static
  
    avformat    configuration: --extra-version='4:0.7.3ubuntu0.11.10.1' --arch=amd64 --prefix=/usr --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --enable-runtime-cpudetect --enable-vaapi --enable-libopenjpeg --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdirac --enable-libmp3lame --enable-librtmp --enable-libx264 --enable-libxvid --enable-libvo-aacenc --enable-version3 --enable-libvo-amrwbenc --enable-version3 --enable-libdc1394 --enable-shared --disable-static
  
    libavutil    51.  7. 0 / 51.  7. 0
  
    libavcodec   53.  6. 0 / 53.  6. 0
  
    libavformat  53.  3. 0 / 53.  3. 0
  
    libavdevice  53.  0. 0 / 53.  0. 0
  
    libavfilter   2.  4. 0 /  2.  4. 0
  
    libswscale    2.  0. 0 /  2.  0. 0
  
    libpostproc  52.  0. 0 / 52.  0. 0

  Is it possible to have alpha channel in an mp4 file ? If so, how do you do it with FFMPEG ?

  Edit : This is the output from running the command.

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'BLUE_LOWER_THIRD.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 537199360
  
      compatible_brands: qt  
  
      creation_time   : 2010-12-21 10:36:51
  
    Duration: 00:00:15.00, start: 0.000000, bitrate: 8050 kb/s
  
      Stream #0.0(eng): Video: png, bgra, 1920x1080, 8043 kb/s, PAR 1920:1920 DAR 16:9, 30 fps, 30 tbr, 30 tbn, 30 tbc
  
      Metadata:
  
        creation_time   : 2010-12-21 10:36:51
  
      Stream #0.1(eng): Data: tmcd / 0x64636D74, 0 kb/s
  
      Metadata:
  
        creation_time   : 2010-12-21 10:39:48
  
  File 'blue_lower_third.mp4' already exists. Overwrite ? [y/N] y
  
  Incompatible pixel format 'bgra' for codec 'libx264', auto-selecting format 'yuv420p'
  
  [buffer @ 0x7e3d80] w:1920 h:1080 pixfmt:bgra
  
  [ffsink @ 0x7edda0] auto-inserting filter 'auto-inserted scaler 0' between the filter 'src' and the filter 'out'
  
  [scale @ 0x7fc480] w:1920 h:1080 fmt:bgra -> w:1920 h:1080 fmt:yuv420p flags:0x4
  
  [libx264 @ 0x7fcf20] using SAR=1/1
  
  [libx264 @ 0x7fcf20] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle Cache64
  
  [libx264 @ 0x7fcf20] profile High, level 4.0
  
  [libx264 @ 0x7fcf20] 264 - core 116 r2042 178455c - H.264/MPEG-4 AVC codec - Copyleft 2003-2011 - 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=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=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=abr mbtree=1 bitrate=200 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.41 aq=1:1.00
  
  Output #0, mp4, to 'blue_lower_third.mp4':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 537199360
  
      compatible_brands: qt  
  
      creation_time   : 2010-12-21 10:36:51
  
      encoder         : Lavf53.3.0
  
      Stream #0.0(eng): Video: libx264, yuv420p, 1920x1080 [PAR 1920:1920 DAR 16:9], q=0-69, 200 kb/s, 30 tbn, 30 tbc
  
      Metadata:
  
        creation_time   : 2010-12-21 10:36:51
  
  Stream mapping:
  
    Stream #0.0 -> #0.0
  
  Press ctrl-c to stop encoding
  
  frame=  450 fps= 11 q=9.0 Lsize=      83kB time=14.93 bitrate=  45.7kbits/s    its/s    
  
  video:75kB audio:0kB global headers:0kB muxing overhead 10.287784%
  
  frame I:2     Avg QP:18.30  size:  2584
  
  [libx264 @ 0x7fcf20] frame P:118   Avg QP:16.22  size:   310
  
  [libx264 @ 0x7fcf20] frame B:330   Avg QP:16.75  size:   106
  
  [libx264 @ 0x7fcf20] consecutive B-frames:  1.8%  0.9%  1.3% 96.0%
  
  [libx264 @ 0x7fcf20] mb I  I16..4: 49.7% 50.0%  0.3%
  
  [libx264 @ 0x7fcf20] mb P  I16..4:  0.5%  0.0%  0.0%  P16..4:  0.3%  0.0%  0.0%  0.0%      0.0%    skip:99.0%
  
  [libx264 @ 0x7fcf20] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  0.3%  0.0%  0.0%  direct: 0.0%  skip:99.6%  L0:37.2% L1:62.6% BI: 0.2%
  
  [libx264 @ 0x7fcf20] final ratefactor: 9.32
  
  [libx264 @ 0x7fcf20] 8x8 transform intra:38.0% inter:56.1%
  
  [libx264 @ 0x7fcf20] coded y,uvDC,uvAC intra: 0.9% 4.2% 2.9% inter: 0.0% 0.1% 0.0%
  
  [libx264 @ 0x7fcf20] i16 v,h,dc,p: 64% 32%  1%  3%
  
  [libx264 @ 0x7fcf20] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu:  0%  2% 97%  0%  1%  0%  0%  0%  0%
  
  [libx264 @ 0x7fcf20] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu:  5% 60% 23%  2%  6%  1%  1%  1%  2%
  
  [libx264 @ 0x7fcf20] i8c dc,h,v,p: 86% 13%  1%  0%
  
  [libx264 @ 0x7fcf20] Weighted P-Frames: Y:0.0% UV:0.0%
  
  [libx264 @ 0x7fcf20] ref P L0: 79.4%  2.1% 13.2%  5.2%
  
  [libx264 @ 0x7fcf20] ref B L0: 61.1% 37.7%  1.2%
  
  [libx264 @ 0x7fcf20] ref B L1: 92.3%  7.7%
  
  [libx264 @ 0x7fcf20] kb/s:40.85