the interoperable mastering format - we are smpte · the interoperable mastering format dom...
TRANSCRIPT
The Interoperable Mastering Format
Dom Jackson, Telestream LLC
SMPTE Bits By The Bay 2017
May 2017
2
Agenda
• Introduction to IMF and versioning
• Key concepts and terminology in IMF
• Elements of an IMF package
• Adoption
• The future
3
It may not be a Tsunami in itself, but it is
certainly a big wave that is coming our
way
It’s also poorly understood
It’s fairly complicated
It can be difficult to deal with
Why are we talking about IMF today?
4
“The IMF is a file-based framework that allows these high-quality
versions, called Compositions, to be efficiently represented,
managed, played back, processed and transformed on file-based
systems.”
SMPTE ST 2067-1 2016
So what is this IMF thing anyway?
IMF is likely to become one of the predominant
formats for B2B transfer of media in the supply chain.
5
IMF was designed to handle the problems of
multiple versions of content in an efficient manner
A mainstream movie can end up with hundreds of
different versions
Creating and storing so many versions of a master
mezzanine file is expensive and unwieldy
Versions?
6
So why is IMF so efficient?
IMF uses a single “Master” version of a piece of
content
To make other versions you just need the differences
from the Master
7
Versions share most of the same basic
ingredients.
Only a few change from recipe to recipe to
make different ones
It’s a bit like baking a cake…
IMF
Key Concepts and Terms
9
Packages
10
IMP = IMF Master Package
• A package consisting of a packing list and all it’s assets.
Complete IMP
• A package containing all the assets required for one or more compositions.
• Sometimes also referred to as a Master Package
Package Types:
11
Partial IMP
• A package that does not contain all the assets required for a composition
• Sometimes also referred to as a Supplemental Package
• Might be used to send assets for an additional language to an existing complete package.
Package Types:
12
Simple IMP
• A package with continuous video and audio
tracks, no cuts or content substitutions.
Complex IMP
• A package where there are cuts or content
substitutions in the Video and / or Audio track.
Note: These are colloquial terms, not from the specification.
Package Types (Simple and Complex):
13
Compositions
14
Examples:
• Directors Cut:
Master Movie with “deletes scenes” added
back
• Lithuanian Airline version
Some scenes from Master Movie cut for
airline distributions
Additional Lithuanian audio and subtitles
Compositions = Versions
15
Applications
16
Different applications allow different video (and
possibly audio) encoding for different uses.
When people talk about IMF today they are talking
about App2 Extended
Applications:
17
Current Applications:
• App 2 and App2 Extended: Jpeg 2000 Video to 4K
• App 3: SStP Video Codec (Sony HDCAM SR)
• App 4: Cinema Mezzanine, also Jpeg2000 video.
Applications:
18
File Naming
19
IMF assumes that filenames are fragile – they can get
changed
They are not reliable identifiers
Files are referred to by their UUID
Asset Map is designed to aid file discovery (but may not be
there)
Filenames are bad!
20
JPEG 2000
21
Very high quality (including lossless)
Royalty free
Resilient to errors
Supports any frame size, bit depth or color space
BUT – computationally expensive
Why JPEG2000?
22
IMSC
23
Internet Media Subtitling and Captioning
Timed Text XML format defined by W3C
“Native” Subtitle / Caption format for IMF (defined in the
specification)
In IMF, the XML is wrapped in MXF Data Essence Track
IMSC
Elements of an IMF Package
25
Tracks contain the “essence” elements used to make compositions.
Tracks are single-essence MXF OP1A files
4 Types:
• Image (IMF-Speak for video) Tracks
• Audio Tracks
• Data Essence Tracks (IMSC XML)
• Ancillary Data Tracks (ST 436 VANC)
Tracks
26
CPL is the “recipe” for a specific composition or version.
XML document specified in ST 2067-3
Specifies Video, Audio and Data elements to be included
in composition.
Has EDL-like functionality (combine video, audio and
data segments from multiple source tracks).
CPL – Composition Playlist
27
XML Manifest of all of the elements in a package
Specified in the D-Cinema Specs ST 429-8
Primarily intended for use when an IMP is being
transmitted between locations
Not a permanent entity
Packing List
28
XML Document detailing the paths of the track files
within the package used for resolving file locations in
a received package.
Specified in the D-Cinema Specs ST 429-9
Primarily intended for use when an IMP is being
transmitted between locations
Not a permanent entity
Asset Map
29
Describes a set of transformations to be made on a
finished composition for specific endpoints
Examples:
• Image cropping and scaling
• Color transforms
• Audio mapping
Published Specification (ST 2067-100) currently has
limited practical use
OPL – Output Profile List
Adoption of IMF
31
Adoption of IMF
Up until 2014 IMF was strictly a “Hollywood” thing
Fall of 2014, Netflix announce that all UHD submissions must
be IMF
January 2016, major studios begin distributing sample IMF
packages to the supply chain
NAB 2016, NABA announced IMF as their standard library
format
A number of major US broadcasters are now adopting IMF
Also seeing considerable interest outside North America
32
Future developments
Possible update or new application for NABA
Possible update to OPL specification
Possible new applications with video codecs more appropriate for broadcast.
Challenges of IMF
34
Challenges:
Not compact (J2K)
Complex multi-file structure
Not human friendly
35
Questions?