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• My bash execution keeps escaping my internal argument, no matter what [duplicate]

  14 janvier 2024, par Michal

  In my bash script, I need to run the following command :
ffmpeg -y -i video.mp4 -vf subtitles=subtitles.srt:force_style='argument1,argument2,argument3' out.mp4

  


  There are two major obstacles. First, the bash script always put subtitles=subtitles.srt in single quotes. The second, I need the single quotes for force_style arguments. But the bash keep escaping the single quotes no matter what. The result is usually something like this :

  


  +ffmpeg -y -i video.mp4 -vf 'subtitles=subtitles.srt:force_style='(backslash)''arguments(backslash)'''

  


  I have read tons of discussions. I tried using params array, escaping, executing with bash -c 'command', nothing was successful. Is there anybody who knows the trick ? Much appreciated.

  


• Why is get_frame_defaults in libavutil an internal function ?

  11 janvier 2024, par zhang

  See the following code from https://ffmpeg.org/doxygen/trunk/frame_8c_source.html#l00622 :

  


  static void get_frame_defaults(AVFrame *frame)
 {
     memset(frame, 0, sizeof(*frame));
  
     frame->pts                   =
     frame->pkt_dts               = AV_NOPTS_VALUE;
     frame->best_effort_timestamp = AV_NOPTS_VALUE;
     frame->duration            = 0;
 #if FF_API_PKT_DURATION
 FF_DISABLE_DEPRECATION_WARNINGS
     frame->pkt_duration        = 0;
 FF_ENABLE_DEPRECATION_WARNINGS
 #endif
 #if FF_API_FRAME_PKT
 FF_DISABLE_DEPRECATION_WARNINGS
     frame->pkt_pos             = -1;
     frame->pkt_size            = -1;
 FF_ENABLE_DEPRECATION_WARNINGS
 #endif
     frame->time_base           = (AVRational){ 0, 1 };
     frame->sample_aspect_ratio = (AVRational){ 0, 1 };
     frame->format              = -1; /* unknown */
     frame->extended_data       = frame->data;
     frame->color_primaries     = AVCOL_PRI_UNSPECIFIED;
     frame->color_trc           = AVCOL_TRC_UNSPECIFIED;
     frame->colorspace          = AVCOL_SPC_UNSPECIFIED;
     frame->color_range         = AVCOL_RANGE_UNSPECIFIED;
     frame->chroma_location     = AVCHROMA_LOC_UNSPECIFIED;
     frame->flags               = 0;
 }


  


  You can see the get_frame_defaults function is marked as static, so not callable from other files. The only way to initialize AVFrame is via av_frame_alloc (plus av_frame_unref and av_frame_move_ref which operated on already initialized AVFrame), which allocates AVFrame in heap.

  


  So there are no native method to initialize non-dynamically-allocated AVFrame object.

  


  By comparison, libavcodec has a similar function av_init_packet which is public, and can be called for AVPacket object created elsewhere (e.g. on stack).

  


• avcodec/jpeg2000htdec : check if block decoding will exceed internal precision

  12 août 2023, par Pierre-Anthony Lemieux

  avcodec/jpeg2000htdec : check if block decoding will exceed internal precision
  Intended to replace https://patchwork.ffmpeg.org/project/ffmpeg/patch/20230802000135.26482-3-michael@niedermayer.cc/
  
  with a more accurate block decoding magnitude bound.
  Fixes : 62433/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JPEG2000_fuzzer-5828618092937216
  
  Fixes : 58299/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JPEG2000_fuzzer-5828618092937216
  
  Previous-version-reviewed-by : Tomas Härdin <git@haerdin.se>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/jpeg2000htdec.c