FFmpeg/doc/multithreading.txt
Michael Niedermayer 80e9e63c94 Merge commit '759001c534287a96dc96d1e274665feb7059145d'
* commit '759001c534287a96dc96d1e274665feb7059145d':
  lavc decoders: work with refcounted frames.

Anton Khirnov (1):
      lavc decoders: work with refcounted frames.

Clément Bœsch (47):
      lavc/ansi: reset file
      lavc/ansi: re-do refcounted frame changes from Anton
      fraps: reset file
      lavc/fraps: switch to refcounted frames
      gifdec: reset file
      lavc/gifdec: switch to refcounted frames
      dsicinav: resolve conflicts
      smc: resolve conflicts
      zmbv: resolve conflicts
      rpza: resolve conflicts
      vble: resolve conflicts
      xxan: resolve conflicts
      targa: resolve conflicts
      vmnc: resolve conflicts
      utvideodec: resolve conflicts
      tscc: resolve conflicts
      ulti: resolve conflicts
      ffv1dec: resolve conflicts
      dnxhddec: resolve conflicts
      v210dec: resolve conflicts
      vp3: resolve conflicts
      vcr1: resolve conflicts
      v210x: resolve conflicts
      wavpack: resolve conflicts
      pngdec: fix compilation
      roqvideodec: resolve conflicts
      pictordec: resolve conflicts
      mdec: resolve conflicts
      tiertexseqv: resolve conflicts
      smacker: resolve conflicts
      vb: resolve conflicts
      vqavideo: resolve conflicts
      xl: resolve conflicts
      tmv: resolve conflicts
      vmdav: resolve conflicts
      truemotion1: resolve conflicts
      truemotion2: resolve conflicts
      lcldec: fix compilation
      libcelt_dec: fix compilation
      qdrw: fix compilation
      r210dec: fix compilation
      rl2: fix compilation
      wnv1: fix compilation
      yop: fix compilation
      tiff: resolve conflicts
      interplayvideo: fix compilation
      qpeg: resolve conflicts (FIXME/TESTME).

Hendrik Leppkes (33):
      012v: convert to refcounted frames
      8bps: fix compilation
      8svx: resolve conflicts
      4xm: resolve conflicts
      aasc: resolve conflicts
      bfi: fix compilation
      aura: fix compilation
      alsdec: resolve conflicts
      avrndec: convert to refcounted frames
      avuidec: convert to refcounted frames
      bintext: convert to refcounted frames
      cavsdec: resolve conflicts
      brender_pix: convert to refcounted frames
      cinepak: resolve conflicts
      cinepak: avoid using AVFrame struct directly in private context
      cljr: fix compilation
      cpia: convert to refcounted frames
      cscd: resolve conflicts
      iff: resolve conflicts and do proper conversion to refcounted frames
      4xm: fix reference frame handling
      cyuv: fix compilation
      dxa: fix compilation
      eacmv: fix compilation
      eamad: fix compilation
      eatgv: fix compilation
      escape124: remove unused variable.
      escape130: convert to refcounted frames
      evrcdec: convert to refcounted frames
      exr: convert to refcounted frames
      mvcdec: convert to refcounted frames
      paf: properly free the frame data on decode close
      sgirle: convert to refcounted frames
      lavfi/moviesrc: use refcounted frames

Michael Niedermayer (56):
      Merge commit '759001c534287a96dc96d1e274665feb7059145d'
      resolve conflicts in headers
      motion_est: resolve conflict
      mpeg4videodec: fix conflicts
      dpcm conflict fix
      dpx: fix conflicts
      indeo3: resolve confilcts
      kmvc: resolve conflicts
      kmvc: resolve conflicts
      h264: resolve conflicts
      utils: resolve conflicts
      rawdec: resolve conflcits
      mpegvideo: resolve conflicts
      svq1enc: resolve conflicts
      mpegvideo: dont clear data, fix assertion failure on fate vsynth1 with threads
      pthreads: resolve conflicts
      frame_thread_encoder: simple compilefix not yet tested
      snow: update to buffer refs
      crytsalhd: fix compile
      dirac: switch to new API
      sonic: update to new API
      svq1: resolve conflict, update to new API
      ffwavesynth: update to new buffer API
      g729: update to new API
      indeo5: fix compile
      j2kdec: update to new buffer API
      linopencore-amr: fix compile
      libvorbisdec: update to new API
      loco: fix compile
      paf: update to new API
      proresdec: update to new API
      vp56: update to new api / resolve conflicts
      xface: convert to refcounted frames
      xan: fix compile&fate
      v408: update to ref counted buffers
      v308: update to ref counted buffers
      yuv4dec: update to ref counted buffers
      y41p: update to ref counted frames
      xbm: update to refcounted frames
      targa_y216: update to refcounted buffers
      qpeg: fix fate/crash
      cdxl: fix fate
      tscc: fix reget buffer useage
      targa_y216dec: fix style
      msmpeg4: fix fate
      h264: ref_picture() copy fields that have been lost too
      update_frame_pool: use channel field
      h264: Put code that prevents deadlocks back
      mpegvideo: dont allow last == current
      wmalossless: fix buffer ref messup
      ff_alloc_picture: free tables in case of dimension mismatches
      h264: fix null pointer dereference and assertion failure
      frame_thread_encoder: update to bufrefs
      ec: fix used arrays
      snowdec: fix off by 1 error in dimensions check
      h264: disallow single unpaired fields as references of frames

Paul B Mahol (2):
      lavc/vima: convert to refcounted frames
      sanm: convert to refcounted frames

Conflicts:
	libavcodec/4xm.c
	libavcodec/8bps.c
	libavcodec/8svx.c
	libavcodec/aasc.c
	libavcodec/alsdec.c
	libavcodec/anm.c
	libavcodec/ansi.c
	libavcodec/avs.c
	libavcodec/bethsoftvideo.c
	libavcodec/bfi.c
	libavcodec/c93.c
	libavcodec/cavsdec.c
	libavcodec/cdgraphics.c
	libavcodec/cinepak.c
	libavcodec/cljr.c
	libavcodec/cscd.c
	libavcodec/dnxhddec.c
	libavcodec/dpcm.c
	libavcodec/dpx.c
	libavcodec/dsicinav.c
	libavcodec/dvdec.c
	libavcodec/dxa.c
	libavcodec/eacmv.c
	libavcodec/eamad.c
	libavcodec/eatgq.c
	libavcodec/eatgv.c
	libavcodec/eatqi.c
	libavcodec/error_resilience.c
	libavcodec/escape124.c
	libavcodec/ffv1.h
	libavcodec/ffv1dec.c
	libavcodec/flicvideo.c
	libavcodec/fraps.c
	libavcodec/frwu.c
	libavcodec/g723_1.c
	libavcodec/gifdec.c
	libavcodec/h264.c
	libavcodec/h264.h
	libavcodec/h264_direct.c
	libavcodec/h264_loopfilter.c
	libavcodec/h264_refs.c
	libavcodec/huffyuvdec.c
	libavcodec/idcinvideo.c
	libavcodec/iff.c
	libavcodec/indeo2.c
	libavcodec/indeo3.c
	libavcodec/internal.h
	libavcodec/interplayvideo.c
	libavcodec/ivi_common.c
	libavcodec/jvdec.c
	libavcodec/kgv1dec.c
	libavcodec/kmvc.c
	libavcodec/lagarith.c
	libavcodec/libopenjpegdec.c
	libavcodec/mdec.c
	libavcodec/mimic.c
	libavcodec/mjpegbdec.c
	libavcodec/mjpegdec.c
	libavcodec/mmvideo.c
	libavcodec/motion_est.c
	libavcodec/motionpixels.c
	libavcodec/mpc7.c
	libavcodec/mpeg12.c
	libavcodec/mpeg4videodec.c
	libavcodec/mpegvideo.c
	libavcodec/mpegvideo.h
	libavcodec/msrle.c
	libavcodec/msvideo1.c
	libavcodec/nuv.c
	libavcodec/options_table.h
	libavcodec/pcx.c
	libavcodec/pictordec.c
	libavcodec/pngdec.c
	libavcodec/pnmdec.c
	libavcodec/pthread.c
	libavcodec/qpeg.c
	libavcodec/qtrle.c
	libavcodec/r210dec.c
	libavcodec/rawdec.c
	libavcodec/roqvideodec.c
	libavcodec/rpza.c
	libavcodec/smacker.c
	libavcodec/smc.c
	libavcodec/svq1dec.c
	libavcodec/svq1enc.c
	libavcodec/targa.c
	libavcodec/tiertexseqv.c
	libavcodec/tiff.c
	libavcodec/tmv.c
	libavcodec/truemotion1.c
	libavcodec/truemotion2.c
	libavcodec/tscc.c
	libavcodec/ulti.c
	libavcodec/utils.c
	libavcodec/utvideodec.c
	libavcodec/v210dec.c
	libavcodec/v210x.c
	libavcodec/vb.c
	libavcodec/vble.c
	libavcodec/vcr1.c
	libavcodec/vmdav.c
	libavcodec/vmnc.c
	libavcodec/vp3.c
	libavcodec/vp56.c
	libavcodec/vp56.h
	libavcodec/vp6.c
	libavcodec/vqavideo.c
	libavcodec/wavpack.c
	libavcodec/xl.c
	libavcodec/xxan.c
	libavcodec/zmbv.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
2013-03-12 03:23:28 +01:00

71 lines
3.0 KiB
Plaintext

FFmpeg multithreading methods
==============================================
FFmpeg provides two methods for multithreading codecs.
Slice threading decodes multiple parts of a frame at the same time, using
AVCodecContext execute() and execute2().
Frame threading decodes multiple frames at the same time.
It accepts N future frames and delays decoded pictures by N-1 frames.
The later frames are decoded in separate threads while the user is
displaying the current one.
Restrictions on clients
==============================================
Slice threading -
* The client's draw_horiz_band() must be thread-safe according to the comment
in avcodec.h.
Frame threading -
* Restrictions with slice threading also apply.
* For best performance, the client should set thread_safe_callbacks if it
provides a thread-safe get_buffer() callback.
* There is one frame of delay added for every thread beyond the first one.
Clients must be able to handle this; the pkt_dts and pkt_pts fields in
AVFrame will work as usual.
Restrictions on codec implementations
==============================================
Slice threading -
None except that there must be something worth executing in parallel.
Frame threading -
* Codecs can only accept entire pictures per packet.
* Codecs similar to ffv1, whose streams don't reset across frames,
will not work because their bitstreams cannot be decoded in parallel.
* The contents of buffers must not be read before ff_thread_await_progress()
has been called on them. reget_buffer() and buffer age optimizations no longer work.
* The contents of buffers must not be written to after ff_thread_report_progress()
has been called on them. This includes draw_edges().
Porting codecs to frame threading
==============================================
Find all context variables that are needed by the next frame. Move all
code changing them, as well as code calling get_buffer(), up to before
the decode process starts. Call ff_thread_finish_setup() afterwards. If
some code can't be moved, have update_thread_context() run it in the next
thread.
If the codec allocates writable tables in its init(), add an init_thread_copy()
which re-allocates them for other threads.
Add CODEC_CAP_FRAME_THREADS to the codec capabilities. There will be very little
speed gain at this point but it should work.
If there are inter-frame dependencies, so the codec calls
ff_thread_report/await_progress(), set AVCodecInternal.allocate_progress. The
frames must then be freed with ff_thread_release_buffer().
Otherwise leave it at zero and decode directly into the user-supplied frames.
Call ff_thread_report_progress() after some part of the current picture has decoded.
A good place to put this is where draw_horiz_band() is called - add this if it isn't
called anywhere, as it's useful too and the implementation is trivial when you're
doing this. Note that draw_edges() needs to be called before reporting progress.
Before accessing a reference frame or its MVs, call ff_thread_await_progress().