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• Undefined reference, using FFMpeg-library (AvCodec) on Ubuntu, 64-bits system

  5 mai 2012, par Anders Branderud

  I am running the example code of the latest FFMpeg-library.
  I have inserted the example code into the file videofecencoder.c :

  /*
  
  * copyright (c) 2001 Fabrice Bellard
  
  *
  
  * This file is part of Libav.
  
  *
  
  * Libav is free software; you can redistribute it and/or
  
  * modify it under the terms of the GNU Lesser General Public
  
  * License as published by the Free Software Foundation; either
  
  * version 2.1 of the License, or (at your option) any later version.
  
  *
  
  * Libav is distributed in the hope that it will be useful,
  
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  
  * Lesser General Public License for more details.
  
  *
  
  * You should have received a copy of the GNU Lesser General Public
  
  * License along with Libav; if not, write to the Free Software
  
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  
  */
  
  #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
  
  
  
  
  
  #include 
  
  #include 
  
  #include 
  
  
  
  #ifdef HAVE_AV_CONFIG_H
  
  #undef HAVE_AV_CONFIG_H
  
  #endif
  
  
  
  #include "libavutil/imgutils.h"
  
  #include "libavutil/opt.h"
  
  #include "libavcodec/avcodec.h"
  
  #include "libavutil/mathematics.h"
  
  #include "libavutil/samplefmt.h"
  
  
  
  #define INBUF_SIZE 4096
  
  #define AUDIO_INBUF_SIZE 20480
  
  #define AUDIO_REFILL_THRESH 4096
  
  
  
  /*
  
  * Video encoding example
  
  */
  
  static void video_encode_example(const char *filename, int codec_id)
  
  {
  
     AVCodec *codec;
  
     AVCodecContext *c= NULL;
  
     int i, out_size, size, x, y, outbuf_size;
  
     FILE *f;
  
     AVFrame *picture;
  
     uint8_t *outbuf;
  
     int nrOfFramesPerSecond  =25;
  
     int nrOfSeconds =1;
  
  
  
  
  
     printf("Video encoding\n");
  
  
  
     /* find the mpeg1 video encoder */
  
     codec = avcodec_find_encoder((CodecID) codec_id);
  
     if (!codec) {
  
         fprintf(stderr, "codec not found\n");
  
         exit(1);
  
     }
  
  
  
     c = avcodec_alloc_context3(codec);
  
     picture= avcodec_alloc_frame();
  
  
  
     /* put sample parameters */
  
     c->bit_rate = 400000;
  
     /* resolution must be a multiple of two */
  
     c->width = 352;
  
     c->height = 288;
  
     /* frames per second */
  
     c->time_base= (AVRational){1,25};
  
     c->gop_size = 10; /* emit one intra frame every ten frames */
  
     c->max_b_frames=1;
  
     c->pix_fmt = PIX_FMT_YUV420P;
  
  
  
     if(codec_id == CODEC_ID_H264)
  
         av_opt_set(c->priv_data, "preset", "slow", 0);
  
  
  
     /* open it */
  
     if (avcodec_open2(c, codec, NULL) < 0) {
  
         fprintf(stderr, "could not open codec\n");
  
         exit(1);
  
     }
  
  
  
     f = fopen(filename, "wb");
  
     if (!f) {
  
         fprintf(stderr, "could not open %s\n", filename);
  
         exit(1);
  
     }
  
  
  
     /* alloc image and output buffer */
  
     outbuf_size = 100000;
  
     outbuf = (uint8_t*) malloc(outbuf_size);
  
  
  
     /* the image can be allocated by any means and av_image_alloc() is
  
      * just the most convenient way if av_malloc() is to be used */
  
     av_image_alloc(picture->data, picture->linesize,
  
                    c->width, c->height, c->pix_fmt, 1);
  
  
  
     /* encode 1 second of video */
  
     int nrOfFramesTotal = nrOfFramesPerSecond * nrOfSeconds;
  
  
  
     /* encode 1 second of video */
  
     for(i=0;i < nrOfFramesTotal; i++) {
  
         fflush(stdout);
  
         /* prepare a dummy image */
  
         /* Y */
  
         for(y=0;yheight;y++) {
  
             for(x=0;xwidth;x++) {
  
                 picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
  
             }
  
         }
  
  
  
         /* Cb and Cr */
  
         for(y=0;yheight/2;y++) {
  
             for(x=0;xwidth/2;x++) {
  
                 picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
  
                 picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
  
             }
  
         }
  
  
  
         /* encode the image */
  
         out_size = avcodec_encode_video(c, outbuf, outbuf_size, picture);
  
         printf("encoding frame %3d (size=%5d)\n", i, out_size);
  
         fwrite(outbuf, 1, out_size, f);
  
     }
  
  
  
     /* get the delayed frames */
  
     for(; out_size; i++) {
  
         fflush(stdout);
  
  
  
         out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
  
         printf("write frame %3d (size=%5d)\n", i, out_size);
  
         fwrite(outbuf, 1, out_size, f);
  
     }
  
  
  
     /* add sequence end code to have a real mpeg file */
  
     outbuf[0] = 0x00;
  
     outbuf[1] = 0x00;
  
     outbuf[2] = 0x01;
  
     outbuf[3] = 0xb7;
  
     fwrite(outbuf, 1, 4, f);
  
     fclose(f);
  
     free(outbuf);
  
  
  
     avcodec_close(c);
  
     av_free(c);
  
     av_free(picture->data[0]);
  
     av_free(picture);
  
     printf("\n");
  
  }
  
  
  
  int main(int argc, char **argv)
  
  {
  
     const char *filename;
  
  
  
     /* register all the codecs */
  
     avcodec_register_all();
  
  
  
     if (argc <= 1) {
  
  
  
         video_encode_example("/grb_1.mpg", CODEC_ID_MPEG1VIDEO);
  
     } else {
  
         filename = argv[1];
  
     }
  
  
  
  
  
     return 0;
  
  }

  When I run gcc videofecencoder.cc -lavcodec I get the following error messages :

  /tmp/ccJg8IDy.o: In function `video_encode_example(char const*, int)':
  
  videofecencoder.cc:(.text+0x35): undefined reference to `avcodec_find_encoder(CodecID)'
  
  videofecencoder.cc:(.text+0x74): undefined reference to `avcodec_alloc_context3(AVCodec*)'
  
  videofecencoder.cc:(.text+0x7d): undefined reference to `avcodec_alloc_frame()'
  
  videofecencoder.cc:(.text+0x113): undefined reference to `av_opt_set(void*, char const*, char const*, int)'
  
  videofecencoder.cc:(.text+0x12b): undefined reference to `avcodec_open2(AVCodecContext*, AVCodec*, AVDictionary**)'
  
  videofecencoder.cc:(.text+0x1f0): undefined reference to `av_image_alloc(unsigned char**, int*, int, int, PixelFormat, int)'
  
  videofecencoder.cc:(.text+0x35c): undefined reference to `avcodec_encode_video(AVCodecContext*, unsigned char*, int, AVFrame const*)'
  
  videofecencoder.cc:(.text+0x3cf): undefined reference to `avcodec_encode_video(AVCodecContext*, unsigned char*, int, AVFrame const*)'
  
  videofecencoder.cc:(.text+0x47c): undefined reference to `avcodec_close(AVCodecContext*)'
  
  videofecencoder.cc:(.text+0x488): undefined reference to `av_free(void*)'
  
  videofecencoder.cc:(.text+0x497): undefined reference to `av_free(void*)'
  
  videofecencoder.cc:(.text+0x4a3): undefined reference to `av_free(void*)'
  
  /tmp/ccJg8IDy.o: In function `main':
  
  videofecencoder.cc:(.text+0x4c3): undefined reference to `avcodec_register_all()'
  
  collect2: ld returnerade avslutningsstatus 1

  The command nm libavcodec.a | grep avcodec_find results in :

  00000000000008e0 T avcodec_find_best_pix_fmt
  
  0000000000000740 T avcodec_find_best_pix_fmt2
  
                   U avcodec_find_encoder
  
  0000000000002ca0 T avcodec_find_decoder
  
  0000000000002cf0 T avcodec_find_decoder_by_name
  
  0000000000002bd0 T avcodec_find_encoder
  
  0000000000002c30 T avcodec_find_encoder_by_name

  I also have another similar error with another library :
  Undefined reference despite linking in OpenFEC-library

  My system : Ubuntu 11, 64-bits machine

  My next step is to try to compile it on VirtualBox with Ubuntu 32 bits (running on a Windows-OS).

• How to record custom videos in Android [on hold]

  27 novembre 2013, par Chirry

  Context :

  Right now I have an App which takes the video from the camera and put some custome bitmaps on the same SurfaceView.

  Question :

  What I'd like is to record a video with the camera view and the custom Bitmaps on it.

  I have heard about AndroidFFmpeg third party codec to record videos, but I don't know how, I mean, is there any function on the AndroidFFmpeg to record videos in Android ?

  Hope you can help me with one this as there is not much information on the internet !

• PHP ffmpeg fetch metadata missing title, author, comment, artist

  19 avril 2012, par chrismacp

  I've been trying to fetch remote mp3 (and other format) meta data using the php5-ffmpeg extension.

  It is working although I am always missing the title, author, comment, artist details.

  I've been scouring the web for an answer but not found any solution.

  I did find this patch http://cvs.pld-linux.org/cgi-bin/viewvc.cgi/cvs/packages/php-ffmpeg/tests-metadata-api.patch which I thought may solve the problem, but I've been unable to compile php-ffmpeg even without the patch so haven't been able to work out if it will fix the problem.

  It seems this extension was abandoned a couple of years ago so I'm not holding out much hope of getting this working.

  Does anyone have any ideas of how to get remote meta data from audio video files using other tools ?

  I am thinking of just parsing the output of ffmpeg itelf using the '-i' option as this does return the correct meta data. Just a bit wary of calling exec in PHP for security reasons.