TimedText/DAPT Implementation Report
CR Exit Criteria
The criteria for DAPT to exit CR arise from the DAPT Status of This Document section and the TTWG Charter Success Criteria.
The DAPT CR exit criteria are:
For this specification to exit the CR stage, at least 2 independent implementations of every feature defined in this specification but not already present in [TTML2] need to be documented in the implementation report. The Working Group does not require that implementations are publicly available but encourages them to be so.
The TTWG Charter §4.1 Requirements for advancing the maturity level of features states:
Within the requirements of the Process each new normative feature will be considered as ready to advance to a higher maturity level if its implementability has been demonstrated.
When considering suitability to advance any feature beyond Candidate Recommendation, at least two independent factors of verification for each normative requirement must be demonstrated, which may come, as relevant for that requirement, from any of:
- Presentation implementation
- Content-producing implementation
- Validating implementation
For example, a feature may be advanced beyond Candidate Recommendation if it has been demonstrated to be implementable on the basis of an open source implementation that successfully processes content from an independent implementation.
Verifying implementations of different types
Each type of implementation can be verified with respect to each feature in different ways.
- Presentation implementation
- generates presentation of test resources in a way that matches the defined semantic for the feature being tested
Note: No features defined in DAPT have a semantic that affects presentation behaviour.
- Content-producing implementation
- generates content that contains the syntax of the feature
- Validating implementation
- correctly identifies whether the syntax and semantics of all the test resources relating to the feature are valid or invalid
Additionally, if a validating implementation that meets all the test criteria also shows that the output of a content-producing implementation is valid, that demonstrates interoperability. Interoperability is a useful and important signal, but goes beyond the minimum requirement of implementability set out in the Charter.
Scope of features
The features of DAPT that are not already part of TTML2 are listed in DAPT §G. Extensions:
#agent #contentProfiles-root #daptOriginTimecode #descType #onScreen #profile-root #represents #scriptEventMapping #scriptRepresents-root #scriptType-root #serialization #source-data #textLanguageSource #xmlLang-audio-nonMatching #xmlLang-root
Presentation tests
None of the DAPT features that are not already part of TTML2 are presentation features. The set of presentation tests is therefore empty.
Validation tests
Validation tests are located in the w3c/dapt-tests repository.
Feature Implementation
Content-producing implementations
The following content-producing implementations have been submitted:
- Netflix has submitted ttal-dapt-conv
Features exercised
| Organisation | Netflix | Count(yes) | |
|---|---|---|---|
| Section | Feature | ttal-dapt-conv | |
| G.2 | #agent | Yes | 1 |
| G.3 | #contentProfiles-root | Yes | 1 |
| G.4 | #daptOriginTimecode | Yes | 1 |
| G.5 | #descType | Yes | 1 |
| G.6 | #onScreen | Yes | 1 |
| G.7 | #profile-root | Yes | 1 |
| G.8 | #represents | Yes | 1 |
| G.9 | #scriptEventMapping | No | 0 |
| G.10 | #scriptRepresents-root | Yes | 1 |
| G.11 | #scriptType-root | Yes | 1 |
| G.12 | #serialization | Yes | 1 |
| G.13 | #source-data | No | 0 |
| G.14 | #textLanguageSource | Yes | 1 |
| G.15 | #xmlLang-audio-nonMatching | No | 0 |
| G.16 | #xmlLang-root | Yes | 1 |
Validating implementations
The following validating implementations have been submitted:
- BBC has submitted ttml-validator
Test results
Tests whose names begin dapt-invld- include resources that a passing validation implementation declares to be invalid.
Tests whose names begin dapt-valid- include resources that a passing validation implementation declares to be valid.
CR Exit criteria summary
| Section | Feature | Content-producing implementations | Validating implementations | Meets CR Exit Criteria? |
|---|---|---|---|---|
| G.2 | #agent | 1 | 1 | Yes |
| G.3 | #contentProfiles-root | 1 | 1 | Yes |
| G.4 | #daptOriginTimecode | 1 | 1 | Yes |
| G.5 | #descType | 1 | 1 | Yes |
| G.6 | #onScreen | 1 | 1 | Yes |
| G.7 | #profile-root | 1 | 1 | Yes |
| G.8 | #represents | 1 | 1 | Yes |
| G.9 | #scriptEventMapping | 0 | 1 | No |
| G.10 | #scriptRepresents-root | 1 | 1 | Yes |
| G.11 | #scriptType-root | 1 | 1 | Yes |
| G.12 | #serialization | 1 | 1 | Yes |
| G.13 | #source-data | 0 | 1 | No |
| G.14 | #textLanguageSource | 1 | 1 | Yes |
| G.15 | #xmlLang-audio-nonMatching | 0 | 1 | No |
| G.16 | #xmlLang-root | 1 | 1 | Yes |
Interoperability testing
BBC and Netflix confirmed that all the documents produced by the documents generated the dapt-ttal-dapt-conv tool's tests are shown to be valid by ttml-validator.
DAPT At-risk features
Some TTML2 features are included in DAPT but marked as "at risk", meaning that any that do not meet the TTWG's inclusion criteria, most likely that they are supported in at least two implementations, will be removed from the specification before it advances to Recommendation. Therefore, we are interested to log any implementations that do support them.
| Organisation | Netflix | BBC | Totals | CR Exit Criteria Passed? | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Section | Feature | ??? | adhere | #V | #X | #P | #T | ||||||
| 4.9.1 Audio Recording | src attribute in <audio> for external resource | 0 | 0 | 0 | 0 | No | |||||||
| 4.9.1 Audio Recording | <source> element child of <audio> for external resource | 0 | 0 | 0 | 0 | No | |||||||
| 4.9.1 Audio Recording | src attribute of `<audio>` element pointing to embedded resource | 0 | 0 | 0 | 0 | No | |||||||
| 4.9.1 Audio Recording | <source> child of <audio> element pointing to embedded resource | 0 | 0 | 0 | 0 | No | |||||||
| 4.9.1 Audio Recording | inline audio resources | 0 | 0 | 0 | 0 | No | |||||||
| 4.9.1 Audio Recording | each of the potential values of encoding in | 0 | 0 | 0 | 0 | No | |||||||
| 4.9.1 Audio Recording | the length attribute on | 0 | 0 | 0 | 0 | No | |||||||
| G.9 #scriptEventGrouping and G.10 #scriptEventMapping | Script Event Grouping and Script Event Mapping | 0 | 0 | 0 | 0 | No | |||||||