[FFmpeg-trac] #4917(undetermined:new): Low framerate in directshow grabbing

FFmpeg trac at avcodec.org
Thu Oct 8 13:20:31 CEST 2015


#4917: Low framerate in directshow grabbing
-------------------------------------+-------------------------------------
             Reporter:  miro82       |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Hi, It seems impossible to capture different devices in their native
 framerate using directshow in higher resolutions.

 I have tested epiphan USB3 grabbers as well as hi-end professional PCIe
 datapath grabbers and get lower framerates than other directshow
 applications.

 As example i get (on different computers and devices)

 ~43-48 fps when capturing 1080p60 content
 ~23 fps when capturing 2048x2048 at 30 Hz content
 ~12 fps when capturing UHD 3840x2160 at 30 Hz content

 I have tested different ffmpeg releases (both GPL and custom LGPL) with
 the same results. The version I'm running right now is the following:
 {{{
 ffmpeg version N-75474-g74e4948 Copyright (c) 2000-2015 the FFmpeg
 developers
   built with gcc 4.9.3 (GCC)
   configuration: --disable-static --enable-shared --enable-gpl --enable-
 version3
  --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig
 --ena
 ble-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-
 libbluray --e
 nable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype
 --enable-
 libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-
 libmp3lame
 --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg
 --ena
 ble-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr
 --enable-
 libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab
 --enable-lib
 vo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx
 --enable-li
 bwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-
 libxavs --e
 nable-libxvid --enable-lzma --enable-decklink --enable-zlib
   libavutil      55.  2.100 / 55.  2.100
   libavcodec     57.  3.100 / 57.  3.100
   libavformat    57.  2.100 / 57.  2.100
   libavdevice    57.  0.100 / 57.  0.100
   libavfilter     6.  6.100 /  6.  6.100
   libswscale      4.  0.100 /  4.  0.100
   libswresample   2.  0.100 /  2.  0.100
   libpostproc    54.  0.100 / 54.  0.100
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/4917>
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