LibWeb+LibMedia: Reject audio⇔video codec mismatches in decodingInfo()

[sideshowbarker]

This aligns our mediaCapabilities.decodingInfo() implementation with WPT expectations to reject an audio codec where a video codec is expected, and reject a video codec where an audio codec is expected. The spec (see w3c/media-capabilities#261) doesn’t explicitly state that requirement — but Gecko and WebKit both also reject such codec mismatches (and pass the relevant WPT subtests).

This also includes a track_type_from_codec_id() bug fix — to correctly classify Theora as a video codec, rather than incorrectly as audio. Fixes #10696.

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⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

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Run ID: 05968065-501f-4369-85cc-eff78b147dfa

📥 Commits

Reviewing files that changed from the base of the PR and between efb6f45 and ec1f836.

📒 Files selected for processing (7)

• Libraries/LibMedia/CodecID.h
• Libraries/LibWeb/MediaCapabilitiesAPI/MediaCapabilities.cpp
• Libraries/LibWeb/MediaCapabilitiesAPI/MediaCapabilities.h
• Libraries/LibWeb/MimeSniff/MimeType.cpp
• Libraries/LibWeb/MimeSniff/MimeType.h
• Tests/LibWeb/Text/expected/wpt-import/media-capabilities/decodingInfo.any.txt
• Tests/LibWeb/Text/input/wpt-import/media-capabilities/decodingInfo.any.js

💤 Files with no reviewable changes (1)

• Libraries/LibWeb/MediaCapabilitiesAPI/MediaCapabilities.h

🚧 Files skipped from review as they are similar to previous changes (6)

• Libraries/LibWeb/MimeSniff/MimeType.h
• Tests/LibWeb/Text/input/wpt-import/media-capabilities/decodingInfo.any.js
• Tests/LibWeb/Text/expected/wpt-import/media-capabilities/decodingInfo.any.txt
• Libraries/LibWeb/MimeSniff/MimeType.cpp
• Libraries/LibMedia/CodecID.h
• Libraries/LibWeb/MediaCapabilitiesAPI/MediaCapabilities.cpp

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📝 Walkthrough

Walkthrough

The PR adds RFC 6381 codec-string mapping for supported audio and video codecs. Media capability validation now strictly validates MIME strings, codec parameters, codec counts, and media/codec type matches. MIME-sniffing code gains string validation. WPT coverage and expected results are updated for the new validation behavior.

Sequence Diagram(s)

sequenceDiagram
  participant Navigator
  participant MediaCapabilities
  participant MimeSniff
  participant CodecID
  Navigator->>MediaCapabilities: decodingInfo(configuration)
  MediaCapabilities->>MimeSniff: is_valid_mime_type_string(content_type)
  MimeSniff-->>MediaCapabilities: MIME validity
  MediaCapabilities->>CodecID: codec_id_from_rfc6381_codec_string(codec_string)
  CodecID-->>MediaCapabilities: codec ID or CodecID::Unknown
  MediaCapabilities-->>Navigator: MediaCapabilitiesInfo

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Possibly related issues

• Issue 10696 — Adds codec-family validation that rejects video codecs in audio configurations and audio codecs in video configurations.

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description directly explains the media codec validation changes and the Theora track classification bug fix.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@Libraries/LibWeb/MediaCapabilitiesAPI/MediaCapabilities.cpp`:
- Around line 90-100: Update the codec validation in is_able_to_decode_media()
so an unrecognized codec ID is rejected or otherwise reported unsupported
instead of reaching the supported result. Reuse the existing
codec_id_from_rfc6381_codec_string/track_type_from_codec_id flow to detect
unknown codecs, while preserving the audio/video track-type mismatch checks.

In `@Tests/LibWeb/Text/input/wpt-import/media-capabilities/decodingInfo.any.js`:
- Around line 377-386: Update the test using videoConfigurationWithDynamicRange
to create an independent clone before overriding contentType, rather than
reusing the mutated fixture. Ensure this media-source decodingInfo test retains
the intended HDR codec configuration and remains order-independent.

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Fix all unresolved CodeRabbit comments on this PR:

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• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 37c24086-ee1b-4eec-a99a-d8687e91ee95

📥 Commits

Reviewing files that changed from the base of the PR and between e94da4a and 868d146.

📒 Files selected for processing (7)

• Libraries/LibMedia/CodecID.h
• Libraries/LibWeb/MediaCapabilitiesAPI/MediaCapabilities.cpp
• Libraries/LibWeb/MediaCapabilitiesAPI/MediaCapabilities.h
• Libraries/LibWeb/MimeSniff/MimeType.cpp
• Libraries/LibWeb/MimeSniff/MimeType.h
• Tests/LibWeb/Text/expected/wpt-import/media-capabilities/decodingInfo.any.txt
• Tests/LibWeb/Text/input/wpt-import/media-capabilities/decodingInfo.any.js

💤 Files with no reviewable changes (1)

• Libraries/LibWeb/MediaCapabilitiesAPI/MediaCapabilities.h

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