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• avcodec/mpeg12dec : Remove disabled frame-threading code

  29 avril, par Andreas Rheinhardt

  avcodec/mpeg12dec: Remove disabled frame-threading code
  
  The MPEG-1 decoder has an update_thread_context function set,
  yet it was never enabled (missing AV_CODEC_CAP_FRAME_THREADS
  flag). So remove it and also the ff_thread_finish_setup() call
  as well as the progress reporting.
  
  (Simply setting the flag would not be enough. The main problems
  are:
  a) The update_thread_context function relies on memcpy'ing
  the whole context instead of only copying the necessary fields.
  This leads to data races which is undefined behaviour.
  (Btw: The check for whether the non-MpegEncContext fields
  of Mpeg1Context should be copied has been broken in
  7f0efe232475d7a704924a3cb308281973e8add3.)
  b) Even an AVBufferRef* is simply copied, without creating a new
  reference.
  c) Copying the whole context happens only during init; when parameters
  change lateron, the change is not propagated to the next thread.
  This affects at least the quant matrix (for MPEG-1).
  d) The MPEG-1/2 decoders are made to decode both MPEG-1 and MPEG-2.
  When MPEG-2 is decoded, another complication arises: In case of
  coded fields, both fields can be in one AVPacket or they can be
  in separate AVPackets. One would need to parse enough of the data
  to be able to determine whether the next thread needs to start
  a new frame or decode the second field of the current frame;
  for this one would need to either postpone calling
  ff_thread_finish_setup() for coded slices altogether or implement
  some form of ff_h2645_packet_split().
  One would also need a second ThreadProgress to signal progress
  of each field.
  e) One would need to reenable waiting in ff_mpv_reconstruct_mb()
  for MPEG-1/2 (and H.261).
  f) Probably lots of other stuff for invalid input that I am currently
  not thinking about.
  If this were done, nothing from the current update_thread_context
  would remain, so one can just nuke it altogether.)
  
  Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/mpeg12dec.c

• avcodec/sanm : recognize common FOBJ sizes

  29 avril, par Manuel Lauss

  avcodec/sanm: recognize common FOBJ sizes
  
  Change the size detection a bit to recognize common video sizes,
  as the FOBJ codecs>=37 cannot always be trusted, since they can
  be embedded in a larger frame.
  
  Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
  

  • [DH] libavcodec/sanm.c

• avcodec/sanm : ignore codec48 compression type 6

  29 avril, par Manuel Lauss

  avcodec/sanm: ignore codec48 compression type 6
  
  Some videos of "StarWars - Making Magic" have this subcompression
  type: data just consists of the 16 byte codec48 header; the DOS player
  and the c48 decoder in the "Mysteries of the Sith" game engine ignore it.
  
  Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
  

  • [DH] libavcodec/sanm.c

• doc/ffprobe : remove entry for show_format_entry

  29 avril, par Gyan Doshi

  doc/ffprobe: remove entry for show_format_entry
  
  The option was removed in 1dd6363581.
  

  • [DH] doc/ffprobe.texi

• ffv1enc_vulkan : support 8 and 16-bit 2-plane YUV formats

  29 avril, par Lynne

  ffv1enc_vulkan: support 8 and 16-bit 2-plane YUV formats
  
  This adds support for all 8-bit and 16-bit 2-plane formats.
  P010 and others require more work as the data's LSB-padded.
  

  • [DH] libavcodec/ffv1enc.c
  • [DH] libavcodec/ffv1enc_vulkan.c
  • [DH] libavcodec/vulkan/ffv1_enc.comp