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• Prevent ffmpeg and libavcodec from writing to screen (command prompt)

  20 novembre 2014, par Krishna

  I get the following output on the commandline when I try to open a particular file. I am using ffmpeg (libavcodec) to write a video reader. The following lines are output after avformat_find_stream_info().

  [mpeg2video @ 0000000000337a60] Invalid frame dimensions 0x0.
  [mpeg2video @ 0000000000337a60] Invalid frame dimensions 0x0.
  [mpeg2video @ 0000000000337a60] Invalid frame dimensions 0x0.
  

  Can anyone help me prevent ffmpeg from writing this to the command prompt. I would like to handle this internally without exposing this to the end user.

  Thank you!

• No such file or directory FFMpeg Error on MAC

  20 novembre 2014, par Nitesh

  I am trying to build a ffmpeg binary using the following link

  http://ffmpegmac.net/HowTo/

  I was successful in creating the binary. I could convert video files easily This is the code i run in the terminal

  ffmpeg -i Test.mp4 -b:v 64k -bufsize 64k test2.flv
  

  This works fine totally But when i run

  ./ffmpeg -re -i  test2.flv  -acodec libfaac -ar 44100 -ab 96k -c: v libx264  -level 41 -      profile baseline -bufsize 20000k -maxrate 25000k -g 250 -r 20 -s 480x270 -flags  -global_header -map 0 -f segment -segment_time 4 -segment_list test.m3u8 -segment_format mpegts stream%05d.ts 
  

  I get a "test2.flv : No such file or directory error" even though the test2.flv exists in the folder. Can you tell me where i might be going wrong. I am doing the above operation to stream the video to my iPhone over air.

  (Note- The command to build the ffmpeg binary i am using is as follows- ./configure --prefix=${TARGET} --enable-nonfree --enable-gpl --enable-pthreads --enable-version3 --enable-libspeex --enable-libvpx --disable-decoder=libvpx --enable-libfaac --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-avfilter --enable-libopencore_amrwb --enable-libopencore_amrnb --enable-filters --arch=x86_64 --enable-runtime-cpudetect && make -j 4 && make install )

  Thanks in advance for your help Regards

• FFMPEG cut video while recording ?

  19 novembre 2014, par Calvin Moss

  So I have found out how to cut a video at a specific time frame by using the following command

  ffmpeg -i input.wmv -ss 00:00:30.0 -c copy -t 00:00:10.0 output.wmv
  ffmpeg -i input.wmv -ss 30 -c copy -t 10 output.wmv
  

  So this works but it works on a video file output.wmv, How could I do this in real time? Basically I want a camera to be running and recording 24/7 and when I click a button it will save the last 30 seconds. So what that means is anything older then 30 seconds I no longer need. So what I want to do is essentially cut off any frames that are older then 30 seconds, from an input stream (webcam) so that I do not fill up the HDD in one day.

• Why does my stream often not have audio when started on crtmpserver ?

  19 novembre 2014, par nonlinearmind

  I'm using ffmpeg to feed source video to a server running crtmpserver which then distributes it as a rtmp stream. It works for the most part, but about half the time, when the stream is created by the source with ffmpeg, crtmpserver streams it without audio.

  To troubleshoot, I tried using Wowza in place of crtmpserver and have not had the same issue. I'm using out-of-the-box configurations for crtmpserver (and for my wowza test). My source audio and video is being sent to crtmposerver with the following pipeline:

  ffmpeg -loglevel error -f video4linux2 -video_size 640x480 -framerate 30 -input_format yuyv422 -i /dev/video7 -f alsa -i hw:0,0 -map 0:0 -map 1:0 -b:v 120k -bufsize 120k -vcodec libx264 -preset ultrafast -crf 28 -acodec aac -strict -2 -f flv -metadata streamName=MyStream tcp://192.168.1.20:6666

  Does anyone know what parameter changes I might make to my crtmpserver conf to solve this problem?

• HTML5 Video OGV conversion on Mac

  19 novembre 2014, par Loren

  When I try recording a screencast with Quicktime or Screenflow and then converting to .ogv for use on the web, I get this error many times:

  $ ffmpeg2theora test.mov
  [audioresample @ 0x7fa903800ee0] Audio sample format conversion failed
  

  The resulting test.ogv file does not play in VLC. I can use ffmpeg to successfully convert mov to mp4. Are there only certain audio types that ffmpeg2theora supports? ffmpeg2theora version 0.29

  More output:

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test.mov':
    Metadata:
      major_brand     : qt  
      minor_version   : 537199360
      compatible_brands: qt  
      creation_time   : 2013-08-26 20:50:37
    Duration: 00:00:07.00, start: 0.000000, bitrate: 1458 kb/s
      Stream #0:0(eng): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 90 kb/s
      Metadata:
        creation_time   : 2013-08-26 20:50:37
        handler_name    : Apple Alias Data Handler
      Stream #0:1(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1200, 1362 kb/s, 30 fps, 30 tbr, 3k tbn, 6k tbc
      Metadata:
        creation_time   : 2013-08-26 20:50:37
        handler_name    : Apple Alias Data Handler