mpeg-ts: speed up initialization

[aler9]

stop scanning for parameters that are not strictly necessary for track identification.

[codecov]

Codecov Report

❌ Patch coverage is 66.26506% with 28 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.35%. Comparing base (367141b) to head (127fe27).

Files with missing lines	Patch %	Lines
pkg/formats/mpegts/track.go	60.60%	24 Missing and 2 partials ⚠️
pkg/formats/mpegts/writer.go	60.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #306      +/-   ##
==========================================
- Coverage   86.12%   85.35%   -0.78%     
==========================================
  Files          92       92              
  Lines        5880     5871       -9     
==========================================
- Hits         5064     5011      -53     
- Misses        558      601      +43     
- Partials      258      259       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.