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• gcc : Undefined Reference Error

  16 mars 2014, par jamie_y

  I would like to use a function 'ff_load_image' defined in ffmpeg/libavfilter/lavfutils.h.

  program.c

  #include "../ffmpeg/libavfilter/lavfutils.h"
  
  int main ()
  {
    uint8_t* data;
  
    int linesize, width, height, log_ctx;
  
    int i = ff_load_image(&data, &linesize, &width, &height, AV_PIX_FMT_RGB24, "blue.jpg", &log_ctx);
  }
  

  Running

  gcc -I$HOME/ffmpeg/include program.c -L$HOME/ffmpeg/lib -lavfilter -lavcodec -lavutil
  

  gives undefined reference errors.

  program.c: In function \u2018main\u2019:
  program.c:9: warning: passing argument 1 of \u2018ff_load_image\u2019 from incompatible pointer type
  ../ffmpeg/libavfilter/lavfutils.h:39: note: expected \u2018uint8_t **\u2019 but argument is of type \u2018uint8_t *\u2019
  program.c:9: warning: passing argument 2 of \u2018ff_load_image\u2019 makes pointer from integer without a cast
  ../ffmpeg/libavfilter/lavfutils.h:39: note: expected \u2018int *\u2019 but argument is of type \u2018int\u2019
  program.c:9: warning: passing argument 3 of \u2018ff_load_image\u2019 makes pointer from integer without a cast
  ../ffmpeg/libavfilter/lavfutils.h:39: note: expected \u2018int *\u2019 but argument is of type \u2018int\u2019
  program.c:9: warning: passing argument 4 of \u2018ff_load_image\u2019 makes pointer from integer without a cast
  ../ffmpeg/libavfilter/lavfutils.h:39: note: expected \u2018int *\u2019 but argument is of type \u2018int\u2019
  program.c:9: warning: passing argument 5 of \u2018ff_load_image\u2019 makes pointer from integer without a cast
  ../ffmpeg/libavfilter/lavfutils.h:39: note: expected \u2018enum AVPixelFormat *\u2019 but argument is of type \u2018int\u2019
  program.c:9: warning: passing argument 7 of \u2018ff_load_image\u2019 makes pointer from integer without a cast
  ../ffmpeg/libavfilter/lavfutils.h:39: note: expected \u2018void *\u2019 but argument is of type \u2018int\u2019
  /home/jamiey/ffmpeg/lib/libavfilter.a(lavfutils.o): In function `ff_load_image':
  /home/jamiey/ffmpeg/libavfilter/lavfutils.c:38: undefined reference to `av_register_all'
  /home/jamiey/ffmpeg/libavfilter/lavfutils.c:40: undefined reference to `av_find_input_format'
  /home/jamiey/ffmpeg/libavfilter/lavfutils.c:41: undefined reference to `avformat_open_input'
  /home/jamiey/ffmpeg/libavfilter/lavfutils.c:66: undefined reference to `av_read_frame'
  /home/jamiey/ffmpeg/libavfilter/lavfutils.c:92: undefined reference to `avformat_close_input'
  /home/jamiey/ffmpeg/libavfilter/lavfutils.c:92: undefined reference to `avformat_close_input'
  /home/jamiey/ffmpeg/libavfilter/lavfutils.c:92: undefined reference to `avformat_close_input'
  /home/jamiey/ffmpeg/lib/libavcodec.a(frame_thread_encoder.o): In function `ff_frame_thread_encoder_free':
  /home/jamiey/ffmpeg/libavcodec/frame_thread_encoder.c:225: undefined reference to `pthread_join'
  /home/jamiey/ffmpeg/lib/libavcodec.a(frame_thread_encoder.o): In function `ff_frame_thread_encoder_init':
  /home/jamiey/ffmpeg/libavcodec/frame_thread_encoder.c:200: undefined reference to `pthread_create'
  /home/jamiey/ffmpeg/lib/libavcodec.a(pthread_frame.o): In function `ff_frame_thread_free':
  /home/jamiey/ffmpeg/libavcodec/pthread_frame.c:575: undefined reference to `pthread_join'
  /home/jamiey/ffmpeg/lib/libavcodec.a(pthread_frame.o): In function `ff_frame_thread_init':
  /home/jamiey/ffmpeg/libavcodec/pthread_frame.c:705: undefined reference to `pthread_create'
  /home/jamiey/ffmpeg/lib/libavcodec.a(pthread_slice.o): In function `ff_slice_thread_init':
  /home/jamiey/ffmpeg/libavcodec/pthread_slice.c:220: undefined reference to `pthread_create'
  /home/jamiey/ffmpeg/lib/libavcodec.a(pthread_slice.o): In function `ff_slice_thread_free':
  /home/jamiey/ffmpeg/libavcodec/pthread_slice.c:118: undefined reference to `pthread_join'
  /home/jamiey/ffmpeg/lib/libavutil.a(rational.o): In function `av_d2q':
  /home/jamiey/ffmpeg/libavutil/rational.c:115: undefined reference to `log'
  /home/jamiey/ffmpeg/libavutil/rational.c:118: undefined reference to `floor'
  /home/jamiey/ffmpeg/lib/libavutil.a(eval.o): In function `eval_expr':
  /home/jamiey/ffmpeg/libavutil/eval.c:183: undefined reference to `trunc'
  /home/jamiey/ffmpeg/libavutil/eval.c:182: undefined reference to `ceil'
  /home/jamiey/ffmpeg/libavutil/eval.c:181: undefined reference to `floor'
  /home/jamiey/ffmpeg/libavutil/eval.c:241: undefined reference to `pow'
  /home/jamiey/ffmpeg/libavutil/eval.c:177: undefined reference to `exp'
  /home/jamiey/ffmpeg/libavutil/eval.c:176: undefined reference to `exp'
  /home/jamiey/ffmpeg/libavutil/eval.c:287: undefined reference to `pow'
  /home/jamiey/ffmpeg/libavutil/eval.c:278: undefined reference to `floor'
  /home/jamiey/ffmpeg/lib/libavutil.a(eval.o): In function `av_strtod':
  /home/jamiey/ffmpeg/libavutil/eval.c:112: undefined reference to `pow'
  /home/jamiey/ffmpeg/libavutil/eval.c:103: undefined reference to `pow'
  /home/jamiey/ffmpeg/libavutil/eval.c:109: undefined reference to `pow'
  /home/jamiey/ffmpeg/lib/libavutil.a(eval.o): In function `parse_primary':
  /home/jamiey/ffmpeg/libavutil/eval.c:394: undefined reference to `sinh'
  /home/jamiey/ffmpeg/libavutil/eval.c:395: undefined reference to `cosh'
  /home/jamiey/ffmpeg/libavutil/eval.c:396: undefined reference to `tanh'
  /home/jamiey/ffmpeg/libavutil/eval.c:397: undefined reference to `sin'
  /home/jamiey/ffmpeg/libavutil/eval.c:398: undefined reference to `cos'
  /home/jamiey/ffmpeg/libavutil/eval.c:399: undefined reference to `tan'
  /home/jamiey/ffmpeg/libavutil/eval.c:400: undefined reference to `atan'
  /home/jamiey/ffmpeg/libavutil/eval.c:401: undefined reference to `asin'
  /home/jamiey/ffmpeg/libavutil/eval.c:402: undefined reference to `acos'
  /home/jamiey/ffmpeg/libavutil/eval.c:403: undefined reference to `exp'
  /home/jamiey/ffmpeg/libavutil/eval.c:404: undefined reference to `log'
  /home/jamiey/ffmpeg/libavutil/eval.c:405: undefined reference to `fabs'
  collect2: ld returned 1 exit status
  

  However, I was successful in running functions in other library, such as the ones in "ffmpeg/libavcodec/avcodec.h". Why is this happening to "ffmpeg/libavfilter/lavfutils.h"?

• How do I crossfade between scenes in ffmpeg using a complex filter ?

  15 mars 2014, par scubed

  I have ffmpeg 2.1.4 and an input movie in.mkv. There are effectively 2 different scenes inside of in.mkv. I want to be able to crossfade between the scenes, preferably with just using a complex filter instead of external programs. Essentially, I want to have something like an overlay but with the alpha changing at a specific time.

  Consider if in.mkv looked like this:

  00:00 - 00:05 scene 1
  00:05 - 00:10 junk
  00:10 - 00:15 scene 2
  

  So, I would want an output that had:

  00:00 - 00:04 scene 1 (0-4)
  00:04 - 00:05 alpha fading between scene 1 (4-5) and 2 (10-11)
  00:05 - 00:09 scene 2 (11-15)
  

  I see that there's a filter for: overlay, alphamerge, and color, but it's not clear how exactly to do this.

  In general, it seems hard to work with pieces of a movie file in ffmpeg. Is there a way to say that I am taking various pieces of the same input file and putting them together without rendering them as separate movies first?

• jpg repeating gif imagemagick [migrated]

  15 mars 2014, par user3417794

  so this is my first post on Stack Overflow after years of being a read-only guy. This time i have hit a wall and can't really get past it and would really appreciate your positive response.

  This is the command that iam using to convert a list of JPEGs to one single Gif. The problem comes when the first frame keeps on repeating after every second within the gif which messes it all up.

  Command:

  convert -delay 10 -loop 0 " + directoryname + "\\*.jpg " + directoryname + "\\output.gif
  

• How to combine a .mp4 video with a .wav audio with an offset in ffmpeg from command line ?

  15 mars 2014, par minder42

  I've got a TV clip in mp4 format containing audio and video, and an WAV audio_commentary track.

  I've been trying to combine them in ffmpeg and then play it online with a flash player (which can only take h264 format)

  What's the best ffmpeg command to accomplish this? My inputs are MP4 video, WAV audio, and an offset in seconds, the time the audio commentary starts relative to the start of the mp4 video.

  I tried

  ffmpeg -i input_audio.wav -i input_vid.mp4 -vcodec copy output.mp4
  

  and

  ffmpeg -vcodec copy -ss offset -i input_audio.wav -i input_video.mp4 output.mp4
  

  nether of these do what I want and output the video in the h264 format that is good for flash players- Is there a way to do this from command line in ffmpeg?

• Creating .flv files on the iphone without using ffmpeg

  15 mars 2014, par inwit

  How does one create .flv files on the iPhone?

  I am aware of ffmpeg (with its LGPL restrictions). But are there other APIs that have been ported to iOS?