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  • Webcam recording with FFmpeg through USB over UTP

    13 septembre 2021, par z32a7ul

    I'm trying to record my webcam with FFmpeg.

    


    I listed the devices with this line :

    


    ffmpeg -list_devices true -f dshow -i dummy


    


    And I test the settings with this one :

    


    ffplay -loglevel verbose -f dshow -rtbufsize 100M -video_size 1280x720 -framerate 60 -video_device_number 0 -audio_device_number 0 -i video="C922 Pro Stream Webcam":audio="Microphone (C922 Pro Stream Web"


    


    The first command outputs this :

    


    ffmpeg version n4.4-10-g75c3969292 Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 10-win32 (GCC) 20210408
  configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw32 --enable-gpl --enable-version3 --disable-debug --disable-w32threads --enable-pthreads --enable-iconv --enable-libxml2 --enable-zlib --enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig --enable-libvorbis --enable-opencl --enable-libvmaf --enable-vulkan --enable-amf --enable-libaom --enable-avisynth --enable-libdav1d --enable-libdavs2 --enable-ffnvcodec --enable-cuda-llvm --enable-libglslang --enable-libgme --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvpx --enable-libwebp --enable-lv2 --enable-libmfx --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librav1e --enable-librubberband --enable-schannel --enable-sdl2 --enable-libsoxr --enable-libsrt --enable-libsvtav1 --enable-libtwolame --enable-libuavs3d --enable-libvidstab --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libzimg --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-ldflags=-pthread --extra-libs=-lgomp
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
[dshow @ 000000000035a000] DirectShow video devices (some may be both video and audio devices)
[dshow @ 000000000035a000]  "C922 Pro Stream Webcam"
[dshow @ 000000000035a000]     Alternative name "@device_pnp_\\?\usb#vid_046d&pid_085c&mi_00#9&1da24ac&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global"
[dshow @ 000000000035a000] DirectShow audio devices
[dshow @ 000000000035a000]  "Microphone (C922 Pro Stream Web"
[dshow @ 000000000035a000]     Alternative name "@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\Microphone (C922 Pro Stream Web"
[dshow @ 000000000035a000]  "Microphone (Realtek High Defini"
[dshow @ 000000000035a000]     Alternative name "@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\Microphone (Realtek High Defini"
dummy: Immediate exit requested


    


    And the second one this :

    


    ffplay version n4.4-10-g75c3969292 Copyright (c) 2003-2021 the FFmpeg developers
  built with gcc 10-win32 (GCC) 20210408
  configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw32 --enable-gpl --enable-version3 --disable-debug --disable-w32threads --enable-pthreads --enable-iconv --enable-libxml2 --enable-zlib --enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig --enable-libvorbis --enable-opencl --enable-libvmaf --enable-vulkan --enable-amf --enable-libaom --enable-avisynth --enable-libdav1d --enable-libdavs2 --enable-ffnvcodec --enable-cuda-llvm --enable-libglslang --enable-libgme --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvpx --enable-libwebp --enable-lv2 --enable-libmfx --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librav1e --enable-librubberband --enable-schannel --enable-sdl2 --enable-libsoxr --enable-libsrt --enable-libsvtav1 --enable-libtwolame --enable-libuavs3d --enable-libvidstab --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libzimg --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-ldflags=-pthread --extra-libs=-lgomp
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
Initialized direct3d renderer.
    nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   
    nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   
    nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   
    nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   
    nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   
    nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   
    nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   
    nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   
    nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   
dshow passing through packet of type video size   170103 timestamp 2074640340000 orig timestamp 2074640336004 graph timestamp 2074640340000 diff 3996 C922 Pro Stream Webcam
    nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   
dshow passing through packet of type video size   166381 timestamp 2074640500000 orig timestamp 2074640502670 graph timestamp 2074640500000 diff -2670 C922 Pro Stream Webcam
    nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   
dshow passing through packet of type video size   173348 timestamp 2074640820000 orig timestamp 2074640816017 graph timestamp 2074640820000 diff 3983 C922 Pro Stream Webcam
    nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   
...


    


    However, if I use a USB cable extender (USB over UTP - This thing consist of two parts : the first one has a male, the second one a female USB A, and they are linked through RJ45 sockets and a Cat5e UTP cable), it does not work at all. The first command prints the same :

    


    ffmpeg version n4.4-10-g75c3969292 Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 10-win32 (GCC) 20210408
  configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw32 --enable-gpl --enable-version3 --disable-debug --disable-w32threads --enable-pthreads --enable-iconv --enable-libxml2 --enable-zlib --enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig --enable-libvorbis --enable-opencl --enable-libvmaf --enable-vulkan --enable-amf --enable-libaom --enable-avisynth --enable-libdav1d --enable-libdavs2 --enable-ffnvcodec --enable-cuda-llvm --enable-libglslang --enable-libgme --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvpx --enable-libwebp --enable-lv2 --enable-libmfx --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librav1e --enable-librubberband --enable-schannel --enable-sdl2 --enable-libsoxr --enable-libsrt --enable-libsvtav1 --enable-libtwolame --enable-libuavs3d --enable-libvidstab --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libzimg --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-ldflags=-pthread --extra-libs=-lgomp
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
[dshow @ 000000000039a000] DirectShow video devices (some may be both video and audio devices)
[dshow @ 000000000039a000]  "C922 Pro Stream Webcam"
[dshow @ 000000000039a000]     Alternative name "@device_pnp_\\?\usb#vid_046d&pid_085c&mi_00#9&1da24ac&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global"
[dshow @ 000000000039a000] DirectShow audio devices
[dshow @ 000000000039a000]  "Microphone (C922 Pro Stream Web"
[dshow @ 000000000039a000]     Alternative name "@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\Microphone (C922 Pro Stream Web"
[dshow @ 000000000039a000]  "Microphone (Realtek High Defini"
[dshow @ 000000000039a000]     Alternative name "@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\Microphone (Realtek High Defini"
dummy: Immediate exit requested


    


    But the second fails with "Could not set video options" :

    


    ffplay version n4.4-10-g75c3969292 Copyright (c) 2003-2021 the FFmpeg developers
  built with gcc 10-win32 (GCC) 20210408
  configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw32 --enable-gpl --enable-version3 --disable-debug --disable-w32threads --enable-pthreads --enable-iconv --enable-libxml2 --enable-zlib --enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig --enable-libvorbis --enable-opencl --enable-libvmaf --enable-vulkan --enable-amf --enable-libaom --enable-avisynth --enable-libdav1d --enable-libdavs2 --enable-ffnvcodec --enable-cuda-llvm --enable-libglslang --enable-libgme --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvpx --enable-libwebp --enable-lv2 --enable-libmfx --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librav1e --enable-librubberband --enable-schannel --enable-sdl2 --enable-libsoxr --enable-libsrt --enable-libsvtav1 --enable-libtwolame --enable-libuavs3d --enable-libvidstab --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libzimg --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-ldflags=-pthread --extra-libs=-lgomp
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
Initialized direct3d renderer.
    nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   

[dshow @ 00000000004de180] Could not set video options
video=C922 Pro Stream Webcam:audio=Microphone (C922 Pro Stream Web: I/O error


    


    What can be the problem ? Is it the extender cable ? What are FFmpeg's requirement on USB cables (and extenders) ?

    


  • ffmpeg not setting GOP size for x264

    5 juillet 2012, par Chris Robinson

    Can someone please explain to me why the following settings :

    ffmpeg -i test.avi -vcodec libx264 -g 2 -keyint_min 1 -sc_threshold 100000000 -bf 1 test.mp4

    produces the following output :

    ffmpeg version N-41668-g564bb24 Copyright (c) 2000-2012 the FFmpeg developers
    built on Jun 17 2012 20:18:05 with gcc 4.6.3
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-runtime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libass --enable-libcelt --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libnut --enable-libopenjpeg --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --ena  libavutil      51. 58.100 / 51. 58.100
     libavcodec     54. 25.100 / 54. 25.100
     libavformat    54.  6.101 / 54.  6.101
     libavdevice    54.  0.100 / 54.  0.100
     libavfilter     2. 81.100 /  2. 81.100
     libswscale      2.  1.100 /  2.  1.100
     libswresample   0. 15.100 /  0. 15.100
     libpostproc    52.  0.100 / 52.  0.100
    Input #0, avi, from 'test.avi':
     Metadata:
       encoder         : Lavf54.6.101
     Duration: 00:00:01.70, start: 0.000000, bitrate: 4258 kb/s
    Stream #0:0: Video: mpeg4 (Simple Profile) (DIVX / 0x58564944), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 29.97 fps, 29.97 tbr, 29.97 tbn, 30k tbc
    Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, s16, 128 kb/s
    [buffer @ 0000000004115600] w:1280 h:720 pixfmt:yuv420p tb:1001/30000 fr:30000/1001 sar:1/1 sws_param:flags=2
    [ffmpeg_buffersink @ 00000000041157a0] No opaque field provided
    [libx264 @ 000000000411f120] using SAR=1/1
    [libx264 @ 000000000411f120] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.2
    [libx264 @ 000000000411f120] profile High, level 3.1
    [libx264 @ 000000000411f120] 264 - core 125 r2200 999b753 - 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=-2 threads=36 lookahead_threads=6 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 keOutput #0, mp4, to 'test.mp4':
     Metadata:
       encoder         : Lavf54.6.101
       Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 30k tbn, 29.97 tbc
       Stream #0:1: Audio: aac ([64][0][0][0] / 0x0040), 48000 Hz, stereo, s16, 128 kb/s
    Stream mapping:
     Stream #0:0 -> #0:0 (mpeg4 -> libx264)
     Stream #0:1 -> #0:1 (mp3 -> libvo_aacenc)
    Press [q] to stop, [?] for help
    [libvo_aacenc @ 0000000001ebe240] Que input is backward in time
    Last message repeated 8 times
    frame=   35 fps=0.0 q=-1.0 Lsize=     466kB time=00:00:01.10 bitrate=3466.6kbits/s dup=1 drop=0    

    video:436kB audio:28kB global headers:0kB muxing overhead 0.558509%
    [libx264 @ 000000000411f120] frame I:1     Avg QP:24.93  size: 92398
    [libx264 @ 000000000411f120] frame P:28    Avg QP:26.82  size: 12010
    [libx264 @ 000000000411f120] frame B:6     Avg QP:30.37  size:  2764
    [libx264 @ 000000000411f120] consecutive B-frames: 74.3%  5.7%  8.6% 11.4%
    [libx264 @ 000000000411f120] mb I  I16..4: 41.5% 40.1% 18.4%
    [libx264 @ 000000000411f120] mb P  I16..4:  3.9%  1.4%  0.6%  P16..4: 14.3%  4.7%  3.2%  0.0%  0.0%    skip:72.0%
    [libx264 @ 000000000411f120] mb B  I16..4:  1.1%  0.4%  0.1%  B16..8: 14.2%  2.8%  0.6%  direct: 1.1%  skip:79.8%  L0:49.8% L1:39.5% BI:10.8%
    [libx264 @ 000000000411f120] 8x8 transform intra:29.9% inter:76.4%
    [libx264 @ 000000000411f120] coded y,uvDC,uvAC intra: 31.1% 34.4% 18.7% inter: 10.2% 6.3% 3.0%
    [libx264 @ 000000000411f120] i16 v,h,dc,p: 62% 34%  3%  0%
    [libx264 @ 000000000411f120] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 18% 23% 38%  4%  4%  3%  3%  2%  5%
    [libx264 @ 000000000411f120] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 40% 35% 16%  1%  2%  2%  1%  1%  1%
    [libx264 @ 000000000411f120] i8c dc,h,v,p: 52% 20% 24%  3%
    [libx264 @ 000000000411f120] Weighted P-Frames: Y:0.0% UV:0.0%
    [libx264 @ 000000000411f120] ref P L0: 70.5% 10.1% 12.1%  7.3%
    [libx264 @ 000000000411f120] ref B L0: 81.1% 16.9%  2.0%
    [libx264 @ 000000000411f120] ref B L1: 89.7% 10.3%
    [libx264 @ 000000000411f120] kb/s:3050.18

    Why am I not getting an I-Frame every second frame ? Is there something else I can set to do enforce this ? If not, can you suggest how to do this using the mpeg4 codec. It's vital that I can extract what type of frame has been encoded during the encoding process and that I can set a specific GOP structure.

  • ffmpeg not setting GOP size for x264

    5 juillet 2012, par Chris Robinson

    Can someone please explain to me why the following settings :

    ffmpeg -i test.avi -vcodec libx264 -g 2 -keyint_min 1 -sc_threshold 100000000 -bf 1 test.mp4

    produces the following output :

    ffmpeg version N-41668-g564bb24 Copyright (c) 2000-2012 the FFmpeg developers
    built on Jun 17 2012 20:18:05 with gcc 4.6.3
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-runtime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libass --enable-libcelt --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libnut --enable-libopenjpeg --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --ena  libavutil      51. 58.100 / 51. 58.100
     libavcodec     54. 25.100 / 54. 25.100
     libavformat    54.  6.101 / 54.  6.101
     libavdevice    54.  0.100 / 54.  0.100
     libavfilter     2. 81.100 /  2. 81.100
     libswscale      2.  1.100 /  2.  1.100
     libswresample   0. 15.100 /  0. 15.100
     libpostproc    52.  0.100 / 52.  0.100
    Input #0, avi, from 'test.avi':
     Metadata:
       encoder         : Lavf54.6.101
     Duration: 00:00:01.70, start: 0.000000, bitrate: 4258 kb/s
    Stream #0:0: Video: mpeg4 (Simple Profile) (DIVX / 0x58564944), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 29.97 fps, 29.97 tbr, 29.97 tbn, 30k tbc
    Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, s16, 128 kb/s
    [buffer @ 0000000004115600] w:1280 h:720 pixfmt:yuv420p tb:1001/30000 fr:30000/1001 sar:1/1 sws_param:flags=2
    [ffmpeg_buffersink @ 00000000041157a0] No opaque field provided
    [libx264 @ 000000000411f120] using SAR=1/1
    [libx264 @ 000000000411f120] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.2
    [libx264 @ 000000000411f120] profile High, level 3.1
    [libx264 @ 000000000411f120] 264 - core 125 r2200 999b753 - 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=-2 threads=36 lookahead_threads=6 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 keOutput #0, mp4, to 'test.mp4':
     Metadata:
       encoder         : Lavf54.6.101
       Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 30k tbn, 29.97 tbc
       Stream #0:1: Audio: aac ([64][0][0][0] / 0x0040), 48000 Hz, stereo, s16, 128 kb/s
    Stream mapping:
     Stream #0:0 -> #0:0 (mpeg4 -> libx264)
     Stream #0:1 -> #0:1 (mp3 -> libvo_aacenc)
    Press [q] to stop, [?] for help
    [libvo_aacenc @ 0000000001ebe240] Que input is backward in time
    Last message repeated 8 times
    frame=   35 fps=0.0 q=-1.0 Lsize=     466kB time=00:00:01.10 bitrate=3466.6kbits/s dup=1 drop=0    

    video:436kB audio:28kB global headers:0kB muxing overhead 0.558509%
    [libx264 @ 000000000411f120] frame I:1     Avg QP:24.93  size: 92398
    [libx264 @ 000000000411f120] frame P:28    Avg QP:26.82  size: 12010
    [libx264 @ 000000000411f120] frame B:6     Avg QP:30.37  size:  2764
    [libx264 @ 000000000411f120] consecutive B-frames: 74.3%  5.7%  8.6% 11.4%
    [libx264 @ 000000000411f120] mb I  I16..4: 41.5% 40.1% 18.4%
    [libx264 @ 000000000411f120] mb P  I16..4:  3.9%  1.4%  0.6%  P16..4: 14.3%  4.7%  3.2%  0.0%  0.0%    skip:72.0%
    [libx264 @ 000000000411f120] mb B  I16..4:  1.1%  0.4%  0.1%  B16..8: 14.2%  2.8%  0.6%  direct: 1.1%  skip:79.8%  L0:49.8% L1:39.5% BI:10.8%
    [libx264 @ 000000000411f120] 8x8 transform intra:29.9% inter:76.4%
    [libx264 @ 000000000411f120] coded y,uvDC,uvAC intra: 31.1% 34.4% 18.7% inter: 10.2% 6.3% 3.0%
    [libx264 @ 000000000411f120] i16 v,h,dc,p: 62% 34%  3%  0%
    [libx264 @ 000000000411f120] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 18% 23% 38%  4%  4%  3%  3%  2%  5%
    [libx264 @ 000000000411f120] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 40% 35% 16%  1%  2%  2%  1%  1%  1%
    [libx264 @ 000000000411f120] i8c dc,h,v,p: 52% 20% 24%  3%
    [libx264 @ 000000000411f120] Weighted P-Frames: Y:0.0% UV:0.0%
    [libx264 @ 000000000411f120] ref P L0: 70.5% 10.1% 12.1%  7.3%
    [libx264 @ 000000000411f120] ref B L0: 81.1% 16.9%  2.0%
    [libx264 @ 000000000411f120] ref B L1: 89.7% 10.3%
    [libx264 @ 000000000411f120] kb/s:3050.18

    Why am I not getting an I-Frame every second frame ? Is there something else I can set to do enforce this ? If not, can you suggest how to do this using the mpeg4 codec. It's vital that I can extract what type of frame has been encoded during the encoding process and that I can set a specific GOP structure.