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• FFmpeg, access violation on av_frame_free when running though Unity

  27 octobre 2016, par Mockarutan

  I’m working on a video recording plugin for Unity using ffmpeg. I’m new to the video encoding domain and just got my code to work today. But I think a might have a few memory leaks and trying to fix them crashes Unity.

  The plugin is written i c++ (as external "C" code) and imported in a c# script in unity with a simple DllImport. Again, this is not my comfort area either, but it works.

  When a screen buffer is rendered, I put in a RGB24 buffer and send it to my c++ function, this one :

  int encode_frame(uint8_t* rgb24Data)
  
  {
  
      AVFrame *frame = av_frame_alloc();
  
      if (!frame)
  
          return COULD_NOT_ALLOCATE_FRAME;
  
  
  
      frame->format = codec_context->pix_fmt;
  
      frame->width = codec_context->width;
  
      frame->height = codec_context->height;
  
  
  
      int ret = av_image_alloc(frame->data, frame->linesize, codec_context->width, codec_context->height, codec_context->pix_fmt, 32);
  
      if (ret < 0)
  
          return COULD_NOT_ALLOCATE_PIC_BUF;
  
  
  
      SwsContext * ctx = sws_getContext(codec_context->width, codec_context->height,
  
          AV_PIX_FMT_RGB24, codec_context->width, codec_context->height,
  
          AV_PIX_FMT_YUV420P, 0, 0, 0, 0);
  
  
  
  
  
      uint8_t * inData[1] = { rgb24Data };
  
      int inLinesize[1] = { 3 * codec_context->width };
  
  
  
      sws_scale(ctx, inData, inLinesize, 0, codec_context->height, frame->data, frame->linesize); // From RGB to YUV
  
  
  
      frame->pts = frame_counter++;
  
  
  
      ret = avcodec_send_frame(codec_context, frame);
  
      if (ret < 0)
  
          return ERROR_ENCODING_FRAME_SEND;
  
  
  
      AVPacket pkt;
  
      av_init_packet(&pkt);
  
      pkt.data = NULL;
  
      pkt.size = 0;
  
  
  
      while (true)
  
      {
  
          ret = avcodec_receive_packet(codec_context, &pkt);
  
          if (!ret)
  
          {
  
              if (pkt.pts != AV_NOPTS_VALUE)
  
                  pkt.pts = av_rescale_q(pkt.pts, codec_context->time_base, video_st->time_base);
  
              if (pkt.dts != AV_NOPTS_VALUE)
  
                  pkt.dts = av_rescale_q(pkt.dts, codec_context->time_base, video_st->time_base);
  
  
  
              av_write_frame(outctx, &pkt);
  
              av_packet_unref(&pkt);
  
          }
  
          else if (ret == AVERROR(EAGAIN))
  
          {
  
              frame->pts = frame_counter++;
  
              ret = avcodec_send_frame(codec_context, frame);
  
              if (ret < 0)
  
                  return ERROR_ENCODING_FRAME_SEND;
  
          }
  
          else if (ret < 0)
  
              return ERROR_ENCODING_FRAME_RECEIVE;
  
          else
  
              break;
  
      }
  
  
  
      // This one
  
      av_frame_free(&frame);
  
  }

  Now, this code might have a lot of issues that I’m not aware of, and you are free to point them out if you like. But the line that gives me error is av_frame_free(&frame);.

  If I run this in a synthetic test app in c++ that I made, it works. I can even run it in a c# synthetic test app (exactly like the c++ one), and it works. But if I run it though Unity, it crashes on the first frame. The log says "Read from location fe7f8097 caused an access violation.".

  I have tried with av_freep() and av_free(). Not sure exactly what makes them different (different example codes use different ones), but none work.

  So, what I’m I missing ? The frame is leaking if I don’t free it right ? But why does it crash in Unity ?

  The whole thing works great in Unity if I don’t have the av_frame_free(&frame);. Resulting video looks great !

  PS. I’m aware (as far as I know) that the frame also leaks if something fails and returns an error code. But one thing at a time.

• Specifying FFMPEG in the requirements section of 'buildozer.spec' causing [libavformat/network.o] Error 1

  18 juillet 2022, par GJ78

  My question relates to how to mitigate an ffmpeg requirement listed in a buildozer.spec that is causing compile errors using buildozer.

  



  GOAL :

  



  Using buildozer to ensure FFMPEG can be embedded within a small Kivy app so i can utilise youtube_dl functionality on my android phone.

  



  THE ISSUE :
Specifying FFMPEG in the requirements section of 'buildozer.spec' causes the following error message :
  
common.mak:60 : recipe for target 'libavformat/network.o' failed
  
make : [libavformat/network.o] Error 1
  
make : Waiting for unfinished jobs...

  



  What have I done to resolve myself :
  
1. Ensured LOG LEVEL 2 is specified.

  



  


  2. Upgraded cython from Version 21 to 27. Then downgraded to 25, then 21 then 20 to see if this resolved anything. It didn't.

  


  3. In BUILDOZER.SPEC, switched between Android NDK crystax-ndk-10.3.2 and android-ndk-r16b. (Note have reverted back to Crystax 10.3.2) in my NDK PATH.

  


  4. In BUILDOZER.SPEC, changed android.api from 19 to 15 (just to see if this has any positive effects).

  


  5. executed : rm -Rf .buildozer between each compiling attempt.

  


  6. Part extract of Buildozer.log :

     



     In file included from libavformat/dump.c:37:0 :
     
libavformat/avformat.h:893:21 : note : declared here
     
 AVCodecContext codec ;
 ^
     
CC libavformat/format.o
     
CC libavformat/golomb_tab.o
     
CC libavformat/h264dec.o
     
CC libavformat/hevc.o
     
CC libavformat/http.o
     
CC libavformat/httpauth.o
     
CC libavformat/id3v1.o
     
CC libavformat/id3v2.o
     
CC libavformat/img2.o
     
CC libavformat/isom.o
     
CC libavformat/log2_tab.o
     
CC libavformat/m4vdec.o
     
CC libavformat/metadata.o
CC libavformat/mov_chan.o
     
CC libavformat/mov.o
     
CC libavformat/movenc.o
     
CC libavformat/movenccenc.o
     
CC libavformat/movenchint.o
     
CC libavformat/mpegvideodec.o
     
CC libavformat/mux.o
     
CC libavformat/network.o
     
In file included from libavformat/network.h:29:0,
     
 from libavformat/network.c:22 :
     
libavformat/os_support.h:67:32 : error : expected declaration specifiers or '...' before '(' token
     
 # define lseek(f,p,w) lseek64((f), (p), (w))
     
 ^
libavformat/os_support.h:67:37 : error : expected declaration specifiers or '...' before '(' token
     
 # define lseek(f,p,w) lseek64((f), (p), (w))
     
 ^
libavformat/os_support.h:67:42 : error : expected declaration specifiers or '...' before '(' token
     
 # define lseek(f,p,w) lseek64((f), (p), (w))
     
 ^
common.mak:60 : recipe for target 'libavformat/network.o' failed
     
make : [libavformat/network.o] Error 1
     
make : * Waiting for unfinished jobs....

  


  7. Part extract of Buildozer.spec

     



     (str) Title of your application

     



     title = myapplication

     



     (str) Package name

     



     package.name = myapp

     



     (str) Package domain (needed for android/ios packaging)

     



     package.domain = org.test

     



     (str) Source code where the main.py live

     



     source.dir = .

     



     (list) Source files to include (let empty to include all the files)

     



     source.include_exts = py,png,jpg,kv,atlas

     



     (list) List of inclusions using pattern matching

     



     source.include_patterns = assets/,images/.png

     



     (list) Source files to exclude (let empty to not exclude anything)

     



     source.exclude_exts = spec

     



     (list) List of directory to exclude (let empty to not exclude anything)

     



     source.exclude_dirs = tests, bin

     



     (list) List of exclusions using pattern matching

     



     source.exclude_patterns = license,images//.jpg

     



     (str) Application versioning (method 1)

     



     version = 0.1

     



     (str) Application versioning (method 2)

     



     version.regex = version = '"['"]

     



     version.filename = %(source.dir)s/main.py

     



     (list) Application requirements

     



     comma seperated e.g. requirements = sqlite3,kivy

     



     requirements = ffmpeg,python2,hostpython2,kivy,youtube-dl

     



     (str) Custom source folders for requirements

     



     Sets custom source for any requirements with recipes

     



     requirements.source.kivy = ../../kivy

     



     (list) Garden requirements

     



     garden_requirements =

     



     (str) Presplash of the application

     



     presplash.filename = %(source.dir)s/data/presplash.png

     



     (str) Icon of the application

     



     icon.filename = %(source.dir)s/data/icon.png

     



     (str) Supported orientation (one of landscape, portrait or all)

     



     orientation = portrait

     



     (list) List of service to declare

     



     services = NAME:ENTRYPOINT_TO_PY,NAME2:ENTRYPOINT2_TO_PY

     



     OSX Specific

     



     author = © Copyright Info

     



     change the major version of python used by the app

     



     osx.python_version = 3

     



     Kivy version to use

     



     osx.kivy_version = 1.9.1

     



     Android specific

     



     (bool) Indicate if the application should be fullscreen or not

     



     fullscreen = 0

     



     (string) Presplash background color (for new android toolchain)

     



     Supported formats are : #RRGGBB #AARRGGBB or one of the following names :

     



     red, blue, green, black, white, gray, cyan, magenta, yellow, lightgray,

     



     darkgray, grey, lightgrey, darkgrey, aqua, fuchsia, lime, maroon, navy,

     



     olive, purple, silver, teal.

     



     android.presplash_color = #FFFFFF

     



     (list) Permissions

     



     android.permissions = INTERNET

     



     (int) Android API to use

     



     android.api = 19

     



     (int) Minimum API required

     



     android.minapi = 9

     



     (int) Android SDK version to use

     



     android.sdk = 20

     



     (str) Android NDK version to use

     



     android.ndk = 10.3.2

     



     (bool) Use —private data storage (True) or —dir public storage (False)

     



     android.private_storage = True

     



     (str) Android NDK directory (if empty, it will be automatically downloaded.)

     



     android.ndk_path = /home/gjones/Downloads/crystax-ndk-10.3.2

     



     (str) Android SDK directory (if empty, it will be automatically downloaded.)

     



     android.sdk_path =

     



     (str) ANT directory (if empty, it will be automatically downloaded.)

     



     android.ant_path =

  


  8. Lastly, when I remove ffmpeg from requirements in buildozer.spec, the .APK compiles successfully and i can deploy it on to my phone with the KIVY GUI. Obviously, ffmpeg functionality is not present.

  


  



  Current Environment Specs :

  



  

  1. Running Linux Mint 17.2 as a Virtual Box VM

  


  2. Buildozer Version : 0.35dev

  


  3. Cython Version : 0.25

  


  



  Any advice would be greatly appreciated.

  



  Lastly, if there is no obvious solution via buildozer, do i need to compile ffmpeg for Android separately and somehow include this somewhere in the buildozer spec file to prevent this error message ?

  



  Thanks in advance.

  


• Sending periodic metadata in fragmented live MP4 stream ?

  20 septembre 2022, par El Sampsa

  As suggested by the topic, I'm wondering if it's possible to send metadata about the stream contents periodically in a fragmented MP4 live stream.

  



  I'm using the following command (1) to get fragmented MP4 :

  



  ffmpeg -i rtsp://admin:12345@192.168.0.157 -c:v copy -an -movflags empty_moov+omit_tfhd_offset+frag_keyframe+default_base_moof -f mp4 ...


  



  My main program reads the fragments from this command from either stdout or from a (unix domain) socket and gets :

  



  ftyp
moov
moof
mdat
moof
mdat
moof
mdat 
...


  



  So, the first fragments I get are ftyp and moov which are metadata and describe the stream contents.

  



  Now a client program connects at a later time to the main program. The problem is, that at that point, the ftype and moov fragments are long gone.

  



  Is there a way (=ffmpeg command option) to make this work similar to MPEGTS (aka mpeg transport stream), and resend metadata periodically with the stream ? Like this :

  



  ftyp
moov
moof
mdat
moof
mdat
moof
mdat 
ftyp
moov
moof
mdat
moof
mdat
moof
mdat 
...


  



  .. or is my only option to cache the ftyp and moov packets in my main program and re-send them to the client program when it requests the stream ?

  



  A related link : What exactly is Fragmented mp4(fMP4) ? How is it different from normal mp4 ?

  



  Caching and resending ftyp and moov each time a new client connects is not that straightforward either .. as it somehow brokes the stream (at least the browser MSE extensions don't like such a stream). There seems to be lots of sequence numbers and stuff in the moof packets that should be modified. (+)

  



  Another option is to pass the stream through another FFmpeg process that does the remuxing (and corrects moof packets). Things are further complicated by the fact that command (1) does not give cleanly-separated ftyp, moov, moof, etc. packets.

  



  Any thoughts / solutions appreciated.

  



  EDIT : regarding (+), MSE seems to have problems playing fragmented MP4 with gaps : https://bugs.chromium.org/p/chromium/issues/detail?id=516114