fix: keep OutputTrack quality even when input stream is updated

[Keukhan]

Summary

Improved OutputTrack quality retention behavior when the source stream is updated, along with minor refactoring.

Key Changes

1. Default Parameter Handling

• OutputTrack now uses parameters defined in the Config as default values during create output track. so, removed previous logic that selected default values based on whether Config parsing was performed.

2. Output Track Initialization

• If no user-defined settings are provided, parameters are automatically derived from decoded frame information:
  • Resolution, Timebase, Framerate, Bitrate, Samplerate, Channel

3. Behavior on Input Stream Update

• Encoding mode

  • OutputTrack keeps its initial quality even if the input stream quality change.

• Bypass mode

  • OutputTrack updates to match the changed input stream quality

[Copilot]

Pull request overview

This PR updates transcoder output-track initialization and update logic to better preserve output quality settings across input stream updates, while ensuring bypass tracks follow input changes.

Changes:

• Refactors CreateOutputTrack(...) to apply config defaults directly (and centralizes skip-frames handling).
• Splits decoded-frame-based output track updates into video/audio-specific paths and adds helper utilities (resolution alignment, skip-frames framerate adjustment).
• Updates bypass-mode output-track updates to refresh additional parameters from the (potentially updated) input track.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 5 comments.

File	Description
src/projects/transcoder/transcoder_stream_internal.h	Updates internal APIs and adds private helpers for decoded-frame updates and alignment/skip-frames handling.
src/projects/transcoder/transcoder_stream_internal.cpp	Implements refactored output-track creation/update logic, adds helpers, and extends profile serialization.
src/projects/transcoder/transcoder_stream.cpp	Adjusts bypass update call to pass the input track into the passthrough updater.

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[Copilot]

Pull request overview

This PR adjusts how TranscoderStream/TranscoderStreamInternal initialize and update OutputTrack parameters so that, in encoding mode, the output keeps its initially-determined quality even if the input stream’s quality changes, while bypass mode continues to follow input changes.

Changes:

• Refactors output-track updates by splitting decoded-frame updates into video/audio helpers and expanding passthrough updates to also take the input_track.
• Simplifies output-track creation to apply config-provided defaults directly (and adds validation for unsupported codec types).
• Extends video profile serialization to include ExtraOptions (via hash) so encoder/profile identity changes when extra options change.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 5 comments.

File	Description
src/projects/transcoder/transcoder_stream_internal.h	Updates method signatures and adds helper/utility declarations used by the new update logic.
src/projects/transcoder/transcoder_stream_internal.cpp	Implements the new retention/update behavior, codec validation, skip-frame/framerate alignment helpers, and serialization change.
src/projects/transcoder/transcoder_stream.cpp	Updates call site to pass input_track into passthrough output-track updates.

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[Keukhan]

@dimiden Please review again. :)

[dimiden]

LGTM