Newest 'ffmpeg' Questions - Stack Overflow

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• ffmpeg -is it possible to increase a clip duration ?

  18 novembre 2011, par dpigera

  I currently have a jpeg file which I converted to an flv using the following command:

  ffmpeg -r 10 -b 180000 -i test.jpg test.mp4
  

  Now, I want to increase the duration of this .mp4 clip, so the picture stays on the screen for more than a split second. Eventually, I hope to merge a stream of these files to create a slide show out of jpeg files.

  Does anyone know how to increase the duration of a clip in ffmpeg?

• FFMPEG won't encode vorbis

  17 novembre 2011, par Doug Wolfgram

  When i try to encode using ogg vorbis, I get the message "Unknown encoder 'Vorbis'"

  I tried using libvorbis as well as vorbis with the same result.

  When I do the following:

  ffmpeg -codecs | grep vorbis
  

  I get:

  D A    vorbis          Vorbis
  

  Which means the encoding is not supported (the missing 'E' between 'D' and 'A')

  I installed form the package provided for Centos 6. Is there some other way to enable the vorbis codec for encoding?

• Split video file from 'n' th frame to end of video in Linux

  17 novembre 2011, par Skkard

  I need to split a video file using frames as the measure, e.g. I need to save the part of the video from the 34th frame to the end of the video in Linux( specifically fedora 16, xfce, 64bit ).

  I've tried using ffmpeg, using the '-vframes' option to specify how many frames to save, but it starts from the beginning, so is not that useful. How can I start from a certain frame in between the video and save the video from there to the end in a new file.

  I know about the '-ss' option, but while converting number of frames to the specified time, there might be errors( or so I believe. Please correct me if I'm wrong ) due to rounding.

  Could you please suggest a method? Thanks!

• Point CMake project to specific include file

  16 novembre 2011, par Unapiedra

  I am trying to build OpenCV 2.3.0 with FFMPEG enabled. Since Ubuntu 11.10 only supplies libavcodec/format with version 0.7 and the ticket #1020(link below) indicates that it should work with 0.8.

  If I try to compile I get the following error:

  [ 18%] Building CXX object modules/highgui/CMakeFiles/opencv_highgui.dir/src/cap_ffmpeg.o
  In file included from /home/chris/src/OpenCV-2.3.0/modules/highgui/src/cap_ffmpeg.cpp:45:0:
  /home/foo/src/OpenCV-2.3.0/modules/highgui/src/cap_ffmpeg_impl.hpp:103:36: fatal error: libavformat/avformat.h: No such file or directory
  compilation terminated.
  

  This file lives in /opt/linux64-debug/include/ffmpeg/libavformat/avformat.h. I tried pointing make at that with CMAKE_INCLUDE_{DIRECTORY,PATH}, CMAKE_PREFIX_PATH and CMAKE_LIBRARY_PATH. None of that worked. ( I always used the path /opt/linux64-debug/include/ffmpeg.)

  https://code.ros.org/trac/opencv/ticket/1020

• Use FFMPEG to create video from jpeg, and index using vlc

  16 novembre 2011, par Greg

  OpenSuse 11.4 FFMEG 0.8.5

  I'm using FFMPEG to create a 5 minute mpeg from about 2100 individual jpegs (7fps). I've been using the following command (OpenSuse 11.4)
  /usr/bin/ffmpeg -y -r 7.01 -i %03d-capture.jpg -s 800x600 -r 25 Event-3692-r1-s1-3.mpg

  Now I Try to open the file (In windows XP with VLC 1.1.11 Player).
  Media->AdvancedFileOpen
  *I select "Show more options" and set StartTime to 5s. I expect that the video should start 5 seconds in, but instead it starts at a seemingling random (although consistent) time of ~30 seconds in.

  I also tried changing ffmpeg command to:
  /usr/bin/ffmpeg -sameq -y -r 7.01 -i %03d-capture.jpg -s 800x600 -r 25 Event-3692-r1-s1-3.mpg
  *This result in about a constant 2x offset (5sec => 10sec) (10s => 20s) etc. But filesize is also about 6x larger, which is a strain on my storage.

  I also tried
  /usr/bin/ffmpeg -y -r 7.01 -i %03d-capture.jpg -s 800x600 -r 25 -f mpegts Event-3692-r1-s1-3.mpg
  *This result in vlc not indexing at all into my video. Also not desired. Anybody have any clues what is going on here. It is very important for me to be able to use this VLC feature and have it work correctly.

  Thanks in advance