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• Anomalie #4228 (Nouveau) : warning et notice

  17 novembre 2018, par Franck D

  Hello :-)

  SPIP 3.3.0-dev [24147] tout neuf avec aucun plug, n’y article (donc rien)
  Test fait chez ovh en php 7.2 :
  Environnement : stable
  Moteur : phpcgi
  Mode développement

  J’ai fait des tests y compris, en changeant de langue pour en prendre une, qui s’écrit de la droite vers la gauche. Sont apparue :

  Quand je vais dans : /ecrire/ ?exec=configurer_langage
  Warning : "continue" targeting switch is equivalent to "break". Did you mean to use "continue 2" ? in .../plugins-dist/compresseur/lib/csstidy/class.csstidy.php on line 891
  Notice : Undefined offset : 1 in .../plugins-dist/compresseur/lib/csstidy/class.csstidy_optimise.php on line 1286

  Quand je vais dans la partie publique du site :
  Notice : Undefined index : auto_compress_css in .../plugins-dist/compresseur/compresseur_fonctions.php on line 137
  Notice : Undefined index : auto_compress_js in .../plugins-dist/compresseur/compresseur_fonctions.php on line 140

  Quand je vais dans : ecrire/ ?exec=configurer_avancees
  Notice : Undefined index : auto_compress_js in .../plugins-dist/compresseur/formulaires/configurer_compresseur.php on line 32
  Notice : Undefined index : auto_compress_css in .../plugins-dist/compresseur/formulaires/configurer_compresseur.php on line 33
  Notice : Undefined index : url_statique_ressources in .../plugins-dist/compresseur/formulaires/configurer_compresseur.php on line 34

• FFMpeg library : how to precisely seek in an audio file

  16 août 2023, par matteoh

  Using the FFMpeg library in my Android app, I try to understand how I can seek in an audio file, at a very precise position.

  



  For example, I want to set the current position in my file to the frame #1234567 (in a file encoded at 44100 Hz), which is equivalent to seek at 27994.717 milliseconds.

  



  To achieve that, here is what I tried :

  



  // this:
av_seek_frame(formatContext, -1, 27994717, 0);

// or this:
av_seek_frame(formatContext, -1, 27994717, AVSEEK_FLAG_ANY);

// or even this:
avformat_seek_file(formatContext, -1, 27994617, 27994717, 27994817, 0);


  



  Using a position in microseconds gives me the best result so far.

  



  But for some reason, the positioning is not totally accurate : when I extract the samples from the audio file, it doesn't start exactly at the expected position. There is a slight delay of about 30-40 milliseconds (even if I seek to the position 0, surprisingly...).

  



  Do I use the function the right way, or even the right function ?

  



  EDIT

  



  Here is how I can get the position :

  



  AVPacket packet;
AVStream *stream = NULL;
AVFormatContext *formatContext = NULL;
AVCodec *dec = NULL;

// initialization:
avformat_open_input(&formatContext, filename, NULL, NULL);
avformat_find_stream_info(formatContext, NULL);
int audio_stream_index = av_find_best_stream(formatContext, AVMEDIA_TYPE_AUDIO, -1, -1, &dec, 0);
stream = formatContext->streams[audio_stream_index];

...

// later, when I extract samples, here is how I get my position, in microseconds:
av_read_frame(formatContext, &packet);
long position = (long) (1000000 * (packet.pts * ((float) stream->time_base.num / stream->time_base.den)));


  



  Thanks to that piece of code, I can get the position of the beginning of the current frame (frame = bloc of samples, the size depends on the audio format - 1152 samples for mp3, 128 to 1152 for ogg, ...)

  



  The problem is : the value I get in position is not accurate : it's actually 30 ms late, approximately. For example, when it says 1000000, the actual position is approximately 1030000...

  



  What did I do wrong ? Is it a bug in FFMpeg ?

  



  Thanks for your help.

  


• avformat/libsrt : add several options supported in srt 1.3.0

  23 octobre 2018, par Matsuzawa Tomohiro

  avformat/libsrt : add several options supported in srt 1.3.0
  Several SRT options are missing. Since pkg_config requires libsrt v1.3.0 and above, it should be able to support options added in libsrt v1.3.0 and below.
  
  This commit adds 8 SRT options.
  
  sndbuf, rcvbuf, lossmaxttl, minversion, streamid, smoother, messageapi and transtype
  
  The keys of option are equivalent to stransmit.
  
  https://github.com/Haivision/srt/blob/v1.3.0/apps/socketoptions.hpp#L196-L223
  Signed-off-by : Marton Balint <cus@passwd.hu>
  

  • [DH] doc/protocols.texi
  • [DH] libavformat/libsrt.c
  • [DH] libavformat/version.h