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• avcodec/itut35 : rename some provider codes

  5 août, par Maryla Ustarroz-Calonge

  avcodec/itut35 : rename some provider codes
  In general, a provider code corresponds to a company/organization, and
  
  the name should be that of the company, not of a given feature.
  
  The feature is signalled in the "provider oriented code".
  The exception is HDR Vivid, where the code 0x0004 indicates the HDR Vivid
  
  feature itself rather than CUVA (China UHD Video Industry Alliance),
  
  according to the UHD World Associations 'HDR Video Technology Part 2-1
  
  Application Guide to System Integration' document.
  ITU_T_T35_PROVIDER_CODE_CUVA -> ITU_T_T35_PROVIDER_CODE_HDR_VIVID
  
  ITU_T_T35_PROVIDER_CODE_LCEVC-> ITU_T_T35_PROVIDER_CODE_VNOVA
  
  ITU_T_T35_PROVIDER_CODE_SMTPE -> ITU_T_T35_PROVIDER_CODE_SAMSUNG
  Signed-off-by : Maryla Ustarroz-Calonge <maryla@google.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/av1dec.c
  • [DH] libavcodec/h2645_sei.c
  • [DH] libavcodec/itut35.h
  • [DH] libavcodec/libdav1d.c
  • [DH] libavformat/matroskadec.c
  • [DH] libavformat/matroskaenc.c

• Input seeking for frame at specified timestamp with Py-AV

  9 décembre 2019, par neonScarecrow

  I have a project already using Py-AV and am trying to replicate a specific ffmpeg command. The goal is to get a frame roughly around the specified timestamp.

  Here’s the ffmpeg commmand :
  https://trac.ffmpeg.org/wiki/Seeking

  ffmpeg -ss 14 -i https://some_url.mp4 -frames:v 1 frame_at_14_seconds.jpg

  Here’s my code :

      #return one frame around 14 seconds into the movie
  
      target_sec = 14 
  
      container = av.open('https://some_url.mp4', 'r')
  
      container.streams.video[0].thread_type = 'AUTO'
  
      video_stream = next(s for s in container.streams if s.type == 'video')
  
      time_base = float(video_stream.time_base)
  
      target_timestamp = int(target_sec / time_base) + video_stream.start_time
  
      video_stream.seek(target_timestamp)
  
      for frame in container.decode(video_stream):
  
          frame.to_image().save('frame_at_14_seconds.jpg')
  
          break

  Additionally, I have found any documentation about this, but does anyone know if either command (ffmpeg/av.open) is downloading the entire file to a tmp file behind the scenes. I’m looking for a less memory-intensive way to read a frame for every second in an up to 60 second video.

• Adding HEVC reference decoder to ffmpeg framework

  4 mars 2014, par Zax

  I have a tweaked HM reference code of HEVC Decoder based on my requirements. I also know that FFMPEG version 2.1 onwards supports HEVC. But its a necessity for me to integrate my modified HM code.

  Hence I have gone through the post :

  http://wiki.multimedia.cx/index.php?title=FFmpeg_codec_howto

  According to this post, I need to define some functions that are needed to add a new decoder support to FFMPEG framework.

  The structure is : typedef struct AVCodec

  I have defined a structure as shown below :

  AVCodec HMHEVC_decoder =
  
  {
  
      .name           = "hmhevc",
  
      .type           = AVMEDIA_TYPE_VIDEO,
  
      .id             = AV_CODEC_ID_HMHEVC,
  
  
  
      .init           = hmhevc_decode_init,
  
      .close          = hmhevc_decode_close,
  
      .decode         = hmhevc_decode_frame,
  
  };

  However, looking at the other examples, I feel I have to add another variable like :

      .priv_data_size = sizeof(HEVCContext),

  But the problem is that I don't have any such context. So in case I don't define this, what are the things that FFMPEG framework wont provide my decoder ?

  Also is definition of this private data context compulsary ?

  What are the other fields that have to be compulsorily defined ?

  My main intention is that FFPLAY should be able to play the decoded frame.