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• What does the left_block_options array represent in the fill_decode_neighbors function of FFmpeg？

  28 décembre 2024, par mike xu

  I am studying the source code of FFmpeg, specifically the fill_decode_neighbors function. I am trying to understand how the decoding process works, especially the usage of the left_block_options array.
Here is the relevant code snippet :

  


  static const uint8_t left_block_options[4][32] = {
        { 0, 1, 2, 3, 7, 10, 8, 11, 3 + 0 * 4, 3 + 1 * 4, 3 + 2 * 4, 3 + 3 * 4, 1 + 4 * 4, 1 + 8 * 4, 1 + 5 * 4, 1 + 9 * 4 },
        { 2, 2, 3, 3, 8, 11, 8, 11, 3 + 2 * 4, 3 + 2 * 4, 3 + 3 * 4, 3 + 3 * 4, 1 + 5 * 4, 1 + 9 * 4, 1 + 5 * 4, 1 + 9 * 4 },
        { 0, 0, 1, 1, 7, 10, 7, 10, 3 + 0 * 4, 3 + 0 * 4, 3 + 1 * 4, 3 + 1 * 4, 1 + 4 * 4, 1 + 8 * 4, 1 + 4 * 4, 1 + 8 * 4 },
        { 0, 2, 0, 2, 7, 10, 7, 10, 3 + 0 * 4, 3 + 2 * 4, 3 + 0 * 4, 3 + 2 * 4, 1 + 4 * 4, 1 + 8 * 4, 1 + 4 * 4, 1 + 8 * 4 }
    };


  


  While I understand that this array plays a role in determining neighboring blocks for decoding, I am unclear about :

  


  The specific meaning of the array values.
How this array interacts with the decoding process, especially in relation to intra-prediction or block positioning.
Instead of a detailed explanation, I would greatly appreciate :

  


  Any keywords I can look up to understand this topic better (e.g., terms from the H.264 standard or FFmpeg documentation).
Links to related documentation, articles, or sections in the H.264 specification.
Suggestions on where I might find similar examples or detailed discussions about intra-block neighbor handling in FFmpeg.
Thank you for any resources or pointers you can provide !

  


• avcodec/vp8 : Move codec-specific init code out of common init

  6 mars, par Andreas Rheinhardt

  avcodec/vp8 : Move codec-specific init code out of common init
  While just at it, also move the init functions inside
  
  the #if CONFIG_VP ?_DECODER (to avoid linking failures).
  
  While just at it, also declare these init functions
  
  as av_cold and uninline the remaining common init function.
  Reviewed-by : Peter Ross <pross@xvid.org>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/vp8.c

• fftools/textformat : Introduce common header and deduplicate code

  28 avril, par softworkz

  fftools/textformat : Introduce common header and deduplicate code
  Also change writer_printf signature in AVTextWriter to use va_list,
  
  so that it can be called by the new function writer_printf()
  
  in tf_internal.h.
  Reviewed-by : Stefano Sabatini <stefasab@gmail.com>
  
  Signed-off-by : softworkz <softworkz@hotmail.com>
  

  • [DH] fftools/textformat/avtextwriters.h
  • [DH] fftools/textformat/tf_compact.c
  • [DH] fftools/textformat/tf_default.c
  • [DH] fftools/textformat/tf_flat.c
  • [DH] fftools/textformat/tf_ini.c
  • [DH] fftools/textformat/tf_internal.h
  • [DH] fftools/textformat/tf_json.c
  • [DH] fftools/textformat/tf_xml.c
  • [DH] fftools/textformat/tw_avio.c
  • [DH] fftools/textformat/tw_buffer.c
  • [DH] fftools/textformat/tw_stdout.c