- articleHow do sound designers use point-of-view and off-screen sound to tell the story, with what concrete techniques, and where does it stop working?
Thom's 2000 interview on What Lies Beneath is the densest account: POV sequences give sound its widest licence; keep dialogue sparse; use visual conditions (water, mist, darkness) as the door to subjective sound; filter real sounds (underwater muffle) rather than add many; keep ambiguity by making voices unintelligible; and do not call attention to the sound design. Rydstrom adds an unlocated-sound principle for horror, Weis a voice-before-image menace technique, Holman off-screen events written into scripts. These are practitioners' stated rules, not tested findings.
- articleWhat are the building blocks of a film soundtrack (dialogue/ADR, effects, backgrounds, Foley, walla, music) and what does each department actually produce before the mix?
Two first-person-heavy sources (Weis 1995 with practitioner interviews; Thom 2000 interview) and two short glossary/textbook excerpts give a working vocabulary: dialogue and ADR are cleaned or re-performed production speech; effects tracks are built from scratch from library, new recordings or combinations; Foley is effects performed to picture (footsteps, cloth, props); walla is a prepared, improvised crowd murmur; a typical final mix groups these as separate elements. The term 'hard effects' does not occur in any page read, so this batch gives no source-based definition of hard effects versus backgrounds beyond the separate 'backgrounds' element in Weis's track layout.
- articleHow should upscaled footage be judged: what do primary sources say about full-reference versus no-reference metrics and their limits?
Blau and Michaeli prove that lower distortion (full-reference measures such as PSNR/SSIM) and better perceptual quality are at odds for any distortion measure, which is why GAN-based upscalers can score worse on PSNR while looking better. Real-ESRGAN reports only the no-reference NIQE and warns such metrics do not track human preference. The VMAF docs describe a full-reference metric trained on subjective data for stated viewing conditions, say it captures gains from enhancement operations, and provide a NEG mode that disables enhancement gain for codec comparisons; its FAQ shows upscaling the distorted clip before comparison. No inspected source states a validated protocol for judging AI-upscaled finishing footage; broadcaster specs require QC but no metric thresholds in the passages read.
- articleWhich artefacts do the original papers and the vendor documentation themselves report for AI upscaling and frame interpolation (invented detail, smearing, ghosting, occlusion errors, flicker)?
The Real-ESRGAN paper reports twisted lines, GAN-training artefacts and failure on out-of-distribution degradations; RIFE reports ghosting by competing methods and lists its own limitations (two-frame input, PSNR/SSIM-centred evaluation); FILM states disocclusions force a model to hallucinate pixels and reports unnatural deformations for extreme motion. The Topaz documentation (vendor) lists strobing on reflective water, distortion of patterned caustics, wobble on dense parallax, per-frame detail differences in Theia, flicker of small repeated patterns and mis-read small text in Starlight HQ. None of these sources reports a measured artefact rate for finishing use; the vendor statements are not tests.
- articleIn an FFmpeg zscale + tonemap HDR-to-SDR chain, which HDR metadata is read, kept, stripped or left stale, and where would an agent silently lose dynamic metadata?
Reading FFmpeg at 5fd305b8 (code only; nothing executed): the HEVC decoder exposes HDR10+ and Dolby Vision as frame side data, but vf_tonemap derives its peak only from MaxCLL, then mastering-display max luminance, then a fixed default (10.0 = 1000 nits for a non-PQ-tagged frame), and never reads dynamic metadata. vf_zscale removes every COLOR_DEPENDENT side-data type (CLL, MDCV, HDR10+, Dolby Vision RPU/metadata) whenever the output transfer or primaries differ from the input. In FFmpeg's own documented chain the first zscale (to linear) therefore strips the metadata before tonemap runs, so the detected peak falls back to the default unless peak= is set. libx265.c has no HDR10+ handling at this pin, so a re-encode drops it silently; x265 needs --dhdr10-info.
- articleHow do I shorten or lengthen a music cue to fit picture and join it cleanly: which crossfade shape, which grid, and what do music editors say about re-cutting for picture changes?
The open DAW documentation gives concrete crossfade and grid facts: Ardour's constant-power crossfade (-3 dB each at the midpoint) is the splice for uncorrelated material, linear (-6 dB each) for highly-correlated signals, symmetric for editing two entire music works together, default fades are short de-clickers; the musical grid (bar, beat divisions) scales with tempo while timecode grids do not. Music editors add that cues are repeatedly lengthened, shortened or reworked as picture changes. No inspected primary source states a rule that cuts should land at phrase boundaries or downbeats; that rule appears only as a synthesis (cut on bar lines of a tempo-mapped grid and crossfade across the join) and in secondary search results not fetched.
- articleWhat is a temp track, what is 'temp love', and what does a music editor actually do from temp dub to cue sheet?
Two music editors describe the same sequence: a temp dub of existing music for previews (no licensing needed), a spotting session with director/editor/composer, cue-by-cue notes with IN/OUT points and director comments, scoring, stems for the final dub, and a music cue sheet listing every cue. Carlson (about forty years in the business) defines 'temp love' as the director or producer falling in love with what they first heard and not wanting it changed. The union page read only lists 'Music Editor' as a classification; the role descriptions come from the two practitioner interviews, one on a single film (The Greatest Showman) and one about a career.
- articleWhat do open sources say about gain staging and headroom for dialogue, and what do they say (and not say) about EQ for dialogue clarity?
Gain staging and headroom are covered qualitatively: Ardour says meters are for avoiding overload and keeping headroom when tracking, defines 0 dBFS as a system limit with no musical meaning, and offers K20/K14/K12 meters with reference scales at -20/-14/-12 dBFS; Netflix's dubbing guidance asks for no compression, limiting or EQ during recording. For EQ, the REAPER guide only says to use ReaEQ gently, and its 80 Hz / 6 kHz examples are detector filters on a compressor, not corrective EQ. No inspected primary source gave dialogue EQ band frequencies or boosts; that gap is recorded as a negative result.
- articleWhat is room tone, how long should I record it, where do I use it, and what goes wrong if I skip it or process it badly?
Room tone is the ambient sound of a space recorded with everyone silent. A practitioner post (iZotope, 2021) and a trade-press guide (No Film School, 2025) agree on 30 to 60 seconds, with the same microphone placement as dialogue, extended when the ambience changes; its uses are filling gaps between dialogue edits and layering under ADR or overdubs recorded elsewhere. Audacity's manual adds a numeric floor for noise profiling (2048 samples, longer is better) and warns that heavy noise reduction damages the remaining audio. The 30-60 s figure comes from secondary/vendor sources, not a standards body.
- articleShould a comic reveal be a surprise or should the audience know first, according to period photoplay and playwriting manuals?
Sargent's rule is to keep the spectator advised and the players in ignorance: in his Griggs-restaurant example the laugh broadens from the moment the audience knows he cannot pay, whereas a reveal at the end gives one short laugh; but he also says anticipation starts the laugh and surprise should complete it (small man beats big man). Esenwein and Leeds recommend ending a comic series on a surprise climax followed by a quick denouement. Archer (stage, 1912) warns it is worse than useless to awaken an expectation and then disappoint it. The sources therefore split: anticipation for sustained laughter, surprise as the topper.
- articleWhat do 1916 photoplay manuals say about planting a fact, repeating a gag with a bigger result, and spacing escalation beats so each one lands?
Sargent (Technique of the Photoplay, 3rd ed. 1916, chs. LVI-LVII) gives concrete rules: show a fact to the audience before you cash it in ('make a deposit before you can write checks'), let a repeated gag escalate (the dropped ice cream repeated after a cut-in leader reminds the audience whose coat it is), chain a slapstick beat into a bigger one (kick, thrown rock, rock hits a third person, both fall), and space beats by fractions of a second so the audience senses what is coming. His scene-writing rule is to describe comic business plainly and in action. These are one trade writer's period rules for silent one- and two-reel films, not tested results.
- articleWhat does a music editor deliver to the dub stage (track grouping, cue sheet, sync check), and what happens to the music there?
The same TV music editor (S5, S6) integrates the recorded cues into the editing session, checks sync, sends the session to the dub stage and prepares a hand-drawn-style dubbing cue sheet "road map". Cues are grouped onto MUSIC-A to MUSIC-D track groups so overlapping cues sit on separate faders (34 music faders in his example). At the dub, dialogue is described as king, music is fitted around it, producers take notes in a final playback and the editors make fixes; mixers then make the 5.1 and stereo masters, an M&E and a DME master. Music-editor deliverables and dub practice here are from one US animated series in 2011.
- articleWhen do modern scoring sessions record to a click, when do they free-time with streamers and punches, and what does each choice cost?
A Los Angeles studio conductor (S8, blog posted 2013, modified 2025) says about 99 percent of his work is on click, that free timing with streamers and punches is rare and impractical for most modern film scores (mixed pre-records, spread-out orchestra, hard to edit takes together), and that he often just follows the Pro Tools counter. A Phaedrus Audio web page (S12) describes the click as indispensable for long fast cues with many hits but mechanical for rubato, and streamers and punches as a way to keep sync on a hit while leaving tempo to the conductor. A TV music editor (S5) says most cues are scored to a click.
- articleWhich scoring/DAW tools have a documented way to map picture hit points to tempo, how do their mechanisms differ, and at which dated versions was this observed?
Vendor documentation observed on 2026-10-22 describes three different mechanisms. Dorico 2.2 (Nov 2018 version history) lets you flag "important" timecode-locked markers and searches one tempo for the flow so those markers fall near beats, and dragging a marker alters the preceding tempo. Logic Pro for Mac 12.3 (page metadata) adjusts the selected tempo points leading up to a hit point so audio aligns. Sibelius 2018.4 stores named hit points that move with the score and leaves tempo adjustment to a Fit Selection to Time plug-in. A 2024 practitioner article (Dorico 5.1.21, Sibelius 2024.3 era) and a 2017 composer account (Digital Performer) confirm the same ideas from use.
- articleHow do I turn a hit point (a timecode I must land on) into a tempo and a click, and how close does the landing need to be?
Tempo times beats equals seconds: the editor (S3) and the Phaedrus Audio page (S12) both reduce hit placement to arithmetic, and S12 gives a worked click-book example in which 80 BPM misses a hit at 34 s by a quarter or half second but 81.13 BPM (17-6 frames per beat at 24 fps) lands it. S12 states a sync tolerance of two film frames (about 41 ms) with a rule of thumb of 0.1 s. A composer (S7) finds a rough tempo by tapping, then uses a software Find Tempo search over a tempo range. The arithmetic in S12 was re-checked by a batch-local script (consistent within rounding).
- articleWhat is a spotting session in film/TV scoring, who attends, and what written output (cue list with timecodes and reasons) should it produce?
Two first-person practitioner accounts (a long-serving TV music editor, 2011; a film composer, 2017) describe spotting as a viewing-and-discussion step that decides where each cue starts, where it ends and why it exists, then produces timecoded notes for the composer. The music editor logs exact start/stop timecodes against a locked-length picture; the composer places start, end, hit and descriptive markers in the DAW. Both accounts come from one US animation-TV pipeline and one composer-teacher, so attendance and tooling differ in features and for other territories.
- articleHow could an agent mark J-cuts and L-cuts in an edit plan so that a human or tool can build and check them?
No inspected source defines a notation for marking split edits in a plan. The pieces exist, though: Salt measures every dialogue cut by two frame counts (A and B) with L-edits as negative A; Apple and Adobe describe the edit as separate audio and video edit points on one clip, with media handles needed. This candidate proposes a small record per cut built from those pieces. It is a synthesis, untested.
- articleWhat are J-cuts, L-cuts and split edits, which direction is which, and what must be in place to make one in an editor?
A split edit makes the sound and picture cut at different times. A J-cut lets the next scene's sound start before its picture; an L-cut lets the previous scene's sound continue over the next picture. Apple's Final Cut Pro guide (page Last-Modified 2026-09-29) and Adobe's Premiere help (page text last updated 2025-08-22, read via an Internet Archive snapshot) agree on the definition and both give the same prerequisite idea: unlink or expand audio from video and move one edge. An open Ohio State textbook (Copyright 2024) gives the same definitions with film examples.
- articleWhich scope (waveform, RGB parade, vectorscope, histogram, gamut diamond) should be used to check what, and does a vendor's '0-100%' rule match EBU R 103's tolerance?
Blackmagic's SmartScope manual assigns luma legality to the waveform (keep blacks at or above 0% and whites at or below 100%), colour-channel legality to the RGB parade ('should be used for checking for illegal colors'), colour balance and tint to the vectorscope, and states a vectorscope alone cannot show illegal levels; a histogram cannot show colour illegality. Tektronix' WFM5200 manual adds that signals legal in digital YCbCr may be illegal when transcoded to RGB and provides Diamond/Spearhead RGB gamut displays with adjustable thresholds. Both vendor texts speak of 0-100% as the limits, whereas EBU R 103 tolerates a preferred band to about -5%/+105% and flags gamut errors only when above 1% of the image.
- articleWhat are the nominal, preferred and total code-value ranges for 8-, 10- and 12-bit Rec.709/BT.2100 video, and what is the difference between narrow ('legal') and full range?
BT.709-6 s4.6 fixes black=16 and nominal peak=235 (8-bit) or 64 and 940 (10-bit), with video data 1-254 / 4-1019 and the rest reserved for timing. BT.2100-3 Table 9 gives narrow range (default) and full range (only by agreement) and the same 64/940 and 256/3760 at 10/12-bit. EBU R 103 v3.0 Table 1 adds a 'Preferred Min/Max' tolerance (8-bit 5-246, 10-bit 20-984) inside the 'Total Video Signal Range' and says values beyond nominal but inside preferred are not an error. The percentage forms (-5.02 to +105.02 preferred; -6.85 to +109.02 total at 10-bit) are the worker's arithmetic.
- articleWhat do practitioners say a sound editor must do to prepare tracks before the mix (separation, premixes, scratch mixes, M&E), and what goes wrong when they do not?
Craft-side preparation, as distinct from delivery specs: split dialogue by mic angle; keep families on separate tracks and premix them into manageable elements; have the major effects and clean-ups ready by the first scratch mix; record the full soundscape under dialogue so an M&E exists; decide with the composer, scene by scene, whether music or effects leads. Documented failures include sketches frozen by a director's liking for the scratch mix, a composer/effects logjam in the final mix, and a live-performance compromise (Philadelphia) that left dialogue and aria on one track.
- articleHow do I duck music under dialogue (sidechain or automatic ducking), what parameter values do open manuals state, and what do practitioners do instead of lowering all the music?
Three mechanisms are documented: an offline effect keyed from a control track (Audacity Auto Duck: -12 dB, 0.5 s fades, 1 s maximum pause, -30 dB RMS threshold), a sidechained compressor (ReaComp auxiliary detector, Ardour a-Compressor sidechain; OBS gives 32:1, -36 dB, 100 ms attack, 600 ms release as a starting point for streaming), and an inverted sidechained gate (ReaGate). A feature-film practitioner account adds a third strategy: deliver music as stems and nudge only the competing stem (a loud horn) down a few dB at the dub so the whole score is not dipped. No inspected source validates specific ducking values for film dialogue.
- articleWhich Dolby Vision trim passes must a colourist actually do for HDR-to-SDR delivery, in what order, and how many targets?
Dolby's guide requires the colourist to review the Rec.709 100-nit mapping across the whole timeline, and to make the 100-nit trim first if any shot is trimmed; extra targets (600/1000 nit) are optional, up to four trims per deliverable, and should be real passes rather than pasted values. Netflix (2022 and 2026-07 snapshots) says HDR is graded first, followed by analysis and a shot-by-shot trim pass, but lists the 100-nit L2/L8 trim values themselves as not required unless creatives want scene-level adjustments. The two statements are compatible if 'review the default mapping' (Dolby, required) is separated from 'deliver authored trim values' (Netflix, optional); the sources do not say so explicitly.
- articleWhat is the normative definition of MaxCLL and MaxFALL that is openly readable, and what does it say about how they are measured?
The CTA-861.3 text is paywalled, but ITU-T H.265 (V11, 01/2026) clause D.3.35 is a free primary text that defines the content light level SEI in terms CTA-861.3 relies on. Per pixel, take EMax = max(R,G,B) in linear light, convert to a light level as the CIE 1931 luminance of equal-amplitude RGB at EMax, scaled so peak white is 10,000 cd/m2 for PQ. max_content_light_level is an upper bound over all samples of the coded video sequence; max_pic_average_light_level is an upper bound on the maximum, over pictures, of the average over samples. The SEI does not itself specify the conversion from decoded samples to linear light.
- articleWhat do OBS Studio's libobs docs say about output frame-rate representation and audio/video sync offset, and is a variable-frame-rate recording mode documented?
OBS (libobs at 32.2.2) runs its output at a fixed frame rate expressed as an integer fraction (fps_num/fps_den), set in the UI as a common, integer or fractional value. The UI strings searched have no variable-frame-rate option, so recordings come out constant frame rate, which is convenient for editing.
- articleWhich licence does an FFmpeg binary carry by default, and which configure options change it?
FFmpeg's licence depends on how it was built. By default it is LGPL v2.1 or later (some files MIT/BSD-style, LGPL overall). Passing --enable-gpl adds GPL parts and makes the whole build GPL v2+, --enable-version3 moves it to (L)GPL v3, and --enable-nonfree builds announce themselves as not legally redistributable. Running the binary with -L prints its licence, which is the quickest check for a bundled copy. FFmpeg is never offered under proprietary terms, even for payment. Its legal page gives a compliance checklist and is not legal advice.
- articleHow much of a VISION3 negative's density range fits in a 10-bit DPX scan at 0.002 versus 0.0025 density per code value, and what does Kodak say changes downstream?
Kodak says a standard 10-bit scan (0.002 density per code value, D-min at code 95) can encode 1.856 density above D-min. That was enough for VISION2 negative but can clip VISION3's extra highlight range. Kodak recommends 0.0025 per code value, recording the choice in the DPX header, and warns that the flatter files affect compositing and colour correction. Two figures need care. The quoted 0.512 extra density is the full-range difference; above D-min at code 95 the gain is 0.464. The contrast change is a factor of 0.8 (20% lower, needing a 1.25x gain to restore), which the paper calls '25% lower contrast'.
- articleWhat does Blackmagic's own documentation (under 25 MB) say about reel names when conforming an EDL/AAF/XML in DaVinci Resolve?
Blackmagic's New Features Guides document a few conform aids. Resolve 16 added partial reel-name matching for conform and ColorTrace, ignoring a set number of characters at the start or end of reel names. Resolve 17 can import XML, EDL or AAF timelines into an empty Media Pool, and timelines preconformed from a flattened master via 'Pre-conformed EDL' can take a different input colour space per clip under Resolve Color Management or ACES. Resolve 19's scripting API exports timeline ALE and CDL and imports OpenTimelineIO. How EDL reel/clip columns, ASC CDL comments or AAF tape names are parsed is not stated in these guides.
- articleWhat has Netflix's As Recorded Dubbing Script scope of work changed over time, and what does its change log say?
Netflix's As Recorded Dubbing Script scope of work dates its own changes. The script was due five calendar days before the secondary audio until a 17 September 2024 change made it three. A 24 September 2025 change added episode-title and main-title rules (use the approved title; don't translate freely) and removed the separate TTAL required-fields and appendix sections. Edit timing is bounded only by the captures read.
- articleHow did the audio rules in the Post Production Branded Delivery Specification change between page labels 5.0 (2022-12-09), 5.1 (2024-08-03) and 5.2 (2026-06-06)?
Netflix's Branded Delivery Specifications changed Atmos rules in two steps. Version 5.1 (change log 12 September 2023) removed the separate 2.0 stereo M&E. Version 5.2 (change log 21 October 2024) widened the Atmos group labels from four (Dialog, Music, Effects, Narration) to seven (adding Group ADR, Backgrounds, Foley), made 5.1 and 2.0 deliverables optional for Atmos mixes, and replaced the '-2 dBFS true-peak' sentence with a recommendation to set limiters at -2.3. The separate Atmos requirements page (v2.3, 'updated for parity' with the Branded spec) still showed the older wording in an April 2026 capture, and showed the 5.2 wording by October 2026 (curator cross-check). So the conflicts recorded earlier were a lagging page, and current Netflix pages agree.
- articleWhat public DCP test material exists in libdcp and ClairMeta_Data, and what licence text covers it?
Two DCP test corpora have licences written for software. libdcp is GPL-2.0, with an SMPTE BSD-style licence for portions. ClairMeta_Data (about 1.1 GB of DCP, MXF and XML test packages) carries a BSD-style YMAGIS licence. Neither says whether its licence covers the test essences and packages, so treat the test media's reuse terms as unclear.
- articleWhat WebVTT test material is in web-platform-tests, and what licence text covers it, including the shared media and fonts the rendering tests reference?
web-platform-tests (including its WebVTT tests) is under the 3-Clause BSD licence. The rendering tests depend on shared media and font files outside webvtt/; the fonts README states no separate licence for them, so the repo-level BSD text is the only stated term.
- articleWhat are the eight Matroska 'Wave 1' test files, what does each exercise, and what licence does the repository state for them?
The IETF Matroska test files (eight .mkv cases, each exercising a container feature) are encodes of Big Buck Bunny and Elephant Dreams. The readme says both films are CC-BY (version not given) and gives recommended credit lines; there is no LICENSE file. Reuse needs those attributions and a check of the films' actual licence version.
- articleWhat do Ofcom's access-services guidelines say about audio description style and subtitle presentation (speed, layout, synchronisation)?
The 2015 Ofcom Code's Annex 4 guidance asks audio description to be in the present tense, to avoid filmic terms like camera angles and the phrase 'we see', and not to cover dialogue or key sounds. It asks pre-recorded subtitles to run normally no faster than 160-180 words per minute, usually in up to two lines, synchronised with speech. The current Code (last updated 15 April 2024) no longer contains this annex and refers to separate Ofcom best-practice guidelines, so cite the 2015 text as a dated version and check the current guidelines.
- articleWhat did the ITC's 2000 guidance say about how to write and record an audio description (tense, what to describe, sound levels)?
The ITC's May 2000 audio description guidance is a describer's manual: seven steps from choosing and viewing the programme through drafting, reviewing, setting the programme sound level, recording and checking. It asks for present-tense description (continuous for ongoing action), not talking over sound effects, and lowering the programme level under description. It is historical guidance from the start of UK digital TV, not current Ofcom policy.
- articleWhat do Video.js v10.1.0 docs and v8.24.2 code do with caption, subtitle and description tracks, and what gaps do the maintainers state?
Video.js changed approach between versions. Video.js 10 renders captions natively so FCC-required OS caption preferences apply (decision dated 2026-02-26), offers menus only for captions and subtitles, has no caption-appearance menu, and points audio description to a described audio track. Video.js 8.24.2 had a Descriptions button and showed description cues in its own display with aria-live assertive, giving captions and subtitles priority when both were on. Moving from v8 to v10 drops the built-in text-description path.
- articleHow does Able Player (v5.0.0) deliver text-based and separate-video audio description, and what are its documented gaps?
Able Player 5.0.0 (MIT) offers two audio-description routes: a WebVTT descriptions track voiced through the browser's Web Speech API (or written to an ARIA live region), or a separate described-video file (data-desc-src). It can pause the video while a description is read, and puts descriptions in its transcript. Open issues report description problems on iOS and Safari.
- articleWhat do the HTML <track> kind values and TextTrack modes mean for description tracks, and is there evidence that browsers voice kind="descriptions" themselves?
The HTML Standard defines a 'descriptions' text track as text intended to be synthesised as audio when the picture can't be seen, and makes voicing it a browser (user agent) job: a showing descriptions track is made available non-visually. Evidence that browsers actually voice such tracks is thin, so web players implement it themselves.
- articleHow does the CRTC's NER-based live-caption accuracy standard work (score formula, error types and deductions, sample size, evaluator certification, monitoring and remediation)?
Canada's CRTC (Broadcasting Regulatory Policy 2019-308, August 2019) replaced the 95% verbatim test for English live captions with an NER accuracy score of at least 98. The score is (captioned words minus NER error deductions) / captioned words x 100, with deductions of 0.25 for benign errors and omitted detail, 0.5 for omitted main meaning and 1.0 for false information. Broadcasters monitor two live programs a month and report annually by 30 November. The Commission may ask for monthly calculations if compliance issues arise.
- articleWhich EN 301 549 V4.1.1 clauses does Annex ZB map to the EAA's AV, access-service and e-reader rows, what is outside its scope (e-books), and what is the presumption-of-conformity status at the pinned sources?
EN 301 549 V4.1.1 Annex ZB maps European Accessibility Act requirements to its clauses. For access services in audiovisual media (Table ZB.5 row 5(b)(ii): subtitles, audio description, spoken subtitles and sign language transmitted fully, synchronised and user-controllable) it lists clauses 4.2.1, 4.2.2, 4.2.4, 4.2.5, 5.1.3.7, 5.1.5, 5.4, 5.5, 5.10, 7, 9.1.2, 10.1.2, 11.1.2 and all control-operation requirements. E-books are out of its scope. Conformity is presumed only for directives under which the standard is cited in the Official Journal; no EAA citation was found in the sources read.
- articleWhat does EN 301 549 clause 7 (ICT with video capabilities) require of a media player, and what changed between V3.2.1 (2021-03) and V4.1.1 (2026-09)?
EN 301 549 V4.1.1 (September 2026) clause 7 requires video players with synchronised audio to offer a subtitle mode and to show subtitles within 100 ms of their timecode. They must keep subtitle data when transmitting, converting or recording, let users adapt subtitle presentation where the player controls it, and offer spoken subtitles and selectable, synchronised audio description. Where the player controls activation, it needs a single-operation toggle for subtitles, audio description or spoken subtitles at the same level as the volume control. V3.2.1 (2021) said 'captions' and required these controls at the same level of interaction as the primary media controls.
- articleWhich audio, video and image formats can c2pa-rs 0.91.4 and c2patool 0.28.2 embed and read manifests for, and which of C2PA 2.4 Appendix A's embeddings have no handler at that pin?
The C2PA Rust SDK (v0.91.4) can embed manifests in WAV, AVI and WebP (RIFF), MP3 and FLAC (ID3-style), and MP4/M4A/MOV (BMFF). Fragmented MP4 (DASH) is supported only for file-based operations. It has no Ogg, font or HTML handler, although C2PA 2.4 Appendix A defines embeddings for Ogg Vorbis (added in 2.3), fonts, HTML, ZIP and text. A ZIP handler exists in code but isn't in the docs table. Ogg Vorbis/Opus support is an open experimental pull request (#2073), not merged as of 2026-10-22. c2patool supports whatever library version it was built with.
- articleExactly which language rows were added, removed or changed between Doc 7's table (version B, 2018-2021) and the registry table today?
The ISDCF register (330 rows) is far larger than Doc 7's 62 entries. 270 rows have no Doc 7 counterpart, mostly region and script variants plus new bare languages. Only KG was dropped, and 91 register codes are four letters long (e.g. ARSA, AZCY).
- articleI found an old ISDCF Doc 7 language table; can I still use its DCNC language codes, or has the registry changed them?
Codes from the old Doc 7 table (version B) mostly still hold. In the current ISDCF register, 58 of its 61 coded languages keep both DCNC code and RFC 5646 tag. Three changed: Kyrgyz is KY (Doc 7 said KG), Flemish VLS now maps to nl-BE (was vls), and Malay MSA maps to ms (was zlm). Look codes up in the register, not the old PDF.
- articleHow did ISDCF Doc 7 (digital cinema language codes) change across its Internet Archive captures, and what did the 2020-12-08 revision change?
ISDCF Doc 7 changed in three steps. Version A (2017) was a 3-page code table. Version B (captured 2018-2021) added languages, region subtags and a revision history. Version C (footer 2021-12-08) drops the table, adds a case-sensitivity section and defers to the ISDCF language register, citing a 2020-12-08 revision. On 2026-10-22 the original PDF URL returns 404, so the register is the only live source.
- articleWhat loudness (LKFS) and true-peak limits do the ABC Australia, Free TV Australia and CBC/Radio-Canada documents state, and which BS.1770 revision do they cite?
Australian and Canadian broadcasters use -24 LKFS and -2 dBTP, not the UK's -23 LUFS and -1 dBTP fail line. ABC (V4.7, 2015) sets -24 LKFS average dialogue level (per Free TV OP48) and -2 dBTP maximum. Free TV OP-59 Issue 4 (2018) allows +/-1 LU and cites BS.1770-3. CBC/Radio-Canada v8.0 (January 2026) requires -24 LKFS +/-2 LU for both programme and dialogue loudness, -2 dBTP, measured with a BS.1770-5 algorithm. CBC v7.0 (2022) also sets -10 dBTP for audio-only content such as podcasts.
- articleWhat programme loudness target, tolerance and true-peak limit do the UK DPP-family delivery documents (BBC, Channel 4, ITV, Sky) state, and where do the documents differ?
UK DPP-family delivery specs all target -23.0 LUFS, recommend -3 dBTP and fail QC above -1 dBTP, but the tolerance depends on which document you read. Channel 4 v5.2 and ITV live v6.3 (2023) allow +/-0.5 LU non-live and +/-1.0 LU live, while the Sky DPP-derived PDF (UK 4.3 2014 / Broadcaster 4.8 2017) allows +/-1.0 and +/-2.0 LU. Loudness range (18 LU) and factual dialogue range (6 LU) are guidance only. The BBC's 2026 file spec gives only a -23 dB dialogue-level setting and refers to DPP010 for QC. NRK v03 allows +/-1.0 LU for live.
- articleWhich W3C timed-text specs (TTML2, IMSC 1.0.1/1.1/1.2/1.3, WebVTT) exist, at what status, and which profile does a major deliverable spec ask for?
As of 2026-10-22 there are separate dated IMSC Recommendations: 1.0.1, 1.1, 1.2 (August 2020) and 1.3 (21 May 2026). IMSC 1.3 is text-only and drops the image profile. An EBU-TT-D file is generally also a valid IMSC 1.2 Text Profile file, with listed exceptions. WebVTT is still a Candidate Recommendation Draft (20 May 2026), not a Recommendation. Platform profiles are narrower: Netflix accepts its restricted IMSC 1.1 Text Profile only for Japanese timed text, so W3C conformance alone is not delivery conformance.
- articleWhat do Amazon's public Prime Video Tech Docs say about audio delivery: loudness, stems, channel layouts, sample rates?
Prime Video's public Tech Docs, as archived, ask for fully mixed program tracks only (M&E and MOS removed), 48 kHz audio in the stated L-R-C-LFE channel mapping, and descriptive audio typed as Narration and paired with same-locale dialog. They list validation failures such as wrong channel counts and audio-video duration mismatches over 2.0 s. Neither archived page states a loudness target or true-peak limit, so a loudness number for Prime Video cannot be cited from these public pages.
- articleHow are hearing-impaired (HI) and visually-impaired narrative (VI-N) audio tracks represented in a DCP, and how do open tools model and check them?
In a DCP, hearing-impaired (HI) and visually-impaired narrative (VIN) audio are dedicated channels inside the main sound track, not separate files. SMPTE ST 428-12 defines HI (0Eh) as a dialog-intelligibility channel and VIN (0Fh) as narration describing picture events, and allows several of each for different languages. libdcp maps the MCA ids 'hi' and 'vin'/'vi-n' to its own channel slots, but its verifier has no HI/VIN-specific check. ClairMeta checks only an even channel count. No inspected tool verifies that a VIN channel actually carries narration or is labelled correctly.