Playback and Review Standards

Abstract

Many reviews, particularly between vendor and production company end up transcoding the source media to a movie format for review. Even after the movie file generation the production company may rename the file to match their own conventions (if they dont transcode it again). Adding metadata to these transcoded files (and provide recommendations on how to carry any metadata through additional transcoding sessions) could help then translate any notes, or annotations back to the source media.

Secondarily it would be good to make recommendations for transcoding for review. During reviews, its common to single frame forward and backwards, color fidelity is often critical to the review process, so we need to know that the resulting media isnt making any color adjustments (this was an issue with h264 in quicktime for a while).

At this point its not clear if this is just a standards process, or if code will need to be developed.

Metadata Standards

Media definition

These fields are for transcoded media, for original frame sequences it shouldn't be necessary. Metadata that should exist in the media file could include:

First Frame, Last Frame	int	Encoding to movie files typically looses the start frame, making it a pain to identify which frame you are looking at. We could look at doing this with timecode, but sometimes you want both timecode and a frame number.
Source filename	string	Something to track where the encoded media came from.
Source frame rate	float	If you are reviewing a proxy, but still want to remap back to the source frame, knowing the source frame rate is required (DO WE NEED THIS AND LAST FRAME?) – useful for high-frame rate media, e.g. 120 fps - (MIGHT MAKE SENSE AS A STRING TO HANDLE 59.94 better?)
Watermarking?	String	Document what sort of watermarking has been applied? - invisible, burnin?

Review definition

Metadata that should exist in the file.

Source ID	string	A unique ID for the company generating the media that can be used to get back to the original media. The main use of this is if the filename changes as it goes through different company pipelines.
Source Entity	string	Identifies the shot, asset or entity. Potentially useful as a burn-in.
Source sub entity	string	This would be the way to identify the media within the source entity without versions. e.g. lets say I have a filepath /shows/spy01/bat001/pix/rnd/precomp_v001/precomp_v001.0001.exr spy01 = SHOW bat001 = SHOT = Source Entity precomp = Source subentity This would be used by an asset management system to group versions, without having to guess what the versioning system is.
source sub entity version	float	Version ID for sub-entity.
Task	string	Taskname if known at creation -
colorspace	string	Many file-formats do already have options for color spaces, but certainly for internal reviews facilities may decide to encode to a non-standard color space. For media that is crossing facilities we should stick to known embedded colorspaces, and allow existing tools to remap where necessary.
date authored	string	The latest date of the original authored content. This would be carried through any transcoding, so we dont end up with the transcoded timestamps.

For doing external reviews (vendor passing media to production company) you may have additional metadata that needs to be passed with the media for review, this would typically be in an excel file (See VES Delivery Specification) with the following columns:

Date Submitted	date string	repeated on each line for cases where the resulting excel sheet is merged.
Vendor	string	Vendor name, repeated on each line for cases where the resulting excel sheet is merged.
Filename	string	The filename that is being shipped to be reviewed.
Source ID	string	Used to map the following fields to the actual media.
review task name	string	The reviewing company may have their own task names, which could be "comp", "anim"
Review for	string	Notes on why the media is being reviewed, e.g. For Final, For Feedback, WIP.
Notes	string	Notes for the reviewer, so they know what they should be commenting on.