7.56.0 - FEL AVPlayer-output route, two-layer FEL join, fastZap default, sequential-origin seeks, DVB SD canvas

Added

• The software host's PiP source now builds its own controller.
  SoftwarePiPSource.makePictureInPictureController() returns an AVPictureInPictureController
  around the display layer (nil when PiP is unsupported), with a SoftwarePiPPlaybackDelegate
  serving play, pause, skip and the time range from the engine's transport, as the AVPlayer path
  gets from AVKit. Skip is clamped to the VOD duration, and the window's playback state is
  invalidated when the engine's state or duration changes. A host no longer re-implements the
  delegate; it still owns the controller, rebuilds it when softwarePiPSource changes, and sets
  pictureInPictureActive.
• Ending a software session closes its PiP window. The engine stops the PiP of the controller it
  made, before the host stops, and resets pictureInPictureActive to false. A host with its own
  controller closes PiP when softwarePiPSource becomes nil. The software path builds a new display
  layer per load, so any load ends PiP there (no hand-over as on the native path).
• A bound AetherPlayerView shapes the software layer like the picture while PiP is active. A PiP
  window mirrors the layer's own geometry, so the layer takes the picture's aspect-fit rectangle
  (resizeAspect, resize) or its aspect-fill rectangle clipped by the view (resizeAspectFill), and
  returns to the full view afterwards. A videoGravity change during PiP re-applies it at once. A host
  that mounts softwarePiPSource.layer in its own view sizes the layer itself.
• macOS: the software layer fits the system PiP window. While PiP is active the layer is laid out at the
  window's size (found through public AppKit and followed on resize; the picture-shaped layout stays when no window is
  found), so the layer's videoGravity fits the picture. The system draws an opaque bar over the top of that
  window for sample-buffer sources, which no public API removes (Apple FB22411168). A picture of another
  aspect during PiP (16:9 to 4:3 and back) keeps the same window: AVKit resizes it to the new picture, and the
  layer follows the window instead of falling back to the view's fit.
• SoftwarePiPSource.isSupported says whether the system offers PiP at all; the controller helper returns
  nil when it is false.
• The PiP source keeps its off-main snapshot fresh without the controller helper, so a host using
  playbackDelegate with its own content source gets current state and duration.
• AetherEngine.probeDolbyVisionEnhancementLayer(url:options:) and prewarmDualLayerDolbyVision().
  The probe reports whether a Profile 7 source carries a FEL or MEL enhancement layer, read off the first RPU
  without decoding. The prewarm compiles the composer shaders ahead of the first dual-layer frame, off the
  cooperative pool. aetherctl gains eltype, elsurvey, elframe and dmpass for the probe, the
  residual survey, a single-frame dump and the display-metadata passthrough check.
• A Profile 7 FEL source with the enhancement layer on its own PID or track now takes the dual-layer route.
  A UHD Blu-ray clip (base layer on PID 0x1011, enhancement layer on 0x1015) used to play as the base layer
  with the RPUs folded in (Profile 8.1), and a Matroska / MP4 file with the enhancement layer as a second video
  track played the base layer alone, because the enhancement layer never reached the decoder. With preferDualLayerDolbyVision
  and the DualLayerDolbyVision trait the demuxer now joins the two layers into the one-unit-per-picture
  form a single-track remux has, pairing the layers in decode order from a shared IRAP and re-anchoring after
  every seek, and the composer runs on it unchanged. With the trait or the preference off, or when the layers
  cannot be joined, the enhancement layer's RPUs are folded into the base layer (Profile 8.1): that is the path
  as before for Blu-ray PIDs, and new for two-track Matroska / MP4 files, which used to play the base layer
  alone (HDR10 when the RPUs sit in the enhancement track). The fold pairs the layers on times converted to
  microseconds, so tracks with different timescales pair too. A base picture now waits up to 128 pictures or
  2 s of presentation time for its RPU (was 8 pictures) before it goes out without one, Blu-ray PIDs included,
  so a whole chunk of a chunk-interleaved MP4 pairs: a source whose enhancement layer is missing or broken
  hands out its video up to 2 s behind the other streams.
• A Profile 7 FEL source can be composed on AVPlayer's own frames instead of on the software host.
  LoadOptions.dualLayerRoute (default .softwareHost, the route as before) takes .avPlayerOutput (macOS, tvOS and iOS
  compile it; only macOS has been run) with the DualLayerDolbyVision trait and preferDualLayerDolbyVision on. AVPlayer then plays the base layer
  and the audio from the engine's loopback stream and owns the clock, so currentTime, seek(to:), play()
  and pause() are its own. The engine takes the decoded frames from an AVPlayerItemVideoOutput, pairs each
  with its enhancement layer (read once, in process, from the segment producer; no second connection), composes
  them with the composer the software host uses and presents the result in a display layer on the item's
  timebase. The dither parity of the compose kernels now follows the frame's position in the stream on this
  route, so a run composes the same bits however its frames arrived. The default route is unchanged. It composes in place into the
  video output's buffers (AETHER_FEL_OUTPUT_INPLACE=0 turns that off), which takes about 113 MB off the
  process on the Mac; the route still needs about 1.8 times the software host's memory there, most of it
  AVPlayer's own conversion of each frame for the video output.

Changed

• A sequential origin seeks inside what the session already holds (AE#958). seek(to:) on a
  sequentialOrigin loopback session lands when the target lies in the resident span that reaches the
  producer's frontier, served from the segment cache without a second request; anything outside it is
  still rejected as .sourceNotSeekable, and the host requests the archive again at the target. Before,
  every seek was rejected, although $isSequentialOrigin documented the in-cache case. residentRanges
  on such a session now reads the muxed durations the append playlist advertises instead of the static
  plan, which the cutter drifts from by up to a GOP.

• selectAudioTrack is ignored on a sequential origin (AE#958), with one log line. The rebuild could
  only reopen the source at byte 0: the native route restarted the programme from the beginning and the
  software route ended the session on its failed reposition. Switch by loading the source again at the
  position with audioSourceStreamIndex set to the chosen TrackInfo.id.

• Loopback live joins default to .fastZap. LoadOptions.liveJoinProfile used to default to
  .standard, whose first manifest waits for the full 3 x TARGETDURATION holdback: at least 18 s, and
  30 s on a 10 s GOP, which a strict-realtime origin can only fill in wall-clock time. A host that never
  chose a profile now gets the bounded join. Measured with aetherctl live --realtime, H.264 + AAC,
  first picture, two runs each (standard / fastZap): 1 s GOP with no backlog 18.9 / 1.8 s; 4 s GOP with
  no backlog 18.9 / 7.2 s; 10 s GOP with no backlog 28.8 / 19.1 s; 10 s GOP after a 22 s connect burst
  6.9 / 1.2 s. With a burst that already covers the holdback both start in about 0.4 s. .standard
  stays available for lean-back viewing that can afford the wait, and aetherctl's --standard-join
  loads it (--fast-zap is still accepted).

• Dual-layer Dolby Vision enhancement chroma is upsampled with the standard's default filter. The
  composer read the enhancement layer's chroma with a co-sited bilinear read, which matched an
  integer model of ETSI GS CCM 001 within one 12-bit code on only 83 to 99% of chroma samples (the worst
  clip, with a large residual, 83% Cb and 90% Cr). It now applies the Annex B.3 default filter
  (vertical centred, horizontal co-sited 8-tap) in integers. The same model now agrees within one 12-bit code on all chroma samples of the test clips except
  3 Cb samples of one clip (largest error 2).
  Luma is unchanged. An enhancement layer at the base layer's size is read exactly as before.

• Dolby Vision FEL frames are composed on a queue of their own, and a GPU that stops completing is reported.
  The video callback only records, pairs and enqueues; a paired frame waits for its GPU slot on a compose queue,
  with two compositions in flight and the output pool reserve independent of that limit. If the queue head waits
  four slices in a row, queued frames go out as the base layer with the RPU that keeps their mapping, and a stall
  that lasts 600 frames, or comes back four times without 240 healthy compositions between, is reported once as
  VideoDecoderError.composerStalled. The inverse-NLQ table and the MMR coefficients are read from per-frame
  tables, and the enhancement layer is upsampled with exact weights and rounded half up (the picture differs by at
  most one code on 0.1 to 1% of samples, the exact ties). Only with the DualLayerDolbyVision trait.

• The dual-layer route composes into the decoded base layer without the output-metadata copy. The copy only
  cost memory there (about 315 MB of IOSurface in the app on the Mac); single-layer paths, the enhancement
  decoders and the software host keep it.

• In-place Dolby Vision FEL compose binds each plane once, as read_write. The in-place path wrote the
  composed frame into the decoded base-layer buffer by binding the same texture twice in one kernel, once to read
  it and once to write it, which Metal does not promise to be coherent. Luma is now one 16-bit read_write
  texture and chroma one 32-bit read_write texture (a Cb and Cr pair per texel), sharing the pool kernels'
  bodies, so the picture is unchanged (0 of 120 frames differ on two real FEL clips, in place against the pool).
  read_write on a 16-bit plane needs read/write texture tier 2, so a device that reports a lower tier composes through the output pool, at the roughly 150 MB of extra memory the
  in-place path saves; its in-place kernels are not even compiled. One default-level log line now gives the
  reported tier and whether in-place compose is on. Only with the DualLayerDolbyVision trait.

Fixed

• A sequential-origin session no longer stalls about 6 s in (AE#958). The first append playlist was
  released on a single segment, and AVPlayer reloads an EVENT playlist only one TARGETDURATION later, so
  a first segment shorter than that ran dry first (restarting 5.68s from end of live playlist; target duration 6s, then a 0.1 s playbackStalled). The gate now holds for more media than that reload
  interval, at most 2 s past the first segment, so a stalling origin (AE#370) still starts.

• A live edge cushion no longer switches .fastZap's bounded start off. liveEdgeCushionSeconds is
  documented to floor the bounded start at the cushion, but any cushion at all barred it, so the join
  waited for the full holdback. On a 10 s GOP that is 45 s under .fastZap, and a 2.5 s "network
  buffer" made an ITV channel wait for real-time segments until the host's watchdog restarted it, every
  time. A shallow first window now qualifies once it holds the cushion, so the join still lands at
  least the cushion behind the edge. Same fixture, 10 s GOP, 22 s burst, 2.5 s cushion: first picture
  26.9 s before, 1.2 to 1.4 s after.

• Rendered DTS:X lost its heights on sinks that need AtmosOutputActivator. The activator ran only for TrueHD
  Atmos, so a DTS:X programme rendered into a bed (objectAudioRendering) never brought a receiver like a Sonos with
  Continuous Audio off to Dolby MAT, and the bed played as stereo PCM. tvOS carries a bed with heights over HDMI only
  as Dolby MAT, so an intact DTS:X bed shows as Dolby Atmos on the receiver either way. The activator now runs for
  every rendered bed, TrueHD Atmos and DTS:X, on the AVPlayer path and the software host alike; still only on a route
  whose every output is HDMI (#834).

• Streaked band around the picture with upscalesLowResolutionVideo (AE#846). The edge fix for VideoToolbox
  super resolution's ringing repeated one row and column of the ML output over the outer 12 samples, which reads
  as streaks on real footage (about 27 px top and bottom on an SD DVD at 4K, on all four sides of an anamorphic
  one). The source now gets 16 mirrored samples on each side before the ML pass and the scaled margin is cropped
  off again, so the ringing falls in the discarded part and the edge keeps its detail. Where VT's size limit
  leaves no room for the margin (1280 wide at 1.5x), the outer 8 output samples on that axis are a bilinear
  scale of the source. Measured against reference frames, the edge band now matches the interior instead of
  losing 4 to 10 dB PSNR. The timing line's clamp step is now edge.

• Data race on the muxer's lifetime fragment counters (AE#966). MP4SegmentMuxer bumped its fragment byte
  and cut totals on the pump thread while the diagnostics heartbeat read them through
  muxerLifetimeFragmentBytes / muxerFragmentCuts with no common lock. Both totals now sit behind their own
  lock. Diagnostics only, no change to the fragments written.

• DVB subtitles authored on a 720x576 display land where they were placed on HD video (AE#971). The
  decoder seeded every bitmap codec's canvas from the video, and dvbsubdec only takes its canvas from a display
  definition segment, or the EN 300 743 default of 720x576, while the context has no size, so SD cues were
  normalized against 1920x1080 and drawn left of centre, above the middle and too small. DVB is no longer seeded;
  PGS is unchanged. SubtitleImage.position is normalized against the decoder's canvas, and canvasSize reports
  the video frame for DVB, because a DVB display covers the whole picture and a 720x576 plane on HD video has
  non-square pixels: a host that maps the canvas aspect-preserving now stretches it onto the picture instead of
  pushing SD cues off the bottom.