VPAAMP 293 : Audio loss occurs when switching audio tracks in multiview streams

[Abhi-jith-S]

Reason for change : To overwrite track-id for audio tracks incase of mismatch. Since the audio track mismatch caused audio loss while tile switching in mutliview streams

Test Procedure : Refer ticket

[Copilot]

Pull request overview

Addresses audio loss during audio-track switches in multiview MP4 streams by detecting track-id mismatches and rewriting the fragment track-id to match the currently selected audio track.

Changes:

• Extends track-id inspection/overwrite logic to include non-init audio fragments in MediaStreamContext::CacheFragment.
• Enhances ISO-BMFF parsing to extract track-id from tfhd when trak isn’t present (typical for media fragments).
• Adds TfhdBox support for reading/overwriting TFHD track-id in-place during box construction.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
MediaStreamContext.cpp	Runs track-id parsing for audio media fragments and overwrites mismatched audio track-id.
isobmff/isobmffbuffer.cpp	Adds TFHD-based fallback for track-id extraction in fragmented MP4.
isobmff/isobmffbox.h	Extends TfhdBox API/state to track and rewrite TFHD track-id.
isobmff/isobmffbox.cpp	Implements TFHD track-id capture + optional overwrite during TFHD construction.

Comments suppressed due to low confidence (2)

MediaStreamContext.cpp:233

• This INFO log now runs for every audio fragment (not just init), which can be very noisy; it also uses %d for a uint32_t track_id. Consider lowering to DEBUG and using correct format specifiers, and avoid setting mIsTrackIdMismatch for the overWriteTrackId (encrypted-header) use-case.

					bool trackIdUpdated = false;
					AAMPLOG_INFO("Audio track_id read from  fragment: %d and track id stored in AAMP instance: %d", track_id, aamp->mCurrentAudioTrackId);
					if(aamp->mCurrentAudioTrackId != -1 && track_id != aamp->mCurrentAudioTrackId)
					{
							buffer.parseBuffer(false, aamp->mCurrentAudioTrackId);
							trackIdUpdated = true;
							aamp->mIsTrackIdMismatch = true;
							AAMPLOG_DEBUG("TrackId mismatch detected for audio, current track_id: %d, next period track_id: %d", aamp->mCurrentAudioTrackId, track_id);
					}

MediaStreamContext.cpp:167

• This condition now includes eMEDIATYPE_AUDIO, so the subsequent track-id extraction runs for non-init audio fragments as well. In that path, IsoBmffBuffer::getTrack_id() can fail (it returns bool) but its return value is currently ignored, leaving track_id as 0 and potentially corrupting mCurrentAudioTrackId / overwrite behavior. Please guard the track-id logic when getTrack_id() returns false.

			if ((actualType == eMEDIATYPE_INIT_VIDEO || actualType == eMEDIATYPE_INIT_AUDIO || actualType == eMEDIATYPE_AUDIO || actualType == eMEDIATYPE_INIT_SUBTITLE) && ret) // Only if init fragment successful or available from cache

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Abhi-jith-S]

Keeping the try-catch block same as trak box construction

[github-advanced-security]

You are seeing this message because GitHub Code Scanning has recently been set up for this repository, or this pull request contains the workflow file for the Code Scanning tool.

What Enabling Code Scanning Means:

• The 'Security' tab will display more code scanning analysis results (e.g., for the default branch).
• Depending on your configuration and choice of analysis tool, future pull requests will be annotated with code scanning analysis results.
• You will be able to see the analysis results for the pull request's branch on this overview once the scans have completed and the checks have passed.

For more information about GitHub Code Scanning, check out the documentation.

[Abhi-jith-S]

Closing the PR as we are waiting for approval of fix