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• Official RealVideo Specifications

  29 juillet 2010, par Multimedia Mike — General

  A little birdie tipped me off to a publicly-accessible URL on the Helix community site (does anyone actually use Helix ?) that contains a bunch of specifications for RealVideo 8 and 9. I have been sifting through the documents to see exactly what they contain as the different files seem to be higher revisions of the same documents. Here is the title, date, and version of each PDF document :

  • RNDecoderPerformanceARM.pdf : Decoder Performance on StrongARM and XScale ; May 12, 2003 ; Version 1.1
  • rv89_decoder_summary.pdf : RealVideo 8/9 Combo Decoder Summary ; October 23, 2002 ; Version 1.0
  • rv9_dec_external_spec_v14.pdf : RealVideo 9 External Specification ; November 7, 2003 ; Version 1.4
  • rv8_dec_external_spec_v20.pdf : RealVideo 8 External Specification ; September 19, 2002 ; Version 2.0
  • RV8DecoderExternalSpecificationv201.pdf : RealVideo 8 External Specification ; October 20, 2006 ; Version 2.01
  • RV8DecoderExternalSpecificationv202.pdf : RealVideo 8 External Specification ; April 23, 2007 ; Version 2.02
  • RV8DecoderExternalSpecificationv203.pdf : RealVideo 8 External Specification ; July 20, 2007 ; Version 2.03
  • RV8DecoderExternalSpecificationv21.pdf : RealVideo 8 External Specification ; September 11, 2007 ; Version 2.1
  • RV9DecoderExternalSpecificationv15.pdf ; RealVideo 9 External Specification ; January 26, 2002 ; Version 1.5
  • RV9DecoderExternalSpecificationv16.pdf ; RealVideo 9 External Specification ; August 17, 2005 ; Version 1.6
  • RV9DecoderExternalSpecificationv18.pdf ; RealVideo 9 External Specification ; September 11, 2007 ; Version 1.8

  Additionally, there is an Excel spreadsheet entitled realvideo-faq.xls that appears to contain some general tech support advice for using Real’s official code. There are also 3 ZIP archives which contain profiling information about the official source code (post processing and entropy decoding top the charts which is no big surprise).

  I guess the latest version of each document (the ones dated September 11, 2007) are worth mirroring. Unfortunately, those latest document versions use a terrible font.

• avcodec/amfenc : add smart access video option

  11 mars, par Evgeny Pavlov

  avcodec/amfenc : add smart access video option
  This commit adds option for enabling SmartAccess Video (SAV)
  
  in AMF encoders. SAV is an AMD hardware-specific feature which
  
  enables the parallelization of encode and decode streams across
  
  multiple Video Codec Engine (VCN) hardware instances.
  

  • [DH] libavcodec/amfenc.h
  • [DH] libavcodec/amfenc_av1.c
  • [DH] libavcodec/amfenc_h264.c
  • [DH] libavcodec/amfenc_hevc.c

• C++ smart pointers to FFmpeg objects

  15 octobre 2024, par Elija

  Can I create and use C++ smart pointers for different pointer types from FFmpeg ?

  


  

  1. "AVCodecContext *" which is used only as a pointer in all functions except deallocation.

  


  


  Alloc :

  


  AVCodecContext *avcodec_alloc_context3(const AVCodec *codec);


  


  Free :

  


  void avcodec_free_context(AVCodecContext **avctx);


  


  Use :

  


  int avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options);


  


  Then the smart pointer :

  


  std::shared_ptr<avcodeccontext> av_codec_context(avcodec_alloc_context3(av_codec),&#xA;[](AVCodecContext* _context)&#xA;{&#xA;  if (_context) avcodec_free_context(&amp;_context);&#xA;});&#xA;avcodec_open2(av_codec_context.get(), av_codec, NULL)&#xA;</avcodeccontext>

  


  Is this correct ?

  


  

  2. "AVDictionary **" which is used in all functions only as a pointer to a pointer.

  


  


  Alloc and use :

  


  int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags);


  


  where pm is a Pointer to a pointer to a dictionary struct. If *pm is NULL a dictionary struct is allocated and put in *pm.

  


  Free :

  


  void av_dict_free(AVDictionary **m);


  


  Then a smart pointer :

  


  std::shared_ptr av_dict(new (AVDictionary*),
[](AVDictionary** _dict)
{
  if (_dict)
  {
    if(*_dict)
      av_dict_free(_dict);
    delete _dict;
  }
});
av_dict_set(av_dict.get(), "key", "value", 0);


  


  Is this correct ?

  


  

  3. "AVFormatContext *" which is used both as a pointer and as a pointer to a pointer.

  


  


  Alloc :

  


  AVFormatContext *avformat_alloc_context(void);


  


  Free :

  


  void avformat_free_context(AVFormatContext *s);


  


  Use :

  


  int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options);


  


  or

  


  int avformat_open_input(AVFormatContext **ps, const char *url, const AVInputFormat *fmt, AVDictionary **options);


  


  where ps is a Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context). May be a pointer to NULL, in which case an AVFormatContext is allocated by this function and written into ps.

  


  Then a smart pointer :

  


  std::shared_ptr<avformatcontext> av_format_context(avformat_alloc_context(),&#xA;[](AVFormatContext* _context)&#xA;{&#xA;  if(_context)&#xA;    avformat_free_context(_context);&#xA;});&#xA;avformat_find_stream_info(av_format_context.get(), NULL);&#xA;</avformatcontext>

  


  Is this correct ? But how can I use it with the avformat_open_input() function, which needs a pointer to a pointer and may want to create an object by this pointer ?