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• ffmpeg - operation not permitted error while conversion

  20 février 2012, par Jomoos

  I am developing an android app. My requirement is that to implement an rtsp streaming server on android. It has to live stream video and audio captured using MediaRecorder. Another requirement is that I have to use live555 as the streaming server. What I get from MediaRecorder is in MP4 or 3GP format. live555 cannot able to stream both. But it can stream audio if I recorded it only in 'RAW_AMR' format. Since live555 support 'mpg' format for streaming, I decided to put someone in middle who can convert 'mp4' or '3gp' to 'mpg', and I chose ffmpeg.

  I have ported live555 and ffmpeg to android. ffmpeg is able to convert the file recorded by MediaRecorder once it is finished. But the problem is that ffmpeg cannot be able to do it concurrently. That is, ffmpeg is not able to convert the file while recording. It shows an Operation not permitted error. I tried the same on my linux machine, using VLC to record instead of MediaRecorder on android. The result is same. ffmpeg is able to convert once the recording is finished, and not able to do the same while recording.

  Here is the ffmpeg command I issued on my linux box :

  ffmpeg -v 9 -loglevel 99 -i test.mp4 test.mpg

  Where test.mp4 is the file to which VLC is recording in mp4 format. and test.mpg is my destination file. The following is the output by ffmpeg on terminal.

  ffmpeg version 0.8.9, Copyright (c) 2000-2011 the FFmpeg developers
  
    built on Feb  1 2012 18:29:27 with gcc 4.6.2 20111027 (Red Hat 4.6.2-1)
  
    configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --extra-cflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic' --enable-bzlib --enable-libcelt --enable-libdc1394 --enable-libdirac --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-x11grab --enable-avfilter --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-runtime-cpudetect
  
    libavutil    51.  9. 1 / 51.  9. 1
  
    libavcodec   53.  8. 0 / 53.  8. 0
  
    libavformat  53.  5. 0 / 53.  5. 0
  
    libavdevice  53.  1. 1 / 53.  1. 1
  
    libavfilter   2. 23. 0 /  2. 23. 0
  
    libswscale    2.  0. 0 /  2.  0. 0
  
    libpostproc  51.  2. 0 / 51.  2. 0
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x1672600] Format mov,mp4,m4a,3gp,3g2,mj2 probed with size=2048 and score=100
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x1672600] ISO: File Type Major Brand: isom
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x1672600] moov atom not found
  
  test.mp4: Operation not permitted

  Would anyone please tell me what is causing the problem ? Or is the scenario above is possible by ffmpeg. That is, is ffmpeg is able to do the conversion at the same time as that of recording ? If it is not possible by ffmpeg, would you please suggest any alternative solutions ?

  NOTE : I am putting a C tag because if it possible by some tweaking in C on ffmpeg, I am ready to do that(I want the solution that badly). But please provide some pointers to the right direction.

• equivalent of QImage::bits() in C/C++

  17 février 2012, par JonnyCplusplus

  I am having an issue using ffmpeg. ffmpeg expects to read in a uint8_t and QImage::bits() is the only way I can generate valid images to feed to ffmpeg to get a valid video. The function ffmpeg(buf) will essentially generate the video I need. The issue is the buffers in each example print out very different results.

  My goad is to get the same result I get with QImage::bits() without using Qt at all. How can I duplicate that using C/C++

  Works :

  QImage getInfo("image");
  
  uint8_t *buf = getInfo.bits();
  
  ffmpeg(buff); // this will work great!

  This does not work :

  FILE *f;
  
  long lSize=0;
  
  uint8_t *buf;
  
  
  
  f = fopen ("image", "rb");
  
  
  
  fseek (f , 0 , SEEK_END);
  
  lSize = ftell (f);
  
  rewind (f);
  
  
  
  buf = (uint8_t*)malloc(lSize);
  
  fread (buf, 1, lSize, f);
  
  ffmpeg(buf);  //junk video!

• FFMPEG 2 Videos transcoded and side by side in 1 frame ?

  3 mars 2016, par dcoffey3296

  I have 2 videos : HEADSHOT.MOV and SCREEN.MOV. They are both large files and I am looking to both shrink (size, bitrate, etc) and place these two side by side in the same, very wide, video frame. The end result would be that when you play the output_video.mp4, you would have a very wide frame with both videos in sync and playing at the same rate.

  Here is the syntatically incorrect version of what I am trying to do :

  ffmpeg -i HEADSHOT.MOV -t 00:02:00 -acodec libfaac -ab 64k -vcodec libx264 -r 30 -pass 1 -s 374x210 -vf "movie=SCREEN.MOV [small]; [in][small] -an -r 30 -pass 1 -s 374x210 overlay=10:10 -t 00:02:00 [out]" -threads 0 output_movie.mp4

  In the above example, I also tried to set a test movie duration for 2 minutes which raises another question, What is the best way to handle 2 movies of varying length (if they are close) ?

  The resources I have found helpful so far are :

  Multiple video sources combined into one and

  http://ffmpeg.org/ffmpeg.html#overlay-1

  Any help/advice is greatly appreciated. I am having trouble with the FFMPEG syntax ! Thank you !