- articleHow is a textless or localised-graphics picture version delivered as an IMF supplemental package at Netflix, and what do SMPTE ST 2067-2/-3 provide for versions and textless markers?
At Netflix a textless (or language) picture version is a supplemental IMF package built on the last approved texted package: its CPL reuses the same track-file IDs and adds one textless insert track, so unchanged shots are not re-delivered. SMPTE ST 2067-2 allows packages that are not complete compositions and ST 2067-3 defines textless marker labels (FFTC/LFTC etc.), but neither defines a 'textless version' as Netflix does.
- articleWhat tense, person, naming and wording rules do the ACB, DCMP and Netflix audio description guides give for writing a description line?
ACB 2009, DCMP and Netflix v2.5 agree on present tense, active voice, third person (Netflix allows second-person plural for some children's content) and objectivity. On film terms they disagree: ACB advises avoiding 'close-up' or 'fade to black', and Netflix allows common film terms such as 'now in close-up' when needed. On naming, all three describe a character by a visible attribute until the name is established, with exceptions (Netflix allows earlier naming in some cases).
- articleWhat do the macOS and Windows docs say must be configured for HDR video to play as HDR on a given screen?
HDR display state depends on OS settings a page cannot see: macOS needs the external display's HDR setting on and plays HDR as SDR on battery when 'Optimize video streaming' is on; Windows leaves HDR to the user, sets an SDR reference white that apps should match, clips content the display cannot show, and has no single standard tone-mapping algorithm. Reviewers should report these settings with any HDR judgement.
- articleWhen review notes go into a CMX3600 EDL as comments (LOC lines) and come back, what is kept and what is lost?
The OTIO CMX 3600 adapter reads '* LOC: <timecode> <COLOR> <text>' into a zero-duration Marker named with the text (source colour word kept in metadata, unknown colours become RED, non-matching lines silently skipped) and writes each marker back as LOC with start timecode, colour and the upper-cased name; duration and Marker.comment are lost and positions depend on the EDL rate. Drawn annotations have no slot.
- articleIf I move review notes between OpenRV and an OTIO timeline, which survive: markers, drawn annotations, hold/ghost settings?
At Open RV 27db5464 the OTIO reader imports markers (name, range, colour, metadata as JSON) and turns OTIO annotation layers into RVPaint strokes placed on each layer's end-inclusive frame, with hold/ghost as session settings; the writer exports markers only when the importer-created otio_metadata property exists and has no annotation/paint code, so drawn notes are import-only and RV-native markers may not export (inference from the guard). No Marker.comment is carried either way.
- articleWhat did Ofcom's four live-subtitling quality reports measure and conclude, and what does the NER model count, when the original NER chapter is not available?
Ofcom's fourth live-subtitling report (2015) measured 98.55% average NER accuracy (97.93% when subtitles above 200 wpm count as errors) and 5.6 s average latency against the 3 s its guidelines recommend; the 98% acceptability threshold came from its external reviewers, not from a stated regulatory requirement.
- articleWhere does the '32 characters, 3 lines' closed-caption rule in a DCP come from, and what do SMPTE ST 429-5:2023 and RDD 52 (the Bv2.1 profile) say about closed-caption packaging?
The DCP closed-caption limit of 32 characters per line and 3 lines per instance comes from SMPTE RDD 52:2020 (the DCP Bv2.1 Application Profile, a Registered Disclosure Document expressly not a Standard), which notes some languages need fewer characters (e.g. 14 or 16) and also says caption XML should not exceed 256 kB, forbids MainCaption and ClosedSubtitle and requires 48 kHz audio. ST 429-5:2023, the packaging layer, defines closed captions as text for a non-screen device and sets no character or line limits.
- articleHow does SMPTE ST 2067-2:2020 carry IMSC timed text and fonts in an IMF package?
SMPTE ST 2067-2:2020 requires an IMF Timed Text Track File to carry one TTML document conforming to the IMSC1.1 Text or Image profile (wrapped per ST 429-5), with non-generic fonts carried as OpenType ancillary resources identified by UUIDv5 derived from the font family name, and defines kinds including subtitle, caption and forced narrative; it sets no characters-per-line or reading-speed limits.
- articleWhat does SMPTE ST 429-2:2023 constrain for timed text in a DCP: fonts, number of subtitle instances, Text and Image elements, tracks?
SMPTE ST 429-2:2023 requires exactly one LoadFont when Text elements are present, says the font resource should not exceed 10 MB (noting legacy systems may not support more than 640 KB), allows at most two visible subtitle instances with up to six Text or three Image elements each, and limits compositions to one on-screen plus six off-screen text tracks; it sets no characters-per-line or reading-speed limits.
- articleWhat does SMPTE ST 428-7:2014 say normatively about subtitle structure, text limits and font carriage for a DCP subtitle file?
SMPTE ST 428-7:2014 defines DCDM subtitle XML with percentage positions, an optional LoadFont naming a font only by urn:uuid (mapping to a file out of scope), PNG sub-pictures bounded by the picture, and ruby, vertical and bidi rules; it advises that a Text string fit one line, with multiple lines as sibling Text elements, and sets no characters-per-line, reading-speed or minimum-duration numbers.
- articleWhat do the publicly readable SMPTE ST 2059-1, ST 2059-2 and ST 12-1 documents define about synchronising video signals and time code?
SMPTE ST 2059-1:2021 defines the SMPTE Epoch (1970-01-01 00:00:00 TAI, equal to the PTP epoch) and how interface signals and ST 12-1 time code are aligned to it; ST 2059-2:2021 profiles IEEE 1588 PTP (default domain 127) with a synchronization-metadata TLV for time-address flags, jam and leap-second data; ST 12-1:2014 defines the time address, drop-frame counting, LTC and VITC. The PDFs are freely readable at pub.smpte.org (SMPTE copyright).
- articleIn Open RV v4.0.2, does the renderer ever read an RVPaint stroke's softDeleted or uuid property, and are soft-deleted strokes drawn?
Open RV draws an annotation only if its component name is in the frame's order list (then filters by eye, point count and startFrame/duration); no render code reads softDeleted or uuid. Open RV's own writers (annotate mode and the OTIO hook) keep deleted items out of the order list, so a softDeleted=1 stroke would be drawn only if a third-party writer left it in the order list (code inference).
- articleExactly which GTO components and typed properties does Open RV create for a pen stroke, a text box and a shape, and which of them does the renderer actually read?
Annotate mode creates typed properties per object (pen: color, width, brush, points, join/cap/splat, startFrame/duration/mode, plus uuid and softDeleted; text: position, colour, size/scale/rotation, font fields, text, plus uuid and softDeleted; shapes: startFrame, duration, eye and geometry). PaintIPNode, which draws them, reads the drawing properties but never uuid or softDeleted.
- articleWhat does EBU R 37 say numerically about sound and picture timing, and do the EBU-TT-D documents (Tech 3380, Tech 3381) state any reading-speed or line-length numbers?
EBU R 37-2007 limits end-to-end sound-picture offset at emission to 40 ms sound-early and 60 ms sound-late, with 5 ms early to 15 ms late at each stage, measured with flash-and-blip markers. EBU-TT-D (Tech 3380) sets layout defaults (cellResolution 32x15, linePadding 0c) but neither it nor Tech 3381 gives reading-speed or line-length limits, which must come from style guides.
- articleWhat does AES TD1008 say about true-peak limiting, codec overshoot and sample-rate conversion when preparing masters for lossy streaming?
AES TD1008 (2021, superseding TD1004) recommends at most -1 dBTP at the input of lossy codecs (high-rate coders around 256 kbps may tolerate -0.5 dBTP), a true-peak limiter as the last element before the codec, and notes downward SRC can create overshoots a limiter placed before it cannot catch; its distribution table targets speech at -18 LUFS (+1 LU), track-normalised music at -16 LUFS and album-loudest tracks at -14 LUFS (+0.2 LU).
- articleWhat subtitling, audio description and signing percentages does Ofcom's Code on Television Access Services set for UK-regulated TV channels, and how are channels and affordability decided?
Ofcom's 2024 access code sets statutory ten-year targets of 80% subtitling (90% Channel 3 and 4; 100% BBC), 10% audio description and 5% signing as percentages of non-advertising programme hours per delivery platform, with interim targets by anniversary (e.g. year 1 10/2/1%, year 5 60/10/3%); Ofcom's July 2025 notice lists 83 channels required in 2026 (82 at Level One). The Code does not cover on-demand services (producer reading of the 2024 statement).
- articleWhat numbers does Ofcom's Code on Television Access Services (updated 20 Nov 2019) set for audio description and subtitling, and which of them are binding targets versus best-practice guidance?
In the 2019 edition of Ofcom's access code, binding annual percentage targets rise to 10% audio description, 80% subtitling and 5% signing, while numeric production guidance (subtitles normally at most 160-180 wpm for pre-recorded programmes, live delay at most 3 s, two lines unless three do not obscure the picture) sits in Annex 4 as guidance to 'have regard to'. This edition is superseded by the 2024 Code (C2-B61-K5-06).
- articleWhat do the FCC closed-captioning quality rules in 47 CFR 79.1 actually require, and do they set numeric timing or line-length limits?
FCC caption quality standards in 47 CFR 79.1(j)(2) require captions to be accurate, synchronous, complete and appropriately placed (readable speed; not blocking important visual content), with a de minimis allowance and case-by-case factors for live programming; the section read contains no numeric speed, line-length or timing limits.
- articleWhat decision criteria do veteran film editors state publicly for choosing performance takes and cut points, and where do they differ?
Three veteran editors describe their working order: Murch ranks emotion, story and rhythm above eye-trace and 2D/3D continuity and drops criteria from the bottom up (his percentage weights are a rhetorical device), and calls the last frame of a shot perhaps the most important choice; Littleton marks the best take per script line and weighs performance first; Schoonmaker puts the best performance take ahead of continuity. These are individual accounts, consistent with the experimental finding that axis violations rarely hurt enjoyment.
- articleDoes the brain treat continuity cuts as a common event, and do cut types differ?
An open-access EEG study (21 viewers) reports neural responses common to continuity cuts (theta synchronisation, delta desynchronisation) interpreted as encoding and segmentation; differences by cut type appeared under one taxonomy but not another, where results matched random groupings. Only continuity cuts were tested, so it says nothing about jump cuts or axis breaks.
- articleDoes crossing the 180-degree line confuse viewers or reduce how much they like a video?
In three experiments with sketch-style videos, viewers noticed 180-degree violations (flagging .42 of critical cuts vs .08 without violation), were slightly more confused (about 8% vs 6% of critical cuts), and liked violated videos just as much (preference .519, Bayes factor favouring no effect). This supports 'detectable and mildly confusing' but not 'harms enjoyment'.
- articleWhat do documentary makers say about paper edits, string-outs and card walls, and where do they disagree on how much structure to plan before editing?
Roger Nygard surveys documentary editing: paper edits from transcripts, assistant-built topic string-outs by transcript word search (his own method), story cards on a wall whose order can invert, interview-first blind assemblies with talking heads moved repeatedly, and judgment-based endings, plus Herzog's counter-position of shooting what you want for the screen. Statements by other filmmakers are second-hand in this article.
- articleHow does a documentary editor describe finding structure from raw footage (string-outs, breakdowns, card boards), with examples and limits?
Editor Maya Mumma organises verite footage by stringing out each card, then each shoot day, then breaking days into beat sequences sorted by character, location and event; she starts archival films with chronology, builds an early card board of beats with parallel thematic columns, keeps a 'good things' bin for strong lines, and found one film's structure by cutting five filmed subjects to three. She says each project differs.
- articleWhat do the W3C MAUR and UAAG 2.0 ask of media players for caption customisation, keyboard operation and sign-language windows?
W3C's MAUR (2015 Note) lists player requirements: configurable caption fonts, sizes, colours and background opacity, caption track toggling, keyboard operation of all functionality, and sign-language video as a track or file shown as picture-in-picture, overlay or parallel video with a user toggle. UAAG 2.0 (2015 Note) adds that alternatives must not obscure controls or video, captions are user-configurable, and alternatives can be resized to at least 50% of the viewport and repositioned. Both are Notes, not Recommendations.
- articleHow do vrecord and QCTools document capturing and checking videotape transfers, and what do they record as fixity and metadata?
vrecord captures via MediaArea's ffmpeg-ma with Blackmagic cards (or AVFoundation for DV on macOS) to FFV1 version 3 with GOP 1 and slice CRCs, writes a framemd5 and logs by default (QCTools XML highly recommended; frame MD5s catch some dropped frames), and checks output against a MediaConch policy (Matroska >= 4, FFV1 >= 3.4, GOP 1). QCTools stores per-frame signal metrics (signalstats, cropdetect, psnr, ssim, ebur128) in a report for review. Neither is a standards conformance tool.
- articleWhat audio and asset deliverables does Netflix require from a dubbing studio besides the script, and what public detail exists on dub cards?
Netflix's premix spec asks for a mono offline-bounced WAV of all premix dialogue with group walla attenuated by 10 dB and a -6 dB true-peak limiter on dialogue or the bounce bus, and the dialogue editorial session as a store-only ZIP named with 48k24b; dub-card requirements could not be read (page is a JavaScript shell; the article API returns not found).
- articleWhat script format and content rules does Netflix publish for the dubbing script (as-recorded script) a dubbing studio must deliver?
Netflix's as-recorded dubbing script is delivered in TTAL (direct upload or its Script Authoring tool) and validated; events are timed to the first and last spoken word, split at pauses of about two seconds, with WALLA for indistinct crowd dialogue; delivery is due three calendar days before the secondary audio (changed from five on 2024-09-17).
- articleIs IMF an archive format for finished films, what do archives and the Library of Congress say about IMF, DCP and MXF as wrappers, and what remains unclear?
LoC's RFS lists IMF (MXF essence, CPL, packaging XML) first for file-based final video; the Academy forum describes IMF as a wrapper in significant industry use, notes an LoC MXF archiving subset (SMPTE RDD 48) and IMF App 5 ACES (ST 2067-50); FIAF 2019 found only CNC and LoC requesting a mezzanine on deposit, with CST recommending IMF (ST 2067-40) as mezzanine. Evidence of IMF as an actual long-term archive master remains thin.
- articleFor a born-digital feature, what do film archives and the Library of Congress say should be deposited: DSM, DCDM or an unencrypted DCP?
FIAF's Technical Commission (2010) accepts only a DCDM or an unencrypted DCP for long-term preservation: the DCDM is ideal but may never exist as a complete set, while the unencrypted DCP is lossy but shows the work exactly as audiences saw it. FIAF's 2019 survey counted unencrypted DCP deposit at 9 archives and DCDM at 7, and LoC's 2025-2026 RFS prefers an unencrypted interop DCP for motion pictures, asking depositors to contact it about DCDM/DSM.
- articleWhat do archives and tools document about using BagIt with OAIS/PREMIS for audiovisual collections, and what went wrong in practice?
Archivematica documents AIPs as BagIt bags containing METS, but its 1.13 page gives inconsistent manifest algorithms across its own examples. Indiana University's MDPI relied on Matroska per-element CRCs written by FFmpeg (about 100 bytes unprotected), packaged film as BagIt tarballs (DPX, WAV, metadata) with a custom multithreaded verifier, and reported that a vendor bagit.txt reading 'BagIt-version' made them re-handle over 2 PB. Per the L07 correction on C2-B10-G2-07, ABNF quoted strings are case-insensitive, so this shows IU's tooling or acceptance criterion, not a proven RFC nonconformance.
- articleWhat rendering failures for RTL, ruby, vertical and text-combine timed text are documented in public renderer issue trackers and test suites?
The imscJS tracker records concrete RTL/CJK failures: per-character spans broke Arabic joining in WebKit (109, closed), sheared vertical Japanese text was cropped by its region (260, closed), rubyReserve broke on Chrome after a switch to CSS ruby-text-container (289, closed 2026-10-10), and ruby style-resolution pruning (162) and xml:space/rubyAlign (185) remain open. One renderer's tracker; a sample, not prevalence.
- articleWhat do IMSC/TTML2, WebVTT and the Netflix Japanese guide say about ruby annotations, vertical text and tate-chu-yoko in subtitles?
IMSC 1.3 permits ruby (via ruby, rubyAlign-minimal, rubyPosition, rubyReserve), text combination and vertical writing; WebVTT has ruby spans, vertical growing-left/right writing and CSS ::cue text-combine-upright but no cue setting for it. Netflix's Japanese profile sets 13 (horizontal) and 11 (vertical) full-width characters per line, half-width counting 0.5, up to 4 characters per second, and ruby/bouten placement by orientation and line.
- articleHow are forced narrative subtitles represented and chosen at playback in IMSC, WebVTT and on Netflix, and what language-specific conventions apply?
IMSC 1.3 marks forced content with itts:forcedDisplay and a player-side displayForcedOnlyMode; Netflix shows FN only when subtitles/CC are off, so full subtitle and SDH files must themselves contain the FN content. WebVTT (CRD read by producer) has no forced-narrative concept; language guides add marking rules (quotes, hyphens, italics).
- articleWhat does an independent evaluation measure when it compares MFA, WhisperX and MMS word alignment against manual alignments, and what are its stated limits?
Against manual alignments on TIMIT and Buckeye (words correctly recognised only), MFA places more word boundaries within 10-100 ms than WhisperX or MMS; on Buckeye WhisperX reaches only 77.4% within 100 ms. The authors note their Buckeye result differs from the original MFA paper (possible long-utterance drift).
- articleHow does WhisperX produce word timestamps, under which separate licences (code, alignment models, diarization), what accuracy does its paper report and on what, and what failure cases does the repository document?
WhisperX (BSD-2 code) transcribes with Whisper and aligns words with a language-specific wav2vec2 model (English default torchaudio WAV2VEC2_ASR_BASE_960H); words with characters outside the model dictionary (numbers, currency) get no timing, overlapping speech is weak, and diarization needs a gated pyannote model with a user agreement.
- articleUnder what separate terms are the Montreal Forced Aligner code and its English acoustic model released, what training data and performance caveats does the model page state, and what does the model page say about its own accuracy metric?
MFA code is MIT while the English acoustic model v3.0.0 is CC BY 4.0 and lists its training corpora; its 0% WER/CER is on training data (not held-out); the page warns about demographic bias and recording consent. Pronunciation dictionaries carry separate licences (not read).
- articleHow does Godot 4.7.2 Movie Maker mode fix the time step and capture audio for offline cinematic capture, and what does it promise about identical output?
Godot Movie Maker renders non-real-time with a fixed step (default 60 fps when --write-movie is used without --fixed-fps), so pacing is perfect regardless of hardware; audio is mixed mix_rate/fps samples per frame and the writer warns when the mix rate is not divisible by fps (audio drift); not meant for live gameplay capture.
- articleHow are timed text tracks carried and validated in IMF packages according to public sources (ST 2067-2 versions, Netflix profile, Photon)?
Netflix Photon validates IMF timed-text track files by mapping kind (0x13), UTF-8 UCSEncoding and an IMSC1 profile NamespaceURI; Netflix's own IMSC 1.1 text profile is currently valid only for Japanese timed text. ST 2067-2 text itself was not read (ZIP-only).
- articleHow do Interop and SMPTE ST 428-7 subtitle files differ inside a DCP, and what do public tool checks and delivery rules encode for each?
As encoded in two open validators, Interop and SMPTE DCP subtitles differ in file form (.xml vs .mxf), root element and timing units, and SMPTE text subtitles require exactly one LoadFont while Interop does not; libdcp checks main-subtitle line lengths at 52 (warning) / 79 (error) characters and closed captions at 32. The validators classify some rules differently (libdcp warning vs ClairMeta error for the 4 s first-subtitle rule).
- articleHow do DCMP, Netflix English (USA) and BBC guides handle music descriptions and song lyrics in captions?
Lyrics marking differs: Netflix ♪ at start and end of each subtitle plus italics; BBC # at the start of lyric subtitles (centred), mood music labelled only when required; DCMP marks nonessential background music with a ♪ icon top right and never at the expense of dialogue. Only Netflix requires italic lyrics.
- articleHow do DCMP, Netflix English (USA) and BBC guidance write sound-effect descriptions, and where do they differ?
All three caption only sound that matters and describe sounds rather than actions; DCMP is most prescriptive on form (lowercase bracketed source+sound, optional onomatopoeia line, participle vs third-person tense), BBC uses white caps on a separate line, Netflix lowercase brackets with detailed descriptions for plot-pertinent sounds.
- articleHow should speaker identification be written in SDH/captions, and where do DCMP, Netflix English (USA) and BBC guidance disagree?
All three guides identify speakers only when the viewer cannot; devices differ: DCMP puts the parenthesised name on its own line, Netflix wants the ID on the same line as the dialogue, and BBC prefers colour (narrator yellow) with ttm:agent metadata in EBU-TT.
- articleWhat does RFC 9639 FLAC allow for channel count, sample rate, length and metadata, and how does it carry a non-default channel layout or WAV chunks?
RFC 9639 FLAC: 1-8 channels, 1-1048575 Hz, 4-32 bits; 36-bit total-sample field (0 = unknown) instead of a RIFF-style byte limit; metadata blocks capped at 2^24 bytes; non-default channel layouts need a Vorbis-comment channel mask and are then not streamable; foreign RIFF/W64/AIFF chunks only via registered APPLICATION blocks (no bext equivalent).
- articleMy WAV is over 4 GB or multichannel with ADM metadata: should I write RF64 or BW64, and how does the file say which it is?
BW64 (BS.2088-2) and RF64 (EBU 3306) share the ds64/64-bit-size mechanism and JUNK reservation; the EBU itself directs implementers to BS.2088 exclusively; BW64 removes RF64's 18-position channel mask and carries ADM via chna/axml; the top-level ID, not the .wav extension, distinguishes them.
- articleDo Godot USD add-ons exist that can write USD for offline finishing, and what do their READMEs state about coverage and builds?
Of two third-party Godot USD GDExtensions read, only godot-usd documents writing USD (scene-graph authoring save with warnings for unsupported edits; prebuilt binaries for macOS arm64 only); godot-usd-importer documents import only. Neither documents rendered-frame output.
- articleWhich Unity Recorder 5.1.7 image-sequence settings matter for handing real-time renders to offline finishing (format, bit depth, colour space, alpha)?
For scene-linear handoff, Unity Recorder 5.1.7 documents a narrow combination (HDRP, non-Game-View source, EXR, tonemapping and dithering off) for 'Linear, sRGB (unclamped)'; EXR is written at 16 bits; alpha is unavailable from Game View or non-alpha formats.
- articleWhat does the Unity USD package document for exporting scenes or animation to USD, and what are its stated limits?
The Unity USD package (3.0.0-exp.5, experimental) exports selected GameObjects and transform overrides to USDC/USDA/USDZ, recommends the Recorder route when runtime compatibility is not needed, and is pinned to USD v20.08 with no Apple Silicon native editor; it is a scene-graph export, not rendered frames.
- articleWhat is lost or silently changed when converting a LUT between CLF and .cube (ordering, domain, bit depth, interpolation, precision), and how could it be tested with three small files?
Copying a 3D table verbatim between CLF (blue-fastest) and Adobe Cube (red-fastest) transposes the red and blue axes; OCIO's Iridas reader (10a43ec1) converts from red-fastest order and turns DOMAIN_MIN/MAX into a min/max op, while its baker writes only LUT_3D_SIZE and six-decimal data with no DOMAIN lines, so baked .cube files carry no input-domain information (static reading).
- articleWhat does the W3C imsc-tests repository contain (TTML source files and reference PNG renderings) and under what licence text can its files be used?
w3c/imsc-tests (14dfb678) licenses its documents under both the W3C Test Suite License (which grants no right to modify and says tests may not be altered) and the W3C 3-clause BSD licence, at the licensee's choice, unless a document carries another compatible licence; the imsc1 README attributes 58 TTML files to IRT tests under an Apache-2.0 licence and 196 to the W3C TTML and IMSC implementation reports.
- articleWhat are the practical SCC/CEA-608 limits (columns, rows, timing, capacity) that public tools document?
pycaption (ad2ddba8) writes SCC for CEA-608 pop-on, roll-up and paint-on modes on a 32-column, 15-row grid, wraps lines at 32 characters, caps a caption at 80 tokens including 8 control codewords, supports drop-frame and non-drop-frame timecode, and times one codeword at 1/29.97 s (static reading).